chronological sequence of the early pleistocene gigantopithecus faunas from cave sites in the chongzuo zuojiang river area south china abstract since 2004 five new early pleistocene cave sites with gigantopithecus blacki and other fossil mammals have been discovered in the chongzuo zuojiang river area guangxi zhuang autonomous region guangxi zar south china these sites include baikong cave of liyu mountain juyuan cave of boyue mountain sanhe and queque caves of wuming mountain and wuming cave of mulan mountain the present study provides a preliminary account of these newly discovered gigantopithecus faunas and discusses their taxonomic composition evolutionary trends and chronology based on recent biostratigraphic and geochronological studies combining faunal and paleomagnetic data the gigantopithecus faunas from the zuojiang river area can be divided into three temporal stages during the early pleistocene the early stage 2 6 1 8 ma is represented by the baikong and boyue faunas which include some neogene relics e g sinomastodon hesperotherium dicoryphochoerus dorcabune and cervavitus and several species that make their first appearance during the pleistocene e g sinicuon dubius pachycrocuta licenti ailuropoda microta sinomastodon jiangnanensis stegodon huananensis and tapirus sanyuanensis the middle stage 1 8 1 2 ma is represented by the sanhe fauna which is characterized by the appearance of ailuropoda wulingshanensis cuon antiquus and tapirus sinensis the late stage 1 2 0 8 ma is represented by the queque fauna which is characterized by a marked decrease in neogene relics and the appearance of a few species that are more typical of the middle pleistocene e g ailuropoda baconi and stegodon orientalis evolutionary trends in the early pleistocene gigantopithecus faunas include a gradual increase in dental size in some of the typical taxa such as g blacki ailuropoda and tapirus and the successive turnover of representative species such as a microta a wulingshanensis a baconi thus far eleven g blacki sites of early pleistocene age have been recorded in southern china and these are primarily concentrated in guangxi zar where more than 70 of early pleistocene g blacki cave sites are known given this temporal and geographic distribution it is possible to infer that guangxi zar represents an important early evolutionary and zoogeographic center for g blacki

the changes in isotope composition and accumulation of snow at vostok station east antarctica over the past 200 years high resolution records of isotope composition dd and accumulation of snow have been obtained from 10 12 m deep snow pits dug in the vicinity of vostok station during the 1979 80 and 1999 2000 antarctic field seasons we employ meteorological balloon sounding and snow stake data to interpret the isotope record in terms of past temperature changes our reconstruction suggests that snow accumulation rate and the near surface air temperature at vostok have varied during the past 200 years between 15 and 30 kg m 2 a 1 and between 56 and 558c respectively with a slight general tendency to increase from the past to the present both parameters reveal a 50 year periodicity that correlates with the pacific decadal oscillation index implying a climatic teleconnection between central antarctica and the tropical pacific

new fossil evidence and diet analysis of gigantopithecus blacki and its distribution and extinction in south china the present paper reports the recently discovered fossil teeth of early pleistocene gigantopithecus blacki and associated mammalian fauna from baeryan cave bijie county in guizhou province and also reviews briefly the known fossil sites of gigantopithecus in south china of pleistocene in early pleistocene gigantopithecus had a wider distribution but withdrew southward in middle pleistocene to a limited area mainly in south china and it disappeared in the late pleistocene according to the present fossil records diet and habitat analysis from carbon isotope evidence is used to investigate the reasons for the extinction of gigantopithecus which fed on a pure c3 diet and lived in a forest habitat it was clearly different from early hominins in south and east africa such as australopithecus africanus paranthropus robustus and paranthropus boisei which had c4 diets the extinction of gigantopithecus was also related to the great changes of climate and environment of the pleistocene especially the last one million years during which homo became more and more prosperous and exerted great pressure on g blacki

effects of firn ventilation on isotopic exchange a new model of isotopic diffusion in the upper few meters of firn tracks the isotopic composition of both the ice matrix and the pore space vapor through time in two dimensions stable isotopes in the vapor phase move through the firn by diffusion along concentration gradients and by advection wind driven ventilation carries atmospheric water vapor into the firn where it mixes with existing pore space vapor unlike previous models our model allows disequilibrium between pore space vapor and the surrounding snow grains we also calculate the isotopic effects of ventilation driven sublimation and condensation in the firn model predictions of isotopic diffusion in firn compare favorably with existing diffusion models model results quantify what other investigators have suggested isotopic change in the upper few meters is more rapid than can be explained by the whillans and grootes 1985 model isotopic equilibration with atmospheric vapor is an important component of post depositional isotopic change and ventilation enhances isotopic exchange by creating regions of relatively rapid sublimation and condensation in the firn

snow and firn permeability at siple dome antarctica the nature of air snow exchange processes depends upon both the physical characteristics of the snow and forcing from the atmosphere an understanding of snow air transport processes and models of these processes are important for interpreting ice cores and for predicting remotely sensed snow surface characteristics accurate modeling requires knowledge of the physical characteristics of the snow and firn in this paper measurements of snow and firn permeability from the surface down to 12 m depth at siple dome antarctica are presented the permeability varies greatly as a function of layer and depth generally increasing to approximately 3 m and generally decreasing below that the maximum permeability 280 10 10 1 0 m2 occurs at approximately 3 m depth the lowest permeability in the top 12 m of snow and firn 10 10 10w m2 was measured in the surface wind pack the measurements show that layering and microstructure have large effects on permeability a mathematical expression for the overall variation of permeability with depth is presented it is shown that snow density is a poor indicator of permeability quantitative microscopy may be helpful in relating observed snow characteristics to permeability and useful in modeling firnification and chemical species transport

