reconstruction of past precipitation δ18o using tree ring cellulose δ18o and δ13c a calibration study near lac d annecy france abstract two sets of living oaks quercus r growing under different hydrological situations were sampled near lac d annecy france the stable isotope composition of the latewood cellulose was analysed in terms of oxygen and carbon isotopic composition for the period 1971 2001 and compared to the nearby monthly meteorological temperature relative humidity and isotopic composition of precipitation records a linear regression shows that 60 of the cellulose oxygen isotopic composition inter annual variations are due to changes in precipitation isotopic composition and relative humidity the small slope between cellulose versus precipitation oxygen isotopic composition suggests a significant contribution of local continental recycling and questions the common assumption that vapour oxygen isotopic composition is at equilibrium with precipitation isotopic composition in europe during the growing season finally the combined use of tree ring oxygen and carbon isotopic composition records enables to account for leaf water enrichment due to stomata stress and to provide a reconstruction r 2 0 64 of the summer precipitation isotopic composition

opening of the grenada back arc basin and evolution of the caribbean plate during the mesozoic and early paleogene abstract geological and geophysical data indicate that the grenada basin was presumably created during the paleocene by sundering of a proto eastern caribbean arc into a remnant arc to the west aves swell and an active arc to the east lesser antilles ridge grenada basin spreading is thought to have been penecontemporaneous with the creation of the yucatan basin located at the opposite side of the caribbean sea i suggest that a continuous mesozoic caribbean arc m c a including the greater antilles the aves lesser antilles system and the aruba blanquilla chain netherland venezuelan antilles was initiated in the pacific probably about 130 120 ma ago its arrival in front of and its subsequent motion inside the central atlantic tethyan seaway caused the opening of both yucatan and grenada basins which occurred at the two initial points of contact with the north and south american cratons in contrast to the style of many other island arcs this back arc spreading event occurred only once in the long history of the m c a the lesser antilles appear to be the oldest currently active intra oceanic island arc

a 240 000 year stable carbon and nitrogen isotope record from a loess like palaeosol sequence in the tumara valley northeast siberia abstract a 15 m loess like palaeosol sequence located in the tumara valley southwest of the verkhoyansk mountains was investigated to reconstruct the late quaternary environmental history of northeast siberia total organic carbon toc and total nitrogen n show several distinct and abrupt shifts during the last 240 ka both proxies have generally low values

stable isotope δ13c δ15n δ18o record of soils in buryatia southern siberia implications for biogeochemical and paleoclimatic interpretations stable isotope analyses of soils significantly contribute to a better understanding of biogeochemical and paleoenvironmental processes this paper presents and discusses stable carbon nitrogen and oxygen isotope 13c 15n and 18o data of representative soils of buryatia southern siberia in undisturbed soils kastanozem phaeozem gleysol podzol leptosol 13c and 15n values of soil organic matter som increase from the organic layers o layers to the mineral topsoils ah horizons and subsoils this primarily indicates advanced c and n mineralization in lower soil horizons and reflects the input of fresh litter in the o layers combined with numerical ages these data indicate that during the last ca 40 ka no c4 grasses prevailed in semiarid regions of buryatia disturbed soils ploughed chernozem and an anthrosol do not show with depth increasing 13c and 15n values but are characterized by fluctuating depth profiles high 15n values in the anthrosol up to 10 5 point to an open n cycle in a middle and late holocene aeolian paleosol record burdukovo 18o of the hemicellulose biomarkers arabinose and xylose show minima in the dark humic buried a horizons and maxima in the greyish silty fine sand layers this reflects the alternation of more arid and more humid conditions this interpretation is also in agreement with higher grain size ratios 20 63 m 2 6 m in the greyish fine sand layers documenting increased wind strength and dust supply som 13c and 15n values of o layers and ah horizons were furthermore investigated along an altitudinal transect in the khamar daban mts from 470 m to 1800 m a s l generally 15n values decrease with increasing altitude giving evidence of more closed n cycles at higher altitudes which are characterized by lower temperatures as an exception 15n of the ah horizons above 1500 m reveals conspicuously positive values presumably because of frequent burning of the dwarf pine belt with high n losses due to volatilization 13c shows no significant altitudinal trend above 750 m a s l but more negative values below 750 m a s l this may be attributed to frequent temperature inversions close to lake baikal similarly this inversion inducing fog and higher humidity close to lake baikal could also explain why 18o of the hemicellulose biomarkers arabinose and xylose do not reflect the altitude effect as it could be expected from 18o of precipitation

