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International Geology Review, Vol. 48, 2006, p. 702–724.Copyright © 2006 by V. H. Winston & Son, Inc. All rights reserved.
Stratigraphy and Detrital Modes of Upper Messinian Post-evaporitic Sandstones of the Southern Apennines, Italy:
Evidence of Foreland-Basin Evolution during the Messinian Mediterranean Salinity Crisis
MIRKO BARONE, SALVATORE CRITELLI,1 EMILIA LE PERA,Dipartimento di Scienze della Terra, Università degli Studi della Calabria, 87036 Arcavacata di Rende (CS), Italy
SILVIO DI NOCERA, FABIO MATANO, AND MARIO TORRE
Dipartimento di Scienze della Terra, Università degli Studi di Napoli Federico II, Largo S. Marcellino 10, 80138 Napoli, Italy
Abstract
During the Messinian, the southern Apennines thrust belt experienced a period of strong tectonicrearrangement and accretion, activation of overthrusts, and consequent migration of depocenters.The upper Miocene successions cropping out in the northern segment of the southern Apenninethrust belt have good potential for improving our understanding of the interplay between Messiniansalinity-crisis events and foreland-basin evolution. The local Messinian stratigraphy includes: (1)pre-evaporitic thin-bedded euxinic marly clay, interbedded with diatomaceous marls; (2) evaporiticlimestone, crystalline gypsum, and reworked gypsum; (3) post-evaporitic deposits subdivided intotwo main units: the Torrente Fiumarella unit and the Anzano Molasse Formation that grade upwardinto ostracod-rich deposits (Lago-Mare facies). The evaporitic and post-evaporitic sequences areseparated by an angular unconformity. This paper deals with the stratigraphic and petrographicstudy of the post-evaporitic deposits. The Torrente Fiumarella unit includes lacustrine and alluvialconglomerates, quartzolithic sandstones containing abundant carbonate detritus, shale, andreworked clastic gypsum. The Anzano Molasse Formation includes thick-bedded deltaic to turbid-itic conglomerates and sandstones passing upward to thin-bedded turbidite sandstones and marly-clayey siltstones. Sandstones are quartzofeldspathic with variable proportions of sedimentary (bothcarbonate and siliciclastic) and plutonic detritus. In particular, two populations are present,plutonic-rich and mixed plutonic-sedimentary. Volcaniclastic layers, composed of dominantly vitricparticles (shards and pumice), are also interbedded within Anzano Molasse sandstones. The Anzanosuccession includes rare freshwater ostracods that increase in abundance in the uppermost Lago-Mare facies. The Lago-Mare facies deposits are represented by silty-marly clay with abundantOstracoda shells (Ilyocypris gibba, Cyprideis torosa and Candona sp.) and intrarenite having abun-dant intrabasinal carbonate particles (ooids, peloids, and bioclasts) and subordinate extrabasinalnoncarbonate and carbonate particles. The post-evaporitic sequences represent an infilled foredeepbasin, with a lacustrine environment progressively deepening and experiencing gravity resedimen-tation. Detrital modes document complex provenance relations from upper Messinian accretedterranes of the southern Apennines thrust belt. Post-evaporitic sandstones in the Irpinia-Dauniasector of the southern Apennines foreland-basin system record both the effects of the forelandtectonic evolution and the Messinian Mediterranean salinity crisis. They may represent alternativemodels for foreland-basin evolution during a restricted time in late Messinian, which can be appli-cable also in other portions of the circum-Mediterranean orogen.
IntroductionGeneral characteristicsDURING THE LATE Messinian, nonmarine (evaporiticand lacustrine) sedimentary basins developed in thecircum-Mediterranean orogenic belts (e.g., Butler
and Grasso, 1993; Cipollari et al., 1999b) during thesalinity crisis (i.e., Hsü et al., 1977), followed by theLago-Mare events (i.e., Bonaduce and Sgarrella,1999). Thrust accommodation, deep dissection ofthe thrust belt, and superimposed evaporite andLago-Mare sedimentation are recorded in the strati-graphic sections of the Messinian peri-Mediterra-nean foreland basins.1Corresponding author; e-mail: critelli@unical.it
0020-6814/06/886/702-23 $25.00 702
POST-EVAPORITIC SANDSTONES 703
Large portions of the southern Italian orogenicsystem (Fig. 1) include diverse Messinian evaporiticand post-evaporitic stratigraphic units in both fore-land basins and syn-rift basins related to the back-arc Tyrrhenian opening (Patacca and Scandone,1989; Cipollari et al., 1999a). The aim of this paperis to discuss lithostratigraphic, sedimentologic, andpetrostratigraphic relations during the Messiniansalinity crisis in the Irpinia-Daunia portions of thesouthern Apennines, as responses to both salinitycrisis-events and tectonostratigraphic evolution ofthe foreland-basin system. The Irpinia-Dauniaupper Messinian sequences record the space/timeevolution of depozones located between the unde-formed stable margin and orogenic margin of theforeland region during the salinity crisis. In particu-lar, study of the nonmarine Anzano and Fiumarellaunits provides useful lithostratigraphic and petro-logic data for interpretations of similar sedimentarybasins, illustrating interrelations between tectono-stratigraphic evolution of foreland-basin architec-ture and input of the salinity crisis (e.g., rates of
accretion and unroofing, base-level changes, andprovenance). Their close relations may representalternative models for foreland-basin evolutionduring a restricted time in the late Messinian, whichcan be applicable also in other portions of thecircum-Mediterranean orogen.
Stratigraphic relationships among Messinianpre-evaporitic, evaporitic and post-evaporitic deposits in the Mediterranean
The Mediterranean salinity crisis resulted indeposition of a huge volume of Messinian evaporiticsediments, characterized by two major cycles(Lower Evaporites and Upper Evaporites), separatedby a deeply incised erosional surface related to thedrawdown of the Mediterranean Sea (Hsü et al.,1973, 1977; Müller and Mueller, 1991; Krijgsmanet al., 1999). The evaporites are overlain in severalMediterranean sites by Lago-Mare post-evaporiticfacies, which are mostly represented in many of theMediterranean basins by siliciclastic deposits thatcontain fresh- to brackish-water fauna. In some sites
FIG. 1. Tectonic sketch-map of the southern Apennines.
704 BARONE ET AL.
(e.g., the northern Apennines), Upper Evaporitesare not present and post-evaporitic deposits directlyoverlie Lower Evaporites.
