Title: 1 A long duration of the 16O-rich reservoir in the solar nebula , as recorded in fine -grained 2 refractory inclusions from the least metamorphosed carbonaceous chondrite s. 3 4 Authors: 5 Takayuki Ushikubo 1,2*, Travis J. Tenner 1,3, Hajime Hiyagon 4, and Noriko T. Kita 1 6 7 Affiliations: 8 1: WiscSIMS, Department of Geoscience, University of Wisconsin- Madison, 1215 W. 9 Dayton St., Madison, WI 53706 USA 10 2: Kochi Institute for Core Sample Research, Japan Agency for Marine -Earth Science 11 and Technology (JAMSTEC), 200 Monobe -otsu, Nankoku, Kochi 783 -8502 Japan 12 3: Chemistry Division, Nuclear and Radiochemistry, Los Alamos National Laboratory, 13 MSJ514, Los Alamos, NM 87545 USA 14 4: Department of Earth and Pl anetary Science, Graduate school of Science, University 15 of Tokyo, 7-3- 1 Hongo, Bunkyo, Tokyo 113 -0033 Japan 16 17 *: Corresponding author: 18 Takayuki Ushikubo ( ushikubot@jamstec.go.jp) 19 Kochi Institute for Core Sample Research, Japan Agency for Marine -Earth Science and 20 Technology (JAMSTEC), 200 Monobe -otsu, Nankoku, Kochi 783 -8502 Japan 21 Phone: +81-088-878-2187 22 23 24 Submitted to GCA , revised manuscript 25

Abstract 26 Oxygen isotope ratios and corresponding 26Al-26Mg isotope systematics of 27

refractory inclusions from the least metamorphosed carbonaceous chondrites, Acfer 094 28 (C-ungrouped 3.00) and Yamato 81020 (CO3.05), were measured with an ion microprobe. 29 Most of the samples are fine -grained refractory inclusions which are considered as 30 condensates from high temperature Solar Nebular gas. The refractory inclusions 31 consistently exhibit 16O-enriched signatures among their interior phases (spinel, melilite, 32 and high -Ca pyroxene) , as well as phases within their rim stru ctures (spinel, high- Ca 33 pyroxene, and adjacent anorthite) . This observation indicates that aggregated refractory 34 condensates and the formation of rim structure s occurred in the same 16O-rich 35 environment. Evidence for mass-dependent isotopic fractionation in oxygen and 36 magnesium, which would indicate a later flash heating process, was not observed in rim s. 37 All oxygen isotope data from fine-grained CAIs are distributed between the 38 Carbonaceous Chondrite Anhydrous Minera l (CCAM) line and the Primitive Chondrule 39 Mineral (PCM) regression line based on oxygen isotope data from Acfer 094 chondrules. 40 The inferred initial 26Al/27Al ratios, ( 26Al/27Al)0, of spinel -melilite-rich CAIs are 41 (4.08±0.75)×10−5 to (5.05±0.18)×10−5 (errors are 2 σ), which are slightly lower than the 42 canonical value of 5.25× 10−5. As there is no petrologic evidence for re- melting after 43 condensation, t he lower ( 26Al/27Al)0 values of these CAIs indicate either they formed up 44 to ~0.3 Ma after canonical CAIs or they formed before 26Al was homogeneously 45 distributed in the Solar nebula . A pyroxene-anorthite-rich CAI, G92, has an 16O-rich 46 signature like other CAIs but also has an order -of-magnitude less 26Mg-excess in 47 anorthite, corresponding to a ( 26Al/27Al)0 of (5.21±0.54)×10−6. As there is no evidence for 48 a later Mg isotopic disturbance, G92 anorthite is interpreted to have formed by 49 interaction with 16O-rich nebular gas at 2 to 3 Ma after CAI formation. With the 50 observation that 16O-rich refractory inclusio ns, relatively 16O-poor chondrules, and 51 extremely 16O-poor cosmic symplectites within Acfer 094 all plot on the PCM line, it 52 suggests that 16O-rich nebular gas and extremely 16O-poor primordial volatiles represent 53 mass-independent fractionated endmembers in the early Solar system and that the PCM 54 line represents a mixing line of these two endmembers . 55

1. Introduction 56 In the early Solar System, evidence for a n 16O-rich isotopic signature that 57 fractionated independent of mass ( ∆17O ≡ δ17O − 0.52 × δ18O ~ −24‰) has been found in 58 Ca-, Al -rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs) (Clayton et al., 59 1977; Hiyagon and Hashimoto, 1999; Krot et al., 2002; 2010 a). As refractory inclusions 60 (CAIs and AOAs) are commonly interpreted to be the fir st solar system condensates 61 (Grossman, 1972; G rossman et al., 2008) , their oxygen isotope ratios are inferred to 62 reflect the primordial characteristics of the earliest refractory dust forming environment 63 in the solar nebula . In contrast, oxygen isotope ratios of chondrules that formed ~2 64 million years (Ma) after CAIs (Kita and Ushikubo, 2012; Kita et al., 2013 ; Ushikubo et 65 al., 2013) have a smaller mass-independent oxygen isotopic anomaly relative to CAIs , 66 indicating a later oxygen isotope environment that was relatively 16O-poor ( e.g., Clayton 67 et al., 1983; Clayton 2003; Connolly and Huss, 2010; Kita et al., 2010; Krot et al., 2010b; 68 Rudraswami et al., 2011; Weisberg et al., 2011; Nakashima et al., 2012; Ushikubo et al., 69 2012; Sch rader et al., 2013, 2014; Tenner et al., 2013, 2015). 70

Since some CAIs exhibit evidence for later re -heating processes after their 71 initial formation, including significant difference s in ∆17O values between primary 72 phases and secondary phases (Yurimoto et al., 1998; Hsu et al., 2000; Fagan et al., 2007; 73 Ushikubo et al., 2007; Krot et al., 2008; MacPherson et al., 2012; Kawasaki et al., 2015), 74 they are expected to record temporal change s of oxygen isotope environments within the 75 solar nebula. I n addition, detailed petrologic and isotopic studies o f fine-textured Wark-76 Lovering rims surrounding coarse-grained CAIs , which consists of (1) a spinel layer with 77 minor perovskite and hibonite (inner part) ; (2) a melilite/anorthite/secondary altered 78 phase layer (middle part); and (3) a Ti-Al-bearing diopside layer (outer part) (Wark and 79 Lovering, 1977) , suggest that variability in oxygen isotope ratios existed when the W ark 80 and Lovering rims formed (e.g., Yoshitake et al., 2005; Simon et al., 2011 , 2016) . 81 Impartantly, however, Bodénan et al. ( 2014) observed that such an oxygen isotopic 82 variability is not recognized among Wark -Lovering rims from pristine carbonaceous 83 chondrite CAIs. This suggests that the oxygen isotopic variability found in the 84 aforementioned studies, from which refractory inclusions from higher petrologic type 85 chondrites were investigated, could be due to later isotopic disturbance s in chondritic 86 parent bodies. If oxygen isotopic variability ( 16O-rich and 16O-poor environments) existed 87 in the early solar system when coarse -grained CAIs and Wark-Lovering rim formed, it is 88 expected that evidence for oxygen isotopic variability would also be recorded within fine-89 grained CAIs and AOAs ( Grossman and Ganapathy, 1976; Grossman and Steele, 1976). 90 Although c oarse-grained CAIs are advantageous for in-situ high-precision 91

isotope analyses, they experienced re -melting after aggregation of precursor dust 92 condensates and they com monly have positively fractionated Mg and Si isotope ratios. 93 As positive isotopic fractionation in Mg and Si provides evidence for significant 94 evaporative loss by re -melting, primary oxygen isotope ratios of such coarse -grained 95 CAIs are probably modified ( e.g., Wang et al., 2001; Alexander, 2004). In contrast, the 96 texture of fine -grained CAIs and AOAs (e.g., small grain sizes of major phases and 97 complex nodules) indicates that they formed by aggregation of primary condensates from 98 early solar nebular gas. As such, fine -grained CAIs and AOAs are perhaps the best 99 candidates for recording pristine oxygen isotope ratios of early solar system condensates. 100 However, the petrology and isotopic compositions of such fine-scale materials are 101 particularly susceptible t o metamorphism while on chondritic parent bodies. Thus, in 102 order to establish that isotope signatures of fine -grained refractory inclusions are indeed 103 primordial nebular signatures, selection of pristine CAIs and AOAs that properly rul e 104 out evidence for parent body metamorphism is critically important . 105

In this study, we measured oxygen isotope ratios and 26Al-26Mg systematics of 106 fine-grained CAIs and AOAs from Acfer 094 (C- ungrouped 3.00) and Yamato -81020 ( Y-107 81020, CO3.05) . These refractory inclusions shoul d record pristine isotope 108 characteristics because Acfer 094 and Y -81020 are two of the least metamorphosed 109 carbonaceous chondrites (Grossman and Brearley, 2005; Kimura et al., 2008). For 110 example, Acfer 094 chondrules preserve intrinsic oxygen isotope ratio s without any 111 indication of a later oxygen isotopic disturbance , even in mesostasis glass that is highly 112 sensitive to fluid assisted parent body metamorphism (Ushikubo et al., 2012) . In addition, 113 chondrules from both Acfer 094 and Y -81020 have 26Al-26Mg isotope systematics that are 114 primary, with no sign of a later disturbance ( Kunihiro et al., 2004; Kurahashi et al., 2008 ; 115 Hutcheon et al., 2009; Ushikubo et al., 2013). Thus, oxygen isotope ratios and 26Al-26Mg 116 isotope systematics of fin e-grained refractory inclusions from the same meteorites should 117 dependably elucidate the evolution of oxygen isotope ratios in the solar nebula , recording 118 their formation and interaction with ambient gas before accreti ng to the chondritic 119 parent body. 120 121 2. Samples 122

Ten refractory inclusions, including five spinel-melilite-rich CAIs (G5, G16, G49, 123 G104, and Y81020-E-8) , one pyroxene-anorthite-rich CAI ( G92), and four AOAs (G17, 124 G28, G44, and G58) were selected for investigation by secondary ion mass spectrometry 125 (SIMS) (Figs.1-3). Y81020-E-8 is from Y -81020 (CO3.05) and the others are from Acfer 126 094 (C -ungrouped 3.00) . The classification of Acfer 094 refractory inclusions by Krot et 127

al. (2004a) is appli ed in this study. 128 Three of the five spinel -melilite-rich CAIs (G5, G16, and G49) have a fine-129

grained, complex nodular texture. CAI G5 is an irregular -shaped aggregate of multiple 130 nodules (Fig.1a). It consists of gehlenitic melilite ( Åk6) and spinel, along with anorthite 131 and diopside rim s. Some nodules do not contain melilite. CAI G16 is a large CAI (ca. 132 300µm×500µm in size , Fig .1b) consisting of multiple nodules. The l arger nodules consist 133 of melilite ( Åk8-10) and sub-micron spinel grains surrounded by a diopside rim (Fig. 1f). 134 Regarding the smaller nodules, spinel is rare, a thin anorthite layer commonly occurs 135 between the interior melilite and the diopside rim , and olivine grains are found in the 136 accretionary rim (Fig.1g). CAI G49 is a n irregular-shaped aggregate of small nodules , 137 consisting of melilite ( Åk20), tiny s pinel and Al- Ti-rich diopside grains, and a diopside 138 rim (Fig. 1c). A t hin anorthite layer between the interior melilite and the diopside rim is 139 also present in nodules near the edge of th is CAI. 140

The remaining t wo spinel -melilite-rich CAIs have relatively simple textures and 141 larger grain size s. CAI G104 is a fragment of an irregular-shaped spinel -melilite-rich 142 CAI (Fig.1d). It consists of melilite ( Åk8), spinel, Al -Ti-rich diopside, and perovskite. Thin 143 spinel (discontinuous and <2 µm) and diopside (<5µm) layers are observed along the rim. 144 There are several voids in melilite and interstitial space of spinel grains. Al-Ti-rich 145 diopside and perovskite commonly occur around these voids (Fig.1 h). 146

CAI Y81020-E-8 is round and ~500µm in diameter ( Fig.1e). It consists mostly of 147 melilite ( Åk14-21), spinel, and perovskite. The c entral portion of this CAI has likely been 148 lost during sample preparation. Y81020-E-8 is surrounded a double -layered rim of spinel 149 (10 to 30 µ m in width) and melilite (~5 µ m in width); a diopside rim appears to be absent 150 (Fig.1i). 151

CAI G92 is an irregular-shaped pyroxene-anorthite-rich CAI that is 300 µm × 152 150 µm in size . It consists of anorthite and Al -Ti-rich diopside , with small amounts of 153 melilite ( Åk19-25) and spinel (Fig.2a). Al-Ti-rich diopside is often associated with voids 154 (Fig.2b). A thin diopside rim (~3 µm) is also observed. Anhedral melilite and Al- Ti-rich 155 diopside (typically <10 µ m in size) are enclosed by anorthite. Spinel (typically <3 µm in 156 size) occurs either in melilite or near the diopside rim. No ferromagnesian phase s, such 157 as olivine or low -Ca pyroxene , are observed outside of the diopside rim. 158

All AOAs studied consist of multiple Ca -, Al -rich domains enclosed by olivine. 159 Among them, Ca-, Al -rich domains of G17 ( ~200 µm × 100 µm in size, Fig.3a ) and G28 160 (~400 µm × 300 µm in size, Fig. 3b) consist of spinel and Al- Ti-rich diopside but almost 161 no anorthite (Fig.3e). In contrast, Ca -, Al -rich domains of fragment G44 ( ~200 µm × 150 162 µm in size, Fig. 3c) and G58 ( ~400 µm × 300 µm in size, Fig. 3d) consist of spinel, anorthite, 163

a n d Al -Ti -ri c h di o p si d e ( Fi g. 3f). 1 6 4

1 6 5

3. A n al yti c al p r o c e d u r e s3. A n al yti c al p r o c e d u r e s 1 6 6

3. 1. 3. 1. S E M o b s e r v ati o n a n d S E M o b s e r v ati o n a n d m aj o r el e m e n t a n al y si s b y m aj o r el e m e n t a n al y si s b y E P M AE P M A 1 6 7

Ba c k s c att e r e d el e ct r o n ( B S E) a n d s e c o n d a r y el e ct r o n i m a g e s w e r e o bt ai n e d b y 1 6 8

t h e Hi t a c hi S -3 4 0 0 s c a n ni n g el e ct r o n mi c r o s c o p e ( S E M) at U ni v e r s i t y of Wi s c o n si n-1 6 9

M a di s o n ( U W-M a di s o n) . Maj o r el e m e n t o xi d e ( Si O 2 , Ti O2 , Al2 O 3 , C r2 O 3 , F e O, M n O, M g O, 1 7 0

C a O, N a 2 O, a n d V 2 O 5 ) c o n c e n t r ati o n s of mi n e r al s w e r e o bt ai n e d wi t h t h e C A M E C A S X 5 1 1 7 1

el e ct r o n -p r o b e mi c r o a n al y z e r ( E P M A) at U W -M a di s o n u si n g a 1 5 k V a c c el e r ati n g v ol t a g e , 1 7 2

a 1 0 n A b e a m c u r r e n t, a f ull y f o c u s e d b e a m, a n d r e s p e cti v e p e a k a n d b a c k g r o u n d 1 7 3

c o u n ti n g ti m e s of 1 0 a n d 5 s . St a n d a r d s c o n si s t e d of oli vi n e ( F o0, 8 3, 8 9, 1 0 0 ), p y r o x e n e 1 7 4

(e n s t ati t e, w oll a s t o ni t e, a u gi t e, j a d ei t e) , pl a gi o cl a s e ( A n0, 1 8, 7 8, 9 5 ), g e hl e ni t e, å k e r m a ni t e, 1 7 5

s pi n el ( M g -e n d m e m b e r, i n t e r m e di at e M g -F e e n d m e m b e r, a n d c h r o mi u m -s pi n el) , r u til e, 1 7 6

h o r n bl e n d e, c h r o mi t e , h e m ati t e, m a g n eti t e, t e p h r oi t e, a n d V-m et al . C al c ul at e d d et e cti o n 1 7 7

li mi t s ( at 9 9 % c o nfi d e n c e ) w e r e 0. 0 2, 0. 0 3, 0. 0 2, 0. 0 7, 0. 0 5, 0. 0 5, 0. 0 3, 0. 0 3, 0. 0 4, a n d 0. 0 7 1 7 8

wt %, r e s p e cti v el y f o r t h e o xi d e s li s t e d a b o v e. 1 7 9

1 8 0

3. 2 3. 2 I s ot o p e a n al y siI s ot o p e a n al y si s b y SI M Ss b y SI M S 1 8 1

Ox y g e n t h r e e -i s ot o p es a n d 2 6 Al -2 6 M g i s ot o p e s y s t e m ati c s w e r e m e a s u r e d u si n g 1 8 2

t h e Wi s c S I M S C A M E C A I M S -1 2 8 0 S e c o n d a r y I o n M a s s S p e ct r o m et e r ( SI M S) at t h e 1 8 3

U ni v e r si t y of Wi s c o n si n -M a di s o n. F o u r s e p a r at e s e s si o n s (i. e., O a n d M g i s ot o p e a n al y s e s 1 8 4

wi t h diff e r e n t b e a m di a m et e r s ) w e r e c o n d u ct e d , i n o r d e r t o o bt ai n i s ot o pi c si g n at u r es of 1 8 5

m ul ti pl e p h a s e s t h at h a v e a r a n g e of g r ai n si z e s a m o n g i n di vi d u al r ef r a ct o r y i n cl u si o n s. 1 8 6

Aft e r e a c h a n al yti c al s e s si o n, S I M S pi t s w e r e a s s e s s e d b y S E M a n d d at a f r o m 1 8 7

pi t s wi t h i r r e g ul a ri ti e s ( e. g., o v e rl a p pi n g m ul ti pl e p h a s e s, c r a c k s , o r i n cl u si o n s) w e r e 1 8 8

r ej e ct e d. 1 8 9

1 9 0

3. 2. 1 O x y g e n t h r e e3. 2. 1 O x y g e n t h r e e --i s ot o p e a n al y si si s ot o p e a n al y si s 1 9 1

F o r o x y g e n t h r e e -i s ot o p e a n al y si s, a 1 3 3 C s + p ri m a r y i o n b e a m wi t h a 2 0 k V t ot al 1 9 2

a c c el e r ati n g v ol t a g e w a s u s e d. A c a r b o n c o at of ~ 2 5 n m t hi c k n e s s w a s a p pli e d o n t h e 1 9 3

s a m pl e s u rf a c e a n d a n o r m al i n ci d e n c e el e ct r o n g u n w a s u s e d f o r c h a r g e c o m p e n s ati o n 1 9 4

of t h e s a m pl e s u rf a c e. T h e a c c el e r ati n g v ol t a g e of s e c o n d a r y i o n s w a s 1 0 k V. 1 9 5

A s a r e s ul t of t h e s m all g r ai n si z e (t y pi c all y < 1 0 µ m i n si z e) of mi n e r al s i n 1 9 6

s a m pl e s, a s m all 1 3 3 C s + p ri m a r y b e a m ( ~ 3 µ m, ~ 2 5 p A ) w a s m ai nl y u s e d f o r o x y g e n t h r e e-1 9 7

i s ot o p e a n al y s e s of f o r s t e ri t e, m elili t e, s pi n el, a n o rt hi t e, a n d Al -Ti -ri c h di o p si d e wi t hi n 1 9 8

t h e i n t e ri o r of r ef r a ct o r y i n cl u si o n s a n d t h ei r ri m s. S e c o n d a r y i o n s of o x y g e n i s ot o p e s 1 9 9

w e r e si m ul t a n e o u sl y d et e ct e d , u si n g o n e F a r a d a y c u p ( F C) f o r 1 6 O − a n d t w o el e ct r o n 2 0 0

m ul ti pli e r s ( E M) f o r 1 7 O − a n d 1 8 O − , r e s p e cti v el y. T h e m a s s r e s ol vi n g p o w e r ( M R P at 1 0 % 2 0 1

p e a k h ei g h t) w a s s et t o ~ 2 2 0 0 f o r 1 6 O − a n d 1 8 O − , a n d ~ 6 0 0 0 f o r 1 7 O − , r e s p e cti v el y. T h e 2 0 2

t y pi c al c o u n t r at e of 1 6 O − w a s 2. 3 × 1 0 7 c p s. T h e s e a n al yti c al c o n di ti o n s a r e si mil a r t o t h o s e 2 0 3

d e s c ri b e d i n N a k a m u r a et al. ( 2 0 0 8) a n d U s hi k u b o et al. ( 2 0 1 2) . 2 0 4

F o r l a r g e r g r ai n s, a hi g h e r- i n t e n si t y 1 3 3 C s + p ri m a r y b e a m ( ~ 1 5 µ m, ~ 3 n A) w a s 2 0 5

u s e d f o r o x y g e n t h r e e -i s ot o p e a n al y s e s of s e v e r al f o r s t e ri t e s a n d Al -Ti -ri c h di o p si d e s i n 2 0 6

A O A s. I n t hi s c o nfi g u r ati o n, s e c o n d a r y i o n s of o x y g e n i s ot o p e s w e r e si m ul t a n e o u sl y 2 0 7

m e a s u r e d wi t h t h r e e F C d et e ct o r s , u si n g a 1 0 1 0 o h m r e si s t o r f o r 1 6 O − a n d 1 0 1 1 o h m 2 0 8

r e si s t o r s f o r 1 7 O − a n d 1 8 O − , r e s p e cti v ely. T h e m a s s r e s ol vi n g p o w e r ( M R P at 1 0 % p e a k 2 0 9

h ei g h t) w a s s et t o ~ 2 2 0 0 f o r 1 6 O − a n d 1 8 O − , a n d ~ 5 0 0 0 f o r 1 7 O − , r e s p e cti v el y. T h e t y pi c al 2 1 0

c o u n t r at e of 1 6 O − w a s 2. 7 × 1 0 9 c p s. T h e s e a n al yti c al c o n di ti o n s a r e si mil a r t o t h o s e 2 1 1

d e s c ri b e d i n Ki t a et al. ( 2 0 1 0) a n d U s hi k u b o et al. ( 2 0 1 2). 2 1 2