the link between tectonic and paleoclimatic events at 2 8 2 5mabp in the lake baikal region abstract the records of diatom abundance clay fraction content and magnetic susceptibility from lake baikal drill core bdp 96 1 reflect the climate driven plio pleistocene evolution of the lake baikal sedimentation system in addition to the dramatic variations in the proxy records in response to the northern hemisphere ice ages the baikal record also indicates climatic deterioration from 2 8 to 2 5 ma bp with evidence for an early siberian glaciation around the matuyama gauss paleomagnetic reversal boundary the drill core data also allow correlation of this early glacial interval with the basin wide seismic sequence boundary b10 which marks the unconformity produced by the active neotectonic phase in the baikal rift zone at the bdp 96 drill site however the strong b10 acoustic reflection was produced not by an erosional boundary but instead by deposition of glacial clay layers the paleomagnetic age scale of bdp 96 1 constrains the upper age of the neobaikalian uplift subsidence phase in the baikal sayan region at ca 2 5 ma bp the coincident timing of the paleoclimatic and tectonic events recorded in lake baikal sediments suggests a close causal link between regional tectonics and climate and indicate that the late pliocene uplift contributed to the initiation of the early glaciation in southeast siberia between 2 8 and 2 6 ma bp by creating an elevated terrain with lower snowline favorable for alpine glaciation and by changing the heat balance of the region

composition of solar wind noble gases released by surface oxidation of a metal separate from the weston meteorite abstract surface sited noble gases were released from metal separates from the weston meteorite by step wise oxidation at temperatures below 400 c gas release from residual silicates in the separates was successfully suppressed by prior pyrolysis at somewhat higher temperatures than the combustions helium neon and argon extracted from the metal show clear evidence of a solar wind signature xenon and nitrogen on the other hand were dominated by air so that no solar component could be identified for these gases uncertainties on krypton isotopes were too large to yield useful conclusions helium neon and argon elemental and isotopic ratios appear to depend on depth within the metal grains in most cases becoming heavier with increasing oxidation of the metal the cause of this dependence on amount of oxidation is not yet known ratios derived for the surface sited component are therefore somewhat model dependent our best estimates are that at the time of weston s exposure the solar wind4he36ar ratio was around3 6 104 20ne36ar was close to 45 4he3he was about 2500 20ne22ne about 13 3 13 4 21ne22ne about 0 033 0 035 and36ar38ar about 5 5 5 7 these ratios indicate that weston did not acquire its solar wind gases from a recent exposure to solar wind but more probably at a time in the past similar to or even earlier than the exposure time of apollo 17 breccias such as 79035 the36ar38ar ratio in conjunction with other recent determinations of this value suggests that it is no longer appropriate to assume that the solar and terrestrial values are equivalent

genesis and properties of black soils in buryatia southeastern siberia russia abstract soils with deep and dark brown to black humic surface horizons derived from sandy silty aeolian and alluvial sediments are relatively fertile and store huge amounts of carbon globally they mainly correlate with steppe ecosystems because their deep and dark epipedons are frequently rich in black carbon it was recently suggested that they developed due to prevalent burning of the semiarid vegetation this paper describes six soils with deep and dark humic surface horizons located in catchments of the selenga and uda rivers in buryatia southeastern semiarid siberia the organic matter of most of these soils not only originates from grass steppe but in addition from trees and shrubs five soils can be classified as chernozems and kastanozems wrb 2006 one soil is a deep and black anthrosol occurring in patches in the region all soils have calcic horizons below the mollic epipedon some with cambic bw horizons in between as the parent material does not contain carbonates aeolian input and hydrolysis of ca silicates contribute to the development of the secondary carbonate accumulation which is frequently cryoturbated all profiles are more or less stratified due to solifluction texture ratios 2 al 2 o 3 and al 2 o 3 100 al 2 o 3 na 2 o increased concentrations of tio 2 mgo and fe 2 o 3 presumably indicate advanced formation of chlorite radiocarbon analyses indicate that these deep and dark mollic horizons started to develop during the more humid holocene climatic optimum ca 7000 5000 bp palynological studies confirm expansion of forests in the lake baikal region in this period this is in agreement with higher alkane ratios nc27 nc31 in most of the deep and dark a horizons indicating that these epipedons diagnostic for chernozems and kastanozems did not develop exclusively under grass steppe thus supporting the hypothesis that a significant part of the soil organic matter is inherited from trees and shrubs this seems to be in contrast to middle europe and the russian plain where chernozems presumably developed during the early and mid holocene under grass steppe and subsequent degraded with increasing humidity and invasion of forests high contents of black carbon in the calcic chernozem p4 and lower ones in the long lasting occupied hortic anthrosol indicate that the deep and dark a horizons of mollisols most likely do not result from frequent burning but from biochemical processes