During the Messinian salinity crisis, the coevalstratigraphic successions suggest a relatively homo-geneous depositional setting in Italy and in manyparts of the Mediterranean, as lithology and faciesarrangement of both pre-evaporitic deposits and pri-mary evaporites of the Apennine foredeep and otherMediterranean basins are similar. The sedimentaryrecord of the Lago-Mare differs among basins inthickness, ranging from a few meters to several-hundred meters, in facies (widely variable fromlacustrine to alluvial), and in composition, althoughsiliciclastics predominate. For example, post-evaporitic sequences include several formations inthe diverse districts of the Apennines-SicilianMaghrebian chains: “di tetto” and Cusercoli forma-tions, previously named as Colombacci Formation(Bassetti et al., 1994; Roveri et al., 1998, 2003) inthe northern Apennines; the Arenazzolo Formationin Sicily (Decima and Wezel, 1973) and its equiva-lent in southeastern Calabria (Cavazza and DeCelles, 1998), and the Anzano Molasse andFiumarella units in the Campanian Apennines(Matano, 2002; Matano et al., 2005).
A main problem concerning the Messinian salin-ity crisis is represented by stratigraphic relation-ships of the evaporites with both the underlying pre-evaporitic deposits and the overlying post-evaporiticdeposits, both in central basins and in peripheralbasins of the Mediterranean. The evaporites in mostcases conformably overlie the pre-evaporitic depos-its both in marginal basins and in the center of theMediterranean (Clauzon et al., 1996; Krijgsman etal., 1999). Only in the Sorbas basin (southeastSpain), some authors (e.g., Martin and Braga, 1994;Riding et al., 1998, 1999) have suggested that anerosional unconformity separates the evaporitesfrom the underlying pre-evaporitic marls; theycorrelated it to the sea-level drop that led to evapor-ite deposition in the Mediterranean center. Anerosional unconformity between the pre-evaporiticand evaporitic units has been recognized also inAlmerìa-Nìjar basin (Aguirre and Sànchez-Almazo,2004).
In several sectors of the circum-Mediterraneanthrust belts, the transition from evaporitic to post-evaporitic deposits is conformable, although thecontact is erosional in Cyprus (Orszag-Sperber etal., 2000; Rouchy et al., 2001), Sicily (Decima andWezel, 1973), Crete (Delrieu et al., 1993) and Vera
basin (southeastern Spain, Fortuin et al., 1995). Incontrast, the contact is continuous and gradual inmost internal basins of southern Spain (Sorbas,Murcia, Almerìa-Nìjar basins; Playà et al., 2000;Aguirre and Sànchez-Almazo, 2004).
In the Apennines foreland-basin system, post-evaporitic deposits unconformably cover evaporitesequences, as the result of a Messinian regionaltectonic phase (Ciaranfi et al., 1973; Elter et al.,1975; Di Nocera et al., 1976; Colalongo et al., 1978;Roveri et al., 2003), whereas in Sicily, the angularunconformity is located between the Lower Evapor-ites and the Upper Evaporites (Decima and Wezel,1971). In fact, the Arenazzolo Formation in Sicily(Decima and Wezel, 1971) postdates the UpperEvaporites, whereas the Colombacci Formation inthe northern Apennines is equivalent to the UpperEvaporites (Hsü et al., 1973; Colalongo et al., 1978;Vai, 1997).
In the Irpinia-Daunia Mountains area (southernApennines) evaporitic and post-evaporitic Messin-ian successions are well exposed. We present newstratigraphic and petrologic data, which lead to abetter understanding of tectonic evolution andpaleonvironmental conditions of post-evaporiticdeposits of the study area in the framework of lateMessinian events in the Mediterranean basin.
Geological Setting
The southern Apennines thrust belt (Fig. 1) ispart of the Africa-verging circum-MediterraneanApennine-Maghrebides orogenic belt. It resultsmainly from progressive NE-vergent thrusting ofMesozoic–Tertiary sedimentary units over theApulian foreland. The belt is associated with theTyrrhenian backarc basin to the southwest andthe Bradano foredeep to northeast. The Apulianforeland is represented by a Mesozoic–Cenozoiccarbonate platform, which is stratigraphically cov-ered in the southwestern flexured margin by terrige-nous deposits of the Pliocene–Pleistocene Bradanoforedeep (D’Argenio et al., 1975; Mostardini andMerlini, 1986; Doglioni, 1991; Roure et al., 1991).
The pre-orogenic Apulian continental marginconsists of pelagic basins and carbonate platforms,spanning the Triassic to the Miocene (D’Argenio etal., 1975; Mostardini and Merlini, 1986), whichwere gradually covered during the Miocene to EarlyPleistocene by deep-marine to continental forelandclastic wedges related to progressive flexure of litho-sphere beneath the advancing Apenninic thrust belt
POST-EVAPORITIC SANDSTONES 705
FIG
. 2. G
eolo
gica
l map
of t
he I
rpin
ia-D
auni
a se
ctor
of t
he s
outh
ern
Ape
nnin
es, I
taly
(mod
ified
afte
r M
atan
o et
al.,
200
5).
706 BARONE ET AL.
and cratonward shifting of the Apennine foredeep(Patacca et al., 1990, Sgrosso, 1998; Critelli, 1999).
After the Tyrrhenian backarc rifting, a signifi-cant shift of the foreland-basin system toward theENE occurred from Late Tortonian to Early–MiddlePleistocene (Patacca et al., 1990; 1993). During thelate Messinian, the Mediterranean salinity crisisproduced a wide diffusion of evaporitic to non-marine sedimentary basins both along the Tyrrhen-ian border of the chain and in foredeep-forelandsectors of the southern Apennines.
The study area falls in the Irpinia-Daunia sectorlocated in eastern margin of the northern part of thesouthern Apennines (Fig. 1). A complex imbricatedsystem occurred within the studied sector of thethrust belt (Fig. 2), formed by Middle Triassic toUpper Miocene shallow-marine to deep-marinecarbonate and pelagic successions of the Frigento,Fortore, Daunia and “Vallone del Toro” tectonicunits (see for a more complete description Matano etal., 2005; and Basso et al., 2002). Upper Messinian(Altavilla Basin) and Lower Pliocene (Ariano IrpinoBasin) thrust-top-basin clastic sequences are wide-spread in the study area (D’Argenio et al., 1975;Basso et al., 2002; Ciarcia et al., 2003) and illus-trate the progressive eastward migration of deforma-tion and accretion of tectonic units. Thesesequences progressively cover Mesozoic andTertiary deposits of Frigento, Fortore, Daunia, andVallone del Toro tectonic units (Fig. 2), which arefolded and thrust eastward over the buried Apulianthrust system (Roure et al., 1991; Pescatore et al.,2000; Matano and Di Nocera, 2001; Basso et al.,2002).
During the salinity crisis, the Frigento andFortore units were already assembled within thethrust belt, while Daunia and Vallone del Toro unitswere located in the undeformed foreland region(Basso et al., 2002; Di Nocera et al., 2002) withinthe Daunia unit (Monte Castello Evaporites Forma-tion) and the Vallone del Toro unit. Evaporiticdeposits are conformably present only withinDaunia and Vallone del Toro units, and were depos-ited before their tectonic deformation. Conse-quently, evaporite deposition can be referred toforedeep and forebulge depozones.