F o r s m all a n d l a r g e s p ot a n al y s e s, t h e c o u n t r at e of 1 6 O H − w a s m e a s u r e d 2 1 3

i m m e di at el y aft e r e a c h o x y g e n i s ot o p e a n al y si s. Th e c o n t ri b u ti o n of 1 6 O H − t o 1 7 O − w a s 2 1 4

e s ti m at e d f oll o wi n g m et h o d s d e v el o p e d b y H e c k et al., (2 0 1 0) , a n d w a s t y pi c all y f o u n d t o 2 1 5

b e < 0. 1 ‰ . 2 1 6

A S a n C a rl o s oli vi n e s t a n d a r d (δ 1 8 O V S M O W = 5. 3 2 ‰ , Ki t a et al., 2 0 1 0) w a s u s e d a s 2 1 7

t h e r u n ni n g s t a n d a r d . T h e i n s t r u m e n t al bi a s eff e ct o n δ 1 8 O (i. e. t h e m at ri x eff e ct) w a s 2 1 8

c ali b r at e d b a s e d o n a n al y s e s of m ul ti pl e s t a n d a r d s ( F o 1 0 0 a n d F o 8 9 f o r oli vi n e, s y n t h eti c 2 1 9

g e hl e ni t e a n d å k e r m a ni t e f o r m elili t e, di o p si d e a n d s y n t h eti c Al -Ti -ri c h di o p si di c gl a s s 2 2 0

f o r p y r o x e n e, s pi n el, a n d a n o rt hi t e, T a bl e s E A 1 a n d E A 3 ). N o a p p a r e n t m at ri x eff e ct o n 2 2 1

∆ 1 7 O w a s o b s e r v e d ( T a bl e E A 3 ). P r o c e d u r e s f o r t h e i n s t r u m e n t al bi a s c o r r e cti o n a n d f o r 2 2 2

d at a r e d u cti o n a r e d e s c ri b e d i n Ki t a et al. ( 2 0 0 9) a n d T e n n e r et al. ( 2 0 1 3) . T h e e xt e r n al 2 2 3

r e p r o d u ci bili t i e s of b r a c k eti n g s t a n d a r d a n al y s e s w e r e a s si g n e d a s t h e u n c e rt ai n t y of 2 2 4

u n k n o w n s a m pl e s. T y pi c al u n c e rt ai n ti e s ( 2 S D) of δ 1 8 O, δ 1 7 O, a n d ∆ 1 7 O w e r e ± 1. 1 ‰ , 2 2 5

± 1. 1 ‰ , a n d ± 1. 1 ‰ , r es p e cti v el y, wi t h t h e s m all b e a m a n al yti c al s etti n g , a n d ± 0. 2 6 ‰, 2 2 6

± 0. 6 1 ‰, a n d ± 0. 5 9 ‰ , r es p e cti v el y, wi t h t h e l a r g e b e a m a n al yti c al s etti n g. 2 2 7

2 2 8

3. 2. 2 3. 2. 2 2 62 6 AlAl --2 62 6 M g i s ot o p e s y s t e m ati c sM g i s ot o p e s y s t e m ati c s 2 2 9

F o r a n al y s is of Al a n d M g i s ot o p e s , a n 1 6 O − p ri m a r y b e a m wi t h a 2 3 k V t ot al 2 3 0

a c c el e r ati n g v ol t a g e w a s u s e d. A ~ 2 5 n m t hi c k c a r b o n c o at w a s a p pli e d o n t h e s a m pl e 2 3 1

s u rf a c e. T h e a c c el e r ati n g v ol t a g e of s e c o n d a r y i o n s w a s 1 0 k V. 2 3 2

A s m all 1 6 O − p ri m a r y b e a m ( 5 t o 7 µ m, 4 0 t o 1 5 0 p A) w a s u s e d f o r a n al y s e s of 2 3 3

a n o rt hi t e a n d m elili t e. S e c o n d a r y i o n s of 2 4 M g + , 2 5 M g + , a n d 2 6 M g + w e r e d et e ct e d b y a n 2 3 4

a xi al E M d et e ct o r t h at o p e r at e d b y m a g n eti c p e a k s wi t c hi n g. S e c o n d a r y 2 7 Al + i o ns w e r e 2 3 5

d et e ct e d b y a F a r a d a y c u p l o c at e d at t h e hi g h m a s s si d e of t h e a xi al E M d et e ct o r d u ri n g 2 3 6

t h e m e a s u r e m e n t of 2 5 M g + . T h e m a s s r e s ol vi n g p o w e r w a s s et at ~ 4 0 0 0, w hi c h i s 2 3 7

s uffi ci e n t f o r t h e s e p a r atin g 4 8 C a 2 + a n d 2 4 M g H + i n t e rf e r e n c e s. D e a d ti m e of t h e E M 2 3 8

d et e ct o r w a s 2 4. 9 n s, a s d et e r mi n e d b y M g i s ot o p e a n al y s e s of m elili t e a n d a n o rt hit e 2 3 9

s t a n d a r d s. T hi s a n al yti c al p r ot o c ol i s si mil a r t o t hat d e s c ri b e d i n U s hi k u b o et al. ( 2 0 1 3). 2 4 0

F o r s m all b e a m a n al y s e s, s y n t h eti c gl a s s s t a n d a r d s ( Å k 1 5 a n d a n o rt hi ti c gl a s s 2 4 1

wi t h 1 wt % M g O) w e r e u s e d t o d et e r mi n e r e s p e cti v e i n s t r u m e n t al m a s s bi a s e s ( T a bl e 2 4 2

E A 4 ). T h e p r o c e d u r e s t o c al c ul at e t h e m a s s-d e p e n d e n t f r a cti o n ati o n ( δ 2 5 M g D S M 3 ) a n d t h e 2 4 3

2 6 M g -e x c e s s ( δ 2 6 M g * ) a r e p r o vi d e d i n El e ct r o ni c A n n e x ( E A -1) . T h e δ 2 5 M g D S M 3 u n c e rt ai n t y 2 4 4

of m elili t e u n k n o w n s i s a s si g n e d a s {( 2 S E i nt e r n al)2 +( 2 S E st d )2 }1/ 2 . T h e u n c e rt ai n ti e s of t h e 2 4 5

δ 2 5 M g D S M 3 v al u e of a n o rt hi t e a n d t h e δ 2 6 M g * v al u e s of m elili t e a n d a n o rt hi t e a r e a s si g n e d 2 4 6

a s t h e i n t e r n al 2 S E ( 2 S E i nt e r n al) of e a c h a n al y si s b e c a u s e s t ati s ti c al u n c e rt ai n ti e s b a s e d 2 4 7

o n t ot al c o u n t s of si g n al s a r e si g nifi c a n tl y l a r g e r t h a n r e p r o d u ci bili ti e s of s p ot -t o-s p ot 2 4 8

a n al y s e s ( T a bl e 2 a n d T a bl e E A 4 f o r δ 2 6 M g * v al u e s of m elili t e , T a bl e 2, a n d T a bl e S 2 i n 2 4 9

U s hi k u b o et al., 2 0 1 3 f o r δ 2 5 M g D S M 3 a n d δ 2 6 M g * v al u e s of a n o rt hi t e, r e s p e cti v el y) . 2 5 0

F o r l a r g e r p h e n o c r y s t s c o n si s ti n g of f o r s t e ri t e, s pi n el, a n d Al -Ti -ri c h di o p si d e, a 2 5 1

hi g h e r -i n t e n si t y 1 6 O − p ri m a r y b e a m ( ~ 1 0 µ m, 2. 2 n A) w a s e m pl o y e d . S e c o n d a r y i o n s of 2 5 2

2 4 M g + , 2 5 M g + , 2 6 M g + , a n d 2 7 Al + w e r e si m ul t a n e o u sl y d et e ct e d b y f o u r F a r a d a y c u p s . T h e 2 5 3

m a s s r e s ol vi n g p o w e r w a s s et at ~ 2 2 0 0 a n d t h e t aili n g of i n t e rf e r e n c e p e a k s w a s 2 5 4

n e gli gi bl y s m all. O v e r all, t hi s c o n di ti o n i s si mil a r t o t h at d e s c ri b e d i n Ki t a et al. ( 2 0 1 2) 2 5 5

a n d U s hi k u b o et al. ( 2 0 1 3). 2 5 6

F o r l a r g e b e a m a n al y s e s, a S a n C a rl o s oli vi n e s t a n d a r d ( δ 2 5 M g D S M 3 = − 0. 0 2 ‰ ) 2 5 7

w a s u s e d a s t h e r u n ni n g s t a n d a r d . T h e δ 2 5 M g D S M 3 m a t ri x eff e ct w a s c ali b r at e d b a s e d o n 2 5 8

a n al y s e s of m ul ti pl e s t a n d a r d s ( F o 1 0 0 a n d S a n C a rl o s oli vi n e ( F o 8 9 ) f o r oli vi n e, di o p si d e 2 5 9

a n d s y n t h eti c Al -Ti -ri c h di o p si di c gl a s s f o r p y r o x e n e, a n d s pi n el, T a bl e E A 4 ). T h e 2 6 0

p r o c e d u r e t o c al c ul at e t h e m a s s -d e p e n d e n t f r a cti o n ati o n ( δ 2 5 M g D S M 3 ) a n d 2 6 M g -e x c e s s 2 6 1

(δ 2 6 M g * ) i s p r o vi d e d i n El e ct r o ni c A n n e x ( E A -1) . T h e e xt e r n al r e p r o d u ci bili t y of 2 6 2

b r a c k eti n g s t a n d a r d a n al y s e s ( 2 S D) i s a s si g n e d a s t h e u n c e rt ai n t y of u n k n o w n s a m pl e s. 2 6 3

T y pi c al u n c e rt ai n ti e s of δ 2 5 M g D S M 3 a n d δ 2 6 M g * w e r e ± 0. 1 9 ‰ a n d ± 0. 1 1 ‰, r es p e cti v el y. 2 6 4

T h e r el ati v e s e n si ti vi t y f a ct o r s ( R S F, ( 2 7 Al/ 2 4 M g)/( 2 7 Al + /2 4 M g + )) of s pi n el, Al-Ti -2 6 5

ri c h di o p si d e, m elili t e, a n d a n o rt hi t e w e r e d et e r mi n e d b a s e d o n E P M A d at a a n d r e s ult s 2 6 6

of s t a n d a r d a n al y s e s b y S I M S ( T a bl e E A 4). 2 6 7

2 6 8

44 . R e s ul t s. R e s ul t s 2 6 9

Re p r e s e n t ati v e m aj o r el e m e n t c o m p o si ti o n s of i n di vi d u al p h a s e s a n d a n al y si s 2 7 0

p o si ti o n s f r o m s a m pl e s b y E P M A a r e s u m m a ri z e d i n T a bl e E A 2 a n d Fi g u r e E A 1 . O x y g e n 2 7 1

t h r e e -i s ot o p e d at a a n d M g i s ot o p e d at a a r e s u m m a ri z e d i n T a bl e 1 a n d T a bl e 2 , 2 7 2

r e s p e cti v el y. L o c ati o n s of i n di vi d u al a n al y s e s wi t hi n r ef r a ct o r y i n cl u si o n s a r e s h o w n i n 2 7 3

Fi g u r e E A 2. All i n di vi d u al d at a , i n cl u di n g a n al y s e s of r u n ni n g s t a n d a r d s, a r e s h o w n i n 2 7 4

T a bl e E A 5- 8 . 2 7 5

2 7 6

4. 1. 4. 1. O x y g e n i s ot o p e O x y g e n i s ot o p e r ati o sr ati o s 2 7 7

O x y g e n i s ot o p e r ati o s of all m e a s u r e d s a m pl e s a r e si g nifi c a n tl y 1 6 O- ri c h 2 7 8

(∆ 1 7 O < − 2 0 ‰ ) a n d a r e di s t ri b u t ed n e a r t h e C C A M li n e (T a bl e 1 , Fi g. 4). F o r a gi v e n 2 7 9

r ef r a ct o r y i n cl u si o n, t h e ∆ 1 7 O v al u e s of all m e a s u r e d p h a s e s a r e c o n si s t e n t wi t hi n 2 8 0

a n al yti c al u n c e rt ai n t y ; t h e o nl y e x c e p ti o n i s a r el ati v el y 1 6 O- p o o r d at u m f r o m a t hi n 2 8 1

m elili t e l a y e r at t h e ri m of Y 8 1 0 2 0 - E- 8 (∆ 1 7 O = − 1 4. 3 ± 0. 5 ‰ , Fi g. 4 a). N o d et e ct a bl e 2 8 2

s y s t e m ati c diff e r e n c e s i n b ot h δ 1 8 O a n d ∆ 1 7 O a r e o b s e r v e d b et w e e n o x y g e n i s ot o p e r ati o s 2 8 3

of mi n e r al s i n t h e i n t e ri o r a n d t h o s e of mi n e r al s i n t h e ri m ( i. e. Ti, Al -b e a ri n g di o p si d e 2 8 4

a n d s pi n el i n C A I s a n d oli vi n e at t h e e d g e of A O A s ) ( T a bl e 1, Fi gs. 4 a n d 5) . S u btl e 2 8 5

v a ri ati o n of o x y g e n i s ot o p e r ati o s al o n g a sl o p e 1 li n e wi t hi n e a c h i n cl u si o n ( e. g., A O A 2 8 6

G 5 8, Fi g. 4 k) a r e r e c o g ni z e d. H o w e v e r, t h e s e diff e r e n c e s a r e s m al l w h e n c o n si d e ri n g t h e 2 8 7

a n al yti c al u n c e rt ai n t y . A v e r a g e d ∆ 1 7 O of t h e C A I s a n d A O A s s t u di e d h a v e v al u e s of − 2 2. 0 2 8 8

t o − 2 4 . 3‰ , a n d h a v e u n c e rt ai n t y r a n gi n g f r o m 0. 3 ‰ t o 0. 9 ‰ ( T a bl e 1). 2 8 9

2 9 0

4.4. 22 .. M a g n e si u m i s ot o p e M a g n e si u m i s ot o p e r ati o s a n d r ati o s a n d t h e t h e 2 62 6 AlAl --2 62 6 M g i s ot o p e s y s t e m ati c sM g i s ot o p e s y s t e m ati c s 2 9 1

M a g n e si u m i s ot o p e r ati o s ( δ 2 5 M g D S M 3 a n d δ 2 6 M g * ), 2 7 Al/ 2 4 M g r ati o s, a n d t h e 2 9 2

r e g r e s si o n li n e s of t h e Al -M g i s ot o p e s y s t e m ati c s a r e s u m m a ri z e d i n T a bl e 2. T h e 2 6 Al -2 9 3

2 6 M g i s ot o p e s y s t e m ati c s of all m elili t e -ri c h C A I s ( Y 8 1 0 2 0- E- 8, G 5, G 1 6, G 4 9, a n d G 1 0 4) 2 9 4

e x hi bi t si n gl e li n e a r c o r r el ati o n s i n δ 2 6 M g * v s. 2 7 Al/ 2 4 M g (Fi g s. 6 a-f). T h e 2 7 Al/ 2 4 M g r ati o s 2 9 5

of m elili t e -ri c h C A I s a r e hi g hl y v a ri a bl e (f r o m 1 0 t o 7 2). M elili t e i n C A I G 5 i s hi g hl y 2 9 6

g e hl e ni ti c (Al -ri c h, 2 7 Al/ 2 4 M g = 4 6 t o 7 2) a n d i n C A I G 4 9 i t i s å k e r m a ni ti c ( M g -ri c h, 2 9 7

2 7 Al/ 2 4 M g = 1 0 t o 1 8) r el ati v e t o ot h e r m elili t e -ri c h C A I s ( 2 7 Al/ 2 4 M g = 1 5 t o 3 7). A n o rt hi t e 2 9 8

i n C A I G 1 6 h a s a v e r y hi g h 2 7 Al/ 2 4 M g r ati o a n d a l a r g e 2 6 M g -e x c e s s ( ~ 1 5 6 0 a n d ~ 5 3 0 ‰ , 2 9 9

r e s p e cti v el y, T a bl e 2 ). T h e i nf e r r e d i ni ti al 2 6 Al/ 2 7 Al r ati o s, ( 2 6 Al/ 2 7 Al) 0 , of m elili t e-ri c h 3 0 0

C A I s a r e (4. 0 8 ± 0. 7 5) × 1 0 − 5 t o (5. 0 5 ± 0. 1 8) × 1 0 − 5 . T h e s e v al u e s a r e wi t hi n t h e (2 6 Al/ 2 7 Al) 0 3 0 1

r a n g e of C A I s f r o m C V c h o n d ri t e s b u t a r e sli g h tl y l o w e r t h a n t h e c a n o ni c al S ol a r S y s t e m 3 0 2

v al u e of ( 5. 2 5 ± 0. 0 2) × 1 0 − 5 ( e. g., J a c o b s e n et al., 2 0 0 8; L a r s e n et al., 2 0 1 1; M a c P h e r s o n et 3 0 3

al., 2 0 1 2 ; Ki t a et al., 2 0 1 3) . O n e A O A, G 1 7, h a s a n i nf e r r e d (2 6 Al/ 2 7 Al) 0 of (5. 3 2 ± 0. 8 1) × 1 0 − 5 , 3 0 4

w hi c h i s b a s e d o n d at a f r o m oli vi n e, Al -Ti -ri c h di o p si d e, a n d s pi n el ( Fi g. 6i ). T h e o t h e r 3 0 5

th r e e A O A s , G 2 8, G 4 4, a n d G 5 8 , d o n ot c o n t ai n hi g h -Al/ M g p h a s e s t h at a r e l a r g e e n o u g h 3 0 6

f o r M g i s ot o p e a n al y s e s b y S I M S . 3 0 7

R e g a r di n g t h e 2 6 Al -2 6 M g i s ot o p e s y s t e m ati c s of a n o rt hi t e -ri c h C A I G 9 2, t w o 3 0 8

di s ti n ct t r e n d li n e s a r e p r o d u c e d w h e n pl otti n g 2 7 Al/ 2 4 M g v s. 2 6 M g -e x c e s s ( δ 2 6 M g * ) ( Fi gs . 3 0 9

6 g, 6 h ). I n p a rti c ul a r, m elili t e a n d Al -Ti -ri c h di o p si d e d at a of C A I G 9 2 a r e di s t ri b u t e d 3 1 0

al o n g a si n gl e t r e n d li n e . T h e sl o p e of t h e t r e n d li n e u si n g o nl y Al -Ti -ri c h di o p si d e d at a 3 1 1

i s 0. 3 3 ± 0. 1 9 wi t h i n t e r c e p t of 0. 1 8 ± 0. 1 7, w hi c h o v e rl a p s wi t h t h e m elili t e d at a. T h e sl o p e 3 1 2

of t h e t r e n d li n e u si n g b ot h Al -Ti -ri c h di o p si d e a n d m elili t e d at a i s 0. 3 7 5 ± 0. 1 4, 3 1 3

c o r r e s p o n di n g t o a n i nf e r r e d (2 6 Al/ 2 7 Al) 0 of ( 5. 2± 2. 0) × 1 0 − 5 (Fi g. 6 g). Al t h o u g h w e c a n n ot 3 1 4

d et e r mi n e t h e o ri gi n of Al -Ti -ri c h di o p si d e wi t h c e rt ai n t y , a c o n si s t e n t di s t ri b u ti o n of Al -3 1 5

Ti -ri c h di o p si d e a n d m elili t e d at a s u g g e s t s t h e s e a r e p ri m a r y p h a s e s . I n c o n t r a s t, 3 1 6

a n o rt hi t e d at a f r o m G 9 2 e x hi bi t hi g h 2 7 Al/ 2 4 M g ( > 7 0 0) a n d 2 6 M g -e x c e s s e s t h at a r e 3 1 7

si g nifi c a n tl y s m all e r t h a n t h o s e f r o m t h e r e g r e s si o n li n e of m elili t e a n d Al -Ti -ri c h 3 1 8

di o p si d e d at a ( Fi g. 6 h ). A s s u mi n g t h at a n o rt hi t e f o r m e d b y r e pl a c i n g m elili t e a n d t h at 3 1 9

M g wi t hi n a n o rt hi t e h a d o ri gi n all y d e ri v e d f r o m t h e m elili t e t h at i t r e pl a c e d (s e e 3 2 0

di s c u s si o n i n s e cti o n 5. 2), th e r e g r e s si o n li n e u si n g d at a f r o m m elili t e a n d a n o rt hi t e i n 3 2 1

G 9 2 h a s a sl o p e of 0. 0 3 7 4 ± 0. 0 0 3 9 wi t h a n i n t e r c e p t of 2. 6 ± 1. 1 ‰ a n d a n i nf e r r e d 3 2 2

(2 6 Al/ 2 7 Al) 0 of ( 5. 2 1± 0. 5 4 ) × 1 0− 6 (Fi g. 6 h , T a bl e 2 ). W e n ot e t h at t h e i nf e r r e d (2 6 Al/ 2 7 Al) 0 3 2 3

b e c o m e s sli g h tl y r e d u c e d [(4. 6 ± 2. 1 ) × 1 0− 6 ] u si n g o nl y a n o rt hi t e d at a a n d i t i s sli g h tl y 3 2 4

hi g h e r [( 5. 5 9 ± 0. 5 3 ) × 1 0− 6 ] if a s s u mi n g n o 2 6 M g -e x c e s s w h e n a n o rt hi t e f o r m e d. 3 2 5

