the lilliput effect in the aftermath of the end permian extinction event early triassic animal body fossils and trace fossils are small relative to those in older and younger intervals size decreases sharply through the end permian extinction event and permian triassic boundary and the smallest sizes are encountered in the parvus and isarcica zones of the earliest induan animals appearing within these two zones are also exceedingly small compared to younger congenerics and conspecifics temporary dramatic size decrease of surviving taxa in the immediate aftermath of the extinction event is an example of the lilliput effect coined by urbanek a 1993 biotic crises in the history of upper silurian graptoloids a palaeobiological model historical biology 7 29 50 body size increases somewhat from the carinata zone mid induan but remains depressed for the duration of the early triassic and pre extinction sizes are not commonly recorded until at least the middle triassic marine and terrestrial faunas appear to be similarly affected the lilliput effect and longer term size reduction could be the result of several factors environmental parameters such as marine anoxia due to low atmospheric concentrations of oxygen at this time coupled with sluggish ocean circulation in a greenhouse world and food shortage are the likely proximal causes for the early triassic lilliput effect no single cause can explain all the observations and a combination of factors are likely to be involved

anomalous early triassic sediment fluxes due to elevated weathering rates and their biological consequences analysis of 16 marine permian triassic boundary sections with a near global distribution demonstrates systematic changes in sediment fluxes and lithologies in the aftermath of the end permian crisis sections from continent margin and platform settings exhibit higher bulk accumulation rates bars and more clay rich compositions in the griesbachian earliest triassic relative to the changhsingian latest permian these patterns which largely transcend regional variations in tectonic setting sequence stratigraphic factors and facies are hypothesized to have resulted from a substantial average 7 increase in the flux of eroded material from adjacent land areas owing to accelerated rates of chemical and physical weathering as a function of higher surface temperatures increased acidity of precipitation and changes in landscape stability tied to destruction of terrestrial ecosystems this sediment surge may have been a contributory factor to the latest permian marine biotic crisis as well as to the delayed recovery of early triassic marine ecosystems owing to the harmful effects of siltation and eutrophication contemporaneous deep sea sections show no increases in sediment flux across the permian triassic boundary owing to their remoteness from continental siliciclastic sources and location below the paleo carbonate compensation depth

timing of recovery from the end permian extinction geochronologic and biostratigraphic constraints from south china four volcanic ash beds bracket the early middle triassic boundary as defined by conodont biostratigraphy in a stratigraphic section in south china high precision u pb dates of single zircons allow us to place the early to middle triassic olenekian anisian boundary at 247 2 ma magnetic reversal stratigraphy allows global correlation the new dates constrain the early triassic interval characterized by delayed biotic recovery and carbon cycle instability to 5 m y this time constraint must be considered in any model for the end permian extinction and subsequent recovery

postapocalyptic greenhouse paleoclimate revealed by earliest triassic paleosols in the sydney basin australia the permian triassic boundary in the sydney basin of australia is coincident with a pronounced decrease in 13 c isotopic values of organic carbon the last coals anywhere in the world for all of the early triassic ca 6 m y time and extirpation of the glossopteris flora at the top of the illawarra and newcastle coal measures coal bearing paleosols of the latest permian represent extensive swamplands of the seasonally deciduous glossopteris flora in a humid cold temperate lowland southwest of an andean style volcanic arc stone rolls large ribs of floor rock up into the coal within some of the uppermost coals of the permian coal measures can be interpreted as string bogs of a kind now found in cold climates at latitudes of 68 70 which is compatible with a paleomagnetically estimated paleolatitude of 65 85 s for the sydney basin paleolatitude was not much different for earliest triassic time but paleosols of that age include inceptisols and entisols showing substantial chemical and textural weathering more like soils now forming at latitudes of 40 58 than those within polar circles this anomalous high latitude warmth set in at the permian triassic boundary sedimentation rates increased at the boundary marked by geochemically unusual acidification of clay and a dramatic carbon isotopic excursion these changes in environments and ecosystems can be explained by soil erosion following deforestation implied by the plant extinctions and abundant fungal remains at the permian triassic boundary evidence from paleosols can now be added to that from paleontological and isotopic studies showing that disruption of the carbon cycle at the permian triassic boundary resulted in a co 2 or ch 4 post apocalyptic greenhouse paleoclimate

palaeoenvironments and faunal recovery after the end permian mass extinction abstract strata of the lower triassic werfen formation dolomites northern italy record deposition in a wide range of palaeoenvironments from peritidal to outer ramp settings this enables accurate assessment of faunal recovery following the end permian mass extinction by eliminating facies related effects extinction of the shelly taxa appears to be rapid and occurs in the latest permian tesero oolite horizon disappearance of the various trace fossil taxa appears to be more gradual following the extinction the lower and middle griesbachian are characterised by laminated sediments containing low diversity bedding plane assemblages ichnological geochemical and sedimentological data show evidence of widespread low oxygen conditions normally oxygenated waters return in the late griesbachian and there is a moderate increase in tiering above and below the surface macrofaunal and ichnofossil diversity decrease markedly during the smithian with the appearance of more terrigenous strata possibly reflecting an increased run off and more brackish conditions complete recovery begins in the basal spathian with an increase in tiering above and below the substrate crinoids and ammonoids appear for the first time in the werfen formation and the ichnogenus rhizocorallium re appears global correlation is hindered by poor biostratigraphy in the dolomites region however on a broad scale it appears as though many of the palaeoenvironmental changes are repeated worldwide current available data suggest that the re appearance of some trace fossil taxa e g diplocraterion rhizocorallium may be globally synchronous

biotic impacts of temperature before during and after the end permian extinction a multi metric and multi scale approach to modeling extinction and recovery dynamics abstract extinction and delayed recovery during the end permian extinction and early triassic has been linked to environmental instability brought on by volcanic outgassing and greenhouse conditions but the relative importance of the myriad of environmental stressors at this time on recovery dynamics is not well understood previous workers have documented both overall delayed biotic recovery for the entirety of the early triassic but also incipient recoveries that appear to occur relatively early after the initial extinction event here we explore the patterns of extinction and recovery using several metrics of ecological complexity in marine benthic communities using a global dataset and compare several multiple regression models to determine which set of abiotic factors best predicts extinction and recovery dynamics we additionally test the importance of temporal scale of analysis in interpretations of recovery dynamics and modeling results by including analyses at the epoch stage and substage scales bracketing the interval of extinction and recovery we find differences in mode of recovery between the ecological metrics analyzed with some metrics exhibiting an early triassic recovery lag while others recover continuously or immediately following the initial extinction event we also find evidence of a global dienerian minimum with overall levels of community complexity significantly lower than earlier griesbachian communities suggesting a synchronous disturbance to the progression of recovery at this time the regression model with 18oapatite mean values as the response variable is most often found to be the best fit model across all time scales analyzed though proxies of rock record fidelity and paleontological sampling effort become more important in finer timescale analyses likely due to dwindling sample numbers out of the models tested these results suggest that global ocean temperatures best predict patterns of extinction and recovery across several ecological metrics and that thermal episodes during the initial extinction event and subsequently in the early triassic recovery period significantly suppressed benthic marine community health

