ELSEVIER Earth and Planetary Science Letters 160 (1998) 587–592

Express Letter

Oxygen isotope measurements of mammoth and reindeer skeletalremains: an archive of Late Pleistocene environmental conditions in

Eurasian Arctic

L. Genoni a, P. Iacumin a, V. Nikolaev b, Yu. Gribchenko c, A. Longinelli a,*

a University of Trieste, Department of Geological, Environmental and Marine Sciences, Laboratory of Isotope Geochemistry,Via E. Weiss 6, 34127 Trieste, Italy

b Institute of Geography, Russian Academy of Sciences, Department of Glaciology, 29 Staromonetny per., Moscow 109017, Russiac Institute of Geography, Russian Academy of Sciences, Laboratory of Evolutionary Geography, 29 Staromonetny per.,

Moscow 109017, Russia

Received 12 February 1997; accepted 14 May 1998

Abstract

58 samples of fossil mammoth and reindeer teeth and bones of various ages and coming from different locations werestudied for the oxygen isotopic composition of their phosphate. Samples from Siberia have interstadial (Marine IsotopeStage 3), stadial (MIS 2), late-glacial and post-glacial ages. Russian and Ukrainian samples refer to the late-glacial andtransitional (between the interstadial and glacial stages) time. The Ž18O of palaeoenvironmental waters were calculatedfrom the Ž18Op obtained from fossil samples by means of the isotope equations calibrated on modern specimens ofelephants and deer respectively. The Ž18Ow obtained are generally lighter than those measured nowadays in the sameareas and not far from those measured on ice cores of Holocene age, the isotopic differences being not greater than afew Ž units. The calculated values are also in fairly good agreement with some isotopic values obtained from Siberianpermafrost samples. According to the results obtained it seems that the elephant and deer equations can be reasonably usedrespectively in the case of fossil mammoth and deer skeletons to evaluate environmental palaeowaters. 1998 ElsevierScience B.V. All rights reserved.

Keywords: Eurasia; Arctic region; Pleistocene; paleoenvironment; oxygen; isotopes; mammals; bones

1. Introduction

A fairly large amount of palaeogeographic infor-mation obtained so far allows the development ofreliable reconstructions of Late Pleistocene environ-mental conditions in northern Eurasia [1–3]. How-ever, quantitative or semi-quantitative methods wereseldom used. Important pieces of information come

Ł Corresponding author. Tel.: C39 (40) 6762-153; Fax: C39 (40)6762-152; E-mail: labgeois@univ.trieste.it

from papers [4–6] reporting the isotopic compositionof ice cores from deep boreholes in central Arctic icecaps (Severnaya Zemlya archipelago). The Holoceneice showed Ž18O values of about �20 š 1‰ whilethe basal broken ice, composed of different ice lay-ers and supposed to be Pleistocene in age, yieldedlighter Ž18O values as low as �26‰. Another groupof papers deals with the isotopic composition ofSiberian underground (permafrost) ice [7–12].

This research was carried out to obtain furtherinformation on the mean isotopic composition of

0012-821X/98/$19.00 1998 Elsevier Science B.V. All rights reserved.PII S 0 0 1 2 - 8 2 1 X ( 9 8 ) 0 0 1 1 3 - 7

588 L. Genoni et al. / Earth and Planetary Science Letters 160 (1998) 587–592

Fig. 1. Sampling sites of mammoth and reindeer samples in Siberia and Russia.

environmental water and, hence, on atmospheric pre-cipitation throughout the Late Pleistocene by meansof investigations on mammal skeletal remains. Infact, according to the possibility of using mammalteeth and bones for quantitative palaeoclimatolog-ical and palaeoenvironmental reconstructions [13–15], mammoth and reindeer skeletal remains of dif-ferent ages were collected from different areas ofSiberia and of the European part of Russia (Fig. 1)and studied for the oxygen isotopic composition oftheir phosphate (Ž18Op). The possibility of convert-ing Ž18Op values of fossil mammal teeth and bonesinto Ž18O of palaeoenvironmental water and, hence,into a palaeoclimatological parameter, is essentiallyrelated to the availability of isotopic scales calibratedon living specimens of the same species, collectedfrom different climatic areas [15–17]. In the caseof mammoths it is obviously impossible to estab-lish such a scale. In the case of reindeer, living orrecent specimens are available and we are planningto calibrate an isotopic scale in the near future eventhough the range of local climatological conditionsin the areas inhabited by reindeer is rather narrow,the yearly mean Ž18O values of environmental wa-ter being roughly in the range of �12 to �13‰(Longinelli, unpubl. data).