I n a d di ti o n t o C A I G 9 2 , a n o rt hi t e i s al s o o b s e r v e d i n m elili t e -ri c h C A I, G 1 6 , 3 2 6

o c c u r ri n g a s a t hi n l a y e r ( ~ 5 µ m) b et w e e n m elili t e a n d t h e di o p si d e ri m ( Fi g. 1 g ). 3 2 7

H o w e v e r, a n o rt hi t e i n C A I G 1 6 h a s a l a r g e 2 6 M g -e x c e s s w hi c h i s c o n si st e n t wi t h t h e 3 2 8

r e g r e s si o n li n e of c o e xi s ti n g Al -Ti -ri c h di o p si d e a n d m elili t e t h at c o r r e s p o n d s t o a 3 2 9

(2 6 Al/ 2 7 Al) 0 of ( 4. 7 1 ± 0. 1 5) × 1 0− 5 (Fi g. 6 d , e) . T h u s, a n o rt hi t e g r ai n s f r o m t w o diff e r e n t C A I s, 3 3 0

G 9 2 a n d G 1 6, r e c o r d di s ti n ct 2 6 Al -2 6 M g i s ot o p e si g n at u r e s wi t hi n t h e s a m e t hi n s e cti o n . 3 3 1

Hi g h p r e ci si o n M g i s ot o p e d at a of M g -ri c h p h a s e s ( oli vi n e, Al -Ti -ri c h di o p si d e, 3 3 2

a n d s pi n el) o bt ai n e d b y l a r g e b e a m a n a l y s e s i n di c at e t h at ma s s -d e p e n d e nt M g i s ot o p e 3 3 3

f r a cti o n ati o n (δ 2 5 M g D S M 3 ) i s s m all ( 0. 0 ± 1. 5‰ / a m u, T a bl e 2 ). T hi s r e s ul t i s c o n si s t e n t wi t h 3 3 4

t h e fi n e-g r ai n e d t e xt u r e s a n d/ o r i r r e g ul a r s h a p e s of t h e s a m pl e s , w hi c h s u g g e s t s t h e y 3 3 5

a v oi d e d r e -m el ti n g a n d a s s o ci at e d e v a p o r ati v e l o s s t o t h e s u r r o u n di n g e n vi r o n m e n t. A 3 3 6

f e w δ 2 5 M g D S M 3 v al u e s of hi g h -2 7 Al/ 2 4 M g p h a s e s ( m elili t e a n d a n o rt hi t e) t h at w e r e 3 3 7

o bt ai n e d b y s m all b e a m a n al y s e s a r e si g nifi c a n tl y hi g h e r t h a n ot h e r d at a i n t h e s a m e 3 3 8

i n cl u si o n, b e y o n d t h e a n al yti c a l u n c e rt ai n t y (e. g., # 5 3 of G 5 , # 5 0 of G 4 9, a n d # 3 7 of G 9 2 3 3 9

i n T a bl e 2 ). T h e s e a r e p r e s u m a bl y o u tli e r s of s m all b e a m a n al y s e s, b u t w e c a n n ot 3 4 0

c o m pl et el y r ul e o u t t h e e xi s t e n c e of δ 2 5 M g D S M 3 h et e r o g e n ei t y wi t hi n e a c h i n cl u si o n. 3 4 1

3 4 2

55 . Di s c u s si o n. Di s c u s si o n 3 4 3

5. 1. 5. 1. 1 61 6 OO --e ne n ri c hri c h e d e n vi r o n m e n t of r ef r a ct o r y i n cl u si o n f o r m ati o ne d e n vi r o n m e n t of r ef r a ct o r y i n cl u si o n f o r m ati o n 3 4 4

Wi t hi n a gi v e n i n cl u si o n, o x y g e n i s ot o p e r ati o s of i t s ri m s t r u ct u r e s, i n cl ud i n g 3 4 5

di o p si d e a n d s pi n el i n C A I s, a s w ell a s oli vi n e at t h e e d g e of A O A s, c a n b e c o m p a r e d t o 3 4 6

t h o s e of i n t e ri o r p h a s e s, i n o r d e r t o d et e r mi n e w hi c h o x y g e n i s ot o p e r e s e r v oi r s w e r e 3 4 7

s a m pl e d . Wi t h t h e e x c e pti o n of o n e d at u m ( di s c u s s e d b el o w), o u r r e s ul t s i n di c at e t h at 3 4 8

o x y g e n i s ot o p e r ati o s of mi n e r al s b ot h i n t h e ri m a n d i n t h e i n t e ri o r of t h e s a m e i n cl u si o n 3 4 9

a r e i n di s ti n g ui s h a bl e, a n d s h o w n o s y s t e m ati c diff e r e n c e s ( Fi gs . 4 a n d 5 ). T hi s r e s ul t i s 3 5 0

di s ti n ct f r o m v a ri a bl e o x y g e n i s ot o p e r ati o s of W a r k -L o v e ri n g ri m s a s s o ci at e d wi t h 3 5 1

c o a r s e -g r ai n e d C A I s f r o m C V c h o n d ri t e s ( e. g., Yo s hi t a k e et al., 2 0 0 5; Si m o n et al., 2 0 1 1, 3 5 2

2 0 1 6) , b u t i n a g r e e m e n t wi t h o x y g e n i s ot o p e r ati o s of C A I s f r o m p ri s ti n e C R, C O, a n d 3 5 3

C H c h o n d ri t e s ( B o dé n a n et al., 2 0 1 4; J a c o b s e n et al., 2 0 1 4 ; K r ot et al., 2 0 1 6). 3 5 4

T h e si n gl e, r el ati v el y 1 6 O- p o o r si g n at u r e ( ∆ 1 7 O ~ − 1 4 ‰ ) of m elili t e o u t si d e of t h e 3 5 5

ri m s pi n el l a y e r of C A I Y 8 1 0 2 0 - E- 8 ( Fi g. 1e a n d 4 b) c a n b e i n t e r p r et e d i n a c o u pl e w a y s. 3 5 6

F o r e x a m pl e, it c o ul d b e a n i n t ri n si c si g n at u r e ( c o n d e n s ati o n f r o m a r el ati v el y 1 6 O-3 5 7

d e pl et e d n e b ul a r g a s) o r i t c o ul d b e t h e r e s ul t of l at e r m et a m o r p hi s m. T h e a n al y z e d 3 5 8

r e gi o n of t hi s m elili t e i s s u r r o u n d e d b y fi n e -s c al e c r a c k s a n d v oi d s a n d di r e ctl y c o n t a ct s 3 5 9

wi t h t h e m at ri x , a s t h e di o p si d e l a y e r i n t hi s C A I i s di s c o n ti n u o u s ( Fi g. E A 2, Y 8 1 0 2 0- E-3 6 0

8 _ 2) . C o n si d e ri n g t h e s u s c e p ti bili t y of o x y g e n i s ot o p e di s t u r b a n c e wi t hi n m elili t e ( e. g., 3 6 1

F a g a n et al., 2 0 0 4; B o d é n a n et al., 2 0 1 4) , w hil e al s o t a ki n g i n t o a c c o u n t t h e c o n si s t e n t 3 6 2

1 6 O- ri c h si g n at u r e of ot h e r C A I ri m p h a s e s f r o m t h e l e a s t m et a m o r p h o s e d c a r b o n a c e o u s 3 6 3

c h o n d ri t e s ( e. g., B o d é n a n et al., 2 0 1 4; J a c o b s e n et al., 2 0 1 4 ; K r ot et al., 2 0 1 6; t hi s s t u d y), 3 6 4

t h e r el ati v el y 1 6 O- p o o r si g n at u r e of m elili t e o u t si d e of t h e ri m s pi n el l a y e r of Y 8 1 0 2 0 - E-3 6 5

8 i s p r o b a bl y t h e r e s ul t of l at e r i s ot o pi c e x c h a n g e , ei t h e r i n t h e s ol a r n e b ul a o r i n t h e 3 6 6

p a r e n t b o d y. 3 6 7

C A I s f r o m t hi s s t u d y h a v e a s m all b u t a p p r e ci a bl e r a n g e i n a v e r a g e d ∆ 1 7 O 3 6 8

v al u e s, o n t h e o r d e r of a f e w p e r -mil w h e n c o n si d e ri n g u n c e rt ai n ti e s ( T a bl e 1 , Fi g. 4, 5, 3 6 9

a n d 8 a). Wi t h t h e e x c e p ti o n of t h e o u t e r m o s t m elili t e l a y e r of Y 8 1 0 2 0 - E- 8, a s di s c u s s e d 3 7 0

i n t h e p r e vi o u s p a r a g r a p h, o x y g e n i s ot o p e r ati o s of C A I ri m s a r e wi t hi n t h e r a n g e of 3 7 1

t h o s e f r o m t h ei r c o r r e s p o n di n g i n t e ri o r p h a s e s ( e. g., T a bl e 1 a n d Fi g s . 4 a n d 5) . T hi s 3 7 2

i n di c at e s t h at b ot h of t h e s e C A I c o m p o n e n t s f o r m e d i n t h e s a m e o x y g e n i s ot o p e 3 7 3

e n vi r o n m e n t a n d t h at t h ei r i n t ri n si c o x y g e n i s ot o p e r ati o s h a v e n ot b e e n di s t u r b e d aft e r 3 7 4

t h ei r f o r m ati o n . C o n si d e ri n g t h e p ri s ti n e n at u r e of A cf e r 0 9 4 a n d Y -8 1 0 2 0 c h o n d ri t e s, 3 7 5

t h e sli g h t ∆ 1 7 O v a ri ati o n i n t h ei r C A I s m o s t li k el y r efl e ct s t h at of t h e o x y g e n i s ot o p e 3 7 6

e n vi r o n m e n t w h e r e C A I s f o r m e d. Si mil a r, a s w ell a s sli g h tl y l a r g e r ∆ 1 7 O v a ri ati o n s al o n g 3 7 7

t h e P C M li n e a r e al s o f o u n d i n hi b o ni t e a n d s pi n el -hi b o ni t e i n cl u si o n s f r o m C M 3 7 8

c h o n d ri t e s ( K ö ö p et al., 2 0 1 6 ). Al t h o u g h e xt r e m el y 1 6 O- ri c h i n cl u si o n s ( ∆ 1 7 O d o w n t o 3 7 9

~ − 3 7 ‰, K o b a y a s hi et al., 2 0 0 3; G o u n ell e et al., 2 0 0 9, s e e al s o Fi g. E A 1 -2 i n U s hi k u b o et 3 8 0

al., 2 0 1 2 f o r c o m p a ri s o n) h a v e b e e n f o u n d, w e d o n ot r e c o g ni z e s u c h a n e xt r e m el y 1 6 O-3 8 1

ri c h si g n at u r e i n t h e s a m pl e s, s u g g e s ti n g ei t h e r t h e o c c u r r e n c e of e xt r e m el y 1 6 O- ri c h 3 8 2

e n vi r o n m e n t o r f o r m ati o n of i n cl u si o n s i n a n e xt r e m el y 1 6 O- ri c h e n vi r o n m e n t w a s r a r e. 3 8 3

R e g a r di n g t h e o ri gi n of C A I ri m s, it ha s b e e n p r o p o s e d t h at W a r k -L o v e ri n g ri m s 3 8 4

f o r m e d b y a l at e r fl a s h h e ati n g e v e n t, l e a di n g t o i n t e n s e e v a p o r ati v e l o s s ( e. g., W a r k a n d 3 8 5

B o y n t o n, 2 0 0 1) . S u c h a p r o c e s s i s c o n si d e r e d t o b e r e s p o n si bl e f o r p o si ti v e m a s s -3 8 6

d e p e n d e n t i s ot o p e f r a cti o n ati o n t h at i s c o m m o nl y o b s e r v e d i n F( U N) i n cl u si o n s a n d 3 8 7

n o r m al C A I s ( e. g., Cl a yt o n a n d M a y e d a, 1 9 7 7; W a s s e r b u r g et al., 1 9 7 7; G r o s s m a n et al., 3 8 8

2 0 0 8; K r ot et al., 2 0 1 4 a). Al t h o u g h t h e s a m pl e s f r o m t hi s s t u d y a r e m ai nl y fi n e -g r ai n e d 3 8 9

C A I s , t h e y h a v e si mil a r t e xt u r e s (i. e. t hi n s pi n el a n d di o p si d e l a y e r e d st r u ct u r e s ) as 3 9 0

t h o s e o b s e r v e d i n W o r k-L o v e ri n g ri m s . H o w e v e r, t h e ri m δ 1 8 O v al u e s (T a bl e 1 , Fi g. 5 b) 3 9 1

a n d δ 2 5 M g D S M 3 v al u e s (T a bl e 2 ) f r o m A cf e r 0 9 4 a n d Y-8 1 0 2 0 r ef r a ct o r y i n cl u si o n s e x hi bit 3 9 2

n ei t h e r m a s s -d e p e n d e n t i s ot o p e f r a cti o n ati o n n o r v a ri a bili t y i n ∆ 1 7 O . T h e s e d at a i n di c at e 3 9 3

t h at l at e r p r o c e s s e s , s u c h a s a n i n t e n s e fl a s h r e -h e ati n g e v e n t, a r e n ot n e c e s s a r y t o 3 9 4

p r o d u c e t h e ri m s t r u ct u r e of C A I s. I n a d di ti o n, si mil a r 1 6 O- ri c h o x y g e n i s ot o pi c 3 9 5

si g n at u r e s, a s w ell a s g e n e r al a g r e e m e n t of o x y g e n i s ot o p e r ati o s b et w e e n C A I i n t e ri o r 3 9 6

p h a s e s a n d t h ei r ri m s ( i n cl u di n g fi n e-g r ai n e d C A I s a n d c o a r s e -g r ai n e d W a r k - L o v e ri n g 3 9 7

ri m -b e a ri n g C A I s) a r e c o n si s t e n tl y o b s e r v e d i n C A I s f r o m p ri s ti n e c a r b o n a c e o u s 3 9 8

c h o n d ri t e s ( B o d é n a n et al., 2 0 1 4; J a c o b s e n et al., 2 0 1 4 ; K r ot et al., 2 0 1 6; t hi s s t u d y). 3 9 9

C o m bi n e d t h e s e r e s ul t s i n di c at e t h at all c o m p o n e n t s a n d t e xt u r e s of C A I s, i n cl u di n g 4 0 0

c o n d e n s ati o n of r ef r a ct o r y p h a s e s f r o m n e b ul a r g a s, a g g r e g ati o n, a n d f o r m ati o n of ri m 4 0 1

l a y e r s, o c c u r r e d i n t h e s a m e 1 6 O- ri c h e n vi r o n m e n t . T h e o b s e r v e d o x y g e n i s ot o p e 4 0 2

v a ri a bi li t y a m o n g W a r k -L o v e ri n g ri m s of c o a r s e -g r ai n e d C V c h o n d ri t e C A I s i s p r o b a bl y 4 0 3

e x pl ai n e d b y o x y g e n i s ot o p e e x c h a n g e wi t h 1 6 O- p o o r m at e ri al s d u ri n g p a r e n t b o d y 4 0 4

m et a m o r p hi s m . 4 0 5

4 0 6

5. 2. 5. 2. ∆∆ 1 71 7 O O v s.v s. ((2 62 6 Al/Al/ 2 72 7 Al)Al) 00 of C A I s: of C A I s: A n e ni g m ati c aA n e ni g m ati c a n o rt hi t en o rt hi t e --ri c h C A I h a vi n g l o w (ri c h C A I h a vi n g l o w ( 2 62 6 Al/Al/ 2 72 7 Al)Al) 00 4 0 7

a n da n d aa nn 1 61 6 OO --ri c h siri c h si g n at u r e.g n at u r e. 4 0 8

Fi g u r e 7 s u m m a ri z e s t h e r el ati o n s hi p b et w e e n ∆ 1 7 O a n d ( 2 6 Al/ 2 7 Al) 0 of t h e 4 0 9

r ef r a ct o r y i n cl u si o n s i n t hi s s t u d y; dat a f r o m A cf e r 0 9 4 c h o n d r ul e s ( U s hi k u b o et al., 4 1 0

2 0 1 3) a r e al s o s h o w n f o r c o m p a ri s o n. I nf e r r e d ( 2 6 Al/ 2 7 Al) 0 v al u e s of C A I s Y 8 1 0 2 0 - E- 8, G 5, 4 1 1

G 1 6, G 4 9, a n d G 1 0 4 r a n g e f r o m ( 4. 0 8 ± 0. 7 5)× 1 0 − 5 t o ( 5. 0 5 ± 0. 1 8)× 1 0 − 5 , w hi c h a r e sli g h tl y 4 1 2

l o w e r t h a n t h e c a n o ni c al v al u e o f ( 5. 2 5± 0. 0 2) × 1 0 − 5 ( Fi g. 7). T h e s e v al u e s a r e si mil a r t o 4 1 3

t h o s e of m el t e d C A I s f r o m C V a n d C R c h o n d ri t e s ( M a ki d e et al. , 2 0 0 9; M a c P h e r s o n et 4 1 4

al., 2 0 1 2) . A s C A I s Y 8 1 0 2 0 - E-8, G 5, G 1 6, G 4 9, a n d G 1 0 4 h a v e w ell -d efi n e d i s o c h r o n s, 4 1 5

and because they have primitive textures , such a s small grain size s and multi- nodule 416 structures, they likely did not experience a later re -melting process. Assuming this is 417 true, and also assuming homogeneously distributed 26Al after “canonical” CAIs formed 418 (e.g., Kita et al., 2013), t heir slightly lower ( 26Al/27Al)0 values indicate formation up to 419 ~0.3Ma after canonical CAIs (Fig. 7). However, it cannot be ruled out that these fine -420 grained CAIs formed prior to homogeneous distribution of 26Al and that the range of 421 (26Al/27Al)0 values among Acfer 094 and Y -81020 refractory inclusions represents 422 variability of 26Al abundance in the early solar system when they formed . For AOA G17, 423 the inferred ( 26Al/27Al)0 value of (5.32±0.81)×10−5 is consistent with the canonical value 424 of CAIs . As such, this AOA could be as old as other CAIs although the present data are 425 not of sufficient precision to discuss fine -scale differences of formation age s. Regarding 426 oxygen isotope ratios, all of the aforementioned CAIs, as well as AOA G17, are 16O-rich, 427 likely reflecting the value of the nebular gas over this time period. 428

CAI G92 is also 16O-rich, but its constituent anorthite has a n order -of-429 magnitude low er inferred (26Al/27Al)0, ( 5.21±0.54)×10−6, when compared to the CAIs and 430 the AOA mentioned above (Fig. 7). However, there is also an other trend line 431 corresponding to a (26Al/27Al)0 of (5.2±2.0)×10 −5 that is observed among Al-Ti-rich 432 diopside and melilite in CAI G92 (Fig. 6g, Table 2), making it evident that this CAI 433 initially had a near -canonical ( 26Al/27Al)0, like the other refractory inclusions . A l ater 434 isotopic disturbance in the Acfer 094 parent body is unlikely to explain the lower δ26Mg* 435 values in G92 anorthite be cause (1) as mentioned in the Introduction, Acfer 094 is one of 436 the least metamorphosed carbonaceous chondrites (Gresh ake, 1997; Kimura et al., 2008) 437 and (2) the 26Al-26Mg systematics of both the anorthite rim layer in CAI G16 (Fig. 6e) 438 and small anorthite grains in chondrules from the same thin section do not exhibit 439 evidence for isotopic disturbance (t his study, Kita et al., 2013; Ushikubo et al., 2013). As 440 such, we i nterpret that the lower ( 26Al/27Al)0 of G92 anorthite (Fig. 6h) recorded the 441 timing of a later thermal process in the solar nebula. 442

Like anorthite in CAI G92, Krot et al. (2014b ) reported tha t anorthite in some 443 AOAs from CH chondrites ha ve similar 16O-rich oxygen isotope ratios but low δ26Mg* 444 values. They proposed that such an isotopic signature in anorthite could be explained by 445 Mg isotopic exchange with surrounding Mg -rich phases during a days -to-weeks long 446 thermal annealing event at high temperatur e (~1100 °C ) coupled with a slow cooling rate 447 (~0.01 K/h) . Such conditions would be necessary because the diffusivity of Mg in 448 anorthite is significantly higher than that of oxygen at >1000 °C . However, such a 449 scenario is unlikely for G92 because a linear correlation between 27Al/24Mg ratios and 450 δ26Mg* values in anorthite is not consistent with a later isotopic disturbance of the 27Al-451

2 4 M g s y s t e m ati c s i n a n o rt hi t e ( e. g., P o d o s e k et al , 1 9 91 ; M a c P h e r s o n et al., 2 0 1 2) . 4 5 2

F u rt h e r , t h e n e a r-c a n o ni c al i s o c h r o n p r o d u c e d b y Al -Ti -ri c h di o p si d e a n d m elili t e i n G 9 2 4 5 3