earliest triassic claystone breccias and soil erosion crisis abstract chemostratigraphic methods 13corg for pinpointing the permian triassic boundary in nonmarine rocks of antarctica australia and south africa have drawn attention to unusual claystone breccias at this horizon of the greatest extinction in the history of life on earth these rocks differ from other breccias in having a high proportion of clasts with birefringence microfabrics sepic plasmic fabrics characteristic of soils and can be called sepic pedoliths in the terminology of soil science at many localities earliest triassic sepic pedoliths are thin 5 15 cm beds but some fill shallow paleochannels and pinch out laterally other non marine breccias at the permian triassic boundary are dominated by fragments of coal pedogenic carbonate nodules and deeply weathered volcanic rock fragments earliest triassic sepic pedoliths record an unusually severe and widespread episode of soil erosion associated with forest dieback at the permian triassic boundary comparable sepic pedoliths are found in debris flows after clear cutting of forests in western oregon today studies of these modern deposits show that sepic soil peds do not withstand weathering for more than a few months such clayey clasts are held together mainly by roots and fungi which decay rapidly in soils and streams these modern analogs demonstrate that terminal permian soil erosion was rapid and profound sepic pedoliths are also known at other times of mass extinction such as the triassic jurassic boundary but are not yet known before the devonian advent of trees and forested clayey soils

palynofacies analysis of the permian triassic transition in the amb section salt range pakistan implications for the anoxia on the south tethyan margin the uppermost chhidru formation and the lower part of the mianwali formation were sampled in the amb valley salt range pakistan for the study of the particulate organic matter pom content in order to evaluate the depositional environment during the permian triassic transition the pom content was assigned to four distinct palynofacies palynofacies a d palynofacies a recovered from siltstone within the white sandstone unit of the upper permian chhidru formation indicates a shallow marine oxic shelf setting recorded from the siltstone intercalations in the kathwai member of the basal mianwali formation the griesbachian palynofacies b is characterised by abundant acritarchs indicating a transgressive event palynofacies c recovered from the siltstone of the lowest ceratite marls middle dienerian is dominated by terrestrial organic particles and indicates shallowing of the depositional environment whereas 40 cm above palynofacies d represents transgressive oxygen depleted conditions the comparison with sections from the australian tethyan margin shows that oxygen depleted conditions occurred during the griesbachian in the perth basin while in the bonaparte basin oxygenated conditions prevailed hence oxygen depleted facies do not correspond to a single synchronous permian triassic oceanic anoxic event but depend on local geography and bathymetry

india and java contrasting records intimate connections abstract the archaeological paleontological and hominin records of india and java are compared it is argued that during the lower and middle pleistocene the palaeolithic technology in both the regions was large flake acheulian lfa which is attested to by numerous sites in peninsular india some finds from pinjor exposures in nw india and the site of ngebung in the sangiran dome area of java we argue that the non acheulian assemblages attributed to this period actually come from later contexts during the lower and middle pleistocene fauna in java associated with homo erectus was related to the indian pinjor fauna although hominin fossils have not been found in india for this time period it is likely that homo erectus was the maker of the lfa tools in india given the presence of lfa in java in strata with a pinjor related fauna and homo erectus sometime during the late pleistocene the fauna in java underwent a very significant change from the earlier pinjor related fauna stegodon homo erectus fauna to the punung fauna elephas homo sapiens this change is related to an ecological shift from a more savannah like to a more rainforest like environment it is during this time rather than earlier that the movius line has an archaeological paleontological and ecological validity

did early man reach java during the late pliocene abstract homo erectus pithecanthropus reached java from the asian continent and became one of the oldest islanders in the world this article deals with the palaeomagnetic and 40 ar 39 ar dating of the lower lahar a layer located at the base of the fossil bearing series of the sangiran dome combined 40 ar 39 ar and palaeomagnetic data show that the deposition of the lower lahar marking the emergence of the first dryland at sangiran took place at the end and just after the olduvai subchron therefore c 1 7 million years can be considered as a maximal theoretical age for the arrival of the first hominids at sangiran

geochronology of early human settlements in java what is at stake abstract despite the fact java island is a volcanic area it has been challenging to build a chronological framework of its early human settlements from the oldest lower pleistocene homo erectus up to the dispersals that followed the last glacial maximum lgm various dating methods are implemented on volcanic effluents sedimentary deposits speleothems and also on fossils including direct analyses on human remains thanks to radiometric and palaeodosimetric grounded techniques as well as to magnetostratigraphy however a number of results must be considered with caution in order to identify specific bias originating from reworking of volcanic effluents or post depositional geochemical evolution such bias might well explain apparent contradictions between absolute dating results and other chronologically significant proxies e g biostratigraphy converging age estimates resulting from the implementation of several dating methods though being sometimes less precise seem to have a higher reliability

high resolution clay mineral and major elemental characterization of a permian triassic terrestrial succession in southwestern china diagenetic and paleoclimatic paleoenvironmental significance abstract relatively high resolution clay mineralogical and chemical index of alteration cia analyses were conducted on the terrestrial lubei section in southwestern china to gain a better understanding of the paleoclimatic paleoenvironmental evolution on land during the permian triassic transition p tr transition clay mineral species include illite smectite mixed layers i s illite irregular chlorite expandable mixed layers c e chlorite kaolinite vermiculite hydroxyl interlayered mineral him and corrensite cia values are as high as approaching 100 in the permian and show a gradual and subtle decrease towards the lowermost triassic where a sudden decrease to persistently