2. Materials and methods

A first group of 58 samples of mammoth andreindeer teeth and bones was studied along withthree deer bones coming from different locations.Siberian samples (Fig. 1) yielded conventional 14Cages of about 10, 11 (post-glacial time), 13, 14, 15(late glacial), 20–21 (glacial stage), 39–41 and over40 ka BP (interstadial stage). Russian and Ukrainiansamples (Fig. 1) yielded conventional 14C ages ofabout 13.5–16.1 (late glacial time), 20.6–23.4 and23.4–25.3 ka BP (transition between interstadial andglacial stages). Samples are apparently well pre-served and this may be particularly true in the caseof Siberian samples due to the low temperature andthe permafrost conditions still existing at least inYakutia and along the coast of the Leptev Sea.

As regards the chemical treatment of the samples,the technique described in [18,19] was used and theAg3PO4 samples were reacted with BrF5 at about600ºC for 12 h; the O2 obtained from this reac-tion was then converted to CO2 by cycling over hotgraphite in the presence of a Pt catalyst and mea-sured for its 46=44 ratios by means of a FinniganDelta S or a Fisons Optima mass spectrometer. Thestandard deviation of repeated measurements on the

L. Genoni et al. / Earth and Planetary Science Letters 160 (1998) 587–592 589

same sample is about š0.1 to š0:2‰ (1¦ ). All thesamples were measured at least in double and oftenin triplicate, the reported value being the mean valueof consistent results.

3. Results and discussion

The mean oxygen isotope values obtained fromteeth and bone phosphate are reported in Table 1(total data set are available as an EPSL OnlineBackground Dataset 1). While waiting for furtherdevelopments of these studies, a possible way toevaluate the reliability and the palaeoclimatologicalmeaning of the reported data is to try to ‘translate’the Ž18Op in terms of Ž18Ow (isotopic compositionof environmental water) by applying the equationsalready established for mammals biologically closeto mammoths and reindeers, respectively, i.e. modernelephants [16] and modern deer [15]. This can bedone assuming the measured Ž18Op values equal orvery close to the pristine isotopic composition ofthe fossil samples. As regards the reliability of thereported values, we carried out measurements ofthe oxygen isotopic composition of bone carbonateŽ18Oc, along with the Ž18Op measurements, on someof the studied samples. By comparing the relevantdata and according to the conclusions reported in[20] (Fig. 2), we can conclude that, at least in thecase of these samples, no clear diagenetic changesapparently took place. Consequently, the reportedisotopic results may be considered representative ofthe Upper Pleistocene and Holocene environmentalconditions in the studied areas. The mean Ž18Ow

values calculated according to the equations givenby [15] and [16] are reported in Table 1.

The only available references for evaluating thereliability of the Ž18Ow calculated from fossils are:(1) the weighted mean yearly isotopic values mea-sured on atmospheric precipitation in nearby areas;(2) the Ž18O values measured on ice cores drilledin ice caps in Severnaya Zemlya [4–6]; (3) the Ž18Ovalues obtained from the Siberian permafrost [7–12].

Modern mean Ž18O values of atmospheric precip-itation are �15.7‰ at Amderma, on the Arctic coast

1 http:==www.elsevier.nl=locate=epsl,mirror site: http:==www.elsevier.com=locate=epsl

between Novaya Zemlya and the Yamal Peninsula[21], about �20–21‰ at Yamal Peninsula (north-western Siberia) [8], close to �24‰ in the area atthe mouth of Kolyma River (eastern Siberia) [11],and between �13 and �15‰ in western Siberia(Perm and Pechora, respectively) [21]. In westernRussia and Ukraine the data available suggest Ž18Ovalues close to �10‰ near the Polish border andclose to �11‰ in the Moscow area [21]. These val-ues become progressively lighter eastward reaching�15 š 1‰ in the area between the Baikal Lake andthe Ob River, where our samples 11 to 15 comefrom.