( Fi g. 6 g) i s n ot c o n si s t e n t wi t h M g i s ot o pi c e x c h a n g e wi t h a dj a c e n t a n o rt hi t e. If a n o rt hi t e 4 5 4

i n G 9 2 f o r m e d a s e a rl y a s ot h e r p h a s e s, t h e a c c u m ul at e d 2 6 M g -e x c e s s w o ul d h a v e b e e n 4 5 5

l a r g e r t h a n 3 0 0‰ i n δ 2 6 M g * (e. g. , a n o rt hi t e i n C A I G 1 6, Fi g. 6 e) at t h e ti m e of t h e t h e r m al 4 5 6

a n n e ali n g e v e n t. T h u s, e v e n t h o u g h M g i s a mi n o r el e m e n t i n a n o rt hit e ( < 0. 1 wt %), 4 5 7

a n o m al o u sl y hi g h δ 2 6 M g * v al u e s ( u p t o a f e w p e r mil) i n M g-ri c h p h a s e s a r e e x p e ct e d t o 4 5 8

b e o b s e r v e d if M g i s ot o pi c e x c h a n g e o c c u r r e d ( e. g., P o d o s e k et al., 1 9 9 1; M a c P h e r s o n et 4 5 9

al., 2 0 1 2) . M o r e o v e r, c o n t r a r y t o t y pi c al A O A s, a n o rt hi t e i n G 9 2 i s t h e p r e d o mi n a nt 4 6 0

p h a s e a n d i s n ot al w a y s a s s o ci at e d wi t h s pi n el , m e a ni n g t h at c o m pl et e r e s et ti n g of t h e 4 6 1

a n o rt hi t e 2 6 Al -2 6 M g s y st e m ati c s b y i s ot o pi c e x c h a n g e wi t h M g -ri c h p h a s e s w o ul d 4 6 2

p r o b a bl y t a k e m u c h l o n g e r. I n c o n t r a s t, e x c h a n g e wi t h a n 1 6 O- p o o r a m bi e n t g a s w o ul d 4 6 3

h a v e eff e cti v el y o c c u r r e d b e c a u s e of t h e fi n e -g r ai n e d t e xt u r e i n t hi s C A I. 4 6 4

A s a n al t e r n ati v e t o t h e l o w e x c e s s- 2 6 M g i n G 9 2 a n o rt hi t e b ei n g d u e t o s oli d -4 6 5

s t at e e x c h a n g e -i n d u c e d r e s etti n g, a m o r e li k el y p o s si bili t y i s t h at G 9 2 o ri gi n all y f o r m e d 4 6 6

a s a fi n e-g r ai n e d m elili t e -ri c h C A I , a n d t h at t h e a n o rt hi t e r e pl a c e d t h e m elili t e aft e r 4 6 7

m o s t of t h e 2 6 Al d e c a y e d. T hi s i d e a p r e s u p p o s e s t h at t h e o c c u r r e n c e of l o w δ 2 6 M g * i n 4 6 8

a n o rt hi t e -ri c h C A I G 9 2 i s n ot a c oi n ci d e n c e, b u t i s i n s t e a d t h e r e s ul t of l at e r hi g h 4 6 9

t e m p e r at u r e p r o c e s s i n t h e s ol a r n e b ul a. R e pl a c e m e n t of m elili t e b y a n o rt hi t e c o ul d h a v e 4 7 0

o c c u r r e d b y i n t e r a cti o n wi t h t h e a m bi e n t g a s : C a 2 Al 2 Si O 7 ( G e hl e ni t e) + 3 Si O( g) + M g( g) 4 7 1

+ 4 H 2 O( g) → C a Al 2 Si 2 O 8 ( a n o rt hi t e) + C a M g Si2 O 6 ( di o p si d e) + 4 H2 ( g) ( K r ot et al., 2 0 0 4 b), 4 7 2

o r u n d e r a n o xi di zi n g e n vi r o n m e n t, a s t h e f oll o wi n g r e a cti o n: C a 2 Al 2 Si O 7 + Si O( g) + 4 7 3

H 2 O( g) + C O 2 ( g) → C aAl 2 Si 2 O 8 + C a( O H) 2 ( g) + C O( g) i s al s o p r o p o s e d ( H a s hi m ot o, 1 9 9 2). 4 7 4

E v e n t h o u g h s pi n el ( M g Al 2 O 4 ) a n d å k e r m a ni t e ( C a2 M g Si 2 O 7 ) c o ul d h a v e p a rtl y 4 7 5

c o n t ri b u t e d M g a n d Si t o p r o d u c e di o p si d e i n t h e s e r e a cti o n s, r e pl a c e m e n t of m elili t e 4 7 6

r e q ui r e s i n c o r p o r ati o n of Si O f r o m o u t si d e of t h e C A I. A s s u c h, t h e o x y g e n i s ot o p e r ati o 4 7 7

of a n o rt hi t e p r o d u c e d b y r e a cti o n m u s t h a v e b e e n aff e ct e d b y t h e o x y g e n i s ot o p e r ati o of 4 7 8

a n a m bi e n t g a s . A s s u mi n g t h e c o m p o si ti o n of t h e i ni ti al m elili t e of C A I G 9 2 w a s t h e 4 7 9

s a m e a s t h at of r e m ai ni n g m elili t e ( Å k2 0 ), a n d t h at M g w a s c o m pl et el y c o n s u m e d t o f o r m 4 8 0

di o p si d e b y r e pl a c e m e nt of m elili t e , a b u n d a n t di o p si d e ( ~ 2 0 m ol a r % of a n o rt hi t e , 4 8 1

a s s u mi n g g e hl e ni t e : å k e r m a ni t e = a n o rt hi t e : di o p si d e = 4 : 1 ) w o ul d h a v e f o r m e d wi t h 4 8 2

a n o rt hi t e . Si n c e s u b -µ m hi g h -C a p y r o x e n e i n cl u si o n s i n a n o rt hi t e a n d s m all a n d 4 8 3

i r r e g ul a r-s h a p e d Al -Ti -ri c h di o p si d e g r ai n s a r e a b u n d a n t i n t h e i n t e ri o r of C A I G 9 2 ( Fi g. 4 8 4

2 b), t h e y m a y h a v e f o r m e d b y r e pl a c e m e n t of m elili t e . H o w e v e r, d u e t o t h e li mi t ati o n of 4 8 5

a n al y si s s p ot si z e b y S I M S ( ~ 3µ m i n si z e f o r O i s ot o p e a n al y s e s a n d ~ 1 0 µ m f o r M g i s ot o p e 4 8 6

a n al y s e s of M g -ri c h p h a s e s) , w e c o ul d n ot p e rf o r m i s ot o p e a n al y s e s of s u b -µ m di o p si d e 4 8 7

i n cl u si o n s, n o r c o ul d w e a n al y z e t h e o u t e r m o s t m a r gi n of di o p si d e, i n o r d e r t o i n v e s ti g at e 4 8 8

if t h ei r c h a ra ct e ri s ti c s w e r e e s t a bli s h e d d u ri n g t h e r e pl a c e m e n t of m elili t e. Wi t h r e g a r d 4 8 9

t o a n o rt hi t e, v e r y lo w M g c o n c e n t r ati o n s of a n o rt hi t e i n G 9 2, a s w ell a s t h o s e of t h e t hi n 4 9 0

a n o rt hi t e l a y e r i n G 1 6 (2 7 Al/ 2 4 M g = 7 0 0 t o 1 5 6 0, 0. 0 3 t o 0. 0 1 5 wt. % M g O ), s u g g e s t th at t h e 4 9 1

f o r m ati o n p r o c e s s of a n o rt hi t e i n t h e s e C A I s w a s diff e r e n t t h a n t h at of i g n e o u s a n o rt hi t e 4 9 2

i n t y p e B C A I s (t y pi c all y 2 7 Al/ 2 4 M g = 1 0 0 t o 6 0 0, 0. 2 3 t o 0. 0 4 wt. % , e. g., P o d o s e k et al., 4 9 3

1 9 9 1; G o s w a mi et al., 1 9 9 4; M a ki d e et al., 2 0 0 9; Ki t a et al., 2 0 1 2). I n a d di ti o n, t h e 4 9 4

a b s e n c e of a n o m al o u sl y hi g h δ 2 6 M g * a m o n g G 9 2 M g -ri c h p h a s e s i s c o n si st e n t wi t h t h e 4 9 5

r e pl a c e m e n t of m elili t e b y a n o rt hi t e , aft e r m o s t 2 6 Al h a d d e c a y e d . If G 9 2 a n o rt hit e 4 9 6

i ni ti all y f o r m e d wi t h t h e c a n o ni c al a b u n d a n c e of t h e s h o rt -li v e d n u cli d e 2 6 Al, f oll o w e d b y 4 9 7

l at e r M g i s ot o pi c e x c h a n g e, a n o c c u r r e n c e of a n o m al o u sl y hi g h δ 2 6 M g * (i. e. a b o v e t h e 4 9 8

c a n o ni c al i s o c h r o n ) w o ul d b e e x p e ct e d i n M g -ri c h p h a s e s s u c h a s s pi n el, Al -Ti -ri c h 4 9 9

di o p si d e, a n d m elili t e ( e. g., P o d o s e k et al., 1 9 9 1; M a c P h e r s o n et al., 20 1 2 ). I n s t e a d, if 5 0 0

a n o rt hi t e f o r m e d b y r e pl a c i n g p ri m a r y m elili t e aft e r t h e d e c a y of m o s t 2 6 Al, i t mi g h t h a v e 5 0 1

i n h e ri t e d t h e 2 6 M g -e x c ess of pr e c urs or m elilit e ( e. g., δ 2 6 M g * : ~ 3‰, Fi g s. 6 g a n d 6 h) . I n t hi s 5 0 2

c a s e, t h e sl o p e of t h e r e g r e s si o n li n e u si n g a n o rt hi t e a n d m elili t e d at a r e p r e s e n t s t h e 5 0 3

(2 6 Al/ 2 7 Al) 0 w h e n a n o rt hi t e f o r m e d . A n ot h e r p o s si bili t y i s t h at G 9 2 an o rt hi t e h a d n o 5 0 4

2 6 M g - e x c e s s w h e n i t i ni ti all y f o r m e d, b e c a u s e i t i n c o r p o r at e d M g f r o m t h e a m bi e n t g a s . 5 0 5

I f t hi s i s t h e c a s e , t h e r e g r e s si o n li n e t h r o u g h t h e o ri gi n u si n g a n o rt hi t e d at a w o ul d b e 5 0 6

a p p r o p ri at e , a s w ell a s i t s c o r r e s p o n di n g i nf e r r e d (2 6 Al/ 2 7 Al) 0 , ~ 5. 5 × 1 0 − 6 , w hi c h is sli g htl y 5 0 7

hi g h er t h a n t h e i nf e r r e d (2 6 Al/ 2 7 Al) 0 of 5. 2 1 × 1 0 − 6 w h e n u si n g a n o r thi t e a n d m elili t e d at a . 5 0 8

H e r e w e a s s u m e t h at Al w a s a b s e n t f r o m t h e a m bi e n t n e b ul a r g a s b e c a u s e of i t s hi g hl y 5 0 9

r ef r a ct o r y n at u r e ( e. g., L o d d e r s, 2 0 0 3). R e g a r dl e s s of w h et h e r o r n ot G 9 2 a n o rt hi t e 5 1 0

i ni ti all y i n h e ri t e d 2 6 M g -e x c ess fr o m m elilit e, 2 6 Al w o ul d h a v e b e e n s u p pli e d f r o m t h e 5 1 1

r e a ct e d p ri m a r y m elil i t e. A s s u mi n g t hi s f o r m ati o n m e c h a ni s m i s c o r r e ct, t h e 2 6 Al -2 6 M g 5 1 2

s y s t e m ati c s of G 9 2 a n o rt hi t e a n d m elili t e , w h o s e d at a a r e di s t ri b u t e d al o n g a si n gl e 5 1 3

r e g r e s si o n li n e ( M S W D = 0. 9 5, Fi g. 6 h) , c a n b e u s e d t o d e d u c e t h e ti m e i n t e r v al b et w e e n 5 1 4

t h e C A I f o r m ati o n a n d t h e l at e r f o r m ati o n of a n o rt hi t e. 5 1 5

T h e i nf e r r e d ( 2 6 Al/ 2 7 Al) 0 , ( 5. 2 1 ± 0. 5 4) × 1 0− 6 , of G 9 2 a n o rt hi t e i n di c at e s f o r m ati o n 5 1 6

2 . 3 M a aft e r C A I s ( Fi g. 7 ). T hi s r e s ul t c oi n ci d e s wi t h t h e ti mi n g of c h o n d r ul e f o r m ati o n 5 1 7

a m o n g o r di n a r y a n d c a r b o n a c e o u s c h o n d ri t e s ( e. g., Ki t a a n d U s hi k u b o, 2 0 1 2; U s hi k u b o 5 1 8

et al., 2 0 1 3). A s si mil a r a g e s a r e al s o o b s e r v e d i n C A I -c h o n d r ul e c o m p o u n d o bj e ct s i n C R 5 1 9

c h o n d ri t e s (( 2 6 Al/ 2 7 Al) 0 of < 2 × 1 0 − 6 t o ( 3. 8 ± 1. 3) × 1 0 − 6 , M a ki d e et al., 2 0 0 9), e n e r g eti c e v e n t s 5 2 0

i n t h e s ol a r n e b ul a t h at i m p o s e d i g n e o u s a n d m et a m o r p hi c p r o c e s s e s a m o n g C A I s a n d 5 2 1

c h o n d r ul e s a r e i nf e r r e d t o h a v e o c c u r r e d a t 2 – 3 M a aft e r c a n o ni c al C A I f o r m ati o n . 5 2 2

R e g a r di n g c h o n d r ul e f o r m ati o n, i t i s i nf e r r e d t h at t h e e n vi r o n m e n t w a s 1 6 O- p o o r r el ati v e 5 2 3

t o t h e e n vi r o n m e n t w h e r e r ef r a ct o r y i n cl u si o n s f o r m e d, a s o x y g e n i s ot o p e r ati o s of 5 2 4

c h o n d r ul e s a r e t y pi c all y ∆ 1 7 O = − 6 t o 2 ‰ ( C o n n oll y a n d H u s s, 2 0 1 0; Ki t a et al., 2 0 1 0; K r ot 5 2 5

et al., 2 0 1 0 b; R u d r a s w a mi et al., 2 0 1 1; W ei s b e r g et al., 2 0 1 1; N a k a s hi m a et al., 2 0 1 2; 5 2 6

U s hi k u b o et al., 2 0 1 2; S c h r a d e r et al., 2 0 1 3, 2 0 1 4; T e n n e r et al., 2 0 1 3, 2 0 1 5) . T hi s 5 2 7

i nf e r e n c e i s al s o s u p p o rt e d b y c h a r a ct e ri s ti c s of C A I -c h o n d r ul e c o m p o u n d o bj e ct s, a s 5 2 8

t h ei r 1 6 O- ri c h C A I -li k e d o m ai n s a r e e n cl o s e d b y 1 6 O- p o o r f e r r o m a g n e si a n mi n e r al s 5 2 9

( M a ki d e et al., 2 0 0 9). I n c o n t r a s t, C A I G 9 2 d o e s n ot c o n t ai n 1 6 O- p o o r f e r r o m a g n e si a n 5 3 0

p h a s e s ( oli vi n e a n d l o w -C a p y r o x e n e) o r F e -Ni m et al ( Fi g. 2 b) . T h u s, e v e n t h o u g h G 9 2 5 3 1

a n o rt hi t e h a s a si mil a r i nf e r r e d (2 6 Al/ 2 7 Al) 0 a s c h o n d r ul e s, i t diff e r s f r o m c h o n d r ul e s a n d 5 3 2

C A I -c h o n d r ul e c o m p o u n d o bj e ct s. C o m bi n e d, t h e s e c h a r a ct e ri s ti c s of C A I G 9 2 i n di c at e 5 3 3

t h e e xi s t e n c e of a n 1 6 O- ri c h e n vi r o n m e n t ( ∆ 1 7 O ~ − 2 3 ‰, Fi g s. 4 g a n d 7) t h at w a s d e v oi d of 5 3 4

1 6 O- p o o r f e r r o m a g n e si a n d u s t , a p p r o xi m at el y 2 – 3 M a aft e r C A I f o r m ati o n. 5 3 5

A c o n c ei v a bl e s c e n a ri o i s t h at G 9 2 a n o rt hi t e f o r m e d at t h e i n n e r e d g e of t h e 5 3 6

s ol a r n e b ul a , w h e r e a m bi e n t g a s m a y s till h a v e b e e n 1 6 O- ri c h 2 – 3 M a aft e r C A I 5 3 7

f o r m ati o n s ( p o s si bl y b e c a u s e t hi s r e gi o n i s c l o s e t o t h e S u n, t h e p r e d o mi n a n t r e s e r v oi r 5 3 8

of 1 6 O- ri c h s ol a r g a s). T h e n, f oll o wi n g t h e f o r m ati o n of a n o rt hi t e, C A I G 9 2 c o ul d h a v e 5 3 9

b e e n t r a n sf e r r e d t o t h e o u t e r a s t e r oi d b el t. H o w e v e r, t hi s s c e n a ri o s e e m s u nli k el y 5 4 0

b e c a u s e ( 1) i t w o ul d h a v e b e e n diffi c ul t t o a v oi d a n y r e p r o c e s si n g u n til ~ 2 M a aft e r C A I s 5 4 1

if G 9 2 r e m ai n e d cl o s e t o t h e S u n o v e r t h at ti m e i n t e r v al; a n d ( 2) o u t w a r d m a s s tr a n s p o rt 5 4 2

w a s li k el y i n s uffi ci e n t ~ 2 M a aft e r C A I s ( Ci e sl a, 2 0 1 0; J a c q u et, 2 0 1 3). 5 4 3

Al t e r n ati v el y, a m o r e pl a u si bl e s c e n a ri o i s t h at G 9 2 a n o rt hi t e f o r m e d at a l a r g e 5 4 4

v e rti c al di s t a n c e r el ati v e t o t h e c h o n d r ul e -f o r mi n g mi d -pl a n e of t h e p r ot o pl a n et a r y di s k. 5 4 5

H e r e, i t i s a s s u m e d ( 1) a n 1 6 O- ri c h g a s w o ul d h a v e b e e n a m aj o r o x y g e n i s ot o pi c 5 4 6

c o m p o n e n t , b e c a u s e i t h a s b e e n u bi q ui t o u sl y p r e s e n t t h r o u g h o u t t h e hi s t o r y of t h e S ol a r 5 4 7

S y s t e m ; a n d ( 2) t h e mi d-pl a n e of t h e p r ot o pl a n et a r y di s k w a s d o mi n at e d b y 1 6 O- p o o r 5 4 8

sili c at e d u s t ( e. g., T e n n e r et al., 2 0 1 5) a n d e a rl y S ol a r S y s t e m H 2 O i c e ( e. g., S a k a m ot o et 5 4 9

al., 2 0 0 7), p a r ti c ul a rl y aft e r c o oli n g of t h e s ol a r n e b ul a a n d wi t h r e d u c e d t u r b ul e n t fl o w. 5 5 0

T h e f o r m e r a s s u m p ti o n i s p o s si bl e w h e n c o n si d e ri n g t h at t h e p r e s e n t s ol a r wi n d i s 1 6 O-5 5 1

ri c h ( ∆ 1 7 O = − 2 8. 4 ± 1. 8 ‰, M c K e e g a n et al., 2 0 1 1). T h e l att e r i s v ali d b e c a u s e hi g h d u s t t o 5 5 2

g a s r ati o s ( e. g. E b el a n d G r o s s m a n, 2 0 0 0; Al e x a n d e r 2 0 0 4 ), a s w ell a s e n h a n c e m e n t of 5 5 3

H 2 O i c e ( e. g., F e d ki n a n d G r o s s m a n, 2 0 0 6; 2 0 1 6) , w e r e li k el y n e c e s s a r y t o c r e at e a n 5 5 4

e n vi r o n m e n t o xi di z e d e n o u g h t o f o r m t h e c h o n d r ul e a s s e m bl a g e. T h e s ettli n g of 1 6 O- p o o r 5 5 5

H 2 O i c e a n d d u s t t o w a r d t h e mi d -pl a n e of t h e p r ot o pl a n et a r y di s k w o ul d h a v e c a u s e d a 5 5 6

v e rti c al o x y g e n i s ot o pi c g r a di e n t i n t h e p r ot o pl a n et a r y di s k ( e. g., Y u ri m ot o et al., 2 0 0 7) 5 5 7

at t h e ti m e of c h o n d r ul e f o r m ati o n s . U n d e r s u c h a n e n vi r o n m e n t, p r o d u ct s of hi g h -5 5 8

t e m p e r at u r e p r o c e s s e s w o ul d h a v e diff e r e n t o x y g e n i s ot o p e r ati o s a s a f u n cti o n of t h ei r 5 5 9

v e rti c al di s t a n c e f r o m t h e mi d -pl a n e. F o r e x a m pl e, T e n n e r et al. ( 2 0 1 5) d e m o n s t r at e d 5 6 0

t h at v a ri a bl e a d di ti o n s of 1 6 O- p o o r d u s t a n d H 2 O i c e (∆ 1 7 O ~ − 6 ‰ a n d + 5 ‰, r e s p e cti v el y) 5 6 1

t o 1 6 O- ri c h g a s ( ∆ 1 7 O ~ − 2 8. 4 ‰) c a n e x pl ai n t h e o b s e r v e d ∆ 1 7 O – M g # t r e n d a m o n g 5 6 2

f e r r o m a g n e si a n sili c at e s i n c a r b o n a c e o u s c h o n d ri t e c h o n d r ul e s. A s s u c h, m at e ri al s t h at 5 6 3

f o r m e d v e rti c all y f a r f r o m t h e mi d-pl a n e c o ul d h a v e b e e n e n ri c h e d i n 1 6 O, b e c a u s e s u c h 5 6 4

a r e gi o n w o ul d h a v e b e e n d e pl et e d i n 1 6 O- p o o r d u s t a n d H 2 O i c e, a n d t h e r ef o r e w o ul d 5 6 5

h a v e b e e n d o mi n at e d b y 1 6 O- ri c h g a s. W e n ot e t h at l a r g e sili c at e p a rti cl e s li k e C A I G 9 2 5 6 6

( a f e w h u n d r e d µ m i n si z e ) m u s t h a v e b e e n r a r e at a v e rti c all y di s t a n t pl a c e f r o m t h e 5 6 7

mi d -pl a n e aft e r t h e s ettli n g of d u s t s t o t h e mi d -pl a n e ( e. g., Ci e sl a, 2 0 0 9; J a c q u et, 2 0 1 3). 5 6 8