timing of the early triassic carbon cycle perturbations inferred from new u pb ages and ammonoid biochronozones based on analyses of single thermally annealed and chemically abraded zircons a new high precision u pb age of 251 22 0 20 ma is established for a volcanic ash layer within the kashmirites densistriatus beds of early smithian age early triassic from the luolou formation northwestern guangxi south china this new date together with recalculated uncertainties of previous u pb ages from the same section m ovtcharova h bucher u schaltegger t galfetti a brayard j guex new early to middle triassic u pb ages from south china calibration with ammonoid biochronozones and implications for the timing of the triassic biotic recovery earth planet sci lett 243 2006 463 475 allows constraining the time framework of the early triassic and leads to an estimated duration of i ca 0 7 0 6 my for the smithian and ii a maximal duration of ca 1 4 0 4 my for the griesbachian dienerian time interval the new u pb age considerably reduces the absolute age gap comprised between the permian triassic boundary and the spathian late early triassic the new age framework provides the basis for the calibration of a new carbonate carbon isotope and ammonoid records of the early triassic luolou fm which in turn are of high significance for global correlations and for carbon cycle modeling this calibration indicates that the most significant and fastest early triassic carbon isotope perturbations occur between the earliest smithian and the early spathian thus spanning a time interval of about 1 my whatever caused these carbon cycle shifts of high intensity and short duration there is evidence for connections between these fluctuations the pulsate recovery of ammonoids and conodonts as well as climate changes

abrupt chemical weathering increase across the permian triassic boundary previous studies have suggested a variety of causes for the end permian extinction event including a bolide impact flood basalt volcanism methane clathrate dissociation or some combination of catastrophic processes one common feature of these hypotheses is the prediction of an enhanced earliest triassic greenhouse new high resolution geochemical results from graphite peak antarctica support an abrupt increase in chemical weathering in the earliest triassic among otherwise genetically similar paleosols of similar provenance relative to the latest permian paleosols the earliest triassic paleosol exhibits greater leaching greater accumulation of immobile rees and evidence of lower soil po2 with no evidence of an erosional unconformity between the paleosols which are separated by 15 cm stratigraphically these results support a rapid shift perhaps 10 000 years to an earliest triassic greenhouse and a role for methane release in the extinction event and its aftermath

constraining the cause of the end guadalupian extinction with coupled records of carbon and calcium isotopes abstract a negative c 13 excursion in carbonate sediments near the guadalupian lopingian middle late permian boundary has been interpreted to have resulted from a large carbon cycle disturbance during the end guadalupian extinction event ca 260 ma however the carbon isotope data alone are insufficient to uniquely determine the type and magnitude of perturbation to the global carbon cycle calcium isotopes can be used to further constrain the cause of a carbon isotope excursion because the carbon and calcium cycles are coupled via caco3 burial in this study we present coupled carbon and calcium isotope records from three guadalupian lopingian g l sections in china penglaitan and chaotian and turkey koserelik tepe the c 13 and ca 44 40 records differ among our studied sections and do not co vary in the same manner no section shows c 13 and ca 44 40 changes consistent with massive rapid volcanic co2 emissions or methane clathrate destabilization additionally many sections with large 3 changes in c 13 exhibit o 18 evidence for diagenetic alteration only one section exhibits a large excursion in the ca 44 40 of limestone but the absence of a similar excursion in the ca 44 40 of conodont apatite suggests that the limestone excursion reflects a mineralogical control rather than a perturbation to the global calcium cycle hence we interpret the large isotopic changes observed in some sections to have resulted from local burial conditions or diagenetic effects rather than from a large carbon and calcium cycle disturbance perturbations to the global carbon and calcium cycles across the g l transition were much less intense than the disturbances that occurred across the subsequent permian triassic boundary this finding is consistent with the much smaller magnitude of the end guadalupian extinction relative to the end permian

paleophysiology and end permian mass extinction physiological research aimed at understanding current global change provides a basis for evaluating selective survivorship associated with permo triassic mass extinction comparative physiology links paleontological and paleoenvironmental observations supporting the hypothesis that an end permian trigger most likely siberian trap volcanism touched off a set of physically linked perturbations that acted synergistically to disrupt the metabolisms of latest permian organisms global warming anoxia and toxic sulfide probably all contributed to end permian mass mortality but hypercapnia physiological effects of elevated pco2 best accounts for the selective survival of marine invertebrates paleophysiological perspectives further suggest that persistent or recurring hypercapnia global warmth also played a principal role in delayed triassic recovery more generally physiology provides an important way of paleobiological knowing in the age of earth system science 2007 elsevier b v all rights reserved

sudden and extreme hyperthermals low oxygen and sediment influx drove community phase shifts following the end permian mass extinction abstract we present a correlated record of carbon isotope geochemistry and sedimentological analysis for the lower triassic werfen formation from the italian dolomites macro and mid sized fossil diversity ecology and climate sensitivity are included to provide an integrated account of the benthic response to paleoenvironmental change novel communities developed in the wake of the mass extinction during pervasive fluctuations in environmental conditions in the sedimentary sequences of the werfen formation of the italian dolomites microbialites microconchids foraminifera and ubiquitous flat clams formed a complex community within the first 500 000 years later increased sea surface temperatures and inundation of the seafloor with siliciclastic sediments favored infaunal bivalves and microgastropods persistent trends in the environment can produce directional often irreversible community shifts defined here as phase shifts phase shifts in ecosystem structure can be driven by environmental shifts across threshold boundaries to produce an abrupt and dramatic novel community composition a phenomenon readily observed during the early triassic previously described disaster forms including flat clams microconchids foraminifera and microbialites are re envisioned as a phase shift community we hypothesize that the unique persistent and reoccurring microbialite and mid sized fauna assemblages observed during the initial recovery from the end permian mass extinction and re appearing throughout the early triassic typify a phase shift community in the smithian infaunal bivalves and microgastropods represent a second phase shift community developed in response to a persistent directional rise in sea surface temperatures and enhanced sediment influx we compare and contrast phase shifts with other models for ecosystem recovery including trophic competition and earth system succession

changes in the global carbon cycle occurred as two episodes during the permian triassic crisis coeval records of ocean atmosphere and terrestrial change are crucial to understanding the pattern and causes of global mass extinction across the permian triassic boundary ptb however relationships among changes in different settings remain largely unclear primarily due to the challenges associated with the correlation among disparate records here we compare marine carbon isotopic records with marine and terrestrial environmental and biotic events recorded in sediments from the meishan ptb section of south china time scaled carbonate carbon isotopes exhibit two gradual major shifts across the ptb at meishan and these are duplicable elsewhere around the tethys ocean the two shifts are associated with two episodes of enhanced terrestrial weathering indicated by an increased abundance of 13 c enriched moretanes relative to hopanes and an elevated abundance of black carbon fragments key marine events previously reported for the ptb including photic zone euxinia faunal mass extinction and cyanobacterial expansion also occur as two episodes coinciding with both of the progressive shifts to negative 13 c values and enhanced weathering the temporal sequence of the duplicable events suggests that the biotic crisis was a consequence of prolonged and episodic changes in the marine and continental systems and argues against an extraterrestrial impact as the main cause