late glacial and holocene environmental change reconstructed from floodplain and aeolian sediments near burdukovo lower selenga river valley lake baikal region siberia abstract floodplain and aeolian sediments near burdukovo reveal a detailed record of holocene environmental change in the lower selenga river valley lake baikal region siberia during the late pleistocene and early holocene fine grained alluvium accumulated on the floodplain followed by a period of increased landform stability and subsequent pedogenic formation this part of the stratigraphical sequence yielded rich assemblages of terrestrial molluscs which increase in species diversity from early pioneer communities with about ten taxa to levels containing over twice that number the land snail assemblages also record an episode of relatively drier local habitats prior to 9 2 ka bp with subsequent wetter conditions lasting until 8 0 ka bp this was followed by an abrupt and sustained change in floodplain deposition shifting from overbank alluvium to aeolian sedimentation within which a series of weakly developed soil horizons formed during the middle and late holocene periods the onset of aeolian processes and relatively drier conditions in the middle holocene at burdukovo coincides with major changes observed both in other regional palaeoenvironmental proxy records and in local archaeological sequences although it is still not clear how the two are linked

changes in vegetation type on the chinese loess plateau since 75 ka related to east asian summer monsoon variation abstract floral communities in terrestrial habitats such as steppes are highly sensitive to regional climate changes here we generated carbon and nitrogen isotope profiles for soil organic matter som in the weinan loess paleosol section in order to investigate changes in floral communities on the chinese loess plateau clp and their relationship to climate variation since 75 ka 13csom at weinan ranges from 23 6 to 18 0 and 15nsom ranges from 3 4 to 5 5 modeling based on the 13csom record suggests that the proportion of c4 plants c4 has varied from lower during cold intervals with minima of 24 32 at 73 1 ka 20 9 ka lgm and 0 6 ka to higher during warm intervals with maxima of 62 64 at 53 0 ka and 8 2 ka the 13csom and 15nsom profiles are strongly correlated r 0 82 p

reconstruction of environmental changes during the late glacial and holocene reflected in a soil sedimentary sequence from the lower selenga river valley lake baikal region siberia assessed by lipid molecular proxies abstract sediments of lake baikal and smaller lakes in its surroundings have been frequently used to trace paleoenvironmental changes however these sediments integrate environmental proxies over large areas and the processes leading to alteration of terrestrial signals are not fully understood more specific information can be derived from terrestrial archives such as alternating soil sediment sequences near the village of burdukovo southeast of lake baikal such sequences are accessible along the 5 m high right terrace of the selenga river however terrestrial archives can be associated with degradation of organic matter therefore lipid molecular proxies were applied in the current study to trace environmental and vegetation shifts as well as incorporation and degradation of organic matter alkane and fatty acid molecular proxies as part of the lipid fraction are well known for their diagnostic character to trace sources of organic matter and its degradation several parameters including the carbon preference indices of alkanes and fatty acids indicated a well preservation of the organic matter in the investigated sequence furthermore the organic matter in the c horizons of the terrestrial upper part of the sediments was most likely overprinted by rooting of the plants growing on respective overlaying soils as reflected by the average chain length of fatty acids and alkanes and the relative composition of long chain n alkanes c 25 33 the 3 5 m thick sequence enabled tracing of vegetation shifts the alkane composition argued for changes in the grass dominated vegetation cover within the different phases of the holocene until today whereas a birch and willow dominated deciduous forest vegetation as traced in other archives of the larger baikal area could not be determined in the burdukovo sequence by lipid molecular proxies the scatter in the alkane and fatty acid composition revealed only minor vegetation shifts throughout the holocene nevertheless some changes in the lipid composition indicated a change in the plant community as coniferous trees have often similar alkane patterns to grass vegetation it cannot be excluded that conifers also contributed to a certain degree to the molecular record in the burdukovo sequence the general decrease in the carbon preference index of alkanes since approximately 4 ka bp until recent times further argues for an increasing admixture of coniferous lipids to the record lipid molecular proxies of sediment that formed 2 8 2 6 ka bp revealed the incorporation of deciduous tree derived organic matter most likely originating from birch that grew elsewhere in the catchment of the selenga river the proxies enabled an assessment of site specific vegetation shifts and degradation of organic matter in the soil sediment sequence of the burdukovo area and thus provide more specific information related to a certain area than lacustrine sediments integrating over larger catchments