It i s m o r e f a v o r a bl e t h at m u c h s m all e r r ef r a ct o r y i n cl u si o n s w o ul d p r e v ail at l a r g e 5 6 9

v e rti c al di s t a n c e f r o m t h e mi d -pl a n e. A s s u c h, s m all r ef r a ct o r y i n cl u si o n m a y h a v e a 5 7 0

hi g h e r li k eli h o o d of s h o wi n g e vi d e n c e f o r r e -h e ati n g e v e n t s i n a n 1 6 O- ri c h e n vi r o n m e n t . 5 7 1

C o n si d e ri n g t h e p r e v al e n c e of c h o n d r ul e s i n u n e q uili b r at e d c h o n d ri t e s ( 2 0-8 0 5 7 2

v ol u m e p e r c e n t; S c ott et al., 1 9 9 6) , i t i s e vi d e n t t h at o n e o r m o r e p e r v a si v e p r o c e s s e s 5 7 3

p r o d u c e d sili c at e m el t s ~ 2 M a aft e r C A I s, a n d s e v e r al m e c h a ni s m s t h at h a v e b e e n 5 7 4

p r o p o s e d f o r t h ei r f o r m ati o n ( s e e Ci e sl a, 2 0 0 5; D e s c h et al., 2 0 1 2 f o r r e vi e w) . As s u mi n g 5 7 5

t h e e n e r g y s o u r c e of G 9 2 a n o rt hi t e f o r m ati o n w a s si mil a r t o t h at w hi c h f o r m e d 5 7 6

c h o n d r ul e s, a v e rti c all y di s t a n t l o c ati o n f r o m t h e mi d -pl a n e of t h e p r ot o pl a n et a r y di s k 5 7 7

s e e m s a m o r e a p p r o p ri at e si t e t h a n t h e i n n e r e d g e of t h e s ol a r n e b ul a t o e x pl ai n b ot h a 5 7 8

y o u n g e r a n o rt hi t e f o r m ati o n a g e ( ~2 M a aft e r C A I s) a n d t h e l a ck of a c c u m ul at e d 5 7 9

f e r r o m a g n e si a n p h a s e s. 5 8 0

5 8 1

5. 3. 5. 3. 1 61 6 OO --ri c h ri c h d u s t d u s t c o m p o n e n t a n d c o r r el ati o n li n e sc o m p o n e n t a n d c o r r el ati o n li n e s 5 8 2

Fi n e -g r ai n e d C A I s a n d A O A s f o r m e d b y a g g r e g ati o n of p ri m a r y c o n d e n s at e s 5 8 3

f r o m e a rl y s ol a r n e b ul a r g a s, a n d t h e y a v oi d e d r e -m el ti n g b y a l at e r h e ati n g e v e n t i n t h e 5 8 4

s ol a r n e b ul a. Th e li mi t e d r a n g e of δ 2 5 M g D S M 3 v al u e s a m o n g t h e fi n e -g r ai n e d r ef r a ct o r y 5 8 5

i n cl u si o n s s t u di e d ( − 0. 4 t o 1. 3‰ ) s u p p o rt s t hi s i d e a. T h u s, w e s u g g e s t t h at fi n e -g r ai n e d 5 8 6

C A I s a n d A O A s f r o m t y p e 3. 0 0-3. 0 5 c h o n d ri t e s a r e t h e b e s t c a n di d at e s f o r r e c o r di n g 5 8 7

p ri s ti n e o x y g e n i s ot o p e r ati o s of e a rl y s ol a r s y s t e m c o n d e n s at e s. 5 8 8

Fi g u r e 8 s h o w s a v e r a g e d o x y g e n i s ot o p e r ati o s of i n di vi d u al r ef r a ct o r y 5 8 9

i n cl u si o n s ( Fi g.8 a) , a s w ell a s t h o s e f r o m A O A f o r st e ri t e a n d Al-Ti -ri c h di o p si d e ( Fi g. 8 b, 5 9 0

s e e al s o T a bl e 2) o bt ai n e d u si n g a hi g h i n t e n si t y p ri m a r y b e a m ( s m all b e a m d at a a r e 5 9 1

o nl y u s e d t o c al c ul at e a v e r a g e d v al u e s of i n di vi d u al s a m pl e s, d u e t o t h ei r l a r g e 5 9 2

u n c e rt ai n t i e s). T h e o x y g e n i s ot o p e r ati o s of fi n e -g r ai n e d A cf e r 0 9 4 a n d Y -8 1 0 2 0 5 9 3

r ef r a ct o r y i n cl u si o n s a r e ti g h tl y di s t ri b u t e d b et w e e n t h e C C A M li n e ( Cl a yt o n et al., 1 9 7 7) 5 9 4

a n d t h e P C M r e g r e s si o n li n e d efi n e d b a s e d o n oli vi n e a n d l o w -C a p y r o x e n e d at a f r o m 5 9 5

A cf e r 0 9 4 c h o n d r ul e s ( U s hi k u b o et al., 2 0 1 2). D e vi ati o n s i n a v e r a g e d δ 1 8 O v al u e s f r o m 5 9 6

t h e C C A M li n e, r el ati v e t o t h e m a s s - d e p e n d e n t i s ot o p e f r a cti o n ati o n t r e n d 5 9 7

(δ 1 7 O = 0. 5 2 × δ 1 8 O) , r a n g e f r o m − 0. 6‰ (C A I G 1 6) t o + 1. 9 ‰ (C A I G 5) , wi t h a n a v e r a g e v al u e 5 9 8

of + 0. 6 ‰ . T h e s e r e s ul t s i n di c at e t h at o x y g e n i s ot o p e r ati o s of p ri s ti n e C A I p r e c u r s o r 5 9 9

d u s t s w e r e di s t ri b u t e d al o n g t h e C C A M li n e , o r, at m o s t, w e r e ~ 1 ‰ t o t h e ri g h t of t h e 6 0 0

C C A M li n e. N ot e t h at w e c a n n ot p r e ci s el y d et e r mi n e t h e o x y g e n i s ot o p e r ati o of t h e 6 0 1

p ri m o r di al n e b ul a r g a s f r o m fi n e -g r ai n e d r ef r a ct o r y i n cl u si o n d at a b e c a u s e t h e d e g r e e of 6 0 2

e q uili b r i u m o x y g e n i s ot o p e f r a cti o n ati o n b et w e e n g a s a n d d u s t c a n v a r y a s a f u n cti o n of 6 0 3

t e m p e r at u r e a n d g a s c o m p o si ti o n ( e. g., δ 1 8 O v al u e of oli vi n e c o ul d b e 2 t o 3 ‰ li g h t e r t h a n 6 0 4

t h at of a m bi e n t g a s, Cl a yt o n et al., 1 9 9 1; Ki t a et al., 2 0 1 0) . R e g a r di n g t h e P C M li n e 6 0 5

( U s hi k u b o et al., 2 0 1 2) a n d i t s u n c e rt ai n t y ( ~ ± 0. 7 ‰), i t i s i n di s ti n g ui s h a bl e f r o m t h e 6 0 6

A cf e r 0 9 4 a n d Y -8 1 0 2 0 r ef r a ct o r y i n cl u si o n d at a. T hi s i s a n i m p o rt a n t c o n si d e r ati o n f o r 6 0 7

t w o r e a s o n s. Fi r s t, i t i n di c at e s t h at A cf e r 0 9 4 c h o n d r ul e s a n d r ef r a ct o r y i n cl u s i o n s 6 0 8

r e p r e s e n t a c o n si s t e n t mi xi n g li n e of e a rl y S ol a r S y s t e m m at e ri al s. S e c o n d, a n d wi t h 6 0 9

r e s p e ct t o r eli ct oli vi n e g r ai n s i n A cf e r 0 9 4 c h o n d r ul e s, t h e m o s t 1 6 O- ri c h e x a m pl e s h a v e 6 1 0

o x y g e n i s ot o p e r ati o t h at a r e i n di s ti n g ui s h a bl e f r o m A cf e r 0 9 4 r ef r a ct o r y i n cl u si o n d at a 6 1 1

( Fi g. 9). T hi s o v e rl a p i s c o n si s t e n t wi t h t h e i d e a t h at 1 6 O- ri c h r eli ct oli vi n e d e ri v e d f r o m 6 1 2

r ef r a ct o r y i n cl u si o n r el at e d m at e ri al ( e. g., A O A, oli vi n e i n t h e a c c r eti o n a r y ri m of C A I s). 6 1 3

B e y o n d li n ki n g A cf e r 0 9 4 c h o n d r ul e s a n d r ef r a ct o r y i n cl u si o n s t o g et h e r , t h e 6 1 4

P C M li n e c a r ri e s wi t h i t ot h e r i m p o rt a n t c h a r a ct e ri s ti c s. F o r e x a m pl e, o x y g e n i s ot o p e 6 1 5

d at a f r o m e xt r e m el y 1 6 O- p o o r A cf e r 0 9 4 c o s mi c s y m pl e cti t e s ( S a k a m ot o et al., 2 0 0 7; S et o 6 1 6

et al., 2 0 0 8) pl ot o n t h e P C M li n e ( Fi g. 9). Th e P C M li n e al s o i n t e r s e ct s wi t h t h e 6 1 7

t e r r e s t ri al f r a cti o n ati o n ( T F) li n e at δ 1 8 O = 5. 8 ± 0. 4 ‰ ( U s hi k u b o et al., 2 0 1 2), w hi c h i s i n 6 1 8

a g r e e m e n t wi t h t h e t e r r e s t ri al m a n tl e v al u e (δ 1 8 O = 5. 5 ± 0. 2 ‰; Eil er, 2 0 0 1 ). T a ki n g all of 6 1 9

t h e s e t hi n g s i n t o c o n si d e r ati o n, i t i s a p p a r e n t t h at m o s t p ri m a r y m at e ri al s f r o m 6 2 0

c a r b o n a c e o u s c h o n d ri t e s e x p e ri e n c e d v e r y li ttl e m a s s -d e p e n d e n t o x y g e n i s ot o p e 6 2 1

f r a cti o n ati o n. F u rt h e r, if all of t h e af o r e m e n ti o n e d m at e ri al s wi t hi n A cf e r 0 9 4 a r e i n d e e d 6 2 2

r el at e d, i t s u g g e s t s t h at 1 6 O- ri c h n e b ul a r g a s a n d 1 6 O- p o o r ( o r 1 7, 1 8 O- ri c h) p ri m o r di al 6 2 3

v ol atil e s r e p r e s e n t e n d m e m b e r s of a li n e a r t r e n d (i. e., t h e P C M li n e) wi t h a m a s s -6 2 4

i n d e p e n d e n t f r a cti o n at e d sl o p e of ~ 1. 0. 6 2 5

6 2 6

6. C o n cl u si o n s6. C o n cl u si o n s 6 2 7

O x y g e n i s ot o p e r ati o s a n d 2 6 Al -2 6 M g i s ot o p e s y s t e m ati c s of m ul ti pl e p h a s e s i n 6 2 8

r ef r a ct o r y i n cl u si o n s ( 5 s pi n el -m elili t e -ri c h C A I s , 1 p y r o x e n e-a n o rt hi t e -ri c h C A I, a n d 4 6 2 9

A O A s ) f r o m t h e l e a s t m et a m o r p h o s e d c a r b o n a c e o u s c h o n d ri t e s, A cf e r 0 9 4 ( C-u n g r o u p e d 6 3 0

3. 0 0) a n d Y -8 1 0 2 0 ( C O 3. 0 5) , w e r e i n v e s ti g at e d. 6 3 1

All s a m pl e s h a v e 1 6 O- ri c h si g n at u r e s b u t e x hi bi t s u btl e a n d d et e ct a bl e 6 3 2

v a ri a bili t i e s i n o x y g e n i s ot o p e r ati o s a m o n g i n di vi d u al r ef r a ct o r y i n cl u si o n s 6 3 3

(∆ 1 7 O = − 2 2. 0 ± 0. 5 ‰ t o − 2 4. 3 ± 0. 3 ‰ ). T hi s i n di c at e s sli g h t o x y g e n i s ot o p e v a ri ati o n s of 6 3 4

e a rl y s ol a r n e b ul a r g a s w h e r e r ef r a ct o r y i n cl u si o n s f o r m e d. 6 3 5

Wi t hi n a n al yti c al u n c e rt ai n ti e s, o x y g e n i s ot o p e r ati o s of ri m s pi n el a n d di o p si d e 6 3 6

m at c h t h o s e of i n t e ri o r p h a s e s i n e a c h C A I. I n a d di ti o n, n o a p p a r e n t m a s s -d e p e n d e nt 6 3 7

i s ot o pi c f r a cti o n ati o n i s o b s e r v e d i n O a n d M g i sot o p e r ati o s of ri m p h a s e s . T h e s e 6 3 8

o b s e r v ati o n s d o n ot a g r e e wi t h fl a s h h e ati n g a n d e v a p o r ati v e l o s s of r el ati v el y v ol atil e 6 3 9

el e m e n t s d u ri n g ri m f o r m ati o n. I n s t e a d, o u r r e s ul t s s u g g e s t t h at c o n d e n s ati o n a n d 6 4 0

a g g r e g ati o n of i n t e ri o r p h a s e s , a s w ell a s t h e f o r m ati o n of C A I ri m s t r u ct u r e s, o c c u r r e d 6 4 1

i n t h e s a m e e n vi r o n m e n t. 6 4 2

I nf e r r e d i ni ti al 2 6 Al/ 2 7 Al r ati o s of s pi n el -m elili t e -ri c h C A I s (( 4. 0 8 ± 0. 7 5) × 1 0 − 5 t o 6 4 3

( 5. 0 5 ± 0. 1 8) × 1 0− 5 ) a r e sli g h tl y l o w e r t h a n t h e c a n o ni c al v al u e of 5. 2 5 × 1 0 − 5 . A s m o st 6 4 4

s pi n el -m elili t e -ri c h C A I s h a v e n o p et r ol o gi c e vi d e n c e f o r r e-m el ti n g aft e r c o n d e n s ati o n, 6 4 5

t h e o b s e r v e d l o w e r i ni ti al 2 6 Al/ 2 7 Al r ati o s i n di c at e ei t h e r c o n d e n s ati o n of r ef r a ct o r y 6 4 6

p h a s e s o c c u r r e d u p t o ~ 0. 3 M a aft e r c a n o ni c al C A I s o r t h e y f o r m e d b ef o r e 2 6 Al w a s 6 4 7

h o m o g e n e o u sl y di s t ri b u t e d i n t h e S ol a r n e b ul a . 6 4 8

A p y r o x e n e -a n o rt hi t e -ri c h C A I, G 9 2, h a s a n 1 6 O- ri c h si g n at u r e 6 4 9

(∆ 1 7 O = − 2 3. 3 ± 0. 3 ‰ ), li k e ot h e r C A I s. H o w e v e r, t h e r el ati v el y l o w ( 2 6 Al/ 2 7 Al) 0 of G 9 2 6 5 0

a n o rt hi t e (( 5. 2 1 ± 0. 5 4) × 1 0− 6 ), i n di c at e s i t f o r m e d b y a r e a cti o n b et w e e n p ri m a r y m elili t e 6 5 1

a n d 1 6 O- ri c h n e b ul a r g a s a p p r o xi m at el y 2. 3 M a aft e r C A I f o r m ati o n. T h e o x y g e n a n d 6 5 2

m a g n e si u m i s ot o p e si g n at u r e s s u g g e s t t h e e xi s t e n c e of 1 6 O- ri c h g a s i n a n e n vi r o n m e n t 6 5 3

d e v oi d of f e r r o m a g n e si a n d u s t. T hi s e n vi r o n m e n t w a s p r e s e n t d u ri n g t h e ti mi n g of 6 5 4

c h o n d r ul e f o r m ati o n. 6 5 5

Fi n all y, a v e r a g e d o x y g e n i s ot o p e r ati o s of r ef r a ct o r y i n cl u si o n s a r e di s t ri b u t e d 6 5 6

al o n g t h e C C A M li n e a n d t h e P C M li n e , w hi c h i s t h e r e g r e s si o n li n e b a s e d o n o x y g e n 6 5 7

i s ot o p e d at a f r o m A cf e r 0 9 4 c h o n d r ul e s . Si n c e t h e P C M li n e al s o o v e rl a p s wi t h o x y g e n 6 5 8

i s ot o p e d at a of e xt r e m el y 1 6 O- p o o r c o s mi c s y m pl e cti t e s ( ∆ 1 7 O ~ 8 3 ‰ ), t h e li n e a r 6 5 9

r el ati o n s hi p a m o n g t h e s e m at e ri al s i s i n t e r p r et e d t o r e p r e s e n t mi xi n g of t w o e n d m e m b e r 6 6 0

c o m p o n e n t s i n t h e s ol a r n e b ul a: t h at of 1 6 O- ri c h s ol a r n e b ul a r g a s, a n d t h at of e xt r e m el y 6 6 1

1 6 O- p o o r ( o r 1 7, 1 8 O- ri c h) p ri m o r di al v ol atil e s . 6 6 2

6 6 3

A c k n o wl e d g e m e n tA c k n o wl e d g e m e n t ss 6 6 4

W e t h a n k J o h n W. V all e y a n d Mi c h a el J. S pi c u z z a f o r o x y g e n i s ot o p e a n al y s e s of 6 6 5

s t a n d a r d s b y a l a s e r fl u o ri n ati o n a n d g a s -s o u r c e m a s s s p e ct r o m et r y, J o h n F o u r n ell e f o r 6 6 6

a s si s t a n c e wi t h E P M A a n al y si s , a n d Ji m K e r n f o r t e c h ni c al a s si s t a n c e wi t h S I M S 6 6 7

operation. We are grateful to Dr. K. Nagashima, an anonymous reviewer, and the 668 associate editor Dr. A. N. Krot for constructive review comments and suggestions. This 669 work is supported by the NASA Cosmochemis try program (NNX07AI46G, NNX11AG62G , 670 NTK). WiscSIMS is partly supported by NSF (EAR03 -19230, EAR07- 44079, EAR10-671 53466). 672

Figure caption s 673 Figure 1 : Backscattered electron images of spinel- melilite-rich CAI s (a) G5, (b) G16, (c) 674 G49, (d) G104, (e) Y81020 -E-8, and enlarged views of (f) a large nodule in G16, (g) a small 675 nodule in G16, (h) the melilite-rich interior of G104, and (i) the spinel layer in Y81020 -676 E-8. Scale bars indicate 100 µ m for (a) to (e), 50 µm for (f) to (h ), and 20 µm for ( i), 677 respectively. Abbreviations: mel=melilite, sp=spinel, an=anorthite, di=(Al -Ti-rich) 678 diopside, ol=olivine, and pv=perovskite 679 680 Figure 2 : Backscattered electron images of (a) diopside-anorthite-rich CAI G92, and (b) 681 enlarged view of G92 . Scale bars indicate 100 µm for (a) and 50 µm for (b), respectively . 682 Abbreviations are same as Fig.1. 683 684 Figure 3 : Backscattered electron images of AOAs (a) G17, ( b) G28, ( c) G44, (d ) G58 , and 685 enlarged views of (e) anorthite -free Ca -, Al -rich domain in G17, (f) anorthite -bearing Ca- , 686 Al-rich d omains in G44 . Scale bars indicate 100 µm for (a) to (d) and 50 µm for (e) and 687 (f), respectively . Abbreviations are the same as in Fig.1 688 689 Figure 4: Oxygen three -isotope diagrams . A ll the measured data in this study are shown 690 in (a). A dotted rectangle at the lower left in (a) indicates the upper limit of the ranges of 691 the enlarged views, (b) to (k). Diagrams from individual spinel- melilite-rich CAIs (sp-mel 692 CAIs) include Y81020-E-8 (b), G5 (c), G16 (d), G49 (e), G104 (f). G92 (g) is a pyroxene-693 anorthite-rich CAI (px-an CAI) . AOAs include G17 (h), G28 (i), G44 (j), G58 (k). Reference 694 lines are Terrestrial F ractionation (TF, continuous line in (a) ), Carbonaceous Chondrite 695 Anhydrous Mineral (CCAM , dashed line), Primitive Chondrule Mineral (PCM, solid line), 696 and Young and Russell (Y&R , gray solid line). Errors are 95% confidence . 697 698 Figure 5 : Comparison of (a) ∆17O and (b) δ 18OVSMOW values between averaged values of 699 individual CAIs and their rim s. CAIs data are shown in ascending order of average ∆ 17O 700 values. Errors are 95% confidence. 701 702 Figure 6: 26Al-26Mg isotope systematics of (a) Y81020-E-8 , (b) G5, (c) G49, (d) and (e) G16, 703 (f) G104, (g) and (h) G92, (i) G17. Inferred ( 26Al/27Al)0 values are shown. Formulae of 704 individual regression lines are provided in Table 2. Similar scale s of X and Y axes are 705 applied to each plot for proper comparisons of slope s from individual regression lines . 706 Errors are 95% confidence. 707 708

Figure 7: (26Al/27Al)0 vs. ∆17O of the samples (CAIs and AOA) studied. Filled gray circles 709 are data from five spinel- melilite-rich CAIs G5, G16, G49, G104, and Y -81020-E-8. Open 710 squares are data from AOAs G17, G28, G44, and G58. Two filled black circles represent 711 (26Al/27Al)0 values of the diopside -melilite (5.2 ×10−5) and the melilite -anorthite (5.2 ×10−6) 712 systems in CAI G92 . Chondrule data from Acfer 094 reported by [1] Ushikubo et al. 713 (2012) and [2] Ushikubo et al. ( 2013) are also shown for comparison . Vertical dotted line 714 indicates the canonical value of ( 26Al/27Al)0 (5.25×10−5). Errors are 95% confidence. 715 716 Figure 8: Oxygen three -isotope plots of (a) average values of individual CAIs and AOAs 717 and (b) individual AOA analyses with a large primary beam and multiple -FC detectors. 718 Errors are 95% confidence. 719 720 Figure 9: Oxygen three -isotope plots of refractory inclusions (averaged values of CAIs 721 and AOAs, this study), chondrules (averaged values and individual relict olivine data, 722 Ushikubo et al., 2012), and cosmic symplectites (spot analysis data of COS, Sakamoto et 723 al., 2007) from Acfer 094. Four reference lines are same as Fig . 4. 724