simulating permian triassic oceanic anoxia distribution implications for species extinction and recovery the biggest mass extinction in the phanerozoic at the end of the permian has been associ ated with oceanic changes but the exact dynamics are still debated intensifi ed stratifi cation widespread anoxia chemocline excursions and large scale ocean overturn events have all been invoked as contributors to the extinction in this study the effects of possible changes in environmental conditions such as an increase in nutrient input or dust fl uxes into the ocean or an intensifi cation of the biological pump on permian triassic ocean chemistry are inves tigated series of sensitivity experiments were performed with a fully coupled climate carbon cycle model none of the forcings alone generates extensive low oxygen conditions in the deep sea these are only simulated by an intense eutrophication in combination with an enhanced biological pump but still confi ned to the central panthalassic tethys and the eastern boreal oceans our fi ndings support the conclusions from a recent geochemical study of a japanese deep panthalassa section that around the permian triassic boundary the oxygen minimum zone expanded considerably while the deep panthalassa remained ventilated the warming induced increase in low oxygen conditions within the water column aggravated adverse exist ing conditions and likely contributed to the extinction peak upwelling of toxic water was probably regionally confi ned and hence not the main cause for the end permian marine and terrestrial mass extinction widespread deep sea anoxia generated by a strong increase in weathering and the related enhanced nutrient input into the oceans is probably closely linked to the delayed recovery of species in the early triassic

sequencing events across the permian triassic boundary guryul ravine kashmir india abstract the permian triassic boundary ptb section at guryul ravine kashmir india comprises a 100 m thick apparently conformable succession of mixed siliciclastic carbonate sediments deposited in a deep shelf or ramp setting this section although long important in debates concerning placement of the ptb has not previously been the focus of an integrated chemostratigraphic study in the present study samples from a 20 m thick interval straddling the ptb were analyzed for major and trace element concentrations toc tic rees and organic 13c 15n to investigate contemporaneous environmental changes the guryul ravine section exhibits a sequence of discrete events that provide potentially important information about the character and cause s of the ptb two transient negative c isotopic excursions within the upper changxingensis zone predate the late permian event horizon lpeh i e the global mass extinction event by 200 400 kyr and are associated with the onset of a major eustatic rise and with secondary extinction peaks these excursions may record minor environmental disturbances prior to the main end permian crisis supporting an intrinsic mechanism such as volcanism and climate change rather than an extrinsic mechanism such as a bolide impact the onset of a large 4 0 to 4 5 sustained negative c isotope shift marks the lpeh which is located at the zewan khunamuh formation contact 260 cm below the biostratigraphically defined ptb the guryul ravine section exhibits a stepwise extinction pattern with the largest peak between the lpeh and ptb and a secondary peak just above the ptb a pattern similar to that observed in the meishan d gssp

oldest human expansions in eurasia favouring and limiting factors 1 introductionon november 26e28 2008 an international conference wasorganised at the museum national d histoire naturelle paris france the topic was the oldest human expansions in eurasia under theaspect of the factors which could favour or limit the humansettlements while fossil human remains are scarce in eurasia lithicassemblages suggest at least two phases of human settlement or and techno cultural spread from africa to eurasia the rst one attested by mode 1 lithic industries is observed at dmanisi georgia at 1 8 ma in asia in china and pakistan around 2 ma and in europe for example in spain since 1 2e1 4 ma at orce atapuerca in italy monte poggiolo ca 1 ma pirro nord at least1 3 ma and in france pont de lavaud le vallonnet around 1 ma some dates in china and indonesia support the idea of earliersettlementsincontinentalandislandasiathanineurope whiletheoldest tool kit in africa dates to 2 6 ma kada gona ethiopia a second phase is marked by the appearance of new tools especially handaxes and cleavers these large tools do occur inafrica around 1 6e1 7 ma konso ethiopia kokiselei kenya andaround 1 4e1 2 ma in the middle east ubeidiya israel they areconsideredasthe rstindicatorsofacheuliantradition ormode2 consisting in shaping large tools on akes or blocks these toolsappear outside africa with different time lags according togeographical areas in asia the rst ones occur around 1 2 ma isampur india and then become more signi cant with anincreasing number of sites around 800 ka in eastern asia e china and south eastern asia ngebung java in western and southerneurope acheuliansitesonlyappeararound600e700ka asattestedbythe recent discoveriesin centreregion france la noira in chervalley and they become more numerous from 500 ka onwards inspain atapuerca galeria ambrona in italy visogliano castel diguido in northern and southern france somme river terraces caune de l arago in the european continent assemblages withbifaces characteristic of acheulian onlyoccurin a geographical areastretching from southern europe to great britain however theyare lacking in central europe and the rhine river is considered asa frontier but they do exist in the caucasus near the central asianborder while they are unknown further east in tadjikistan these two waves of populating probably include numerousarrivals and we do not know whether these arrivals led each timeto a permanentsettlement particularlyif the hominin groups weresmall and geographically dispersed this time lag between asia and europe regarding the peoplingphases and their consequences is debated today within the scien ti c community what could be the migratory paths from africa toboth asia and europe or from africa to asia then to europe whomoved homo antecessor homo heidelbergensis were there somecontacts between distinct human groups rather than shiftingpopulations these questions also concern the diffusion modalitiesof technical traditions and the effect of climatic and environmentalconditions on human movements the latter could explain chro nological lags and restriction of human settlements to some areasonly however it has to be kept in mind that convergencephenomena could also happen at a regional scale in the tool kits this may be the case for acheulian people the present state of knowledge on the earth s climatic storyduringthelasttwomillionyearsshowslocalphenomenacombinedto global changes for example increase of glaciations around800ka whenclimaticcyclesshiftedtothe100kaperiodicity astheeccentricity parameter of terrestrial orbit became more importantthan the obliquity of earth s axis earlier periodicity of 41 ka mis20 characterised by strong marine regression took place at thesame time as the matuyamaebrunhes geomagnetic inversion 780 ka and is considered as an accurate chronological marker recent results of various research teams contribute to builta more complete and precise picture of the past the betterknowledge of the palaeoenvironment allows a new appraisalregarding the spread of technical behaviours in relation to theenvironmental context highlighted by new issues concerningafrica some major questions were discussed during the conference 1 the geographical dispersal of each type of lithic industry 2 the chronological gaps in the hominin settlements in thevarious areas of eurasia 3 the periods when climatic or topographic variations had animportant role favouring or limiting the human expansion insome regions