on the frequency distribution of net annual snow accumulation at the south pole the frequency distribution of stratigraphic layer thickness in cores and a snowmine at south pole is not compatible with a significant number 1 of missing layers associated with zero accumulation years inferred from pole height measurements a reconciliation of these data sets is needed if observed stratigraphic records are to be used as reliable paleoclimate indicators three explanations for the discrepancy are offered namely i during a significant number of years a visible stratigraphic horizon does not form or is not identified ii the true distribution is characterized by two maxima with a secondary maximum centered around zero layer thickness or iii the pole height measurements are misinterpreted and there are very few zero accumulation years at south pole with the currently available data it is not possible to discriminate among these three possibilities

paleoecology of pleistocene mammals and paleoclimatic change in south china evidence from stable carbon and oxygen isotopes abstract the role of climate change in the evolution and diversification of hominoids remains a hotly debated issue stable isotope analyses of fossil mammals that coexisted with the hominoids can provide insights into hominoid palaeoenvironments and shed light on this debate here we report results of stable carbon and oxygen isotope analyses of tooth enamel samples from a variety of pleistocene mammals including pandas deer elephants pigs rhinos and bovids from two hominoid fossil localities yugong cave and baxian cave in south china enamel 13c values indicate that most of the mammals living in the study area during the late middle pleistocene had c3 based diets but a small number of individuals consumed some c4 grasses this indicates the presence of c4 plants in the region during the late middle pleistocene most likely in patches of open areas in a predominantly forested environment however during the early late pleistocene all of the mammals examined had c3 based diets except one bovid and one panda that may have ingested small amounts of c4 plants this indicates a dense forested environment with little c4 grasses during the early late pleistocene like the early pleistocene pygmy panda ailuropoda microta from yanliang cave the late middle pleistocene ailuropoda baconi from yugong cave and the early late pleistocene ailuropoda melanoleuca from baxian cave had higher mean diet 13c values than other co occurring herbivores indicating they preferred relatively open forest habitats and had more restricted diets compared to other mammals the reconstructed mean paleo meteoric water 18ow values are lower than the annual average 18ow value of modern precipitation in the region suggesting that the climatic conditions during the times when these pleistocene mammals were alive were colder and or wetter than today in addition 18o values of the obligate drinkers pigs rhinos bovids display an overall decreasing trend accompanied by increased range of 18o variations from the early pleistocene to the early late pleistocene this suggests that the regional climate became colder and or wetter with increased seasonality from the early pleistocene to the early late pleistocene likely related to intensified glaciation the change in climate to colder conditions may be responsible for the extinction of the gigantopithecus in this region

geomorphic evolution and stratigraphy of price and capers inlets south carolina a three dimensional model for a tidal inlet barrier island depositional system was constructed through examination of 37 vibracores and 10 auger drill holes on capers and dewees islands south carolina two cycles of southerly inlet migration and subsequent abandonment resulted in beach ridge truncation on the northern ends of both barriers historical evidence indicates that these tidal inlets migrated 1 5 km to the south owing to a dominant north south longshore transport direction the hydraulic inefficiency of these over extended inlet channels caused shorter more northerly oriented channels to breach through the ebbtidal deltas after inlet reorientation large wave formed swash bars migrated landward closing former inlet channels weakened tidal currents through the abandoned channels permitted clay plugs to form thick impermeable seals over active channel fill sand and shell price and capers inlets formed during the onset of the holocene transgression following submergence of the ancestral plio pleistocene santee river drainage system coarse poorly sorted inlet deposited sand disconformably overlies pleistocene estuarine clay and is capped by a dense clay plug shoreline reorientation and landward retreat of a primary barrier island chain occurred between the first and second cycles of inlet channel migration and abandonment beach ridges prograded seaward over the first inlet sequence a second cycle of inlet migration truncated the northernmost portion of these beach ridges and scoured into the clay plug of the earlier inlet deposit abandonment of this channel resulted in deposition of a second abandoned inlet channel clay plug abandoned tidal inlet channels exhibit u shaped strike and crescentic to wedge shaped dip geometries basal poorly sorted inlet sands are sealed beneath impermeable abandoned channel silt and clay washover deposits and salt marsh multiple episodes of inlet migration and abandonment during a rising sea level deposited stacked inlet fill sequences within the barrier islands the resultant stratigraphy consists of interlayered fining upward active inlet fill sand overlain by thicker abandoned inlet fill clay plugs these clay plugs form impermeable zones between adjacent barrier island sand bodies shoreline transgression would remove the uppermost barrier island deposits sealing the inlet fill sequences between pleistocene estuarine clay and shoreface to shelf silt and clay

isotopic diffusion in cold snow and firn molecular mixing in cold snow and firn is ordinarily controlled by vapor diffusion diffusion through or along the ice matrix is slow whereas diffusion from the air to within separate grains is comparatively rapid thus mixing occurs in the vapor phase and exchange with the local ice involves all the water molecules a quantification of these concepts is applied to the diffusion of oxygen isotopic depth profiles in southern greenland and at dome c antarctica it successfully describes the smoothing of measured profiles the smoothing rate is strongly dependent on temperature and density of the firn