R ef e r e n c e sR ef e r e n c e s :: 7 2 5

Al e x a n d e r C. M. O’ D. ( 2 0 0 4) C h e mi c al e q uili b ri u m a n d ki n eti c c o n s t r ai n t s f o r c h o n d r ul e 7 2 6

a n d C A I f o r m ati o n c o n diti o n s. G e o c hi m. C o s m o c hi m. A ct a 6 86 8 , 3 9 4 3-3 9 6 9. 7 2 7

7 2 8

B o d é n a n J. -D., St a r k e y N. A., R u s s ell S. S., Wri g h t I. P., a n d F r a n c hi I. A. ( 2 0 1 4) A n 7 2 9

o x y g e n i s ot o p e s t u d y of W a r k -L o v e ri n g ri m s o n t y p e A C A I s i n p ri mi ti v e c a r b o n a c e o u s 7 3 0

c h o n d ri t e s. E a rt h Pl a n et. S ci. L ett. 4 0 14 0 1 , 32 7 -3 3 6. 7 3 1

7 3 2

Ci e sl a F. J. ( 2 0 0 5) C h o n d r ul e -f o r mi n g p r o c e s s e s – A n o v e r vi e w. I n C h o n d ri t e s a n d t h e 7 3 3

p r ot o pl a n et a r y di s k. A S P C o nf e r e n c e S e ri e s, V ol. 3 4 1 ( e d s. A. N. K r ot, E. R. D. S c ott, a n d 7 3 4

B. R ei p u rt h). A s t r o n o mi c al S o ci et y of t h e P a cifi c, S a n F r a n ci s c o, p p. 8 1 1 -8 2 0. 7 3 5

7 3 6

Ci e sl a F. J. ( 2 0 0 9) T w o -di m e n si o n al t r a n s p o rt of s oli d s i n vi s c o u s p r ot o pl a n et a r y di s k s. 7 3 7

I c a r u s , 2 0 02 0 0 , 6 5 5-6 7 1. 7 3 8

7 3 9

Ci e sl a F. J. ( 2 0 1 0) T h e di s t ri b u ti o n s a n d a g e s of r ef r a ct o r y o bj e ct s i n t h e s ol a r n e b ul a. 7 4 0

I c a r u s 2 0 82 0 8 , 4 5 5-4 6 7. 7 4 1

7 4 2

Cl a yt o n R. N. ( 2 0 0 3) O x y g e n i s ot o p e s i n m et e o ri t e s. I n Tr e ati s e o n G e o c h e mi s t r y 1 , 7 4 3

M et e o ri t e s, C o m et s, a n d Pl a n et s ( e d. A. M. D a vi s). El s e vi e r -P e r g a m o n, O xf o r d, p p. 1 2 9 -7 4 4

1 4 2. 7 4 5

7 4 6

Cl a yt o n R. N. a n d M a y e d a T. K. ( 1 9 7 7) C o r r el at e d o x y g e n a n d m a g n e si u m i s ot o p e 7 4 7

a n o m ali e s i n All e n d e i n cl u si o n s, I: O x y g e n. G e o p h y s. R e s. L ett. 44 , 2 9 5-2 9 8. 7 4 8

7 4 9

Cl a yt o n R. N., M a y e d a T. K., G o s w a mi J. N., a n d Ol s e n E. J. ( 1 9 9 1) O x y g e n i s ot o p e 7 5 0

s t u di e s of o r di n a r y c h o n d ri t e s. G e o c hi m. C o s m o c hi m. A ct a 5 55 5 , 2 3 1 7-2 3 3 7. 7 5 1

7 5 2

Cl a yt o n R. N., M a y e d a T. K., H u t c h e o n I. D., M oli ni -V el s k o C., O n u m a N., I k e d a Y., a n d 7 5 3

Ol s e n E. J. ( 1 9 8 3) O x y g e n i s ot o pi c c o m p o si ti o n s of c h o n d r ul e s i n All e n d e a n d o r di n a r y 7 5 4

c h o n d ri t e s. I n C h o n d r ul e s a n d t h ei r o ri gi n s ( e d. E. A. Ki n g). L u n a r Pl a n et. I n s t., H o u s t o n, 7 5 5

T X, p p. 3 7 -4 3. 7 5 6

7 5 7

Cl a yt o n R. N., O n u m a N., G r o s s m a n L., a n d M a y e d a T. K. ( 1 9 7 7) Di s t ri b u ti o n of t h e p r e -7 5 8

s ol a r c o m p o n e n t i n All e n d e a n d ot h e r c a r b o n a c e o u s c h o n d ri t e s. E a rt h Pl a n et. S ci. L ett. 7 5 9

3 43 4 , 2 0 9-2 2 4. 7 6 0

761 Connolly Jr. H. C. and Huss G. R. (2010) Compositional evolution of the protoplanetary 762 disk: Oxygen isotopes of type -II chondrules from CR2 chondrites. Geochim. Cosmochim. 763 Acta 74, 2473- 2483. 764 765 Desch S. J., M orris M. A., Connolly Jr. H. C., and Boss A. P. (2012) The importance of 766 experiments: Constraints on chondrule formation models. Meteorit. Planet. Sci. 47, 1139-767 1156. 768 769 Ebel D. S. and Grossman L. (2000) Condensation in dust -enriched systems. Geochim. 770 Cosmochim. Acta 64, 339 -366. 771 772 Eiler J. M. (2001) Oxygen isotope variations of basaltic lavas and upper mantle rocks. In 773 Reviews in mineralogy and geochemistry 43, Stable isotope geochemistry (Eds. J. W. 774 Valley, D. R. Cole). The mineralogical society of America, Washington DC, pp.319 -364. 775 776 Fedkin A. V. and Grossman L. (2006) The fayalite con tent of chondritic olivine: Obstacle 777 to understanding the condensation of rocky material. In Meteorites and the Early Solar 778 System II (eds. D. S. Lauretta and H. Y. McSween). Univ. of Arizona Press, Tucson, pp. 779 279-294. 780 781 Fedkin A. V. and Grossman L. (2016) Effects of dust enrichment on oxygen fugacity of 782 cosmic gases. Meteorit. Planet. Sci. 51, 843-850. 783 784 Fagan T. J., Guan Y., and MacPherson G. J. (2007) Al -Mg isotopic evidence for episodic 785 alteration of Ca -Al-rich inclusions from Allende. Meteorit. Pl anet. Sci. 42, 1221- 1240. 786 787 Fagan T. J., Krot A. N., Keil K., and Yurimoto H. (2004) Oxygen isotopic evolution of 788 amoeboid olivine aggregates in the reduced CV3 chondrites Efremovka, Vigarano, and 789 Leoville. Geochim. Cosmochim. Acta 68, 2591- 2611. 790 791 Goswami J. N., Srinivasan G., and Ulyanov A. A. (1994) Ion microprobe studies of 792 Efremovka CAIs: I. Magnesium isotope composition. Geochim. Cosmochim. Acta 58, 431-793 447. 794 795 Gounelle M., Krot A. N., Hagashima K., and Kearsley A. (2009) Extreme 16O enrichment 796

i n c al ci u m-al u mi n u m -ri c h i n cl u si o n s f r o m t h e I s h e y e v o ( C H/ C B) c h o n d rit e. A s t r o p h y s. 7 9 7

J. 6 9 86 9 8 , L 1 8 -L 2 2 . 7 9 8

7 9 9

G r e s h a k e A. ( 1 9 9 7) T h e p ri mi ti v e m at ri x c o m p o n e n t s of t h e u ni q u e c a r b o n a c e o u s 8 0 0

c h o n d ri t e A cf e r 0 9 4: A T E M s t u d y. G e o c hi m. C o s m o c hi m. A ct a 6 16 1 , 4 3 7-4 5 2. 8 0 1

8 0 2

G r o s s m a n L. ( 1 9 7 2) C o n d e n s ati o n i n t h e p ri mi ti v e s ol a r n e b ul a. G e o c hi m. C o s m o c hi m. 8 0 3

A ct a 3 63 6 , 5 9 7-6 1 9. 8 0 4

8 0 5

G r o s s m a n J. N. a n d B r e a rl e y A. J. ( 2 0 0 5) T h e o n s et of m et a m o r p hi s m i n o r di n a r y a n d 8 0 6

c a r b o n a c e o u s c h o n d ri t e s. M et e o ri t. Pl a n et. S ci. 4 04 0 , 8 7-1 2 2. 8 0 7

8 0 8

G r o s s m a n L. a n d G a n a p at h y R. ( 1 9 7 6) Tr a c e el e m e n t s i n t h e All e n d e m et e o ri t e– I I. Fi n e -8 0 9

g r ai n e d, C a -ri c h i n cl u si o n s. G e o c hi m. C o s m o c hi m. A ct a 4 04 0 , 9 6 7-9 7 7. 8 1 0

8 1 1

G r o s s m a n L., Si m o n S. B., R ai V. K., T hi e m e n s M. H., H u t c h e o n I. D., Willi a m s R. W., 8 1 2

G al y A., Di n g T., F e d ki n A. V., Cl a yt o n R. N., M a y e d a T. K. ( 2 0 0 8) P ri m o r di al 8 1 3

c o m p o si ti o n s of r ef r a ct o r y i n cl u si o n s. G e o c hi m. C o s m o c hi m. A ct a 7 27 2 , 3 0 0 1-3 0 2 1. 8 1 4

8 1 5

G r o s s m a n L. a n d St e el e I. M. ( 1 9 7 6) A m o e b oi d oli vi n e a g g r e g at e s i n t h e All e n d e 8 1 6

m et e o ri t e. G e o c hi m. C o s m o c hi m. A ct a 4 04 0 , 1 4 9-1 5 5. 8 1 7

8 1 8

H a s hi m ot o A. ( 1 9 9 2) T h e eff e ct of H 2 O g a s o n v ol atili ti e s of pl a n et -f o r mi n g m aj o r 8 1 9

el e m e n t s: I. E x p e ri m e n t al d et e r mi n ati o n of t h e r m o d y n a mi c p r o p e rti e s of C a -, Al-, a nd 8 2 0

Si -h y d r o xi d e g a s m ol e c ul e s a n d i t s a p pli c ati o n t o t h e s ol a r n e b ul a. G e o c hi m. C o s m o c hi m. 8 2 1

A ct a 5 65 6 , 5 1 1-5 3 2. 8 2 2

8 2 3

H e c k P. R., U s hi k u b o T., S c h mi t z B., Ki t a N. T., S pi c u z z a M. J., a n d V all e y J. W. ( 2 0 1 0) 8 2 4

A si n gl e a s t e r oi d al s o u r c e f o r e xt r at e r r e s t ri al O r d o vi ci a n c h r o mi t e g r ai n s f r o m S w e d e n 8 2 5

a n d C hi n a: Hi g h -p r e ci si o n o x y g e n t h r e e -i s ot o p e S I M S a n al y si s. G e o c hi m. C o s m o c hi m. 8 2 6

A ct a 7 47 4 , 4 9 7-5 0 9. 8 2 7

8 2 8

Hi y a g o n H., a n d H a s hi m ot o A. ( 1 9 9 9) 1 6 O E x c e s s e s i n Oli vi n e I n cl u si o n s i n Y a m at o -8 2 9

8 6 0 0 9 a n d M u r c hi s o n C h o n d ri t e s a n d T h ei r R el ati o n t o C A I s. S ci e n c e 2 8 32 8 3 , 8 2 8-8 3 1. 8 3 0

8 3 1

H s u W., W a s s e r b u r g G. J., H u s s G. R. ( 2 0 0 0) Hi g h ti m e r e s ol u ti o n b y u s e of t h e 2 6 Al 8 3 2

chronometer in the multistage formation of a CA I. Earth Planet Sci. Lett. 182, 15 -29. 833 834 Hutcheon I. D., Marhas K. K., Krot A. N., Goswami J. N., and Jones R. H. (2009) 26Al in 835 plagioclase-rich chondrules in carbonaceous chondrites: Evidence for an extended 836 duration of chondrule formation. Geochim. Cosmo chim. Acta 73, 5080-5099. 837 838 Jacobsen B., Han J. M., Matzel J. E., Brearley A. J., Hutcheon I. D. (2014) Oxygen 839 isotopes in Fine -grained spinel- pyroxene and melilite -rich CAIs in the ALHA 77307 840 CO3.0 carbonaceous chondrite. Lunar Planet. Sci. XLV . #2789 (abs tr.). 841 842 Jacobsen B., Yin Q. -Z., Moyner F., Amelin Y., Krot A. N., Nagashima K., Hutcheon I. D., 843 Palme H. (2008) 26Al-26Mg and 207Pb-206Pb systematics of Allende CAIs: Canonical solar 844 initial 26Al/27Al ratio reinstated. Earth Planet Sci. Lett. 272, 353- 364. 845 846 Jacquet E. (2013) On vertical variations of gas flow in protoplanetary disks and their 847 impact on the transport of solids. Astron. Astrophys. 551, A75. 848 849 Kawasaki N., Kato C., Itoh S., Wakaki S., Ito M., and Yurimoto H. (2015) 26Al- 26Mg 850 chronology and oxyge n isotope disturbance of multiple melting for a type C CAI from 851 Allende. Geochim. Cosmochim. Acta 169, 99 -114. 852 853 Kimura M., Grossman J. N., and Weisberg M. K. (2008) Fe- Ni metal in primitive 854 chondrites: Indicators f classification and metamorphic conditions for ordinary and CO 855 chondrites. Meteorit. Planet. Sci. 43, 1161 -1177. 856 857 Kita N. T., Nagahara H., Tachibana S., Tomomura S., Spicuzza M. J., Fournelle J. H., 858 Valley J. W. (2010) High precision SIMS oxygen three isotope study of chondrules in LL3 859 chondrites: Role of ambient gas during chondrule formation. Geochim. Cosmochim. Acta 860 74, 6610- 6635. 861 862 Kita N. T., and Ushikubo T. (2012) Evolution of protoplanetary disk inferred from 26Al 863 chronology of individual chondrules. Meteorit. Planet. Sci. 47, 1108- 1119. 864 865 Kita N. T., Ushikubo T., Fu B., and Valley J. W. (2009) High precision SIMS oxygen 866 isotope analysis and the effect of sample topography. Chem. Geol. 264, 43 -57. 867 868

Ki t a N. T., U s hi k u b o T., K ni g h t K. B., M e n d y b a e v R. A., D a vi s A. M., Ri c ht e r F. M., a n d 8 6 9

F o u r n e ll e J. H. ( 2 0 1 2) I n t e r n al 2 6 Al -2 6 M g i s ot o p e s y s t e m ati c s of a T y p e B C A I: R e m el ti n g 8 7 0

of r ef r a ct o r y p r e c u r s o r s oli d s. G e o c hi m. C o s m o c hi m. A ct a 8 68 6 , 3 7-5 1. 8 7 1

8 7 2

Ki t a N. T., Yi n Q. -Z., M a c P h e r s o n G. J., U s hi k u b o T., J a c o b s e n B., N a g a s hi m a K., 8 7 3

K u r a h a s hi E., K r ot A. N., J a c o b s e n S. B. ( 2 0 1 3) 2 6 Al -2 6 M g i s ot o p e s y s t e m ati c s of t h e fi r s t 8 7 4

s oli d s i n t h e e a rl y s ol a r s y s t e m. M et e o ri t. Pl a n et. S ci. 4 84 8 , 1 3 8 3-1 4 0 0. 8 7 5

8 7 6

K o b a y a s hi S., I m ai H., a n d Y u ri m ot o H. ( 2 0 0 3) N e w e xt r e m e 1 6 O- ri c h r e s e r v oi r i n t h e 8 7 7

e a rl y s ol a r s y s t e m. G e o c h e m. J. 3 73 7 , 6 6 3-6 6 9. 8 7 8

8 7 9

K ö ö p L., N a k a s hi m a D., H e c k P. R., Ki t a N. T., T e n n e r T. J., K r ot A. N., N a g a s hi m a K., 8 8 0

P a r k C., a n d D a vi s A. M. ( 2 0 1 6 ) N e w c o n s t r ai n t s o n t h e r el ati o n s hi p b et w e e n 2 6 Al a n d 8 8 1

o x y g e n, c al c ui m, a n d tit a ni u m i s ot o pi c v a ri ati o n i n t h e e a rl y S ol a r S y s t e m f r o m a 8 8 2

m ul ti el e m e n t i s ot o pi s s t u d y of s pi n el -hi b o ni t e i n cl u si o n s. G e o c hi m. C o s m o c hi m. A ct a 8 8 3

1 8 41 8 4 , 1 5 1 -1 7 2 . 8 8 4

8 8 5

K r ot A. N., C h a u s si d o n M., Y u ri m ot o H., S a k a m ot o N., N a g a s hi m a K., H u t c h e o n I. D., 8 8 6

a n d M a c P h e r s o n G. J. ( 2 0 0 8) O x y g e n i s ot o pi c c o m p o si ti o n s of All e n d e t y p e C C A I s: 8 8 7

E vi d e n c e f o r i s ot o pi c e x c h a n g e d u ri n g n e b ul a r m el ti n g a n d a s t e ri o d al m et a m o r p hi s m. 8 8 8

G e o c hi m. C o s m o c hi m. A ct a 7 27 2 , 2 5 3 4-2 5 5 5. 8 8 9

8 9 0

K r ot A. N., F a g a n T. J., K eil K., M c K e e g a n K. D., S a hij p al S. H u t c h e o n I. D., P et a e v M. 8 9 1

I., a n d Y u ri m ot o H. ( 2 0 0 4 a ) C a, Al -ri c h i n cl u si o n s, a m o e b oi d oli vi n e a g g r e g at e s, a n d Al -8 9 2

ri c h c h o n d r ul e s f r o m t h e u ni q u e c a r b o n a c e o u s c h o n d ri t e A cf e r 0 9 4: I. Mi n e r al o g y a n d 8 9 3

p et r ol o g y. G e o c hi m. C o s m o c hi m. A ct a 6 86 8 , 2 1 6 7-2 1 8 4. 8 9 4

8 9 5

K r ot A. N., M a c P h e r s o n G. J., Ul y a n o v A. A., a n d P et a e v M. I. ( 2 0 0 4 b ) Fi n e-g r ai n e d, 8 9 6

s pi n el -ri c h i n cl u si o n s f r o m t h e r e d u c e d C V c h o n d ri t e s Ef r e m o v k a a n d L e o vill e: I. 8 9 7

Mi n e r al o g y, p et r ol o g y, a n d b ul k c h e mi s t r y. M et e o ri t. Pl a n et. S ci. 3 93 9 , 1 5 1 7-1 5 5 3. 8 9 8

8 9 9

K r ot A. N., M c K e e g a n K. D., L e s hi n L. A., M a c P h e r s o n G. J., S c ott E. R. D. ( 2 0 0 2) 9 0 0

E xi s t e n c e of a n 1 6 O- ri c h g a s e o u s r e s e r v oi r i n t h e s ol a r n e b ul a. S ci e n c e , 2 9 52 9 5 , 1 0 5 1-1 0 5 4. 9 0 1

9 0 2

K r ot A. N., N a g a s hi m a K., Ci e sl a F. J., M e y e r B. S., H u t c h e o n I. D., D a vi s A. M., H u s s 9 0 3

G. R., a n d S c ott E. R. D. ( 2 0 1 0 a ) O x y g e n i s ot o pi c c o m p o si ti o n of t h e S u n a n d m e a n o x y g e n 9 0 4

isotopic composition of the protosolar silicate dust: Evidence from refractory inclusions. 905 Astrophys. J. 713, 1159 -1166. 906 907 Krot A. N., Nagashima K., van Kooten E. M. M. E., and Bizzarro M. (2016) High -908 temperature rims around calcium -aluminum-rich inclusions from the CR, CB, and CH 909 carbonaceous chondrites. Lunar Planet. Sci. XLV II. # 1203 (abstr.). 910 911 Krot A. N., Nagashima K., Yoshitake M., and Yurimoto H. (2010b) Oxygen isotopic 912 compositions of chondrules from the metal -rich chondrites isheyevo (CH/CB b), MAC 913 02675 (CB b) and QUE 94627 (CB b). Geochim. Cosmochim. Acta 74, 2190- 2211. 914 915 Krot A. N., Nagashima K., Wasserburg G. J., Huss G. R., Papanastassiou D., Davis A. 916 M., Hutcheon I. D., Bizzarro M. (2014a ) Calcium -aluminum-rich inclusions with 917 fractionation and unknown nuclear effects (FUN CAIs): I. Mineralogy, petrology, and 918 oxygen isotopic compositions. Geochim. Cosmochim. Acta 145, 206 -247. 919 920 Krot A. N., Park C., and Nagashima K. (2014b) Amoeboid olivine aggregates from CH 921 carbonaceous chondrites. Geochim. Cosmochim. Acta 139, 131- 153. 922 923 Kunihiro T., Rubin A. E., McKeegan K. D., Wasson J. T. (2004) Initial 26Al/27Al in 924 carbonaceous-chondrite chondrules: Too little 26Al to melt asteroids. Geochim. 925 Cosmochim. Acta 68, 2947- 2957. 926 927 Kurahashi E., Kita N. T., Nagahara H., and Morishita Y. (2008) 26Al-26Mg systematics of 928 chondrules in a primitive CO chondrite. Geochim. Cosmochim. Acta 72, 3865- 3882. 929 930 Larsen K. K., Trinquier A., Paton C., Schiller M., Wielandt D., Ivanova M. A., Connelly 931 J. N., Nordlund Å., Krot A. N., Bizzarro M. (2011) Evidence for magnesium isotope 932 heterogeneity in the solar protoplanetary disk. Astropys. J. Lett. 735, L37 (7pp). 933 934 Lodders K. (2003) Solar system abundances and condensation temperatures of the 935 elements. Astrophys. J. 591, 1220- 1247. 936 937 MacPherson G. J., Kita N. T., Ushikubo T., Bullock E. S., and Davis A. M. (2012) Well -938 resolved variations in the formation ages for Ca -Al-rich inclusions in the early Solar 939 System. Earth Planet Sci. Lett. 331-332, 43 -54. 940