controls on regional marine redox evolution during permian triassic transition in south china abstract although oceanic anoxia is regarded as a leading cause of the permian triassic boundary ptb mass extinction its timing extent and underlying causes remain unclear here we conducted a high resolution fe s c mo geochemical study of the entire changhsingian and lowermost induan succession in a carbonate ramp setting at ganxi western hubei province south china six stratigraphic units representing discrete redox intervals were identified based on integrated fe s c mo data units i iii are of latest wuchiapingian to early changhsingian age with units i and iii characterized by euxinia and unit ii by uncertain redox conditions unit iv of mid changhsingian age records a gradual transition from euxinic to ferruginous conditions units v and vi spanning the latest permian mass extinction lpme to earliest triassic interval were deposited under dominantly ferruginous conditions punctuated by both euxinic and oxic episodes redox variations at ganxi were controlled by contemporaneous oceanographic changes in the upper oceanic thermocline region i euxinia in units i and iii may record elevated marine productivity as suggested by mean organic carbon accumulation rates or ocar of 6 5 and 5 1 mg cm2 kyr respectively that was possibly related to upwelling ii the euxinic to ferruginous transition from unit iv to units v vi can be attributed to a combination of reduced sulfate availability and rising terrigenous iron inputs mean fe of 1 7 and 3 9 respectively for units v iv and vi compared to 1 0 for units i iii and iii transient intervals of euxinia in units v and vi were facilitated by enhanced sulfate fluxes related to episodic volcanism during this interval an integration of the redox data from ganxi with previously published data from the shangsi and xiakou sections suggests that enhanced weathering fluxes were most likely the key factor controlling the marine redox transition from euxinic to ferruginous conditions during the latest permian across the south china region

the matuyama brunhes boundary interval 500 900 ka in north atlantic drift sediments summary ocean drilling program odp sites 984 and 983 located on north atlantic sediment drifts provide high resolution records across the matuyama brunhes boundary at odp site 984 bjorn drift iceland basin the mean sedimentation rate in the 500 900 ka interval is 12 cm kyr 1 based on an age model derived by matching the planktonic and benthic oxygen isotope records to an ice volume model the matuyama brunhes polarity transition at site 984 as defined by virtual geomagnetic polar vgp latitudes 50 has an apparent duration of 7 kyr with a mid point at 773 5 ka compared with 772 5 ka at neighbouring site 983 outside the polarity transition at both sites 984 and 983 excursions in vgp latitudes to values 20 at 540 590 and 670 ka correspond to troughs in the palaeointensity record new u channel palaeomagnetic data across the matuyama brunhes boundary for working and archive halves of core sections from three holes at both sites 984 and 983 augment data published by channell lehman 1997 and are compared with back to back 1 cm 3 discrete samples clusters of vgps in the south atlantic and northeast asia in both u channel and discrete sample records imply that polarity transition fields have characteristics similar to the modern non axial dipole nad field

mass extinctions and sea level changes abstract review of sea level changes during the big five mass extinctions and several lesser extinction events reveals that the majority coincide with large eustatic inflexions the degree of certainty with which these eustatic oscillations are known varies considerably thus the late ordovician and end cretaceous extinctions are associated with unequivocal major regressions demonstrated from numerous widespread regions in contrast the multiple high frequency sea level changes reported for the frasnian famennian crisis based on the supposed depth preferences of conodont taxa have little support from sequence stratigraphic analyses which reveals the interval to be one of highstand the end permian mass extinction has long been related to a severe first order lowstand of sea level newell n d 1967 revolutions in the history of life geol soc am spec pap 89 63 91 based primarily on the widespread absence of latest permian ammonoid markers but field evidence reveals that the interval coincides with a major transgression newell s hypothesis that marine extinctions are related to shelf habitat loss during severe regression remains tenable for the end guadalupian and end triassic extinction events but not for other crises rapid high amplitude regressive transgressive couplets are the most frequently observed eustatic changes at times of mass extinction with the majority of extinctions occurring during the transgressive pulse when anoxic bottom waters often became extensive the ultimate cause of the sea level changes is generally unclear a glacioeustatic driving mechanism can only be convincingly demonstrated for the end ordovician and end devonian events at other times it is speculated that they may relate to the widespread regional doming and subsequent collapse caused by the impingement of superplumes and ultimate eruption on the base of the lithosphere

altered river morphology in south africa related to the permian triassic extinction the permian triassic transition in the karoo basin of south africa was characterized by a rapid and apparently basin wide change from meandering to braided river systems as evidenced by preserved sedimentary facies this radical changeover in river morphology is consistent with geomorphic consequences stemming from a rapid and major die off of rooted plant life in the basin evidence from correlative nonmarine strata elsewhere in the world containing fluvial permian triassic boundary sections suggests that a catastrophic terrestrial die off of vegetation was a global event producing a marked increase in sediment yield as well as contributing to the global 13 c excursion across the permian triassic boundary

insular dwarfism in canids on java indonesia and its implication for the environment of homo erectus during the early and earliest middle pleistocene abstract several canid fossils which were originally discovered and described in the early 20th century are known from early and earliest middle pleistocene of java indonesia here we revise the taxonomy and relative age of the javanese canid fossils in light of recent developments in the taxonomy and phylogeny of canidae and new insights in the evolution of island mammals results show that cuon was absent during the early and earliest middle pleistocene while the large sized xenocyon previously megacyon was present in the early pleistocene and replaced by the small sized xenocyon previously mececyon during the earliest middle pleistocene the latter is probably an anagenetic dwarf derived from the larger form of the preceding period the change in body size of xenocyon on java over time is likely the effect of increased competition within the carnivore guild within the restricted boundaries of the island simultaneously with a pronounced body size shift a dietary shift from large sized prey to much smaller prey must have taken place in order to meet energetic constraints the degree of endemism of terrestrial mammals of the earliest middle pleistocene horizon of the site trinil which has also yielded homo erectus fossils indicates that during this period java was marginally isolated which allowed for a corridor dispersal to the island with subsequent vicariance the nature and degree of isolation may have been similar to that of late pleistocene sicily but of a longer duration given the higher degree of dwarfism of the stegodon antilope and canid the following continentalisation enabled the invasion by mainland terrestrial mammals as is seen in younger layers at trinil and eventually by homo sapiens and cuon in the late pleistocene holocene