The Anzano and Fiumarella post-evaporitic unitsare characterized by dominantly coarse-grainedstrata with lacustrine and alluvial facies (Dessau,1952; Crostella and Vezzani, 1964; Basso et al.,2001, 2002; Matano, 2002). They represent syn-
orogenic deposits unconformably covering the fourtectonic units exposed in the study area (Fig. 2).
Methods and Petrography
Stratigraphic studies, detailed mapping (at1:10,000 scale), and sample collection were carriedout in the study area (Fig. 2) to detail the strati-graphic evolution of sedimentary sequences and toillustrate tectono-stratigraphic evolution of syn-orogenic basins in the Irpinia-Daunia sector of thesouthern Apennines during the Messinian salinitycrisis. Stratigraphic sections of Messinian post-evaporitic formations were studied to provide adetailed stratigraphic framework for petrographicalanalyses; gypsum facies have been previously stud-ied and discussed by Matano et al. (2005).
Twenty-eight medium-to-coarse-grained sand-stone samples from upper Messinian successionswere selected for thin-section analysis. About 500points were counted for each thin section (etchedand stained for plagioclase and potassium feldspar)according to the Gazzi-Dickinson method (Gazzi,1966; Dickinson, 1970; Ingersoll et al., 1984; Zuffa,1985). Point-count results and recalculated parame-ters are shown, respectively, in Tables 1 and 2.
Sandstones include abundant quartz as mono-crystalline and polycrystalline grains, the formerwith tectonic fabric (metamorphic grains withcrenulate subgrain boundaries) and without tectonicfabric (sedimentary or volcanic nature). Both plagio-clase and K-feldspar (orthoclase, microcline, andperthite) also represent important components;plagioclase is commonly altered to sericite. Bothplagioclase and k-feldspar are present as singlecrystals and in plutonic or rarely metamorphic phan-eritic rock fragments. Coarse-grained plutonic rockfragments include mainly granodiorite, but graniticfragments are also present. Fine-grained lithic frag-ments are mainly sedimentary, represented by chert,siltstone, shale, and extrabasinal carbonates asmicrite, biomicrite, sparitic and biosparitic lime-stones; metasedimentary (mainly fine grained schistand phyllite); ophiolitic lithic fragments are rare,whereas volcanic fragments having microlitic andfelsitic textures are minor.
The diagenetic phases in order of decreasingabundance, are: patchy calcite cement, pore-fillingcalcite, poikilotopic calcite, and calcite partlyreplacing quartz and feldspar.
POST-EVAPORITIC SANDSTONES 707
Messinian Stratigraphy in theIrpinia-Daunia Mountains
In the study area, the Daunia unit mainly recordsthe interplay between foreland-basin tectono-strati-graphic evolution and salinity-crisis events. Threeintervals can be distinguished in the Messinian suc-cession: (1) pre-evaporitic; (2) evaporitic; and (3)post-evaporitic (Fig. 3).
Pre-evaporitic intervalThe pre-evaporitic interval (Fig. 3), up to 30 m
thick, comprises thin-bedded laminitic dark-greymarly clays and marls, interbedded with light-greyash layers and whitish marly diatomites containing
fish scales (Matano et al., 2005). The depositionalenvironment was probably an anoxic pelagic starvedbasin, similar to other typical pre-evaporitic succes-sions (e.g., Dazzaro et al., 1988; Vai, 1997; Bellancaet al., 2001), the lack of significant exposures doesnot permit verification if the diatomite-bearingsuccession displays a cyclical pattern as in Sicily(Bellanca et al., 2001). The diatomites overlie bothbase-of-slope to basin calcarenite, calcilutite, andmarly clay strata (Faeto Formation), and pelagicclayey marls (“Toppo Capuana” clayey marl Forma-tion). A volcaniclastic layer locally marks the transi-tion between pre-evaporitic and evaporiticsuccessions; two other volcaniclastic layers areabove and below the transition (Fig. 3). The transi-
FIG. 3. Schematic stratigraphic column of the Messinian succession cropping out in the Irpinia-Daunia Mountains(modified after Matano et al., 2005).
708 BARONE ET AL.
TAB
LE 1
. Pet
rogr
aphi
c R
esul
ts o
f Mod
al A
naly
sis1
Anz
ano
Mol
asse
Uni
tT.
Fiu
mar
ella
Uni
tLa
go-m
are
Petr
ogra
phic
cla
sses
01-SC 528
01-SC 547
01-SC 523
01-SC 520
01-SC 529
01-SC 548
01-SC 527
01-SC 522
01-SC 525
01-SC 536
01-SC 533
01-SC 530
01-SC 526
01-SC 521
01-SC 531
01-SC 535
01-SC 546
01-SC 532
01-SC 550
01-SC 534
01-SC 549
01-SC 565
01-SC 544
01-SC 566
01-SC 567
01-SC 543
01-SC 538
01-SC 539
NC
E
Q
Qua
rtz
(sin
gle
crys
tals
)10
611
210
289
123
8590
8790
127
126
7693
9191
115
123
104
103
174
115
147
105
124
114
190
3146
Poly
crys
talli
ne q
uart
z w
ith te
cton
ite fa
bric
101
62
46
74
41
45
53
1114
49
35
21
177
7
Poly
crys
talli
ne q
uart
z w
ithou
t tec
toni
te fa
bric
25
61
11
11
22
612
1011
810
104
59
810
Qua
rtz
in m
etam
orph
ic R
.F.
175
1115
146
1110
51
13
58
12
16
66
31
Qua
rtz
in p
luto
nic
R.F
.50
3529
2641
2946
3419
3024
2113
177
247
54
106
3654
110
52
2
Qua
rtz
in p
luto
nic
or g
neis
sic
R.F
.1
31
11
Cal
cite
rep
lace
men
t on
quat
rz34
2426
4526
3625
2933
4932
2126
2546
946
3427
1024
1929
104
292
K
K-f
elds
par
(sin
gle
crys
tals
)73
7151
6250
4767
4446
5779
5567
4039
6468
5128
6556
1345
217
167
17
K-f
elds
par
in m
etam
orph
ic R
.F.
11
1
K-f
elds
par
in p
luto
nic
R.F
.30
3120
2437
815
1219
56
1513
310
2715
73
1912
345
61
31
2
Cal
cite
rep
lace
men
t on
K-f
elds
par
1213
47
45
101
45
21
513
71
163
113
91
81
5
P
Plag
iocl
ase
(sin
gle
crys
tals
)53
4331
2049
4656
4752
7889
6679
7537
9759
4440
9551
954
138
216
Plag
iocl
ase
in v
olca
nic
R.F
. 1
Plag
iocl
ase
in m
etam
orph
ic R
.F.