The mean Ž18O values of Holocene ice are closeto �20š 1‰ on the Severnaya Zemlya archipelago,the overall range of measured values ranging from�17.5 to �21.5 in the Vavilov ice cap (79º200N) andfrom �18.0 to �23.5 in the Academy of Sciencesice dome (80º300N) [5]. Pleistocene ice buried byblocks of frozen sediments under the Vavilov ice capyielded Ž18O values as low as �26‰ [4].

Ground sheet ice (probably buried Pleistoceneglacial ice) yields values between �16 and �20‰in western Siberia [7,10] and �20.5–22.5 in theYenisei River valley [22,12]. The isotopic results ob-tained from underground ice (permafrost) for variousclimatic stages and locations range between�15 and�26.7 for northwestern Siberia [8]. In the Kolymalowland (Yakutia) Ž18O values range from about �25to �32.5‰ in the case of ice wedges and betweenabout �20 and �30 for segregated ice [11]. Un-derground ice from Lyahovsky Island (NovosiberianIsland archipelago) varies between �22 and �25(last interglacial) and between �28 and �35.5‰(Late Pleistocene glaciation). It should be pointedout that the isotopic composition of the ice wedgesis supposed to reflect the mean isotopic values ofwinter precipitation.

The mean Ž18Ow calculated from samples fromnorth Siberia (Table 1) range (independent of theirage) between �17.3 and �20.7‰. These values arevery close to the modern mean isotopic compositionof atmospheric precipitations measured in these ar-eas, almost equal to Holocene ice values measured atslightly higher latitudes and definitely quite compati-ble compared to permafrost Ž18O, taking into accountthe different meaning of these two variables (yearlymean values versus winter mean values). Apart from

590 L. Genoni et al. / Earth and Planetary Science Letters 160 (1998) 587–592

Table 1Number and type of samples measured, sampling sites, mean oxygen isotopic composition of bone and tooth phosphate (total data set areavailable as an EPSL Online Background Dataset) and mean oxygen isotopic composition of local environmental water calculated fromthe measured Ž18Op values by means of the isotopic equations on modern elephants (excluding data from arid areas) [16] and moderndeer [15]

Sample No. Measured samples Site 14C age (ka BP) Sample type Ž18Op š s.d. Ž18Ow š s.d.

Northern Siberia8 2 Yakutia 10 M tusks 6.5 š 0.1 �17.9 š 0.2

16 2 Bolshoy Lyahovsky Is. >40 M tuskCbone 5.2 š 0.3 �19.3 š 0.317 1 Rebrovo >40 M bone 5.5 �18.918 2 Kondrat’evo unknown M dent. C enamel 3.8 š 0.4 �20.7 š 0.419 7 Sviatoy unknown M tusk C bones 5.5 š 0.9 �19.0 š 1.021 1 Mamontova Gora unknown M tooth 6.9 �17.422 1 Turancha River unknown M bone 7.0 �17.3

Southern Siberia11 11 Afontova Gora II 13 R bones 10.1 š 0.6 �13.4 š 0.611 1 Afontova Gora II 13 M bone 9.2 �15.011 4 Afontova Gora II 14 R bones 11.0 š 0.8 �12.9 š 0.811 1 Afontova Gora II 15 R bone 10.5 �13.314 1 Listvenka 13–14 R bone 11.2 �12.715 3 Kashtanka 20–21 R bones 10.5 š 0.4 �13.3 š 0.412 3 Bolshaya Slezneva unknown D bones 9.8 š 1.4 �13.9 š 1.3

Russia and Ukraine1 5 Eliscevichi 14.3 M teeth C bones 12.7 š 0.6 �11.3 š 0.75 3 Mezhirich 14.3 M tusk C bones 13.4 š 0.2 �10.5 š 0.34 3 Yudinovo 13.6–15.8 M bones 13.8 š 0.2 �10.1 š 0.26 4 Avdeevo 20.8–22.7 M teeth 12.2 š 0.4 �11.8 š 0.53 5 Khotylevo 23.7–25 M teeth C bones 12.4 š 0.7 �11.6 š 0.8

Fig. 2. Oxygen isotopic composition of bone carbonate versusoxygen isotopic composition of bone phosphate for some of thestudied samples. Both variables are reported versus V-SMOW.