the early pleistocene gigantopithecus sinomastodon fauna from juyuan karst cave in boyue mountain guangxi south china abstract as one of the most important quaternary mammalian faunas in southern china the gigantopithecus sinomastodon fauna has received much attention the large primate fossil teeth newly collected from juyuan karst cave in boyue mountain guangxi zhuang autonomous region of southern china can be identified as gigantopithecus blacki the morphology and size of these g blacki teeth differ from those of the middle pleistocene gigantopithecus teeth which hold evidently larger dental dimensions and more complex crenulations from hejiang cave also in guangxi and tham khuyen cave in vietnam however the g blacki teeth from juyuan cave are relatively similar to those from early pleistocene mohui cave and liucheng gigantopithecus cave both in guangxi which suggests that the three cave sites have similar age the juyuan fauna associated with gigantopithecus blacki consisting of 45 mammalian species such as sinomastodon yangziensis ailuropoda wulingshanensis stegodon huananensis and rhinoceros fusuiensis is a typical early pleistocene gigantopithecus sinomastodon fauna of southern china the juyuan fauna is mostly similar to mohui fauna also implying their contemporaneity paleomagnetic analyses demonstrate that the fossil bearing sediments in juyuan cave are dominated by normal polarity combining the faunal analysis and magnetostratigraphic evidence the juyuan sediments can be best correlated with the olduvai normal subchron giving an estimated age of 1 8 ma

new evidence for the incision history of the liuchong river southwest china from cosmogenic 26al 10be burial ages in cave sediments cosmogenic nuclides be 10 and al 26 have been analyzed for sediments from the multilevel riverside caves along the liuchong river at the southeastern margin of the tibetan plateau the liuchong river is the northern origin of wujiang river which passes through the northwestern guizhou plateau and cuts down hundreds of meters into the bedrock leaving behind an abundance of multilevel caves the measured al 26 be 10 ratios produced the apparent burial ages in range of 0 49 2 85 ma taking into account of geomorphic and geological backgrounds the dashi cave located at the highest level along the liuchong river system formed around 0 75 ma ago which probably suggests the initial formation age of the modern wujiang river the resulted incision rate of similar to 480 m ma in guizhou in the last 0 75 ma is slightly higher than those in adjacent areas this feature implies an intensive downcutting history of the liuchong river during the quaternary which might be primarily caused by the uplift of tibetan plateau cut through of the three gorges and soluble carbonate bedrock c 2013 elsevier ltd all rights reserved

controlled experiments on the diffusion rate of stable isotopes of water in artificial firn we studied the diffusion rate of stable isotopes of water ice in a controlled laboratory experiment where isotopically different layers of fabricated firn were stacked this experiment was done in order to study the diffusion rate between the isotopically different layers and to compare the measurements with forward calculated diffusion rates of the fabricated firn stack using three different analytical and numerical methods the layers varied in thickness within the stack and the studied period includes variations in firn temperature we sampled the firn stack on five different dates along the 144 day long experiment we obtained a quantitatively good match between the calculated and measured diffusion rates with a root mean square similarity of 67 80 in the depth averaged diffusion rates despite the good average match we found some qualitative discrepancy between our calculations and our measurements the calculated diffusion rates predict 5 faster isotopic decay of thinner layers and 13 slower decay of thicker layers than our measurements show we speculate that grain size and grain fabric may influence the tortuosity of the firn pack and that the current generalization of tortuosity being a function of firn density as the only free parameter is an oversimplification

esr u series and paleomagnetic dating of gigantopithecus fauna from chuifeng cave guangxi southern china several gigantopithecus faunas associated with taxonomically undetermined hominoid fossils and or stone artifacts are known from southern china these faunas are particularly important for the study of the evolution of humans and other mammals in asia however the geochronology of the gigantopithecus faunas remains uncertain in order to solve this problem a program of geochronological studies of gigantopithecus faunas in guangxi province was recently initiated chuifeng cave is the first studied site which yielded 92 gigantopithecus blacki teeth associated with numerous other mammalian fossils we carried out combined esr u series dating of fossil teeth and sediment paleomagnetic studies our esr results suggest that the lower layers at this cave can be dated to 1 92 0 14 ma and the upper layers can be dated to older than 1 38 0 17 ma correlation of the recognized magnetozones to the geomagnetic polarity timescale was achieved by combining magnetostratigraphic biostratigraphic and esr data the combined chronologies establish an olduvai subchron 1 945 1 778 ma for the lowermost chuifeng cave sediments we also analyzed the enamel 13c values of the gigantopithecus faunas our results show that southern china was dominated by c3 plants during the early pleistocene and that the gigantopithecus faunas lived in a woodland forest ecosystem

effect of atmospheric water vapor on modification of stable isotopes in near surface snow on ice sheets south pole are used to simulate the d 18 o of near surface snow as it evolves in time the sensitivity of d 18 o of near surface snow to wind speed surface temperature and accumulation rate is tested through model experiments a steady wind of 5 10 m s 1 results in annual mean d 18 o enrichment of 3 7 enrichment of the heavy isotope occurs predominantly in buried winter snow layers during summer however in many simulations there is a slight depletion of d 18 o summer layers that occurs as atmospheric water vapor is deposited within the snow during winter postdepositional modification of water stable isotopes in near surface snow also depends on the snow accumulation rate high accumulation rates quickly advect snow layers away from the influence of the atmosphere preventing significant modification low accumulation rates e g at vostok and dome c allow significant postdepositional modification because the near surface snow is exposed to forced ventilation for several annual cycles postdepositional modification during the last glacial maximum lgm at summit greenland is estimated to be greater than the present day postdepositional modification therefore the temperature difference for lgm may be larger than that previously inferred from the d 18 o record however because of the compensating effects of lower temperatures and smaller accumulation during the lgm in antarctica the postdepositional enrichment in east antarctica may be approximately the same for lgm as for the modern climate