32
11
12
1
Plag
iocl
ase
in p
luto
nic
R.F
. 29
3514
2334
1114
1322
1513
2917
1419
5223
47
298
414
56
1
Plag
iocl
ase
in p
luto
nic
or g
neis
sic
R.F
. 1
Cal
cite
rep
lace
men
t on
Plag
iocl
ase
68
45
106
131
812
811
168
244
87
168
123
21
1
M
Mic
as a
nd c
hlor
ite (s
ingl
e cr
ysta
ls)
101
49
116
96
39
155
49
825
135
735
112
1
Mic
as a
nd c
hlor
ite in
vol
cani
c R
.F.
1
Mic
as a
nd c
hlor
ite in
plu
toni
c R
.F.
22
11
11
Mic
as a
nd c
hlor
ite in
plu
toni
c or
gne
issi
c R
.F
1
Mic
as a
nd c
hlor
ite in
met
amor
phic
R.F
. 1
11
L
Volc
anic
lith
ic w
ith m
icro
litic
text
ure
2
Volc
anic
lith
ic w
ith fe
lsiti
c gr
anul
ar te
xtur
e1
1
Phyl
lite
52
21
12
11
17
31
3
Fine
-gra
ined
sch
ist
41
14
77
12
21
12
56
POST-EVAPORITIC SANDSTONES 709Fi
ne-g
rain
ed s
ands
tone
1
Impu
re c
hert
33
31
31
12
2
Silts
tone
11
12
13
1
Met
aren
ite1
Shal
e1
11
34
122
110
15
Den
se m
iner
al (s
ingl
e cr
ysta
ls)
2
CE M
icri
tic li
mes
tone
34
529
442
539
253
228
2519
333
123
1824
406
6044
2710
5
Spar
itic
limes
tone
11
171
61
51
12
12
112
1
Mic
rosp
ariti
c lim
esto
ne1
171
71
115
13
42
16
11
911
267
36
Bio
spar
itic
limes
tone
215
21
Bio
mic
ritic
lim
esto
ne2
11
11
115
1336
4
Foss
il (s
ingl
e sk
elet
on)
12
12
11
215
6066
27
Sing
le s
par
(cal
cite
)1
32
21
21
Und
eter
min
ed li
mes
tone
125
61
32
1
Cl B
iocl
ast
333
203
Mx Si
licic
last
ic M
atri
x 2
210
26
217
119
85
310
151
206
1325
161
91
32
Car
bona
te M
atri
x20
1712
1317
184
3231
114
1835
2115
45
2721
2756
2739
2812
Cm C
arbo
nate
cem
ent (
pore
filli
ng)
3827
1032
3237
3113
2325
2925
1723
1517
1510
513
335
622
8821
3
Car
bona
te c
emen
t (pa
tchy
cal
cite
)21
6929
101
2130
6235
4435
2152
3443
391
1028
4640
8019
6290
53
Oxi
d-Fe
cem
ent
210
24
52
710
310
56
86
77
116
177
22
22
8
Qua
rtz
over
grow
th
12
Cal
cite
rep
lace
men
t on
unde
term
ined
gra
in4
531
2217
4118
4336
3735
4337
5589
2754
9110
84
746
1246
2754
Alte
rite
s2
11
1
Tota
l54
252
050
451
952
450
351
350
650
551
750
250
152
350
750
550
451
650
351
350
050
350
050
652
550
650
250
050
7
1 CE
= e
xtra
basi
nal c
arbo
nate
gra
ins;
CI
= in
trab
sina
l car
bona
te g
rain
s; N
CI
= in
trab
asin
al n
onca
rbon
ate
grai
ns; M
x =
mat
rix;
Cm
= c
emen
t; R
.F. =
coa
rse
grai
ned
rock
frag
men
ts; L
= li
thic
frag
men
ts; Q
= q
uart
z; K
= K
-fel
d-sp
ar; P
= p
lagi
ocla
se; M
= m
icri
te a
nd c
hlor
ite; N
CE
= e
xtra
basi
nal n
onca
rbon
ate
grai
ns.
710 BARONE ET AL.
TAB
LE 2
. Rec
alcu
late
d M
odal
Poi
nt, i
n pe
rcen
t1
Qm
FLt
Qt
FL
Qm
KP
Qp
Lvm
Lsm
LmLv
LsR
gR
vR
mR
gR
sR
mN
CE
CE
CI
P/F
T. F
ium
arel
la U
nit
01-S
C 5
6558
933
609
3187
76
50
950
010
091
09
2671
369
310
0.4
01-S
C 5
4448
484
5048
250
2525
500
5020
080
930
788
57
982
00.
501
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545
6314
2367
1518
819
1021
079
00
100
670
3316
768
8218
00.
501
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566
3812
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7615
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086
00
100
500
509
829
6040
00.
401
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567
367
5740
753
856
97
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00
100
710
298
893
5149
00.
6
X49
1833
5218
3076
1212
190
814
096
740
2629
656
7228
00.
5SD
±12
±17
±21
±11
±17
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±15
±8±8
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8±9
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Mol
asse
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ano
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40
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5537
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5348
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00
100
00
100
980
292
62
991
00.
501
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536
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254
442
5518
2833
067
00
1094
06
8312
598
20
0.6
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2052
426
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300
7023
077
770
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1220
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529
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551
454
5223
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973
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121
754
2199
10
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528
4746
750
464
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357
506
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125
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2492
80
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4744
515
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330
6725
075
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601
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535
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7590
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1393
70
0.5
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4412
4744
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2426
301
6916
183
790
2142
4612
937
00.
5SD
±5±7
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4±2
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78
715
SD±1
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074
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144
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501
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5227
2154
2719
6625
910
585
305
6533
858
1754
2929
467
0.3
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2524
5325
2368
2012
53
9328
370
324
6416
5331
224
7474
0.4
SD±1
±4±4
±2±4
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1 X =
mea
n; S
D =
sta
ndar
d de
viat
ion.
Gra
in p
aram
eter
s: Q
m =
mom
ocry
stal
line
quar
tz; Q
p =
poly
cris
talli
ne q
uart
z; Q
t = Q
m +
Qp;
K =
K-f
elds
par;
P =
Pla
gioc
lase
; F =
P +
K; L
= a
phan
itic
lithi
c gr
ains
; Lt =
L +
Qp
+ C
E;
Lvm
= v
olca
nic
and
met
avol
cani
c; L
sm =
sed
imen
tary
and
met
ased
imen
tary
lith
ics
frag
men
ts; N
CE
= n
on-c
arbo
nate
ext
raba
sina
l gra
ins;
CE
= c
arbo
nate
ext
raba
sina
l gra
ins;
CI
= ca
rbon
ate
intr
abas
inal
gra
ins.