a detailed and critical interpretation of these resultsin terms of palaeoclimatological conditions duringwell defined periods, it seems that the range of val-ues obtained is acceptable, suggesting for the oldersection of the last glacial mean environmental condi-tions not far from those of Holocene and not too far

from modern conditions. This hypothesis seems ac-ceptable on the basis of the following considerations:

(1) According to isotopic investigations on under-ground ice in Yakutia, winter temperatures duringMarine Isotope Stages 2, 4 and 6 were probablyabout 10ºC colder than modern temperatures and 3–4ºC colder during interstadial MIS 3 [9]. Under theseconditions a small isotopic shift in values from mam-moth bones should represent warm summer seasonsand great climatic contrasts between seasons in theLate Pleistocene.

(2) Mammoth herds needed a steppe environmentfor their survival and this excludes the possibilityof extremely severe conditions with a permanentand thick ice cover. Climatological and environmen-tal conditions close to modern conditions in theSiberian Arctic or, at least, not considerably moresevere should be envisaged to allow a developmentof local vegetation sufficient to support mammothherds. Note that, when mammoths reached Sever-naya Zemlya (Allerod; 11–12 ka BP) Ž18Ow were

L. Genoni et al. / Earth and Planetary Science Letters 160 (1998) 587–592 591

close to �20‰ (Holocene value ³ �20 š 1‰ ac-cording to [6]).

Several reindeer and one mammoth bone (mainly13–14 ka BP) from southern Siberia (Fig. 1, sam-ples Nos. 11 and 14) yield Ž18Ow values, calculatedagain by means of the deer equation and the elephantequation respectively, ranging from �12.7 to�15‰.These values are slightly lighter than modern valuesfrom the same area. Three deer bones of unknownage (sample No. 12) yield a mean Ž18Ow of �13.9,within the range of the other values. The palaeocli-matological and palaeoenvironmental conditions forthe same area and for the same period are consid-ered suitable for human occupation according to [2],somehow confirming the above hypothesis. Unfor-tunately, there are no ice or permafrost values tobe considered for a comparison with the calculatedŽ18Ow.

If we now take into account the results obtainedfrom the European part of Russia (Fig. 1 and Table 1—only mammoth samples) the mean Ž18Ow valuescalculated from all the samples available, indepen-dent of their age, are lighter than modern valuesby about 1‰. However, the values obtained fromglacial age (samples 3 and 6) are lighter by about1.5‰ than post-glacial samples (samples 1, 4 and 5).In the case of this area it will be possible to comparethese results with those obtained from the skeletalremains of other fossil mammals for which isotopicscales have already been established.

4. Conclusions

Some considerations are worth being stressed.(1) It seems possible to use mammoth skeletal

material for palaeoclimatological studies using themodern elephant equation [16] to evaluate the iso-topic composition of palaeowaters.

(2) A similar conclusion probably holds also inthe case of reindeer skeletal material if the deer equa-tion [15] is used (recent reindeer skeletal sampleswill be measured soon to confirm this conclusion).

(3) The mean isotopic composition of atmo-spheric precipitation over Siberia during the LatePleistocene and early Holocene was probably notmuch lighter than modern mean annual precipitationin the same areas, the isotopic gradient being at most

of a few Ž units. These conclusions are perhaps re-lated to the fact that Late Pleistocene cold stagesin Siberia were probably characterized by winterscolder than nowadays and hot summers, probablywarmer than modern ones. Cold dry winters andwarm wet summers agree with the conditions re-quired to yield the observed results and to produceenough food for mammoth herds.

(4) According to the data obtained the growthof glaciation in eastern Europe probably proceededunder conditions of a relatively close source of mois-ture (polar front over the North Atlantic) and east-ward direction of airflows.

Acknowledgements

The authors’ thanks are due to Dr. R. Vaikmaefor helpful discussions on the isotopic compositionof Siberian permafrost, to Dr. M. Ramigni for hishelp with the preparation of the samples, to Drs.A.A. Arkhangelov, E.I. Kurenkova, S.A. Lakhin,P.A. Nikolsky and L.D. Sulerzhitsky for supply offossil material and for 14C dating. This research wassupported in Italy by the Ministry of University andScientific Research and in Russia by the RussianFoundation for Fundamental Investigations (Grant96-05-65305). [AC]

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