a new high resolution stratigraphic and palaeoenvironmental record spanning the end permian mass extinction and its aftermath in central spitsbergen svalbard abstract research on the permian triassic boundary ptb along the northern margins of pangaea exposed today in the arctic region has been heavily reliant on field observations where data resolution was consequently determined by outcrop condition and accessibility core drilling in central spitsbergen allowed for a near complete recovery of two 90 m cores through the ptb analyses of the core and nearby outcrops include stratigraphic logging and sampling xrf scanning petrography biostratigraphy isotope geochemistry and geochronology the first appearance datum fad of h parvus in svalbard places the base of the triassic ca 4 m above the base of the vikinghogda formation and ca 2 50 m above the end permian mass extinction epme and its associated sharp negative 13c the ptb therefore falls within the reduviasporonites chalastus assemblage zone in svalbard precise u pb tims dating of two zircon crystals in a tephra layer just above the first documented hindeodus parvus in svalbard gives an age of 252 13 0 62 ma high resolution palaeoenvironmental proxies including si kcps kilo counts per second zr rb k ti fe k and v cr indicate a transition towards a more arid climate in the earliest triassic contemporaneous with prolonged bottom water dysoxic anoxic conditions following an increase in volcanic activity in the late permian statistical analysis of zr rb k ti and v cr elemental ratios suggests that the system was impacted by long eccentricity 400 kyr cyclicity the 13c excursion in organic carbon 13corg record signals a large negative carbon isotope excursion cie associated with the mass extinction event but also records a second smaller negative cie ca 22 m above this interval this younger 13corg excursion correlates to similar cies in the dienerian late induan records of other sections notably in the tethys ocean which have been interpreted as recording a small biotic crisis during the post extinction recovery evidence of this negative cie in spitsbergen suggests that the dienerian crisis may have been global in extent the negative 13corg values are associated with evidence for dysoxia or anoxia in the core and the occurrence of tephra layers in the same interval suggests a possible connection between the dienerian crisis and a discrete episode of volcanic activity

provenance and geochemistry of lower to middle permian strata in the southern junggar and turpan basins a terrestrial record from mid latitude ne pangea abstract the lower to middle permian terrestrial successions in the southern junggar and turpan basins provide a wealth of information regarding the paleoclimatic and paleogeographic evolution of mid latitude ne pangea two sections namely the xiaolongkou section in the southern junggar basin and the southwest sw tarlong section in the turpan basin were systematically studied using detrital zircon geochronology and whole rock geochemical analysis stratigraphic studies suggest that in both sections the lucaogou and hongyanchi formations are dominated by lacustrine deposits while the quanzijie formation represents mixed fluvial lacustrine and loess environments the lucaogou formation displays low cia chemical index of alteration values and th u ratios suggesting semiarid to arid conditions in both sections the hongyanchi formation shows low to intermittently moderate cia values and th u ratios indicating variably semiarid arid conditions alternating with subhumid semiarid episodes the lower part of the quanzijie formation reflects subhumid semiarid to semiarid arid conditions while the upper part of the quanzijie formation mainly records semiarid arid and shifts into subhumid conditions toward the top detrital zircon and element data indicate that within each section all three formations display similar zircon age distributions and geochemical characteristics suggesting no significant changes in provenance during deposition however the provenance characteristics of the two sections differ from each other the xiaolongkou section is rich in felsic material with two detrital zircon age peaks while the sw tarlong section contains more mafic components with a single peak in detrital zircon age spectrum this suggests that the greater junggar turpan basin was highly partitioned with several independent provenance systems active during the early middle permian the abrupt change in depositional environments in both sections may have resulted from uplift of the north tian shan which induced rapid regression of the lakeshore and uplift of sediment source and catchment areas

the rain forest in java through the quaternary and its relationships with humans adaptation exploitation and impact on the forest abstract relations between humans and the rain forest in java island began during the lower pleistocene but clear evidence for anthropic impact and clearance of the forest does not occur until late in the holocene after the rise of the ancient kingdoms on java at the end of 1st millennium a d the history of landscape change in java over the last 2 5 million years appears highly complex and linked to the repetitive expansion and fragmentation of the rain forest over this time these processes are now much better understood thanks to the range of palaeoenvironmental studies undertaken at various altitudes and in locations that show the dynamics of rain forest in response to variations in climatic and regional environmental change the extent of rain forest throughout the holocene appears to have been quite sensitive to small perturbations making it somewhat difficult to discriminate especially for relatively ancient holocene forest recessions between a climatic cause and one of anthropic origin clear evidence of intensive human impact on rain forest is observed late c 1500 years ago a pattern that is repeated in other parts of island southeast asia this paper will focus on the history of the landscape changes in java during the quaternary with special reference to the dynamics of rain forest structure and composition largely drawn from available pollen analyses subsequently the paleoenvironmental palaeoanthropological and archaeological records are considered to investigate the adaptive relationships between human groups and the forest through time

shallow marine dysoxia across the permian triassic boundary evidence from pyrite framboids in the microbialite in south china abstract the end permian mass extinction resulted in the collapse of reef ecosystems and the subsequent formation of microbialites in shallow carbonate platforms in south china large quantities of pyrite framboids are preserved in the microbialites but absent in the underlying skeletal limestone indicating an abrupt shift in water column redox conditions in association with the shallow marine faunal mass extinction detailed study of size distributions of 1374 pyrite framboids found in 9 horizons in laolongdong section in chongqing municipality south china were performed to evaluate this shift in paleo redox condition of the shallow marine environment pyrite framboids in the microbialite average 8 41 m in size comparable with those from modern sediments underlying dysoxic water columns this infers that dysoxic waters in the latest permian might have expanded to reach the shallow marine environments in south china mean diameters of pyrite framboids from mudstones overlying the microbialite are 7 63 m 7 68 m likely indicating continuing intensification of oxygen deficiency in the bottom waters microgastropods ostracods and some foraminifers which survived and flourished in the microbialite almost disappeared during the mudstone deposition possibly reflecting a consequence of oxygen depletion

anomalous marine calcium cycle linked to carbonate factory change after the smithian thermal maximum early triassic abstract extreme greenhouse warming in the latest permian played a key role in the largest animal extinction event ever recorded in earth history the extinction was likely triggered by volcanic eruptions that dramatically increased atmospheric co2 levels and pushed the earth system into a lethally hot greenhouse state with stratified anoxic and more acidic oceans these conditions intensified a few million years later during the middle late smithian thermal maximum stm and a further biodiversity loss occurred during the subsequent cooling across the smithian spathian boundary ssb the marine carbonate factory is expected to have changed during this period but relevant studies are still lacking here we report calcium isotopic data of bulk carbonate rocks 44 40cacarb from two marine carbonate sections jiarong and shitouzhai in south china showing 0 5 0 7 positive shift of 44 40cacarb coupled to a 4 6 positive shift of 13ccarb from the middle smithian to the early spathian box modeling of the marine ca cycle yielded two scenarios i e constant and variable 44 40caseawater that can produce a 0 5 positive shift of 44 40cacarb 1 a local mineralogical shift in primary carbonate mineralogy at both sites from 80 aragonite to 80 calcite or 2 a 10 increase of global carbonate burial flux the former is consistent with a 20 50 fold rise of ca mg ratios and 10 50 fold decrease of sr ca ratios in the study sections and the latter fits well with massive carbonate deposition globally during the early spathian oceanic overturn and upwelling of alkaline deep waters during ssb climatic cooling is proposed as the main reason for the increase in carbonate burial flux thus the ssb transition marks an important step in the recovery of the marine fauna after the end permian mass extinction triggered by climatic cooling ocean ventilation and a pronounced rise in marine carbonate deposition on continental shelves