geology and fauna and preliminary correlation of sediments of the main late cenozoic sites of the transbaikal area abstract the pliocene and pleistocene sediments exposed in eight sections of transbaikalia have been correlated using geological and palynological data together with information on fossil mammals and some paleomagnetic characteristics the most complete sequence of fossiliferous deposits spanning the time interval from the middle pliocene to the late pleistocene is exposed in the tologoi key section the sequence was correlated with other sections primarily on the basis of mammal faunas during deposition of the chikoi suite udunginian chikoian and itantsinian faunal complexes appeared in succession four successive stages in mammal evolution are recognized within the early pleistocene deposition of the krivoyarskaya suite proceeded throughout the time when the tologoi faunistic complex ivolginian and other pleistocene faunas followed each other in the transbaikalian region

asymmetric late pleistocene glaciations in the north basin of the baikal rift russia new morphological sedimentological and radiocarbon data of quaternary deposits from the northern baikal rift document at least three extensive late pleistocene glaciations at 50 ka 40 35 ka and 26 13 ka respectively during these periods valley glaciers advanced from the high rift shoulders 2500 m down to the present day coast of lake baikal 456 m in places the glaciers advanced beyond the present day shoreline into the lake basin as indicated by large moraines exposed in steep cliffs along the lakeshore furthermore stratigraphic relations between lacustrine sequences and glacial deposits as well as 14 c ages of two palaeo shorelines 10 and 4 m above the present lake level show that the last and the penultimate glaciations were followed by relative lake highstands these land based observations document a significant influence of late pleistocene glaciations on the sedimentary development of this lacustrine rift basin the northern baikal rift is characterized by an asymmetric half graben geometry that controls river drainage and sedimentation this asymmetry greatly influenced the development and spatial distribution of pleistocene glaciers on both rift margins on the western flank tilted fault blocks parallel to the rift served as topographic barriers for valley glaciers advancing toward the lake basin only in two locations glaciers could reach the present day coast on the eastern rift flank in contrast structure and drainage conditions allowed the development of numerous consequent streams providing thoroughfares and space for recurrent valley glaciations thus the glaciers on the eastern flank could advance beyond the present day lakeshore into the lake basin in numerous locations these observations indicate that asymmetric rift structure in combination with the effects of global cooling were the important controls on the pleistocene glacial development of the baikal rift

high resolution record of the last climatic cycle in the southern carpathian basin surduk vojvodina serbia abstract high resolution study of the surduk loess palaeosols sequence in serbia vojvodina has been performed within a research project eole focusing on the impact of rapid climatic changes during the last climatic cycle in the european loess belt the methodology used for this multidisciplinary approach is based on a continuous sampling column that allows a very accurate correlation between all studied proxies magnetic susceptibility grain size and organic carbon and the dated samples irsl 14 c according to the stratigraphical and sedimentological data the surduk loess sequence appears as a very complete record of the last climatic cycle 19 m and exhibits a similar pattern than other contemporaneous loess sequences from western central and eastern europe the main difference is the evidence of a drier environment all over the last climatic cycle sedimentological and palaeopedological data the high resolution grain size record 5 cm is well correlated with stratigraphical boundaries and highlights a strong variability within the loess deposition especially during the upper pleniglacial between ca 33 and 15 ka during the upper pleniglacial a succession of millennial timescale events characterised by the deposition of coarser loess are particularly well evidenced by grain size data as in some west european records finally an attempt to correlate the variations of grain size parameters at surduk with the greenland grip dust record is proposed according to this study millennial timescale climatic events that characterise the north atlantic area during the last climatic cycle have thus been recorded in the environments located at the southern border of the european loess belt