evolution and stratigraphy of a regressive barrier backbarrier complex kiawah island south carolina analysis of 75 vibracores from the backbarrier region of kiawah island south carolina reveals a complex association of three distinct stratigraphic sequences beach ridge progradation and orientation controlled backbarrier development during the evolution of kiawah island and resulted in deposition of 1 a mud rich central backbarrier sequence consisting of low marsh overlying fine grained tidal flat lagoonal mud 2 a sandy beach ridge swale sequence consisting of high and low marsh overlying tidal creek channel and point bar sand and foreshore shoreface and 3 a regressive sequence of sandy mixed and muddy tidal flats capped by salt marsh that occurs on the updrift end of the island central backbarrier deposits formed as a result of the development of the initial beach ridge on kiawah island formation of this beach ridge created a backbarrier lagoon in which fine grained estuarine and tidal flat mud accumulated washovers oyster mounds and tidal creek deposits form isolated sand and or shell rich lenses in the lagoon spartina alterniflora low marsh prograded into the lagoon as the tidal flats aggraded barrier progradation and sediment bar bypassing at stono inlet created digitate beach ridges on the northeast end of kiawah island within the beach ridge swales tidal flats were disconformably deposited on shoreface and foreshore sand of the older beach ridges tidal creek drainage systems evolved to drain the swales these rapidly migrating creeks reworked the tidal flat foreshore and shoreface sediments while redepositing a fining upward sequence of channel lag and point bar deposits which served as a substrate for salt marsh colonization this resultant regressive sedimentary package marks the culmination of barrier island development and estuary infilling given enough time and sedimentation the backbarrier sequence will ultimately prograde over the barrier island reworking dune beach and foreshore sediments to form the upper sand rich bounding surface of the barrier lithosome preservation of the regressive sequence is dependent upon sediment supply and the relative rate of sea level rise but the reworking of barrier islands by tidal inlets and migrating tidal creeks greatly alter and complicate the stratigraphic sequence

isotopic diffusion in polar firn implications for interpretation of seasonal climate parameters in ice core records with emphasis on central greenland if it were possible to properly extract seasonal information from ice core isotopic records paleoclimate researchers could retrieve a wealth of new information concerning the nature of climate changes and the meaning of trends observed in ice core proxy records it is widely recognized however that the diffusional smoothing of the seasonal record makes a proper extraction very difficult in this paper we examine the extent to which seasonal information specifically the amplitude and shape of the seasonal cycle is irrecoverably destroyed by diffusion in the firn first we show that isotopic diffusion firn is reasonably well understood we do this by showing that a slightly modified version of the whillans and grootes 1985 theory makes a tenable a priori prediction of the decay of seasonal isotopic amplitudes with depth at the gisp2 site though a small adjustment to one parameter significantly improves the prediction further we calculate the amplitude decay at various other ice core sites and show that these predictions compare favorably with published data from south pole and locations in southern and central greenland and the antarctic peninsula we then present numerical experiments wherein synthetic ice core records are created diffused sampled reconstituted and compared to the original these show that alter diffusive mixing in the entire fini column seasonal amplitudes can be reconstructed to within about 20 error in central greenland but that all information about sub annual signals is permanently lost there furthermore most of the error in the amplitude reconstructions is due to the unknowable variations in the sub annual signal finally we explore how these results can be applied to other locations and suggest that dye 3 has a high potential for meaningful seasonal reconstructions while siple dome has no potential at all an optimal ice core site for seasonal reconstructions has a high accumulation rate and a low temperature

non climate influences on stable isotopes at taylor mouth antarctica the late holocene trends in 18 o differ significantly in two ice cores 30 km apart from the area of taylor dome antarctica it is unlikely that the trend in the core from taylor mouth the flank site is due to a standard 18 o surface temperature relationship assuming that the taylor dome near summit core records local climate variations common to both cores we assess two leading possible causes for the observed differences 1 relative to taylor dome taylor mouth may collect snow from more sources with distinct isotopic compositions 2 vapor motion during prolonged near surface exposure may cause post depositional isotope enrichment at taylor mouth where the accumulation rate is low our model of firn pore space vapor and sublimating ice grains suggests that post depositional processes can modify 18 o values by several o isotopic samples from areas with significantly different accumulation rates near taylor mouth could differentiate between possibilities 1 and 2

effect of accumulation rate on water stable isotopes of near surface snow in inland antarctica 1 postdepositional changes in water stable isotopes in polar firn were investigated at three sites characterized by different accumulation rates along the east antarctic ice divide near dome fuji water stable isotopes major ion concentrations and tritium contents of three 2 4 m deep pits were measured at high resolution 2 cm temporally the snow pits cover the past 50 years with snow accumulation rates in the range of 29 41 kg m 2 a 1 around dome fuji oxygen isotopic profiles in the three pits do not show annual fluctuations but instead exhibit multiyear cycles these multiyear cycles are lower in frequency at dome fuji as compared with the other two sites peaks of water stable isotopes in the multiyear cycles correspond to some ion concentration minima in the pits although such relationships are not observed in coastal regions we propose that the extremely low accumulation environment keeps the snow layer at the near surface which result in postdepositional modifications of isotopic signals by processes such as ventilation and vapor condensation sublimation we estimate that oxygen isotopic ratios could be modified by 10 and that the original seasonal cycle could be completely overprinted under the accumulation conditions at dome fuji moreover stake measurements at dome fuji suggest that the large variability in snow accumulation rate is the cause of the multiyear cycles