carbonate thermoluminescence and its implication for marine productivity change during the permian triassic transition abstract the permian triassic p tr crisis was the largest mass extinction of the phanerozoic and eliminated over 90 of marine species however the nature of marine productivity changes during the crisis is a matter of on going debate here thermoluminescence tl measurements from 144 bulk carbonate samples from meishan south china show two levels of variation in tl peak intensities at 270 c the first order variation is characterized by a rapid nearly three fold increase a secondary variation is interpreted to record periodic fluctuations on a milankovitch scale 20 kyr rhythm the periodic variations of tl are negatively correlated with mn concentrations suggesting primary productivity is a key factor controlling the tl peak intensity by photo reduction of particulate mn in the presence of organic matter therefore the periodic fluctuations of tl were likely controlled by primary productivity changes on orbital timescales a significant rise of tl peak intensities across the p tr boundary represents the rapid increase of dissolved mn associated with enhanced marine productivity and or oceanic anoxia

isotopic signatures of mercury contamination in latest permian oceans sedimentary records from the northwest margin of pangea and the tethys show anomalously high hg levels at the latest permian extinction boundary background 202 hg values are consistent with normal marine conditions but exhibit negative shifts coincident with increased hg concentrations hg isotope mass independent fractionation 199 hg trends are consistent with volcanic input in deep water marine environments in contrast nearshore environments have 199 hg signatures consistent with enhanced soil and or biomass input we hypothesize that the deep water signature represents an overall global increase in volcanic hg input and that this isotope signature is overwhelmed in nearshore locations due to hg from terrestrial sources high productivity nearshore regions may have experienced stressed marine ecosystems due to enhanced hg loading

the late quaternary palaeogeography of mammal evolution in the indonesian archipelago abstract the quaternary faunal evolution for the indonesian archipelago reflects the unique relationship of each island with se asian mainland the recent sub faunas of sundaland kalimantan sumatra java and bali preserved broad connections with the se asian mainland during the latest glacial they are all balanced and show many mainland components alternatively wallacea sulawesi and the lesser sunda islands has always been geographically isolated from the mainland wallacea faunas thus remain unbalanced they lack large carnivores and endemic a significant turnover arrives throughout the region with pronounced global sea level recessions around 0 8 ma during the transition from early pleistocene ep to the middle pleistocene mp by way of comparison the palaeontological records of japan and taiwan also preserve this turnover with ep mp recessions bringing east asian mainland immigrants on java the earliest late pliocene to early pleistocene satir fauna indicates island conditions java became connected to the se asian mainland towards the end of the early pleistocene global cooling brought open woodlands on java an environment evidently preferred by homo erectus in the ci saat fauna and trinil h k fauna as ep mp sea level recessions created a wide corridor across the sunda shelf siwaliks and the se asian mainland terrestrial mammals invaded as is seen in the kedung brubus fauna the succeeding ngandong fauna maintains an open woodland character but shows some endemism homo erectus and stegodon trigonocephalus among others can be distinguished on a subspecies level the late pleistocene marks the earliest known tropical rainforest and the corresponding punung fauna is of chinese affinity with pongo hylobates and elephas maximus homo sapiens probably arrives at this point as well the youngest fossil faunas known from java are the still poorly known cipeundeuy fauna ca 30 ka and the holocene faunas from wajak and sampung while sulawesi and flores remained isolated throughout the quaternary only a limited number of terrestrial vertebrates arrived by crossing sea barriers endemic island faunas with pygmy elephantoids and giant tortoises were present during the early pleistocene ep mp sea level recessions allowed large to medium sized elephantoids to replace the dwarf species around the same time homo erectus appears on the island of flores modern faunas eventually replaced the middle pleistocene island faunas but the time frame has yet to be pinpointed sulawesi presents a unique case its current fauna holds no walanae representatives apart from the phalangers which must have come from the east the ancestors of all other large sulawesi land vertebrates fossil and extant reached the island by crossing the sunda sea as the south sulawesi fauna was stable until the middle pleistocene this area must have constituted a separate palaeo island some localized developments can be observed e g shortening of the metapodials in celebochoerus increasing hypsodonty in stegodon

origin of the epeirogenic uplift of pliocene pleistocene beach ridges in florida and development of the florida karst marine fossils of pleistocene age are known to occur in beach ridges near the border of northern florida and southern georgia at elevations of between 42 and 49 m above mean sea level no evidence exists for a massive melt off of glacial ice which would be required to raise sea level to these elevations florida therefore must have been uplifted epeirogenically during the pleistocene measurement of dissolved solids in florida9s springs demonstrates that the karst area is losing a minimum of 1 2 10 6 m 3 yr of limestone through spring flow the equivalent of 1 m of surficial limestone every 38 000 yr this loss has led to an isostatic uplift of the north central part of the florida peninsula of at least 36 m during pleistocene and holocene time which agrees with observed elevations of marine terraces

revised chronostratigraphy of the lower chinle formation strata in arizona and new mexico usa high precision u pb geochronological constraints on the late triassic evolution of dinosaurs the early history of dinosaurs in north america is obscured by an incomplete fossil record taxonomic uncertainties and speculative correlations of tetrapod bearing rocks as well as poor calibration of the late triassic time scale high precision u pb geochronology provides a reliable means of correlating terrestrial rock formations independent of equivocal lithostratigraphy or vertebrate biostratigraphy and hence the possibility of properly evaluating models for the early radiation and diversification of dinosauria here we present new high precision u pb id tims zircon geochronology from the presumed lowermost strata of the upper triassic chinle formation of the colorado plateau in southwest united states including a mean 206pb 238u date of 219 39 0 16 ma from the renowned placerias quarry bone bed in eastern arizona the new results prompt revisions to the chronostratigraphy of the lower chinle and provide a new temporal context for its rich tetrapod fauna the oldest documented dinosaurs of north america coexisted with their non dinosaurian near relatives for a minimum of 12 m y from ca 223 ma to ca 211 ma in the norian this early dinosauromorph record follows a ca 6 m y period from which no tetrapod fossils have been documented and which was itself preceded by a ca 10 m y depositional hiatus spanning nearly the entire ladinian and carnian stages of the terrestrial north america the supposed late appearance of dinosauromorphs in north america compared to those in south america thus appears to be an artifact of incomplete preservation as well as unsubstantiated age interpretations this together with the conspicuous biogeographic distinctions among the triassic dinosauromorph assemblages invalidates a simple diachronous model for the transcontinental radiation of early dinosaurs