late quaternary vegetation dynamics in the southern amazon basin inferred from carbon isotopes in soil organic matter abstract carbon isotopes of soil organic matter som were used to evaluate and establish the chronology of the vegetation dynamics of an ecosystem presently composed of savannas surrounded by forests the study was carried out on a 200 km transect along highway br 319 on the border of amazonas and rondonia states in southern amazon brazil large ranges in 13 c values were observed in som collected from profiles in the savanna 27 to 14 and forest regions 26 to 19 reflecting changing distribution of 13 c depleted c 3 forest and 13 c enriched c 4 savanna vegetation in response to climate change these results indicate that from about 17 000 to 9000 14 c yr b p the study area was covered by forest vegetation between approximately 9000 and 3000 14 c yr b p savanna vegetation expanded at the expense of the forest although the expansion of savanna did not occur with the same intensity along the study transect this process was very clearly registered by 13 c enrichment in the som since 3000 14 c yr b p the carbon isotope data suggest that forested regions have expanded this study adds to the mounting evidence that extensive forested areas existed in the amazon during the last glaciation and that savanna vegetation expanded in response to warm and dry conditions during the early to middle holocene

the record of cosmogenic radiogenic fissiogenic and trapped noble gases in recently recovered chinese and other chondrites abstract we performed a comprehensive study of the noble gas isotopic abundances in thirty six chondrites including twenty seven chondrites recovered in china the large data base allows us to recognize some new characteristics of the nuclear record in chondritic matter the comparison of the trapped noble gas release pattern for ordinary and carbonaceous chondrites shows that the planetary trapped noble gases in ordinary chondrites are released mainly above 1200 c whereas 85 of these gases in carbonaceous chondrites are degassed at 200 c there exists a clear correlation of the fraction of trapped xe released at 1200 c and petrologic type of chondrites it thus appears that the carrier phases of the trapped noble gases in ordinary and in carbonaceous chondrites may not be the same the ngawi ll3 chondrite is solar gas rich the solar gases in meteorites and lunar surface material are mixtures of solar wind sw and solar energetic particles sep we show that the variations of the 3 he 4 he and 20 ne 22 ne ratios for solar gas rich meteorites and lunar surface material could be either due to preferential diffusive losses of the lighter isotopes of he and ne or due to a change of the sw sep flux ratio with time furthermore we demonstrate that the 81kr concentration is a function of the shielding depth of a sample within the meteoroid deviations from this depth dependency curve are observed for jilin h5 lishui l5 suizhou l6 and dongtai ll6 a complex exposure history for jilin is thus confirmed and is possible for the other three chondrites cosmic ray exposure ages are calculated based on six different nuclides 3he 21ne 38ar 83kr 126xe and 81kr kr in most cases good agreement is observed for the ages derived from the different methods quality classes are assigned to the exposure ages and the age distributions are discussed in some meteorites we observe effects induced by secondary cosmicray produced neutrons epithermal neutron fluxes jn 30 300 ev and fast neutron fluxes jn 5 mev are derived based on the reactions 79br n 80kr and 24mg n 21ne respectively and preatmospheric masses of the meteoroids are estimated we show that the ratio j n 30 300 ev j n 5 mev increases with increasing preatmospheric mass we introduce a 3he exposure age 21ne exposure age vs 4he gas retention age 40ar gas retention age diagram that is a powerful tool for distinguishing different thermal histories of meteoroids finally in some chondrites we observe xe produced by 244pu fission and calculate the time span between fission xe retention in these chondrites and that of the angra dos reis achondrite we find that the ordinary chondrites started to retain fission xe 48 30 ma earlier than angra dos reis we do not observe systematic differences between h l and ll or type 5 and 6 chondrites with respect to the time of fission xe retention