water isotope diffusion rates from the northgrip ice core for the last 16 000 years glaciological and paleoclimatic implications abstract a high resolution 0 05 m water isotopic record o 18 is available from the northgrip ice core in this study we look into the water isotope diffusion history as estimated by the spectral characteristics of the o 18 time series covering the last 16 000 years the diffusion of water vapor in the porous medium of the firn pack attenuates the initial isotopic signal predominantly having an impact on the high frequency components of the power spectrum higher temperatures induce higher rates of smoothing and thus the signal can be used as a firn paleothermometer we use a water isotope diffusion model coupled to a steady state densification model in order to infer the temperature signal from the site assuming the accumulation and strain rate history as estimated using the gicc05 layer counted chronology and a dansgaard johnsen ice flow model the temperature reconstruction accurately captures the timing and magnitude of the bolling allerod and younger dryas transitions a holocene climatic optimum is seen between 7 and 9 ky b2k with an apparent cooling trend thereafter our temperature estimate for the holocene climatic optimum points to a necessary adjustment of the ice thinning function indicating that the ice flow model overestimates past accumulation rates by about 10 at 8 ky b2k this result is supported by recent gas isotopic fractionation studies proposing a similar reduction for glacial conditions finally the record presents a climatic variability over the holocene spanning millennial and centennial scales with a profound cooling occurring at approximately 4000 years b2k the new reconstruction technique is able to provide past temperature estimates by overcoming the issues apparent in the use of the classical o 18 slope method it can at the same time resolve temperature signals at low and high frequencies

inference of accumulation rate patterns from deep layers in glaciers and ice sheets the spatial pattern of accumulation rate can be inferred from internal layers in glaciers and ice sheets non dimensional analysis determines where finite strain can be neglected shallow layer approximation or approximated with a local one dimensional flow model local layer approxima tion and where gradients in strain rate along particle paths must be included deep layers we develop a general geophysical inverse procedure to infer the spatial pattern of accumulation rate along a steady state flowband using measured topography of the ice sheet surface bed and a deep layer a variety of thermomechanical ice flow models can be used in the forward problem to calculate surface topography and ice velocity which are used to calculate particle paths and internal layer shapes an objective tolerance criterion prevents over fitting the data after making site specific simplifications in the thermomechanical flow algorithm we find the accumulation rate along a flowband through taylor mouth a flank site on taylor dome antarctica using a layer at approximately 100 m depth or 20 of the ice thickness accumulation rate correlates with ice surface curvature at this site gradients along flow paths critically impact inference of both the accumulation pattern and the depth age relation in a 100 m core

modeling the isotopic composition of antarctic snow using backward trajectories simulation of snow pit records 1 the quantitative interpretation of isotope records d 18 o dd and d excess in ice cores can benefit from a comparison of observed meteorology with associated isotope variability for this reason we studied four isotope records from snow pits in western dronning maud land dml antarctica covering the period 1998 2001 timing and magnitude of snowfall events on these locations were monitored using sonic height rangers for the distinguished snowfall events we evaluated the isotopic composition of the moisture during transport by combining backward trajectory calculations with isotopic modeling using a rayleigh type distillation model mcim the initial isotope ratio of the moisture was determined frommonthlymeanisotopefields fromageneralcirculation model echam4 the trajectory analysis showed that the southern atlantic ocean is the major moisture sourceforprecipitationindml modelingresultsalongthetrajectoriesrevealedthatmostof the isotopic depletion occurred during the last day of the transport finally a diffusion model was applied to describe the diffusion in the firn layer such that the modeled isotopes couldbecomparedwiththeobservedisotoperecords theresultingmodeledisotopeprofiles were mostly in good agreement with the observed seasonal variability in the snow however at low temperatures especially on the antarctic interior magnitude of the total distillation was underestimated regarding the d excess parameter our results show a large influence of advection height on the final value of d excess in precipitation this in turn points to the importance of the vertical structure of d excess over the oceanic source region which obscures the classical interpretation of this parameter in terms of temperature and relative humidity in the moisture source region

holocene deposits of reservoir quality sand along the central south carolina coastline the holocene coastal sand deposits of the central south carolina coastline were investigated to estimate volumes of reservoir quality rq sediments these sand bodies which vary considerably in size thickness shape and continuity were deposited in a variety of depositional settings including barrier islands ebb tidal deltas exposed sand flats tidal sand ridges and tidal point bars to identify the rq sediment for each sand body type a conservative mud cutoff value of 15 was chosen average thickness values ranged from 6 m for barrier island deposits to 15 m for ebb tidal deltas of the six most significant rq sand depositional environments on the central portion of the south carolina coast ebb tidal delta complexes accounted for 77 of all rq sediments this dominance of the ebb tidal delta deposits is attributed to the relatively large tidal range in the area up to 3 m and to the presence of a number of large incised alluvial valleys which are host to estuarine complexes with large tidal prisms if the holocene sand deposits along the central 115 km of the south carolina coast were preserved in the rock record a total of 1 3 106 ac ft of rq sands would be present a significant amount considering the short time interval of approximately 5000 yr