Sam
ples
01-S
C-5
38/5
39 h
ave
been
plo
tted
only
on
the
NC
E C
E C
I di
agra
m fo
r th
e co
rres
pond
ents
rec
alcu
late
d pa
ram
eter
s. T
he u
nder
lined
par
amet
ers
indi
cate
the
sam
ples
of t
he s
ubpe
trof
acie
s of
Anz
ano
Mol
asse
in th
e R
g-R
s-R
m
tria
ngul
ar p
lot.
POST-EVAPORITIC SANDSTONES 711
tion is marked by a sharp change in lithology frompelagic euxinic pelitic facies into evaporites, char-acterized by stratal conformity.
Evaporitic interval
The evaporitic interval, represented by theMonte Castello Evaporites Formation (Crostella andVezzani, 1964), comprises laterally discontinuousevaporitic limestone and gypsum beds. The MonteCastello Evaporite Formation, whose exposed thick-ness ranges from a few meters to about 50 m,conformably overlies the Lower Messinian portion ofthe Toppo Capuana clayey marl and Faeto forma-tions (Fig. 3).
Evaporitic limestones, which locally representthe entire evaporitic succession, are massive orlaminated, and made of micrite and dolomicrite withmillimetric gypsum and sulfur crystals, spongespicules, and desiccation cavities, such as birdseyesand fenestrae (Dazzaro et al., 1988).
Several types of alternating gypsum lithofaciesoccur, such as selenites, laminated and nodular-laminated gypsum, and coarse clastic gypsum(Matano et al., 2005), with bed thickness rangingfrom a few centimeters up to 10 m.
Thick beds of coarse clastic gypsum (gypsruditesand gypsarenites) constitute the main part of theevaporite succession. Gypsarenites are commonlygraded, with cross-bedded or rippled intervals;gypsrudites are formed from up to 10 m thick bedsof massive or graded breccias in a sandy matrix,with pebbles including various gypsum lithofacies,limestone, and clay chips. They are interbeddedwith fine-grained clastic gypsum. Laminatedgypsum consists of evenly (mm-scale) laminatedlayers, both clastic and crystalline. The layers mayshow small-scale enterolithic folding and laterallylinked hemispheroidal stromatolitic structures(Dazzaro et al., 1988). Layers of coalescent whitishgypsum nodules (up to 3 cm) are commonly associ-ated with laminated gypsum, forming massive bedsup to 5m thick.
Beds of coarse clastic gypsum are gravity-flowdeposits derived from intrabasinal reworking. Theymay have been deposited in both shallow- and deep-water environments. Gypsarenite and gypsrudite areinterpreted as turbidites and debrites respectively;the occurrence of gypsum turbidites and debrisflows does not necessarily indicate a great waterdepth, but does indicate relief within the basin(Matano et al., 2005). The very fine grained clasticlaminated gypsum, intercalated within turbiditic
graded gypsarenites, could suggest a somewhatdeeper subaqueous environment of deposition. Withreference to the nodular-laminated gypsum litho-facies, a late diagenetic origin of the nodular struc-tures, linked with partial anhydritization of gypsum,is supposed for the association with subaqueousstructures and the presence of distortion in adjacentgypsum layers produced by nodule growth (Ciar-apica and Passeri, 1980; Peryt, 1996). Crystallinegypsum is exposed as beds of shallow-tail twincrystals and acicular and granular massive gypsumlayers. Selenitic gypsum and microcrystalline lami-nated gypsum strata can be generally attributed to ashallow-subaqueous environment (Schreiber andDecima, 1976; Schreiber et al., 1976; Vai and RicciLucchi, 1977; Matano et al., 2005).
Post-evaporitic interval
The Monte Castello Evaporites Formation isunconformably capped by post-evaporitic clasticdeposits; the unconformity commonly is marked bydesiccation cracks in both gypsum and evaporiticlimestone, suggesting subaerial exposure. The post-evaporitic interval is represented by two units: theTorrente Fiumarella unit and the Anzano Molasse(Fig. 3). Post-evaporitic successions overlie withangular unconformity the Daunia unit, which wastectonically deformed during the intra-Messiniantectonic phase. Late Messinian post-evaporiticsequences are unconformably covered by Pliocenestratigraphic successions (Amore et al., 1998) of theAriano Supersynthem, which is formed by alluvial,nearshore, and neritic clastic facies associations(Ciarcia et al., 2003).
Lithofacies and Detrital Modes of the Post-Evaporitic Units
Eight detailed stratigraphic sections of post-evaporitic sequences are shown in Figure 4. TheTorrente Fiumarella unit is characterized by clasticcontinental (lacustrine and alluvial) facies (Basso etal., 2001, 2002), with variable thickness from 50 to250 m. The lower interval is mainly coarse grained,the upper interval consists of pelitic and fine-grained arenitic deposits with lenses of silty sands,conglomerates, and reworked clastic gypsum. Theunit is characterized by an overall upward finingtrend, and its sedimentary features are character-ized by strong lateral discontinuity (Fig. 4).
Along the Fiumarella River, the TorrenteFiumarella unit shows different facies and thick-
712 BARONE ET AL.
FIG
. 4. S
trat
igra
phic
logs
of t
he p
ost-
evap
oriti
c de
posi
ts. T
he lo
catio
n of
the
sect
ions
is s
how
n in
Fig
ure
2.
POST-EVAPORITIC SANDSTONES 713
ness: thick coarse-grained strata in the proximalsector (near Flumeri; Fig. 2) are distally replaced bythin-bedded siltstone and mudstone. In the proximalsetting, the basal interval (Fig. 4, log I) mainlyconsists of disorganized, crudely stratified, hetero-
metric granular to pebbly conglomerates (Fig. 5A)with thick to very thick strata (up to 4 m). Lime-stones, marls, arenites, and granites form thepebbles, which are usually moderately to wellrounded with a scarce sandy matrix. Some layers of
FIG. 5. Field photographs showing some lithofacies of the post-evaporitic units (reference to Fig. 5 logs is given).Torrente Fiumarella unit: A. Channelled polymictic conglomerates (log I). B. Graded quartzolithic sandstones passing tosilty clays (log I). Anzano Molasse: C. Amalgamated massive sandy-matrix granule and pebbly conglomerates of Valle diFassa quarry (log VII). D. Detail of the texture of the conglomerates in photo C. E. Thin-bedded and laminated quartzo-feldspathic sandstones (log VII). F. Turbiditic quartzofeldspathic sandstones and clayey siltstones (log VI). G. Volcani-clastic layer (log VI).