last glacial interglacial vegetation and environmental dynamics in southern siberia chronology forcing and feedbacks abstract radiocarbon dated pollen and diatom records from lake kotokel in southern siberia help to reconstruct the environmental history of the area since 47 kyr bp pollen spectra composition and reconstructed biome scores suggest predominance of a tundra steppe vegetation and variable woody cover 5 20 between 47 and 30 kyr bp indicating generally a harsh and unstable climate during this interval conventionally regarded as the interstadial within the last glacial the short term climate amelioration episodes in the glacial part of the records are marked by the peaks in taiga and corresponding minima in steppe biome scores and appear synchronously with the hemispheric temperature and precipitation changes recorded in the greenland ice cores and chinese stalagmites transition to full glacial environments occurred between 32 and 30 kyr bp the interval at 30 24 kyr bp was probably the driest and coldest of the whole record as indicated by highest scores for steppe biome woody coverage

sources and accumulation rates of organic carbon in an equatorial peat bog burundi east africa during the holocene carbon isotope constraints the relationship between organic carbon accumulation rates and 13c 12c ratios of total organic carbon toc was investigated in an highland peat bog core ru 3 from equatorial africa this core yielded a sequence spanning the last 14 kyr and was analysed with a 100 300 yr resolution for toc 13c values the holocene section shows contrasted toc accumulation regimes and toc 13c varying between 28 5 and 19 5 with a few very short isotopic excursions dated at ca 9 3 7 5 4 2 ka b p the organic carbon accumulation rates range from 2 to 20 mg c cm 2 yr 1 they increase when toc becomes more depleted in 13c notably between 12 and 9 8 ka b p 8 5 and 7 8 ka b p and after 1 6 ka b p periods of restricted carbon storage correspond to heavier toc accumulation at 9 3 and between 7 5 and 1 6 ka b p at the study site the variations can be related to variable c4 plant inputs and possibly to changes in the fractionation between co2 and the organic carbon in c3 vascular plants the ru 3 record indicates restricted carbon storage during the periods of increased contribution from c4 plants and or of decreased fractionation between co2 and organic carbon in c3 plants changes in toc 13c values in core ru 3 seem to match fluctuations of east equatorial african lakes high lake stands correspond to low 13c intervals and vice versa this points to indirect climatic forcing of 13c changes in intertropical peats

biomarkers in modern and buried soils of semi desert and forest ecosystems of northern iran abstract in northern iran mean annual precipitation and vegetation vary significantly over short distance from a semi desert to a forest biome these ecosystems likely responded differently on past climate changes we here aim at i testing the applicability of biomarkers leave derived n alkanes their stable carbon isotope composition and c and n stable isotopes of soil organic matter in loess derived soils to identify and differentiate past ecosystems and ii elucidating the variability of these biomarkers in palaeosols we sampled modern topsoils and palaeosol horizons within an ecological gradient covering a range in mean annual precipitation from 200 to 750 mm from the kopet dag semi desert to the hyrcanian forest on the footslopes of the alborz mountains c org n 13 c org 15 n and n alkanes and their compound specific 13 c were analyzed to characterize organic matter composition and sources in modern soils a systematic increase in c org and n was observed with precipitation the 15 n decreased from about 6 to 4 pointing to systematically more degraded organic matter in semi desert soils the leave wax specific ratio of nc 31 nc 33 nc 27 nc 29 n alkanes was 1 for semi desert soils and 13 c org showed no systematic trend in this gradient in loess and palaeosol profiles contents of c org n and n alkanes dropped about a factor 10 compared to modern soils the n alkane ratio and 15 n ratios remained on comparable levels as did the compound specific 13 c in n alkanes however bulk 13 c org was altered from about 27 in modern soil to 23 in loess palaeosols systematically higher c org and n values were observed in palaeo topsoils compared to loess and subsoil stable c isotopes varied rather unsystematically within loess palaeosol sequences while 15 n revealed trends within palaeosols however in contrasting directions with palaesol depth the temporal average n alkane ratio for all palaeosol horizons of one site systematically followed the modern precipitation gradient indicating that in all periods of soil formation a climatic gradient developed