carbon and oxygen isotopic evidence for diets environments and niche differentiation of early pleistocene pandas and associated mammals in south china abstract to better understand the dietary evolution and habitat change of pandas this study analyzed the stable carbon and oxygen isotope compositions of tooth enamel samples from the early pleistocene pandas ailuropoda microta and ailuropoda wulingshanensis and their associated mammals recovered from yanliang cave and longgu cave in south china the enamel 13 c values indicate that mammals living in these cave areas during the early pleistocene had c 3 based diets but some individuals consumed small amounts of c 4 grasses this suggests that c 4 grasses were present in the region during the early pleistocene likely in patches of open areas or savanna woodlands in a predominantly forested landscape the 13 c and 18 o data clearly show niche partitioning among panda pig and other animals the pandas had the lowest enamel 13 c values among all mammals examined indicating that these early pleistocene pandas had pure c 3 diets composed of plants growing in the understories of closed canopy forests a pure c 3 diet for these ancient pandas is consistent with an already established dietary niche of bamboo a c 3 plant in the early pleistocene these ancient pandas also had higher 18 o values than all other contemporaneous mammals except the deer at longgu cave suggesting that they did not drink as much as other large mammals did the available isotope data suggest that pygmy panda a microta was less ecologically flexible compared to other mammals such as pig rhino deer and bovid the limited ecological flexibility of pygmy panda may have contributed to its demise during climatic fluctuations in the pleistocene the reconstructed 18 o values of meteoric water in the study areas during the early pleistocene are lower than the present day mean annual precipitation 18 o values in the region suggesting a wetter climate or stronger summer monsoon in the early pleistocene than today

a sustainable review of the middle pleistocene benchmark sites including the ailuropoda stegodon faunal complex the proboscidean point of view abstract the different ecologies times of extinction and last stand of both elephas and stegodon in south east asia cover almost two million years in the middle pleistocene both taxa belong to the complex ailuropoda stegodon this regional complex is considered to have a chronological significance and further palaeoecological palaeobiogeographical or biochronological studies use this assemblage as a benchmark nevertheless such studies do not provide sufficient information regarding site formation and duration to be consistent enough to do so at an appropriate resolution mis timescale focussing attention on the occurrence of proboscideans a critical review of the robustness of the geological taphonomical and chronological data of middle pleistocene faunal assemblages suggests the necessity to undertake a deep reappraisal of this biochronological benchmark recommendations were provided in the 1980s not to use mixtures of faunal assemblages and progress in geochronology for two decades is available nevertheless a review of proboscideans suggests the necessity of a severe revision leading to scepticism concerning the use of the ailuropoda stegodon complex as an ecological marker extended to other taxa this review casts serious doubts on former and current paleoecological modellings and studies

oxygen 18 16 variability in greenland snow and ice with 10 3 to 105 year time resolution the 3 km long greenland ice sheet project 2 gisp2 ice core presents a 100 000 year detailed oxygen isotope profile covering almost a full glacial interglacial cycle measuranents of isotopic fluctuations in snow frost and atmospheric water vapor samples collected during summer field seasons up to 20 0 are compatible with the large and abrupt 80 160 changes observed in accumulated tim snow pit 15 80 profiles from the gisp2 summit area however show rapid smoothing of the 180 160 signal near the surface beyond about 2 m depth the smoothedi5180 signal is fairly well preserved and can be interpreted in terms of average local weather conditions and climate the longer climate fluctuations also have regional and often global significance in the older part of the record corresponding to marine isotope stages mis 5a to 5d the effect of orbital climate forcing via the 19 and 23 kyr precession cycles and the 41 kyr obliquity cycle is obvious from the end ofmis 5a at about 75 000 years b p till the end of the glacial at the younger dryas preboreal transition at 11 650 years b p the o180 160 record shows frequent rapid switches between intermediate interstadial and low stadial values fourier spectra of the oscillations that are superimposed on the orbitally induced changes contain a strong periodicity at 1 5 kyr a broad peak at 4 0 kyr and additional shorter periods detailed comparison of the gisp2 180 160 record with the vostok antarctica 15d record pacific ocean foraminiferal 180 160 grande pile france tree pollen and insolation indicates that a counterpart to many of the rapid 180 160 fluctuations of gisp2 can be found in the other records and that the gisp2 isotopic changes clearly are the local expression of climate changes of worldwide extent correlation of events on the independent gisp2 and specmap time scales for the interval 10 000 50 000 years b p shows excellent chronometric agreement except possibly for the event labeled 3 1 the glacial to interglacial transition evidently started simultaneously in the arctic and the antarctic but its development and its expression in greenland isotopes was later suppressed by the influence of meltwater especially from the barents sea ice sheet on deep water formation and ocean circulation meltwaters from different ice sheets bordering the north atlantic also influenced ocean circulation during the bolling allerod interstadial complex and the younger dryas and led to a distinct development of european climate and greenland 180 160 values the holocene interval with long term stable mean isotopic values contains several fluauations with periods from years to millennia dominant is a 6 3 year oscillation with amplitude up to 3 to 4 0 periodicities of 11 and 210 years also found in the solar modulated records of the cosmogenic isotopes 1obe and 14c suggest solar processes as the cause of these cycles depression of180 160 values cooling by volcanic eruptions is observed in stacked gisp215 80 records but the effect is small and not likely to trigger major climate changes

depositional origin and facies variability of a middle triassic barrier island complex peejay field northeastern british columbia middle triassic strata of the peejay field in northeastern british columbia are composed of four regressive shorefaces the youngest having been reworked by tidal inlets tidal inlet sublitharenites and bioclastic grainstones form the best reservoir facies these deposits form a series of shoreline parallel narrow sharp based linear sand bodies that eroded the paleoshoreface the orientation geometry and internal sedimentology of these tidal inlet facies suggest that the paleoshoreline was subjected to a wave dominated paleohydrographic regime determining the processes responsible for forming a specific tidal inlet can provide information regarding waves tides and storms characteristic of the depositional setting knowledge of this paleohydrographic regime can aid in predicting the orientation and internal characteristics of tidal inlet reservoir facies improved predictability of reservoir facies geometry and quality can have direct implications on hydrocarbon exploration and development strategies of these and similarly formed hydrocarbon plays of the triassic in the western canada sedimentary basin and elsewhere