714 BARONE ET AL.
brownish arenites and of greenish sandy pelites richin organic matter are present (Fig. 5B). North ofFlumeri (Fig. 2), between Fiego di S. Potito and S.Sofia, two mainly conglomeratic decametric bodiesare present; the upper one is characterized bymorphological relief and continuity for about 1.5km. Coarse-grained bodies are floored by erosionalsurfaces and exhibit a tabular geometry. They repre-sent hyperconcentrated-debris-flow deposition ina shallow-subaqueous environment; in the upperhorizon, embricated pebbles are also present. Theyare interpreted as different evolutionary stages of asmall fan-delta system prograding into a shallowlacustrine basin. They show a downcurrent transi-tion to turbidite sandstones (massive to graded andlaminated couplets), locally rich in a monospecificostracofaunal assemblage with Cyprideis torosa(Basso et al., 1996, 2001), representing a Lago-Maretype facies (Fig. 4, log I), here referred to theAnzano Molasse; in more distal strata, interbeddedlow-density fine-grained turbiditic sandstones andmudstones occur (Fig. 4, logs II-IV-V).
The upper interval, more developed in distal set-tings, is characterized by interbedded mudstones,marly limestones and thin-bedded fine-grainedturbiditic sandstones (Fig. 4, logs III-IV-V). Thefacies are mainly formed of dark-grey, greenish andbrownish sandy clays and marls rich in carbonfragments and with gypsum pebbles, greenish andyellowish fine-grained arenites and silt layers, mas-sive arenites with mollusc shells, marly calcilutites,and lenses of disorganized conglomerates withcalcareous-marly pebbles. A distinctive feature isthe occurrence, near the top of the unit, of someslumped horizons containing polychromatic claysand black shales with scattered siliceous-calcare-ous-marly blocks. In the Vallone del Cerro valley(Fig. 4, log II), silty clays with pebbles of gypsumare present and thick horizons of silty sands andconglomerates are interbedded.
Sandstones of the Torrente Fiumarella are quart-zolithic (Qm49±12 F18±17 Lt33±21); they include abun-dant quartz and feldspar (P/F=0,5; Qm76±15 K12±8P12±8). Aphanitic lithic fragments are dominantlysedimentary (Lm4±9 Lv0±0 Ls96±9), represented byextrabasinal carbonate (micrite, bio-micrite,sparitic, and biosparitic limestone and fossils) andminor siliciclastic fragments. Phaneritic rock frag-ments include also plutonic and metamorphic frag-ments; generally dominant are sedimentary-carbonate types (Rg29±34 Rs65±34 Rm6±3) (Figs. 6 and7). Microfossil associations consist of reworked
planktonic foraminifera and calcareous nanno-plankton species, as well as freshwater ostracods,such as Cyprideis torosa and Candona sp. (Basso etal., 2001, 2002).
The unit consists of slope to basin-plain depos-its; the basin was of the closed-lake type andreceived sporadic coarse detritus input, comingfrom an embryonic alluvial system, which wasdeveloping during emergence of the Apenninechain. The sedimentary lithofacies and their stack-ing patterns suggest repeated transitions fromdeeper to shallower water due to variations of rela-tive base level and of lake-basin infilling, with anoverall deepening trend.
The Anzano Molasse (Crostella and Vezzani,1964) is about 350 m thick and shows an overallupward fining trend (Fig. 4); it can be subdividedinto a lower arenaceous-conglomerate member andan upper arenaceous-pelite member (Matano,2002). The lower member (Fig. 4, log IV-VI-VII-VIII) is composed of granular and pebbly paracon-glomerates in a sandy matrix, and by coarse sand-stones (Figs. 5C–5D). The deposits are typicallymassive or thickly stratified and poorly cemented,locally with continental thin-shelled mollusk shellfragments and carbonized plant fragments. Medium-to coarse-grained sandstones with massive, gradedand laminated textures are present (Fig. 5E). Theupper member (Fig. 4, log III-VI-VII-VIII) consistsof yellow-brown medium to poorly cemented sand-stones, which are medium- to coarse-grained andthinly stratified, and by marly or clayey siltstones,locally rich in carbonized plant fragments andleaf marks. The turbidite sandstones present anerosional basal surface with flute-casts (Fig. 5F);paleocurrent directions are toward N120°–140°(ESE-SE). In the upper member, a discontinuouswhitish tuffite layer (Fig. 5G), formed by 1 or 2 dm-thick strata, is present (Fig. 4, log VI).
The unit consists of various lithofacies of gravitydeposits (cohesionless debris-flows, high-densitypebbly and granular turbidity currents, granular andsandy debris flows, and low-density turbiditycurrents), which form small-scale upward fining andthinning cyclically stacked successions (Matano,2002).
Anzano Molasse Formation sandstones arequartzofeldspathic (Qm44±5 F44±7 Lt12±8), with abun-dant quartz and equal proportions of plagioclase andK-feldspar (P/F=0,5; Qm50±6 K24±4 P26±6). Abun-dance of feldspars, with respect to the TorrenteFiumarella sandstones, suggests increasing contri-
POST-EVAPORITIC SANDSTONES 715
bution from plutonic source areas. Aphanitic lithicfragments (Lm16±21 Lv1±3 Ls83±22) are dominantlysedimentary, both carbonate (extrabasinal) andsiliciclastic fragments (chert, shale and siltstone).Total (phaneritic+aphanitic) rock fragments includevariable proportions of plutonic and sedimentaryfragments. In particular, two subpopulations are evi-dent, one plutonic-rich Rg78±11 Rs7±3 Rm15±11 andone mixed plutonic and sedimentary Rg42±10 Rs46±9Rm12±4 (Figs. 6 and 7).
Volcaniclastic strata (tephra layers) in the upperportions of the Anzano Molasse Formation are com-posed dominantly of neovolcanic detritus as vitricparticles (shards and pumice) (Fig. 7). Crystals arerare and are represented by quartz, sanidine, andplagioclase, and rarely biotite. Chemical analysis,SEM observations, and SEM-EDS microanalysissuggest felsic composition (rhyodacitic to rhyolitic),
confirming the previous study by Di Girolamo et al.(1986).
Intrarenites of the Lago-Mare facies containabundant intrabasinal carbonate particles (ooids,peloids, and bioclast) NCE22±11 CE4±0 CI74±11 andsubordinate extrabasinal noncarbonate and carbon-ate particles. Noncarbonate detritus includesquartz, feldspars, and rare aphanitic lithic frag-ments (Qm52±1 F25±4 Lt24±4; Qm68±2 K20±6 P12±4), aslow-grade metamorphic, sedimentary, and minorphaneritic plutonic rock fragments (Rg16±1 Rs53±1Rm31±3) (Figs. 6 and 7H).