pleistocene climate change natural environments and palaeolithic occupation of the angara baikal area east central siberia abstract diversity of the relief and the pleistocene environments of the mountain areas of sw siberia played a major role in the history of the palaeolithic peopling of this territory the geographical and contextual distribution of the cultural records reflects a climatic instability in the altai area palaeoenvironmental proxy data indicate that the natural conditions during the earlier stages were generally more favourable for early human occupation than during the later stages the cyclic nature of the glacial and interglacial periods led to periodic landscape transformations and generation of specific ecosystems adjusted to particular topographic settings and responding to climatic variations the initial occupation of the broader altai region associated with pebble tool industries from alluvial formations likely occurred during some of the middle pleistocene interglacials accompanying the northern expansion of the temperate zone and biota mixed coniferous and broadleaf forests established in the tectonically active mountain zone with elevations of 1500 2000 m and parklands in the adjacent plains and continental basins provided a wide range of occupation habitats there is limited evidence for persistence of early palaeolithic inhabitation during glacial stages due to inhospitable periglacial conditions the last interglacial warming indicated by re colonization of southern siberia by coniferous taiga forests is linked with the appearance of the mousterian tradition changes in the relief configuration influenced the local climate regime and opened new habitats for the middle palaeolithic population concentrated in the transitional zones of 500 1000 m elevation in the karstic area of the nw altai foothills occupation of the central and southern altai during the early last glacial was impeded by harsh ice marginal environments and expansion of glaciers in the valleys filled by large proglacial lakes progressive warming during the early mid last glacial interstadial stage 59 35 ka bp caused wasting of the ice fields accompanied by cataclysmic releases of ice dammed lakes and large scale erosional processes periodic outbursts of the glacial basins had a dramatic impact on the regional ecosystems also obliterating the earlier cultural records appearance of the transitional early late palaeolithic stone industries reflects adaptation to mosaic interstadial habitats including sub alpine forest dark coniferous forest mixed parklands and open steppe the identical geographical distribution of the middle and late palaeolithic sites and the time transgressive lithic technologies suggest a regional cultural and biological continuity in the broader altai area during the late pleistocene re establishment of cold tundra steppe and tundra forest habitats correlates with the late palaeolithic horizon with developed stone industries dominated by blade flaking techniques these techniques possibly survived in more protected locations characterized by warm microclimates in the northern altai throughout the last glacial maximum 20 18 ka bp emergence of the microlithic assemblages with wedge shape cores is linked with a new cultural adjustment in the final stage of the palaeolithic development responding to transformations of the former periglacial ecosystems towards the end of the pleistocene

paleoenvironments of palaeolithic humans in the baikal region abstract during the last 25 years abundant material on small mammals has been obtained from numerous pleistocene archaeological sites caves and open localities in the baikal region most small mammal fauna localities are dated to sartan time 23 000 10 000 bp with some attributed to karginsk time 50 000 23 000 bp paleontological studies provided a considerable amount of information on environmental changes both in transbaikalia and in the fore baikal region during palaeolithic and mesolithic since the end of middle pleistocene

post glacial history of siberian spruce picea obovata in the lake baikal area and the significance of this species as a paleo environmental indicator abstract the relative abundances of siberian spruce picea obovata and total arboreal pollen in pollen spectra from the lake baikal region and calculation of a steppe forest vegetation index place constraints on the past climatic conditions related to permafrost summer temperatures precipitation and soil moisture availability here we review the data on picea pollen in sub recent spectra the present day distribution of picea obovata and sedimentary records from a number of sites to arrive at a coherent picture of evolution of regional vegetation since the late glacial the expansion of siberian spruce along with steppe vegetation dates back to the undivided bolling allerod interval when this species became dominant in arboreal vegetation steppe landscapes persisted in a large part of the lake baikal watershed prior to 9 2 9 ka when the expansion of arboreal vegetation took place following the younger dryas which seems to have had little effect on regional vegetation and peat accumulation the role of siberian spruce steadily declined until 8 6 6 8 ka in the late holocene the abundance of p obovata rarely exceeded the present day ratio of ca 2 total arboreal pollen departures towards higher picea abundance and higher steppe forest index at ca 6 5 and 3 2 5 ka in selenga delta area appear to reflect periods with decreased temperatures and higher moisture availability in the southern part of the lake baikal watershed