extreme snow metamorphism in the allan hills antarctica as an analogue for glacial conditions with implications for stable isotope composition understanding physical processes in near zero accumulation areas can help us to better understand polar ice core records particularly during periods when accumulation rates were lower than today we report measurements from a 5 m firn core from the allan hills antarctica which include physical properties using computer tomography stable isotope ratios d and 18 o and 210 pb activity the core shows a highly metamorphosed firn with homogeneous and stable structure but with discrete layers near the surface the observed firn structure is caused by a combination of unique depositional and post depositional processes the irregular d and 18 o signal does not follow the stratigraphic sequence and implies post depositional modification caused by microscopic pressure gradients in the firn that can result from either forced ventilation over rough surfaces in the presence of wind or alternating temperature gradients between the firn and the atmosphere our results also indicate impact snow deposition under high winds and with a high initial density and air exchange between the atmosphere and the snowpack 210 pb activity below 0 3 m falls below the detection limit implying that most of the core is more than 100 years old we conclude that the allan hills record provides a unique opportunity to investigate important processes that would have affected ice core records from glacial periods

paleoenvironmental background of the early pleistocene gigantopithecus fauna in bubing basin south china thanks to the presence of the enigmatic gigantopithecus fossils vertebrate paleontologists have spent much time analyzing the pleistocene faunas of southern china although research has been conducted in the region for more than one half century the vast majority of this research has focused on the direct analysis of the associated vertebrate fossils particularly for taxonomic identification purposes in order to develop a firmer understanding of the paleoenvironment in which these various taxa lived there is still a relative paucity of data derived from other lines of evidence besides taxonomic identifications here we contribute to these paleoenvironmental reconstructions of southern china by presenting the results of clay mineral composition and geochemical analyses of the deposits from the early pleistocene mohui cave bubing basin guangxi in general the mohui cave clay mineral samples are dominated by kaolinite which indicates a warm and humid climate the relatively high content of smectite in unit ii implies a relatively long dry season within the overall context of the warm and humid environment based on the chemical index of alteration cia the estimated land surface temperature during the early pleistocene 27 c was much higher than today 21 9 c our results are consistent with previous environmental reconstructions based on vertebrate paleontological and isotopic studies of the gigantopithecus fauna in southern china that the environment during the early pleistocene was warmer and more humid than today

fluid bearing capacity of strandline sand deposits implication for hydrocarbon exploration abstract the fluid bearing capacity of the holocene coastal sand deposits of central south carolina was determined in order to estimate their potential oil in place reservoir capacity these sand bodies which vary considerably in size thickness shape and continuity were deposited in a variety of depositional settings including barrier islands tidal deltas exposed sand flats tidal sand ridges and tidal point bars minimum potential sand thickness and conservative mud cutoff values of 10 15 were used to define each sand body type average thickness values ranged from 20 ft 6 m for barrier islands to 15 ft 4 5 m for exposed sand flats within the study area barrier islands have average sand volumes of 1 3 105 acre ft 1 6 108 m3 sup and tidal delta sands average 1 0 105 acre ft 1 2 108 cm3 potential oil reserve values averaged 7 million bbl for individual barrier islands and 5 million bbl for individual ebb tidal deltas if the holocene sand deposits of the central 50 mi 80 km of the south carolina coast were preserved in place 150 200 million bbl of oil could be contained within the reservoir quality sands of course these values represent only one small segment of geologic time approximately 5 000 years these calculations were based on typical reservoir characteristics and recovery factors found in cretaceous sandstones buried at 5 000 ft 1 500 m in the rocky mountain area average reservoir values used included porosity of 25 oil saturation of 65 formation volume factor of 1 3 and 10 of the sand body occupied by hydrocarbons a better understanding of these strandline sand deposits could improve exploration and future development of these significant potentially oil bearing sands end of article last page 485

preservation assessments and carbon and oxygen isotopes analysis of tooth enamel of gigantopithecus blacki and contemporary animals from sanhe cave chongzuo south china during the early pleistocene abstract as one of the largest primates that ever lived the finding of gigantopithecus blacki mainly occurs in southern china during the early and middle pleistocene previous stable carbon isotope analysis of g blacki teeth showed that it relied on c3 based foods in the early pleistocene however the deficiency of preservation assessment other ape samples and oxygen isotope data may hinder the dietary interpretation and understanding the dietary preference of g blacki compared to human relative apes in this study xrd and ftir were used to assess the crystallinity variation of apatite in fossil enamel of g blacki and animals during the early pleistocene from sanhe cave chongzuo guangxi south china the results indicated that the carbonate group in enamel apatite still retained its biogenic signature although the crystallinity was enhanced during fossilization the carbon isotope values of all fossil animals suggest that they consumed c3 based foods most importantly the oxygen isotope values of all animal fossils show that g blacki as well as pongo was engaged in mixed feeding strategy perhaps relying on grasses plant leaves stems or possible roots that are depleted in 18o moreover lower oxygen isotope values of g blacki than those from pongo are observed suggesting that g blacki preferred plant roots or stems with lower 18o values