Fossil associations are formed by rare freshwaterostracods, includingCyprideis torosa, Ilyociprisgibba, Candona sp., and Loxoconcha sp., and byMiocene reworked planktonic foraminifera (Globi-gerina multiloba, etc.) and calcareous nannoplank-ton species (Basso et al., 2002; Matano, 2002).
FIG. 6. Ternary diagrams showing sandstones composition of the post-evaporitic units. Mean (circle, diamond, andstar) and standard deviation (polygon). Abbreviations: Qm = monocrystalline quartz; F = feldspars, K+P; Lt = aphaniticlithic fragments and fine-grained polycrystalline quartz), K = K-feldspar; P = plagioclase). Aphanitic lithic and phaner-itic rock fragments in Rg (plutonic), Rs (sedimentary), and Rm (metamorphic). NCE = extrabasinal noncarbonate grains;CE = extrabasinal carbonate grains; CI = intrabasinal carbonate grains.
716 BARONE ET AL.
FIG. 7. Photomicrographs of diagnostic grains of the post-evaporitic units. A. Plutonic rock fragment (Rg). B. Phyllitelithic fragment (Lm). C. Polycrystalline quartz with tectonic fabric (Qp). D. Serpentinite lithic fragment (Lo). E. Volcaniclithic fragment with felsitic granular texture (Lvfg). F. Extrabasinal carbonate as micrite limestone (CE). G. General viewof the arenite studied, evidenced by rounded quartz crystal (Qtz) and extrabasinal carbonate as micrite limestone (CE).H. General view of the Lago-Mare intrarenite.
POST-EVAPORITIC SANDSTONES 717
Sedimentary lithofacies, their stacking patterns,and fossil associations of post-evaporitic depositscan be referred to a mainly freshwater lacustrinebasin with an overall deepening trend, receivingabundant coarse detritus from the thrust-belt. Sub-sequent basinal evolution shows a deeper-waterphase characterized by fine-grained facies of gravitydeposits.
Discussion and ImplicationsProvenance relations and regionalpaleogeographic evolution before andduring the Messinian salinity crisis
The pre-evaporitic history of the southern Apen-nines foreland region has been clearly influenced bycollisional processes since the early Miocene, whenthe Lucanian remnant-ocean basin was closed, andthe Mesomediterranean terrane collided with theAdriatic terrane of the Africa plate (Patacca andScandone, 1989; Doglioni, 1991; Guerrera et al.,1993; Critelli, 1999). Onset of continental collisionand subsequent foreland clastic sedimentation are
dated in the southern Apennines as early Miocene,and accretionary processes continued with high sliprates and uplift rates since the early Tortonian(Patacca et al., 1990; Sgrosso, 1998). During theTortonian, the southern Italian orogenic systemabruptly increased its eastward displacement,deforming and incorporating shallow-marine anddeep-marine domains of the Adria continentalmargin within the thrust belt. As a result of this newthrust-belt architecture, the foreland-basin systemshifted eastward toward the Apulia platform, into anarea previously dominated by pelagic and carbonatesedimentation of the Frigento, Fortore, and Dauniaunits (Fig. 8). Detrital modes for the southern Apen-nines foreland sandstone suites testify to abruptlychanging petrofacies during early evolution of theforeland, the result of accretionary processes andexhumation of crystalline terranes of the Mesomedi-terranean microplate (e.g., the Calabrian Arc), thusgenerating voluminous plutonic-metamorphiclasticsandstones. Since the Tortonian, detrital modeshave been dominantly quartzofeldspathic, havingalso contributions from sedimentary source rocks as
FIG. 8. Paleogeographic sketch of the Apenninic domains during the Miocene. Initial backarc rifting of the Tyrrhe-nian Sea, diverse wedge-top and foredeep depozones, and progressive displacement of the outer front of the chain in thesouthern Apennines foreland region.
718 BARONE ET AL.
carbonate platforms and pelagic rocks that wereassembled within the thrust belt.
During the Messinian, the paleogeography andpaleotectonics of the southern Italian orogenicsystem were characterized by the hundred-kilo-meter-wide thrust belt and several small to medium-size depositional basins on both foreland and back-arc flanks of thrust belt (Fig. 8). Also, the salinitycrisis that occurred during the late Messinian pro-duced interaction between clastic and evaporitesedimentation for many of these basins. From thesyn-rift backarc region to intermontane and forelandregions, evaporite sedimentation occured with, orwas followed by, clastic sedimentation (e.g.,Amantea Basin, Crotone and Rossano basins,Irpinia-Daunia basins; Di Nocera et al., 1975;Critelli, 1999; Matano et al., 2005). Detrital modesduring the Messinian sedimentary history in south-ern Italy are marked by regional quartzofeldspathicpetrofacies, suggesting deep unroofing of theCalabrian Arc (e.g., Critelli and Le Pera, 1995,1998; Critelli, 1999).
All sandstones have plutonic and sedimentarydetritus (Fig. 6). Sedimentary detritus is abundantin all sections, and consists of both carbonate andsiliciclastic particles (Fig. 7). Carbonate detritusincludes both pelagic and shelfal microfacies,suggesting provenance from deformed basinal andplatform sequences assembled within the thrustbelt. These particles suggest a provenance of Meso-zoic to Tertiary strata of the Alburno-Cervati-Pollinoand Monti della Maddalena-Monte Marzano units(pre-Tortonian forebulge zone of the orogenicsystem) and from the Sicilide and Lagonegro(Frigento-Fortore) units (pre-Tortonian backbulge),representing the frontal thrust of the post-Tortonianorogenic system (Fig. 8). The abundance of plutonicand metamorphic detritus suggests a provenancefrom both the accreted Calabrian arc terranes and/orthe recycling of these particles from older clasticunits (i.e., pre-Tortonian clastic wedges), assuggested by the presence of variable percentages ofsiliciclastic debris.
Interplay of the Messinian salinity crisis and tectonics
The late Messinian evolutionary history of theIrpinia-Daunia section of southern Apennines fore-land basin system occurred in two key stages (Fig.9). During stage 1 (Fig. 9B), the region underwent amarked restriction for the first time, which resultedin progressive establishment of anoxic, starved con-
ditions during the pre-evaporitic stage, and then, inmarine evaporite sedimentation, about 100 m inthickness, in marginal portions of the foreland basinduring the early part of the late Messinian (evapor-itic stage). Evaporite deposits (the Monte CastelloEvaporites Formation) are dominated by alterna-tions of clastic reworked gypsum beds, laminatedgypsum, and selenitic gypsum beds. Gypsumformed in a restricted/evaporitic shallow- to deeper-water environment fed by marine waters, accordingto Sr isotopic compositions (Matano et al., 2005).The Monte Castello Evaporites are correlated withthe classical Lower Evaporite sequences, as theyoccur in diverse portions of the Mediterraneanregion.