941 Makide K., Nagashima K., Krot A. N., Huss G. R., Hutcheon I. D., and Bischoff A. (2009) 942 Oxygen- and magnesium -isotope compositions of calcium -aluminum-rich inclusions fro m 943 CR2 carbonaceous chondrites. Geochim. Cosmochim. Acta 73, 5018- 5050. 944 945 McKeegan K. D., Kallio A. P. A., Heber V. S., Jarzebinski G., Mao P. H., Coath C. D., 946 Kunihiro T., Wiens R. C., Nordholt J. E., Moses Jr. R. W., Resenfeld D. B., Jurewicz A. J. 947 G., and Burnett D. S. (2011) The Oxygen Isotopic Composition of the Sun Inferred from 948 Captured Solar Wind. Science 332, 1528- 1532. 949 950 Nakamura T., Noguchi T., Tsuchiyama A., Ushikubo T., Kita N. T., Valley J. W., Zolensky 951 M. E., Kakazu Y., Sakamoto K., Mashio E., U esugi K., and Nakano T. (2008) 952 Chondrulelike Objects in Short -Period Comet 81P/Wild 2. Science 321, 1664 -1667. 953 954 Nakashima D., Ushikubo T., Joswiak D. J., Brownlee D. E., Matrajt G., Weisberg M. K., 955 Zolensky M. E., and Kita N. T. (2012) Oxygen isotopes in crystalline silicates of comet 956 Wild 2: A comparison of oxygen isotope systematics between Wild 2 particles and 957 chondritic materials. Earth Planet. Sci. Lett. 357-358, 355- 365. 958 959 Podosek F. A., Zinner E. K., MacPherson G. J., Lundberg L. L., Brannon J. C., Fahey A. 960 J. (1991) Correlated study of initial 87Sr/86Sr and Al -Mg isotopic systematics and 961 petrologic properties in a suite of refractory inclusions fr om the Allende meteorite. 962 Geochim. Cosmochim. Acta 55, 1083- 1110. 963 964 Rudraswami N. G., Ushikubo T., Nakashima D., and Kita N. T. (2011) Oxygen isotope 965 systematics of chondrules in the Allende CV3 chondrite: High precision ion microprobe 966 studies. Geochim. Cosmochim. Acta 75, 7596- 7611. 967 968 Sakamoto N., Set o Y., Itoh S., Kuramoto K., Fujino K., Nagashima K., Krot A. N., 969 Yurimoto H. (2007) Remnants of the early solar system water enriched in hea vy oxygen 970 isotopes. Science, 317, 231 -233. 971 972 Schrader D. L., Connolly Jr. H. C., Lauretta D. S., Nagashima K., Huss G. R., Davidson 973 J., Domanik K. J. (2013) The formation and alteration of the Renazzo -like carbonaceous 974 chondrites II: Linking O -isotope composition and oxidation state of chondrule olivine. 975 Geochim. Cosmochim. Acta 101, 302- 327. 976

977 Schrader D. L., Nagashima K., Krot A. N., Ogliore R. C., and Hellebrand E. (2014) 978 Variations in the O -isotope composition of gas during the formation of chondrules from 979 the CR chondrites. Geochim. Cosmochim. Acta 132, 50 -74. 980 981 Scott E. R. D., Love S. G., and Krot A. N. (1996) Formation of chondrules and chondrites 982 in the protoplanetary nebula. In Chondrules and the Protoplanetary Disk (eds. R. H. 983 Hewins, R. Jones, and E. R. D. Scott). Cambridge Univ. Press, Cambridge, pp. 87- 96. 984 985 Seto Y., Sakamoto N., Fujino K. Kaito T., Oikawa T., and Yurimoto H. (2008) 986 Mineralogical characterization of a unique material having heavy oxygen isotope 987 anomaly in matrix of the primitive carbonaceous chondrite Acfer 094. Geochim. 988 Cosmochim. Acta 72, 2723- 2734. 989 990 Simon J. I., Matzel J. E. P., Simon S. B., Hutcheon I. D., Ross D. K., Weber P. K., and 991 Grossman L. (2016) Oxygen isotopic variations in the outer margins and Wark -Lovering 992 rims of refractory inclusions. Geochim. Cosmochim. Acta 186, 2 42-276. 993 994 Simon J . I., Hutcheon I. D., Simon S. B., Matzel J. E. P., Ramon E. C., Weber P. K., 995 Grossman L., and DePaolo D. J. (2011) Oxygen isotope variations at the margin of a CAI 996 records circulation within the solar nebula. Science 331, 1175 -1178. 997 998 Tenner T. J., Nakashima D., Ushikubo T., Kita N. T., and Weisberg M. K. (2015) Oxygen 999 isotope ratios of FeO -poor chondrules in CR3 chondrites: Influence of dust enrichment 1000 and H 2O during chondrule formation. Geochim. Cosmochim. Acta 148, 228- 250. 1001 1002 Tenner T. J., Ushikubo T., Ku rahashi E., Kita N. T., and Nagahara H. (2013) Oxygen 1003 isotope systematics of chondrule phenocrysts from the CO3.0 chondrite Yamato 81020: 1004 Evidence for two distinct oxygen isotope reservoirs. Geochim. Cosmochim. Acta 102, 226 -1005 245. 1006 1007 Ushikubo T., Guan Y., Hiyagon H., Sugiura N., and Les hin L. A. (2007) 36Cl, 26Al, and O 1008 isotopes in an Allende type B2 CAI: Implications for multiple secondary alteration events 1009 in the early solar system. Meteorit. Planet. Sci. 42, 1267- 1279. 1010 1011 Ushikubo T., Kimura M., Kita N. T., and Valley J. W. (2012) Primordial oxygen isotope 1012

r e s e r v oi r s of t h e s ol a r n e b ul a r e c o r d e d i n c h o n d r ul e s i n A cf e r 0 9 4 c a r b o n a c e o u s c h o n d ri t e. 1 0 1 3

G e o c hi m. C o s m o c hi m. A ct a 9 09 0 , 2 4 2-2 6 4. 1 0 1 4

1 0 1 5

U s hi k u b o T., N a k a s hi m a D., Ki m u r a M., T e n n e r T. J., a n d Ki t a N. T. ( 2 0 1 3) 1 0 1 6

C o n t e m p o r a n e o u s f o r m ati o n of c h o n d r ul e s i n di s ti n ct o x y g e n i s ot o p e r e s e r v oi r s. 1 0 1 7

G e o c hi m. C o s m o c hi m. A ct a 1 0 91 0 9 , 2 8 0-2 9 5. 1 0 1 8

1 0 1 9

W a n g J., D a vi s A. M., Cl a yt o n R. N., M a y e d a T. K., H a s hi m ot o A. ( 2 0 0 1) C h e mi c al a n d 1 0 2 0

i s ot o pi c f r a cti o n ati o n d u ri n g t h e e v a p o r ati o n of t h e F e O-M g O -Si O 2 -C a O -Al 2 O 3 -Ti O 2 r a r e 1 0 2 1

e a rt h el e m e n t m el t s y s t e m. G e o c hi m. C o s m o c hi m. A ct a 6 56 5 , 4 7 9-4 9 4. 1 0 2 2

1 0 2 3

W a r k D., a n d B o y n t o n W. V. ( 2 0 0 1) T h e f o r m ati o n of ri m s o n c al ci u m -al u mi n u m -ri c h 1 0 2 4

i ncl u si o n s: St e p I – Fl as h h e ati n g. M et e o ri t. Pl a n et. S ci. 3 63 6 , 1 1 3 5-1 1 6 6. 1 0 2 5

1 0 2 6

W a r k D. A. a n d L o v e ri n g J. F. ( 1 9 7 7) M a r k e r e v e n t s i n t h e e a rl y e v ol u ti o n of t h e s ol a r 1 0 2 7

s y s t e m: E vi d e n c e f r o m ri m s o n C a -Al -ri c h i n cl u si o n s i n c a r b o n a c e o u s c h o n d ri t e s. P r o c. 1 0 2 8

L u n a r S ci. C o nf. 88 , 9 5-1 1 2. 1 0 2 9

1 0 3 0

W a s s e r b u r g G. J., L e e T., a n d P a p a n a s t a s si o u D. A. ( 1 9 7 7) C o r r el at e d O a n d M g i s ot o pi c 1 0 3 1

a n o m ali e s i n All e n d e i n cl u si o n s: I I . Ma g n e si u m. G e o p h y s. R e s. L ett. 44 , 2 9 9-3 0 2. 1 0 3 2

1 0 3 3

W ei s b e r g M. K., E b el D. S., C o n n oll y J r. H. C., Ki t a N. T., U s hi k u b o T. ( 2 0 1 1) P et r ol o g y 1 0 3 4

a n d o x y g e n i s ot o p e c o m p o si ti o n s of c h o n d r ul e s i n E 3 c h o n d ri t e s. G e o c hi m. C o s m o c hi m. 1 0 3 5

A ct a 7 57 5 , 6 5 5 6-6 5 6 9. 1 0 3 6

1 0 3 7

Yo s hi t a k e M., K oi d e Y., a n d Y u ri m ot o H. ( 2 0 0 5) C o r r el ati o n s b et w e e n o x y g e n-i s ot o pi c 1 0 3 8

c o m p o si ti o n a n d p et r ol o gi c s etti n g i n a c o a r s e -g r ai n e d C a, Al -ri c h i n cl u si o n. G e o c hi m. 1 0 3 9

C o s m o c hi m. A ct a 6 96 9 , 2 6 6 3-2 6 7 4. 1 0 4 0

1 0 4 1

Y u ri m ot o H., It o M. , a n d N a g a s a w a H. ( 1 9 9 8) O x y g e n i s ot o p e e x c h a n g e b et w e e n 1 0 4 2

r ef r a ct o r y in cl u si o n i n All e n d e a n d S ol a r N e b ul a g a s. S ci e n c e 2 8 22 8 2 , 1 8 7 4-1 8 7 7. 1 0 4 3

1 0 4 4

Y u ri m ot o H., K u r a m ot o K., K r ot A. N., S c ott E. R. D., C u z zi J. N., T hi e m e n s M. H., L y o n s 1 0 4 5

J. R. ( 2 0 0 7) O ri gi n a n d e v ol u ti o n of o x y g e n i s ot o pi c c o m p o si ti o n s of t h e S ol a r S y s t e m. I n 1 0 4 6

P r ot o s t a r s a n d pl a n et s V ( e d s. B. R ei p u rt h, D. J e wi tt, K. K eil). T h e U ni v e r sit y of A ri z o n a 1 0 4 7

p r e s s, T u s c o n, A Z, p p. 8 4 9 -8 6 2. 1 0 4 8

Figure 1

100µm

(e) Y81020-E-8

50µm

(f)pvsp

mel

meldi

sp

100µm

(a) G5 mel

sp

di 100µm

(b) G16 meldi

100µm

(c) G49mel

di

100µm

(d) G104

mel

disp

pv

50µm

(g)

an

mel

diol

(h)

50µmsp

mel

dipv

20µm

(i) sp

mel

di

pv

100µm

(a) G92

50µm

(b)

Figure 2

sp

melan

di

Figure 3

100µm

(a) G17

100µm

(b) G28

100µm

(c) G28

100µm

(d) G58

50µm

(e) spdi ol

50µm

(f) an

ol

spdi

Figure 4

(k) G58(AOA)

-38

-40

-42

-46

-48

-50-52

-44

δ17 O

VSMOW

-38-40-42-44-46-48-50-52δ18OVSMOW

(i) G28(AOA)

-38

-40

-42

-46

-48

-50-52

-44

δ17 O

VSMOW

-38-40-42-44-46-48-50-52δ18OVSMOW

(j) G44(AOA)

-38

-40

-42

-46

-48

-50-52

-44

δ17 O

VSMOW

-38-40-42-44-46-48-50-52δ18OVSMOW

(c) G5(sp-mel CAI)

-38

-40

-42

-46

-48

-50-52

-44

δ17 O

VSMOW

-38-40-42-44-46-48-50-52δ18OVSMOW

rim

(d) G16(sp-mel CAI)

-38

-40

-42

-46

-48

-50-52

-44

δ17 O

VSMOW

-38-40-42-44-46-48-50-52δ18OVSMOW

rim

(e) G49(sp-mel CAI)

-38

-40

-42

-46

-48

-50-52

-44

δ17 O

VSMOW

-38-40-42-44-46-48-50-52δ18OVSMOW

rim

(f) G104(sp-mel CAI)

-38

-40

-42

-46

-48

-50-52

-44

δ17 O

VSMOW

-38-40-42-44-46-48-50-52δ18OVSMOW

rim

(g) G92(px-an CAI)

-38

-40

-42

-46

-48

-50-52

-44

δ17 O

VSMOW

-38-40-42-44-46-48-50-52δ18OVSMOW

rim

CCAMPCMY&R

Pyroxene

SpinelMelilite

OlivineAnorthite

(h) G17(AOA)

-38

-40

-42

-46

-48

-50-52

-44

δ17 O

VSMOW

-38-40-42-44-46-48-50-52δ18OVSMOW

(b) Y81020-E-8(sp-mel CAI)

-38

-40

-42

-46

-48

-50-52

-44

δ17 O

VSMOW

-38-40-42-44-46-48-50-52δ18OVSMOW

rim

Rim melilite(−25.3, − 27.4)

100-10-20-30-40-50

10

0

-10

-20

-30

-40

-50

δ18OVSMOW

δ17 O

VSMOW

(a) All data

Rim melilitein Y81020-E-8

Y&R

PCM

Figure 5

G5 G104 G92 G16 G49Y81020-E-8

(a) ∆17O-20

-21

-22

-23

-24

-25

-26

-27

∆17O

(b) δ18OVSMOW

-38

-40

-42

-44

-46

-48

-50

δ18 O

VSMOW

CAI interiorRim spinelRim pyroxene

Figure 6

(a) Y81020-E-8(5.05±0.18)×10−5

0

5

10

15

δ26 M

g*

0 10 20 30 4027Al/24Mg

(d) G16(4.76±0.17)×10−5

0

5

10

15

δ26 M

g*

0 10 20 30 4027Al/24Mg

(b) G5(4.72±0.31)×10−5

0

10

20

30

δ26 M

g*

200 40 60 8027Al/24Mg

(e) G16

200

400

600

0

δ26 M

g*

1000500 20001500027Al/24Mg

(c) G49(4.08±0.75)×10−5

0

2

4

6

δ26 M

g*

0 5 10 15 2027Al/24Mg

(i) G17(5.32±0.81)×10−5

0.0

-0.2

0.5

1.0

δ26 M

g*

0 1 2 3 427Al/24Mg

(f) G104(4.53±0.21)×10−5

0 10 20 30 4027Al/24Mg

0

5

10

15

δ26 M

g*

(g) G92 Px-Mel(5.2±2.0)×10−5

0

2

4

6

δ26 M

g*

0 5 10 15 2027Al/24Mg

(h) G92 Mel -An(5.21±0.54)×10−6

200

400

600

0

δ26 M

g*

1000500 20001500027Al/24Mg

G92 Px-Melregression line

Figure 7

0

−5

−10

−15

−20

−25

∆17O

0(26Al/27Al)0

(×10−5)1 2 3 4 5 6 7

CAIsAOACAI G92Chondrules [1,2]

G92 Px -Mel G92 Mel -An

5.25×10

−5

Figure 8

-40

-42

-44

-46

-48

-50

δ17 O

VSMOW

-40-42-44-46-48-50δ18OVSMOW

(b)

ForsteriteDiopside

-40

-42

-44

-46

-48

-50

δ17 O

VSMOW

-40-42-44-46-48-50δ18OVSMOW

(a)

CAIs

CAI G92AOAs

Y&R

PCM

CCAM

Figure 9

200

150

100

50

0

-50

δ17 O

VSMOW

200150100500-50δ18OVSMOW

(b)

CAIs & AOAsChondrulesRelict olivineCOS (spot)

10

0

-10

-20

-30

-40

-50

δ17 O

VSMOW

100-10-20-30-40-50δ18OVSMOW

Y&R

CCAM

PCM

(a)

T a bl e 1: O x y g e n i s o t o p e r a ti o s o f R e f r a c t o r y I n cl u si o n s f r o m A c f e r 0 9 4.T a bl e 1: O x y g e n i s o t o p e r a ti o s o f R e f r a c t o r y I n cl u si o n s f r o m A c f e r 0 9 4.

S a m pl e/ A n al y si s # a P h a s e b δδ 1 8 O V S M O W ( 2 S E) δδ 1 7 O V S M O W ( 2 S E) ∆∆ 1 7 O ( 2 S E) N ot e

(‰‰ ) (‰‰ ) (‰‰ )

C AI s

Y 8 1 0 2 0 - E - 8Y 8 1 0 2 0 - E - 8# 6 2 S p - 4 5. 7 ± 1. 3 - 4 8. 2 ± 0. 9 - 2 4. 5 ± 0. 5

# 6 3 S p (ri m) - 4 7. 1 ± 1. 3 - 4 8. 2 ± 0. 9 - 2 3. 7 ± 0. 5

# 6 1 M el - 4 5. 9 ± 1. 3 - 4 8. 2 ± 0. 9 - 2 4. 3 ± 0. 5

# 6 6 M el - 4 7. 5 ± 1. 3 - 4 9. 4 ± 0. 9 - 2 4. 7 ± 0. 5

# 6 7 M el (ri m) - 2 5. 3 ± 1. 3 - 2 7. 4 ± 0. 9 - 1 4. 3 ± 0. 5

A v e r a g eA v e r a g e cc - 4 6. 6 ± 0. 7 - 4 8. 5 ± 0. 5 - 2 4. 3 ± 0. 3 e x cl u di n g # 6 7

G 5G 5# 7 5 F a s (ri m) - 4 4. 5 ± 3. 1 - 4 7. 6 ± 1. 0 - 2 4. 4 ± 2. 2

# 7 7 F a s (ri m) - 4 4. 8 ± 3. 1 - 4 7. 2 ± 1. 0 - 2 3. 9 ± 2. 2

# 7 2 S p - 4 5. 0 ± 3. 1 - 4 7. 7 ± 1. 0 - 2 4. 3 ± 2. 2

# 7 4 S p - 4 5. 3 ± 3. 1 - 4 7. 8 ± 1. 0 - 2 4. 3 ± 2. 2

# 7 3 M el - 4 3. 7 ± 3. 1 - 4 6. 4 ± 1. 0 - 2 3. 7 ± 2. 2

# 7 6 M el - 4 4. 9 ± 3. 1 - 4 6. 6 ± 1. 0 - 2 3. 3 ± 2. 2

A v e r a g eA v e r a g e cc - 4 4. 7 ± 1. 3 - 4 7. 2 ± 0. 4 - 2 4. 0 ± 0. 9

G 1 6G 1 6# 8 4 F a s (ri m) - 4 4. 3 ± 0. 7 - 4 6. 0 ± 1. 1 - 2 2. 9 ± 1. 3

# 8 3 M el - 4 5. 7 ± 0. 7 - 4 6. 5 ± 1. 1 - 2 2. 7 ± 1. 3

# 8 6 M el - 4 5. 3 ± 0. 7 - 4 6. 6 ± 1. 1 - 2 3. 0 ± 1. 3

# 8 7 M el - 4 5. 5 ± 0. 7 - 4 6. 8 ± 1. 1 - 2 3. 2 ± 1. 3

# 8 2 A n - 4 4. 2 ± 0. 7 - 4 6. 4 ± 1. 1 - 2 3. 4 ± 1. 3

A v e r a g eA v e r a g e cc - 4 5. 0 ± 0. 4 - 4 6. 5 ± 0. 5 - 2 3. 0 ± 0. 6

G 4 9G 4 9# 9 4 F a s - 3 9. 4 ± 0. 7 - 4 2. 5 ± 1. 0 - 2 1. 9 ± 1. 1

# 9 7 F a s (ri m) - 4 0. 6 ± 0. 7 - 4 3. 5 ± 1. 0 - 2 2. 3 ± 1. 1

# 9 3 M el - 4 1. 5 ± 0. 7 - 4 4. 1 ± 1. 0 - 2 2. 5 ± 1. 1

# 9 5 M el - 4 1. 8 ± 0. 7 - 4 3. 9 ± 1. 0 - 2 2. 2 ± 1. 1

# 9 8 M el - 4 1. 0 ± 0. 7 - 4 2. 5 ± 1. 0 - 2 1. 2 ± 1. 1

A v e r a g eA v e r a g e cc - 4 0. 9 ± 0. 4 - 4 3. 3 ± 0. 5 - 2 2. 0 ± 0. 5

G 9 2G 9 2# 1 0 5 F a s (ri m) - 4 3. 7 ± 0. 6 - 4 6. 3 ± 0. 7 - 2 3. 5 ± 0. 9

# 1 0 8 F a s (ri m) - 4 4. 6 ± 0. 6 - 4 6. 1 ± 0. 7 - 2 2. 9 ± 0. 9

# 1 1 0 F a s - 4 4. 3 ± 0. 6 - 4 6. 2 ± 0. 7 - 2 3. 1 ± 0. 9

# 1 0 6 M el - 4 5. 7 ± 0. 6 - 4 7. 7 ± 0. 7 - 2 4. 0 ± 0. 9

# 1 0 7 M el - 4 6. 3 ± 0. 6 - 4 7. 4 ± 0. 7 - 2 3. 4 ± 0. 9

# 1 0 3 A n - 4 5. 3 ± 0. 6 - 4 6. 3 ± 0. 7 - 2 2. 7 ± 0. 9

# 1 0 4 A n - 4 5. 2 ± 0. 6 - 4 7. 0 ± 0. 7 - 2 3. 5 ± 0. 9

# 1 0 9 A n - 4 5. 1 ± 0. 6 - 4 7. 1 ± 0. 7 - 2 3. 7 ± 0. 9

A v e r a g eA v e r a g e cc - 4 5. 0 ± 0. 4 - 4 6. 8 ± 0. 3 - 2 3. 3 ± 0. 3

G 1 0 4G 1 0 4# 1 1 9 F a s (ri m) - 4 4. 9 ± 1. 0 - 4 7. 1 ± 0. 8 - 2 3. 8 ± 0. 7