dated co occurrence of homo erectus and gigantopithecus from tham khuyen cave vietnam abstract tham khuyen cave lang son province northern vietnam is one of the more significant sites to yield fossil vertebrates in east asia during the mid 1960s excavation in a suite of deposits produced important hominoid dental remains of middle pleistocene age we undertake more rigorous analyses of these sediments to understand the fluvial dynamics of pleistocene cave infilling as they determine how skeletal elements accumulate within tham khuyen and other east asian sites uranium thorium series analysis of speleothems brackets the pleistocene chronology for breaching infilling and exhuming the regional paleokarst clast analysis indicates sedimentary constituents including hominoid teeth and cranial fragments accumulated from very short distances and under low fluvial energy electron spin resonance analysis of vertebrate tooth enamel and sediments shows that the main fossil bearing suite s1 s3 was deposited about 475 thousand years ago among the hominoid teeth excavated from s1 s3 some represent homo erectus and gigantopithecus blacki criteria are defined to differentiate these teeth from more numerous pongo pygmaeus elements the dated co occurrence of homo erectus and gigantopithecus blacki at tham khuyen helps to establish the long co existence of these two species throughout east asia during the early and middle pleistocene

multiple climate shifts in the southern hemisphere over the past three centuries based on central antarctic snow pits and core studies based on the results of geochemical and glaciological investigations in snow pits and shallow cores regional stack series of air temperature in central antarctica in the southern part of vostok subglacial lake were obtained covering the last 350 years it is shown that this parameter varied quasi periodically with a wavelength of 30 50 years the correlation of the newly obtained record with the circulation indices of the southern hemisphere sh shows that the central antarctic climate is mainly governed by the type of circulation in the sh under conditions of zonal circulation negative anomalies of temperature and precipitation rate are observed whereas the sign of the anomalies is positive during meridional circulation in the 1970s the sign of the relationship between many climatic parameters changed which is likely related to the rearrangement of the climatic system of the sh the data suggest that during the past 350 years such events have taken place at least five times the stable water isotope content of the central antarctic snow is governed by the summer temperature rather than the mean annual temperature which is interpreted as the influence of post depositional effects

influence of summer sublimation on δd δ18o and δ17o in precipitation east antarctica and implications for climate reconstruction from ice cores

paleoecologies and paleoclimates of late cenozoic mammals from southwest china evidence from stable carbon and oxygen isotopes abstract to examine paleodiets and habitats of extinct taxa and to understand long term regional climate change we determined the carbon and oxygen isotopic compositions of fossil herbivore teeth and soil samples from six localities in yunnan province southwest china ranging in age from 10 ma to the present although limited in spatial and temporal coverage these initial results reveal significant changes in the environments and diets of mammalian taxa over the last 10 million years prior to 2 3 ma while most mammals examined had pure or nearly pure c 3 diets some individuals consumed a small amount of c 4 grasses up to 20 c 4 since then c 4 grasses became a significant dietary component for most herbivores as indicated by higher enamel 13 c values in the pleistocene yuanmou formation and at shangri la most likely reflecting an increased c 4 biomass in the region the carbon isotope results show that the diets of mammals of 2 5 1 75 ma from shangri la ranged from pure c 3 to pure c 4 while 1 7 ma horses from yuanmou had 0 70 c 4 grasses in their diets mammals living at 8 7 ma in the yuanmou and lufeng region had very similar diets and habitats with similar climatic conditions increased c 4 biomass after 3 4 ma suggests a significant change in certain aspects of regional climate such as increased seasonality of rainfall or an increase in seasonal drought and fires as these factors are important to modern grasslands the data also show that unlike the siwalik fauna in the indian subcontinent mammals in yunnan on the southeast side of the himalayan tibetan plateau lived in an environment dominated by dense forests until 3 4 ma nonetheless both 13 c values of paleosol carbonates and fossil enamels indicate that c 4 grasses were present in the yuanmou region in the latest miocene and pliocene 8 3 5 ma likely in greatly dispersed small patches of open habitats where the forest canopy was broken or on flood plains and the c 4 biomass increased significantly after 3 5 ma the oxygen isotope results from yuanmou xiaohe formation show a positive shift after 8 5 ma which is similar in timing and magnitude to 18 o shifts observed in horses and rhinos from the linxia basin and in fossils and paleosols from pakistan and nepal suggesting a shift toward a drier climate at the northeast southeast and southern borders of the tibetan plateau during the late miocene taken together the carbon and oxygen isotope data indicate a general drying of the local climate over time and a change from a largely dense forest environment at 8 ma to a more open environment with a mosaic of forests and grasslands after 3 4 ma in the yuanmou region intra tooth 13 c and 18 o variations within individual fossil teeth from yuanmou suggest a stronger seasonality of rainfall at 1 7 ma than in the late miocene the spatial and temporal 13 c and 18 o variations observed in mammalian teeth from yunnan likely reflect changes in regional climate and or tectonics but more data are needed to fully explore the significance of the regional patterns in the 18 o and 13 c data in relation to climate and tectonic evolution of the region

seasonal evolution of penitente glaciochemistry at tapado glacier northern chile this study uses stable isotopes and major ions to examine the seasonal evolution of penitentes on the surface of tapado glacier in the norte chico region of the chilean andes a snow pit was sampled in november 2011 and penitentes were sampled during the summer december 2011 and january 2012 the major ion load of the winter snowpack is dominated by ca2 60 so42 16 and no3 13 and there is little influence from marine air masses at the site with most so42 mg2 ca2 and na derived from non sea salt sources during the early ablation season we observe increases in stable isotope ratios and major ion concentrations particularly lithic ions na mg2 and ca2 in the upper reaches of penitentes which is attributed to sublimation and the aeolian deposition of dust particles in the late summer melt replaces sublimation as the dominant ablation process and results in smoothing of the stable isotope profile and the elution of major ions within the penitente snow and ice matrix copyright 2015 john wiley sons ltd