Transition from stage 1 to stage 2 in the southernApennines foreland basin corresponds to a strongtectonic phase (Decima and Wezel, 1971; Elter etal., 1975; Di Nocera et al., 1976; Torre et al., 1988;Patacca and Scandone, 1989). During the intra-Messinian tectonic phase, the Daunia unit wasdeformed and thrust eastward, forming the frontalsector of the late Messinian thrust wedge, and thepropitious conditions for the evaporitic depositionwere terminated. This led to the migration of fore-land-basin depocenters (DeCelles and Giles, 1996;Fig. 9C) and in marginal settings, to the formation ofan important erosional surface (Roveri et al., 2001).General agreement exists that this erosional surfacedeveloped in a subaerial environment during the1500 m sea-level drop, which led to the completedesiccation of Mediterranean in the intervalbetween 5.59 and 5.50 Ma (Krijgsman et al., 1999).
In the study area, marginal evaporites arecapped by an angular unconformity with evidence ofsubaerial exposure (Matano et al., 2005); this wouldagree with a base-level drop related to desiccation ofthe basin. According to Butler et al. (1995) andRoveri et al. (2001), deposition of marginal lower-type evaporites preceded the complete desiccationof the Mediterranean and was controlled by pre-existing foreland-basin morphology.
In stage 2 (Fig. 9C), proximal portions of the fore-land-basin emerged, the result of the intra-Messin-ian tectonic phase, receiving voluminous clasticalluvial-lacustrine sediments, as suggested also bythe presence of freshwater ostracods in the TorrenteFiumarella and Anzano Molasse units (Fig. 4),which accumulated in a thrust-top basin formed onthe Frigento, Fortore, and Daunia thrust sheets.
The Torrente Fiumarella sandstone suiteincludes a quartzolithic petrofacies containing
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720 BARONE ET AL.
abundant plutonic and sedimentary detritus (Fig. 6).The petrofacies is controlled by hydrographic-net-work and basin reorganization related to the salinitycrisis and local tectonics.
The Anzano Molasse sandstones are typical ofthe general quartzofeldspathic petrofacies, abun-dant plutonic and medium-high-grade metamorphicdetritus, and locally important sedimentary contri-butions (Fig. 6) derived from the inner carbonateplatform of the Alburno-Cervati-Pollino units andtheir margins (Monti della Maddalena–Monte Mar-zano units), and from pelagic sequences of the Sicil-ide Complex and Lagonegro basin units (Fig. 8).
Intrarenites of the Lago-Mare succession (Fig. 4)contain abundant intrabasinal carbonate particles(Fig. 6) that are related to the presence of layers veryrich in ostracoda assemblages, a common biofaciesin the Lago Mare event (Bonaduce and Sgarrella,1999; Gliozzi, 1999). This event is recorded inthe whole Apenninic-Maghrebian foreland-basinsystem, in the Tyrrhenian area and in the westernand eastern Mediterranean, suggesting completeMediterranean isolation from the ocean (Hsü et al.,1977).
A sudden change in hydrology of the southernApennines foreland region occurred in the latestMessinian, when a dominantly freshwater bodyreplaced the marine waters, apparently withoutchange in water depth. This new hydrologic regimeis recorded in deep-water basin successions both ofthe northern Apennines (Roveri et al., 2001) and ofthe southern Apennines by organic-rich euxinic lay-ers with gypsum characterized by lower Sr isotopicratios (Matano et al., 2005).
Conclusions
During the Messinian, the southern Apenninesexperienced intense accretion and uplift. Post-evaporitic sandstones in the Irpinia-Daunia sectorof the southern Apennines foreland-basin systemrecord effects of both foreland evolution and theMessinian salinity crisis. Abrupt change from hemi-pelagic and calciturbidite sedimentation to evapor-ite and post-evaporitic clastic sedimentationresulted from the interplay between tectonics andsea-level changes.
Stratigraphic and petrologic studies of theMessinian succession in the Irpinia-Daunia portionsof the southern Apennines foreland-basin systempermit the following conclusions:
1. Evidence suggests the progressive establish-ment of anoxic, starved conditions during the pre-evaporitic stage and a permanent marine connectionduring the evaporitic stage, dominated by reworkedgypsum and laminated selenitic gypsum (MonteCastello Evaporite Formation) in the Daunia unitdomain.
2. The presence of an angular unconformity witherosional features at the base of the post-evaporiticdeposits attests to tectonic deformation of the Dau-nia unit within the thrust belt and its emergence.
3. The presence of continental alluvial andlacustrine deposits (Anzano Molasse and TorrenteFiumarella formations) in the post-evaporiticsequence attests to the influence Lago-Mare eventsand tectonic foreland evolution have exerted onpaleohydrography and basin paleogeography.
Detrital modes document complex provenancerelations with late Messinian accreted terranes ofthe southern Apennines. All sandstones have abun-dant plutonic and sedimentary detritus. Carbonatedetritus includes both pelagic and shelfal microfa-cies, suggesting provenance from deformed basinaland platform sequences assembled within the thrustbelt. The abundance of plutonic and metamorphicdetritus in these sandstones suggests derivationfrom both accreted Calabrian arc terranes and recy-cling from older clastic sequences.
Lithology and facies arrangement of both pre-evaporitic deposits and primary evaporites of thesouthern Apennines foredeep are similar to those ofthe northern Apennines evaporites (Vai and RicciLucchi, 1977) and the “lower evaporites” of Sicily(Decima and Wezel, 1971). The “upper evaporites”of Sicilian basins are not present in the northern andsouthern Apennines foredeep successions, whichare characterized by post-evaporitic clastic depos-its. Study of the nonmarine Anzano-Fiumarellabasin may provide useful data about the evolution ofsimilar sedimentary basins; nonetheless, the studiedsequences provide an example of the effects of theinterplay between tectono-stratigraphic evolution ofa foreland basin and the salinity-crisis in the sedi-mentary record.
Acknowledgments
We are very grateful to Ray Ingersoll, who kindlyreviewed and improved the final version of themanuscript. We are grateful to J. M. Rouchy, J. P.Réhault, and M. Roveri for discussions and review-ing an earlier version of the manuscript. The
POST-EVAPORITIC SANDSTONES 721
research was supported by funds (ex-60%) of theItalian Ministero dell’Università e della RicercaScientifica, project “Paleogeographic and Paleotec-tonic Evolution of the Southern Italian OrogenicSystem and Their Correlations with the Circum-Mediterranean Orogeny” (Resp. S. Critelli), and bythe COFIN-PRIN 2003 project “eventi stratigraficie paleogeografia del Messiniano e del Pliocenenell’Appennino molisano-campano” (Resp. S. DiNocera).
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