# 1 1 5 M el - 4 4. 7 ± 1. 0 - 4 7. 5 ± 0. 8 - 2 4. 3 ± 0. 7

# 1 1 8 M el - 4 5. 2 ± 1. 0 - 4 7. 6 ± 0. 8 - 2 4. 1 ± 0. 7

# 1 2 0 M el - 4 4. 7 ± 1. 0 - 4 5. 6 ± 0. 8 - 2 2. 3 ± 0. 7

A v e r a g eA v e r a g e cc - 4 4. 8 ± 0. 6 - 4 7. 0 ± 0. 4 - 2 3. 6 ± 0. 4

A O A sG 1 7

A O A sG 1 7# 1 2 9 F o - 4 6. 1 ± 1. 1 - 4 8. 2 ± 1. 7 - 2 4. 3 ± 1. 4

# 1 3 0 F o ( e d g e) - 4 6. 7 ± 1. 1 - 4 7. 5 ± 1. 7 - 2 3. 3 ± 1. 4

# 3 1 6 ( 2 n d s e s si o n) d F o ( e d g e) - 4 5. 5 ± 0. 3 - 4 7. 4 ± 0. 6 - 2 3. 7 ± 0. 6

# 1 2 8 F a s - 4 5. 0 ± 1. 1 - 4 7. 4 ± 1. 7 - 2 4. 0 ± 1. 4

# 1 3 1 F a s - 4 5. 4 ± 1. 1 - 4 7. 0 ± 1. 7 - 2 3. 4 ± 1. 4

# 3 1 5 ( 2 n d s e s si o n) d F a s - 4 5. 5 ± 0. 3 - 4 7. 1 ± 0. 6 - 2 3. 5 ± 0. 6

# 1 2 7 S p - 4 5. 7 ± 1. 1 - 4 7. 4 ± 1. 7 - 2 3. 7 ± 1. 4

A v e r a g eA v e r a g e cc - 4 5. 5 ± 0. 3 - 4 7. 3 ± 0. 4 - 2 3. 6 ± 0. 4

G 2 8G 2 8# 1 3 7 F o ( e d g e) - 4 6. 6 ± 0. 9 - 4 8. 3 ± 1. 6 - 2 4. 0 ± 1. 5

# 1 4 0 F o - 4 7. 4 ± 0. 9 - 4 7. 7 ± 1. 6 - 2 3. 0 ± 1. 5

# 3 1 7 ( 2 n d s e s si o n) d F o ( e d g e) - 4 6. 3 ± 0. 3 - 4 7. 8 ± 0. 6 - 2 3. 7 ± 0. 6

# 3 1 8 ( 2 n d s e s si o n) d F o ( e d g e) - 4 6. 4 ± 0. 3 - 4 8. 0 ± 0. 6 - 2 3. 9 ± 0. 6

# 1 3 8 F a s - 4 6. 6 ± 0. 9 - 4 7. 5 ± 1. 6 - 2 3. 3 ± 1. 5

# 1 4 2 F a s - 4 7. 3 ± 0. 9 - 4 8. 5 ± 1. 6 - 2 3. 9 ± 1. 5

# 1 6 3 A n - 4 5. 1 ± 0. 6 - 4 7. 9 ± 0. 9 - 2 4. 5 ± 0. 9

A v e r a g eA v e r a g e cc - 4 6. 3 ± 0. 3 - 4 7. 9 ± 0. 4 - 2 3. 9 ± 0. 3

G 4 4G 4 4# 1 4 8 F o ( e d g e) - 4 6. 5 ± 0. 5 - 4 9. 1 ± 0. 7 - 2 5. 0 ± 0. 8

# 3 1 9 ( 2 n d s e s si o n) e F o ( e d g e) - 4 5. 2 ± 0. 3 - 4 7. 4 ± 0. 6 - 2 3. 9 ± 0. 6

# 1 5 0 F a s - 4 6. 2 ± 0. 5 - 4 8. 4 ± 0. 7 - 2 4. 4 ± 0. 8

# 1 5 1 A n - 4 5. 7 ± 0. 5 - 4 7. 2 ± 0. 7 - 2 3. 5 ± 0. 8

A v e r a g eA v e r a g e cc - 4 5. 6 ± 0. 4 - 4 8. 0 ± 0. 4 - 2 4. 2 ± 0. 4

G 5 8G 5 8# 1 5 7 F o - 4 7. 1 ± 0. 6 - 4 8. 0 ± 0. 9 - 2 3. 5 ± 0. 9

# 1 5 9 F o - 4 6. 6 ± 0. 6 - 4 8. 2 ± 0. 9 - 2 3. 9 ± 0. 9

# 1 6 0 F o - 4 7. 0 ± 0. 6 - 4 8. 8 ± 0. 9 - 2 4. 4 ± 0. 9

# 3 2 0 ( 2 n d s e s si o n) d F o ( e d g e) - 4 5. 5 ± 0. 3 - 4 6. 8 ± 0. 6 - 2 3. 2 ± 0. 6

# 1 6 2 F a s - 4 5. 9 ± 0. 6 - 4 7. 3 ± 0. 9 - 2 3. 5 ± 0. 9

# 1 5 8 F a s - 4 4. 5 ± 0. 6 - 4 6. 1 ± 0. 9 - 2 3. 0 ± 0. 9

A v e r a g eA v e r a g e cc - 4 5. 9 ± 0. 4 - 4 7. 5 ± 0. 4 - 2 3. 5 ± 0. 3

a: A n al y si s p oi nt s ar e s h o w n i n Fi g. E A 2 .b: A b br e vi ati o n s; S p = s pi n el, M el = m elilit e, F a s = Al - Ti -ri c h di o s pi d e, A n = a n ort hit e, F o =f or st eriti c oli vi n e.

c: U n c ert ai nt y of ∆ 1 7 O i s t h e err or of t h e w ei g ht e d m e a n v al u e. A d diti o n al u n c ert ai nti e s of t h e i n str u m e n

d: M ulti pl e - F C s a n al y si s wit h a hi g h i nt e n sit y b e a m.

T a bl e 2: Al - M g i s o t o p e s y s t e m a ti c s o f R e f r a c t o r y I n cl u si o n s f r o m A c f e r 0 9 4T a bl e 2: Al - M g i s o t o p e s y s t e m a ti c s o f R e f r a c t o r y I n cl u si o n s f r o m A c f e r 0 9 4

S a m pl e/ A n al y si s # a P h a s e b δδ 2 5 M g D S M 3 ( 2 S E)2 7 Al/ 2 4 M g ( 2 S E) δδ 2 6 M g *

( 2 S E) N ot e

C AI s

Y 8 1 0 2 0 - E - 8Y 8 1 0 2 0 - E - 8

# 1 0 0 ( 2 n d s e s si o n)c S p (ri m) 1. 1 7 ± 0. 1 4 2. 5 8 3 ± 0. 0 2 7 0. 9 9 ± 0. 1 4

# 1 0 1 ( 2 n d s e s si o n)c S p (ri m) 1. 3 1 ± 0. 1 4 2. 6 3 7 ± 0. 0 2 7 0. 9 3 ± 0. 1 1

# 9, 1 0 d M el 1. 2 1 ± 0. 4 7 2 9. 6 2 ± 0. 2 9 1 0. 9 9 ± 0. 7 9 a v er a g e

# 1 1 M el 0. 9 5 ± 0. 6 2 3 4. 1 7 ± 0. 9 5 1 2. 2 5 ± 1. 0 9

# 1 2, 1 3 d M el - 1. 3 8 ± 0. 4 3 2 0. 7 0 ± 0. 2 4 7. 8 2 ± 0. 7 1 a v er a g e

# 1 4 M el - 0. 9 3 ± 0. 3 9 1 5. 6 5 ± 0. 1 5 5. 4 2 ± 0. 6 2

# 1 5 M el - 0. 0 9 ± 0. 5 0 2 8. 7 4 ± 0. 7 0 1 0. 4 2 ± 0. 8 3

# 1 6 M el 0. 3 6 ± 0. 4 3 1 5. 4 7 ± 0. 2 1 6. 4 0 ± 0. 6 8

# 1 7 M el 0. 8 2 ± 0. 5 9 3 3. 5 9 ± 0. 4 7 1 1. 6 6 ± 1. 0 6

# 1 8 M el - 1. 3 6 ± 0. 5 0 2 8. 7 9 ± 0. 6 0 1 0. 0 2 ± 0. 8 6

a v e r a g e & i s o c h r o na v e r a g e & i s o c h r o n ee 0. 2 1 ± 2. 1 6 δδ 2 6 M g * =( 0. 3 6 3 ±± 0. 0 1 3) ×× (2 7 Al/ 2 4 M g) +( 0. 0 1 ±± 0. 1 0)

(2 6 Al/ 2 7 Al) 0 =( 5. 0 5 ± 0. 1 8) × 1 0 − 5− 5

G 5G 5

# 7 8 ( 2 n d s e s si o n)c F a s (ri m) - 0. 9 4 ± 0. 2 8 0. 3 3 7 ± 0. 0 0 6 0. 1 8 ± 0. 2 0

# 7 7 ( 2 n d s e s si o n)c S p - 0. 7 8 ± 0. 2 8 2. 6 2 4 ± 0. 0 2 7 0. 8 0 ± 0. 1 6

# 5 2 M el - 1. 2 2 ± 1. 6 0 7 2. 0 1 ± 1. 8 6 2 5. 4 8 ± 3. 2 1 1 0 0 c y cl e s# 5 3 M el 2. 8 7 ± 0. 8 8 5 0. 5 5 ± 0. 5 5 1 6. 3 8 ± 1. 6 0

# 5 6 M el - 1. 1 3 ± 1. 0 1 4 5. 9 8 ± 1. 0 1 1 6. 4 5 ± 1. 8 7 1 0 0 - 3 0 0 c y

a v e r a g e & i s o c h r o na v e r a g e & i s o c h r o n ee - 0. 2 4 ± 3. 5 0 δδ 2 6 M g * =( 0. 3 3 9 ±± 0. 0 2 2) ×× (2 7 Al/ 2 4 M g) −− ( 0. 0 3±± 0. 1 3)

(2 6 Al/ 2 7 Al) 0 =( 4. 7 2 ± 0. 3 1) × 1 0 − 5− 5

G 1 6

# 8 0 ( 2 n d s e s si o n)c F a s - 1. 1 8 ± 0. 2 8 0. 7 1 7 ± 0. 0 0 8 0. 3 3 ± 0. 1 9

# 2 0 M el 0. 4 7 ± 0. 6 7 2 8. 0 6 ± 0. 5 0 9. 0 8 ± 1. 3 0

# 2 1 M el 0. 0 8 ± 0. 6 5 3 1. 9 0 ± 0. 4 8 1 1. 0 4 ± 1. 2 0

# 2 2 M el - 0. 7 1 ± 1. 0 3 2 7. 7 9 ± 0. 2 1 1 1. 1 9 ± 2. 1 1 4 1 - 1 5 0 c y c# 2 3 M el - 0. 6 3 ± 0. 6 1 2 0. 7 7 ± 0. 5 2 7. 4 5 ± 1. 1 2

# 2 4 M el - 0. 3 6 ± 0. 6 0 2 3. 0 7 ± 0. 7 2 7. 6 5 ± 1. 0 9

# 2 5 M el 0. 1 4 ± 0. 6 8 2 5. 6 9 ± 0. 4 5 8. 8 6 ± 1. 2 5

# 2 6 M el 0. 4 1 ± 0. 8 6 2 1. 8 7 ± 1. 3 8 7. 2 9 ± 1. 4 5

# 2 8 M el - 1. 4 6 ± 0. 6 2 3 0. 4 8 ± 0. 2 6 1 0. 7 6 ± 1. 2 3

# 2 9 A n 0. 3 0 ± 8. 9 0 1 5 6 1 ± 1 6 5 3 2 ± 2 5 1 - 1 9 c y cl e

a v e r a g e & i s o c h r o na v e r a g e & i s o c h r o n e, fe, f - 0. 3 6 ± 1. 3 8 δδ 2 6 M g * =( 0. 3 4 2 ±± 0. 0 1 2) ×× (2 7 Al/ 2 4 M g) +( 0. 0 9 ±± 0. 1 8)

(2 6 Al/ 2 7 Al) 0 =( 4. 7 6 ± 0. 1 7) × 1 0 − 5− 5

G 4 9

# 8 2 ( 2 n d s e s si o n)c F a s - 0. 1 3 ± 0. 2 8 0. 8 5 9 ± 0. 0 2 8 0. 1 9 ± 0. 2 1

# 4 8 M el 1. 0 9 ± 0. 5 6 1 7. 8 2 ± 0. 1 7 5. 4 8 ± 1. 0 1

# 5 0 M el 2. 2 4 ± 0. 5 6 1 0. 2 1 ± 1. 4 3 2. 2 5 ± 0. 9 2

a v e r a g e & i s o c h r o na v e r a g e & i s o c h r o n ee 1. 0 7 ± 2. 3 7 δδ 2 6 M g * =( 0. 2 9 3 ±± 0. 0 5 4) ×× (2 7 Al/ 2 4 M g) −− ( 0. 0 8±± 0. 2 2)

(2 6 Al/ 2 7 Al) 0 =( 4. 0 8 ± 0. 7 5) × 1 0 − 5− 5

G 9 2

# 6 9 ( 2 n d s e s si o n)c F a s (ri m) - 0. 4 4 ± 0. 2 4 0. 2 7 1 ± 0. 0 1 2 0. 3 3 ± 0. 2 1

# 7 0 ( 2 n d s e s si o n)c F a s - 0. 5 5 ± 0. 2 4 1. 4 7 2 ± 0. 0 4 8 0. 6 5 ± 0. 1 9

# 7 1 ( 2 n d s e s si o n)c F a s - 0. 6 3 ± 0. 2 4 0. 8 0 7 ± 0. 0 2 1 0. 5 0 ± 0. 1 9

# 7 2 ( 2 n d s e s si o n)c F a s (ri m) - 0. 3 9 ± 0. 2 4 0. 3 3 5 ± 0. 0 1 1 0. 2 3 ± 0. 1 6

# 3 8 M el 1. 0 3 ± 0. 7 1 6. 4 3 ± 1. 1 7 2. 8 2 ± 1. 1 0

# 3 3 A n 2. 6 9 ± 5. 8 2 1 3 2 4 ± 1 4 5 8 ± 1 2 1 - 8 5 c y cl e# 3 4 A n 1. 8 3 ± 4. 0 9 1 3 1 0 ± 1 4 4 6. 0 ± 8. 7

# 3 6 A n 3. 1 5 ± 2. 9 0 8 2 2. 5 ± 8. 7 3 4. 8 ± 5. 2

# 3 7 A n 9. 7 4 ± 4. 2 6 7 0 5. 9 ± 7. 7 2 9. 4 ± 8. 0 1 - 1 0 0 c y cl

a v e r a g e & i s o c h r o na v e r a g e & i s o c h r o n e, fe, f - 0. 1 9 ± 1. 3 8 δδ 2 6 M g * =( 0. 3 8 ±± 0. 1 4) ×× (2 7 Al/ 2 4 M g) +( 0. 1 5 ±± 0. 1 4) F a s & M el

(2 6 Al/ 2 7 Al) 0 =( 5. 2 ± 2. 0) × 1 0 − 5− 5 F a s & M el

δδ 2 6 M g * =( 0. 0 3 7 4 ±± 0. 0 0 3 9) ×× (2 7 Al/ 2 4 M g) +( 2. 6 ±± 1. 1) M el & A n

(2 6 Al/ 2 7 Al) 0 =( 5. 2 1 ± 0. 5 4) × 1 0 − 6− 6 M el & A n

G 1 0 4

# 4 0 M el 1. 0 9 ± 0. 6 8 3 7. 4 3 ± 0. 4 2 1 1. 9 4 ± 1. 1 9

# 4 1 M el 0. 9 1 ± 0. 5 6 2 4. 2 3 ± 1. 4 1 8. 8 1 ± 0. 9 9

# 4 4 M el 1. 3 7 ± 0. 6 8 3 5. 9 4 ± 0. 6 2 1 1. 3 3 ± 1. 2 9 1 - 2 1 1 c y cl# 4 6 M el 1. 5 3 ± 0. 4 8 2 4. 3 1 ± 0. 3 3 7. 4 6 ± 0. 8 0

# 4 7 M el 1. 5 6 ± 0. 4 0 2 1. 4 2 ± 0. 1 6 7. 1 3 ± 0. 7 0

a v e r a g e & i s o c h r o na v e r a g e & i s o c h r o n ee1. 2 9 ± 0. 5 6 δδ 2 6 M g * =( 0. 3 2 5 ±± 0. 0 1 5) ×× (2 7 Al/ 2 4 M g) −− ( 0. 0 3±± 0. 0 1) A s s u mi n g t h

(2 6 Al/ 2 7 Al) 0 =( 4. 5 3 ± 0. 2 1) × 1 0 − 5− 5

A O A sA O A sG 1 7

# 6 4 ( 2 n d s e s si o n)c F o (ri m) 0. 3 6 ± 0. 2 4 0. 0 1 ± 0. 1 2

# 6 5 ( 2 n d s e s si o n)c F o (ri m) 0. 5 9 ± 0. 2 4 0. 0 4 ± 0. 1 2

# 6 6 ( 2 n d s e s si o n)c F a s - 0. 3 7 ± 0. 2 4 0. 3 3 2 ± 0. 0 0 5 0. 0 8 ± 0. 1 6

# 6 8 ( 2 n d s e s si o n)c F a s - 0. 3 6 ± 0. 2 4 0. 3 8 5 ± 0. 0 0 6 0. 0 4 ± 0. 1 6

# 6 7 ( 2 n d s e s si o n)c S p 0. 9 8 ± 0. 2 4 2. 4 8 0 ± 0. 0 2 7 0. 9 5 ± 0. 1 2

a v e r a g e & i s o c h r o na v e r a g e & i s o c h r o n ee 0. 2 4 ± 1. 1 9 δδ 2 6 M g * =( 0. 3 8 1 ±± 0. 0 5 8) ×× (2 7 Al/ 2 4 M g) −− ( 0. 0 0 6±± 0. 0 6 9)

(2 6 Al/ 2 7 Al) 0 =( 5. 3 2 ± 0. 8 1) × 1 0 − 5− 5

G 2 8

# 8 3 ( 2 n d s e s si o n)c F o (ri m) 0. 6 8 ± 0. 2 8 0. 0 4 ± 0. 1 6

# 8 4 ( 2 n d s e s si o n)c F o (ri m) 0. 3 4 ± 0. 2 8 0. 0 7 ± 0. 1 6

a v e r a g ea v e r a g e ee 0. 5 1 ± 0. 4 8 0. 0 6 ± 0. 1 2

G 4 4

# 8 9 ( 2 n d s e s si o n)c F o (ri m) 1. 1 2 ± 0. 1 3 0. 0 0 ± 0. 0 8

# 9 2 ( 2 n d s e s si o n)c F o (ri m) 0. 9 2 ± 0. 1 3 0. 0 3 ± 0. 0 8

a v e r a g e & i s o c h r o na v e r a g e & i s o c h r o n ee 1. 0 2 ± 0. 2 8 0. 0 2 ± 0. 0 6

G 5 8

# 9 3 ( 2 n d s e s si o n)c F o (ri m) 0. 6 5 ± 0. 1 3 0. 0 8 ± 0. 0 7

# 9 4 ( 2 n d s e s si o n)c F o 0. 5 5 ± 0. 1 3 0. 0 8 ± 0. 0 9

a v e r a g e & i s o c h r o na v e r a g e & i s o c h r o n ee 0. 6 0 ± 0. 1 3 0. 0 8 ± 0. 0 6

a: A n al y si s p oi nt s ar e s h o w n i n Fi g. E A 2 .b: A b br e vi ati o n s; S p = s pi n el, M el = m elilit e, F a s = Al - Ti -ri c h di o s pi d e, A n = a n ort hit e, F o =f or st eriti c oli vi n e.c: M ulti pl e - F C s a n al y si s wit h a hi g h i nt e n sit y b e a m.d: A v er a g e v al u e of t w o a n al y s e s at t h e s a m e a n al y si s s p ot.

e: Err or s ar e 2 S D f or δ 2 5 M g v al u e s a n d 9 5 % c o nfi d e n c e f or i s o c hr o n s

f: A n ort hit e d at a i s n ot u s e d t o c al c ul at e t h e δ 2 5 M g v al u e.

g: Err or i s 9 5 % c o nfi d e n c e of t h e w ei g ht e d m e a n v al u e.

(( ‰‰ / a m u )/ a m u ) (( ‰‰ ))