changes in productivity and redox conditions in the panthalassic ocean during the latest permian the gujo hachiman section in central japan provides a rare window into environmental conditions within the panthalassic ocean which encompassed more than half the earth s surface at 251 ma the section is characterized by a sharp transition from green gray organicpoor cherts to black siliceous shales in the uppermost permian normalization to the clay fraction demonstrates that apparent increases in the concentrations of organic matter and trace metals above this transition were due primarily to the loss of a diluent biogenic radiolarian silica fl ux and only secondarily to a small shift toward more reducing bottom waters in the black shale pyrite abundance increases by a factor of 30 and is dominated by framboidal grains of probable syngenetic origin these observations suggest that the expansion of lowoxygen conditions within the panthalassic ocean was focused within the oxygen minimum zone rather than at the seafl oor such a pattern implies that 1 changes in nutrient fl uxes and primary productivity rates rather than stagnation of oceanic circulation were a key factor infl uencing oceanic redox conditions around the permian triassic boundary and 2 large regions of the panthalassic ocean underwent only limited redox changes providing potential refugia for marine taxa that survived into the triassic

catastrophic soil erosion during the end permian biotic crisis organic geochemical analyses of sedimentary organic matter from a marine permian triassic transition sequence in northeastern italy reveal a significant influx of land derived diagenetic products of polysaccharides this unique event reflects massive soil erosion resulting from destruction of land vegetation due to volcanogenic disturbance of atmospheric chemistry the excessive supply of soil materials to the oceans provides a direct link between terrestrial and marine ecological crises suggesting that ecosystem collapse on land could have contributed to the end permian marine extinctions

the timing and pattern of biotic recovery following the end permian mass extinction the aftermath of the great end permian period mass extinction 252 myr ago shows how life can recover from the loss of 90 species globally the crisis was triggered by a number of physical environmental shocks global warming acid rain ocean acidification and ocean anoxia and some of these were repeated over the next 5 6 myr ammonoids and some other groups diversified rapidly within 1 3 myr but extinctions continued through the early triassic period triassic ecosystems were rebuilt stepwise from low to high trophic levels through the early to middle triassic and a stable complex ecosystem did not re emerge until the beginning of the middle triassic 8 9 myr after the crisis a positive aspect of the recovery was the emergence of entirely new groups such as marine reptiles and decapod crustaceans as well as new tetrapods on land including eventually dinosaurs the stepwise recovery of life in the triassic could have been delayed either by biotic drivers complex multispecies interactions or physical perturbations or a combination of both this is an example of the wider debate about the relative roles of intrinsic and extrinsic drivers of large scale evolution from a much more devastated planet and biota than the others with only some 10 of species surviving the epme was much harsher than the other mass extinctions during which global species diversity reduced to only about 50 of the pre extinction total 1 2 24 26 this means that the triassic recovery has two profound implications first it may show qualitative as well as quantitative differences from the other post extinction recoveries and second it can act as an exemplar of what to expect at its most extreme when global biodiversity is pushed to the brink there are obvious implications for current concerns about biodiversity loss and recovery resulting from human impacts 27 28 in the past ten years attention has focused on the sedimentary successions in south china these are enormously laterally extensive with some formations extending more than 2 000 km from the zhejiang to yunnan provinces the huge exposures length of the sections and improving dating open up the opportunity to explore physical environmental and biotic changes through the extinction and recovery times in varied marine habitats and compare these with patterns elsewhere in the world fig 1 a fine scale forensic analysis of this extraordinary time in earth s history now becomes possible the end permian mass extinction the epme killed 80 96 of marine animal species and 70 of terrestrial vertebrate species

pedo sedimentary dynamics of the sangiran dome hominid bearing layers early to middle pleistocene central java indonesia a palaeopedological approach for reconstructing pithecanthropus javanese homo erectus palaeoenvironment abstract fossil soils and pedosediments displayed in quaternary fossil bearing formations are an important proxy to describe the evolution of climates and environments through a study of the palaeosols in the sangiran dome a rich hominid bearing site of central java indonesia we characterized their record of terrestrialization through regional volcano tectonic activity and describe palaeoenvironments colonized by hominids the thick sedimentary formations of the sangiran dome are known to reflect the geological evolution of central java from the beginning of the quaternary until the middle pleistocene homo erectus fossils are found in the ca 1 5 ma sangiran or pucangan formation up to the ca 0 8 ma bapang or kabuh formation this study combines field surveying a micromorphological approach and palynological data the characterization of successive pedoclimatic contexts and toposequences helps in reconstruction of the local palaeogeography and climates mainly influenced by south eastern asia monsoon cycles that predominated during periods of palaeosol development the base of the upper sangiran member displays the earliest fully continental deposits corresponding to the development of an open landscape with wide coastal marshes and mangroves with a rain forest cover on the hinterland higher in the stratigraphic succession environments reflect a contrasting seasonal climate with a long dry season alternating with periods of more humid palustrine conditions a further tectonic uplift of the hill ranges bordering the solo depression in which the sangiran dome is located resulted in topographic changes and increasing palaeogeographic heterogeneity and therefore of soilscapes from the upper sangiran member to the bapang lower member erosion of soil cover caused the accumulation of pedosediments in topographic depressions these pedosedimentary deposits as well as volcanic ash accumulations were sudden and sometimes bury palaeoreliefs catena gilgai recurrent aridity proxies occur in the palaeosols found in the bapang formation which yielded the most numerous hominid fossils reflecting a long dry season and an open vegetation landscape

high frequency fluctuations in redox conditions during the latest permian mass extinction abstract new high resolution geochemical and sedimentological data from fiskegrav east greenland reveal fluctuations in marine redox conditions associated with the final disappearance of bioturbating organisms during the latest permian mass extinction lpme sedimentological observations imply a transgressive episode and associated geochemical evidence for decreasing oxygen availability and the establishment of persistently ferruginous fe 2 rich conditions implies the shoreward migration of oxygen deficient waters the long term decline in dissolved oxygen do availability could have been exacerbated by increasing water temperatures reducing the solubility of oxygen and promoting thermal stratification mixing of the water column could have been further inhibited by freshwater influxes that could have generated salinity contrasts that reinforced thermal stratification enhanced runoff could also have increased the delivery of nutrients to the marine shelf stimulating biological oxygen demand bod during the transition to persistently ferruginous conditions we identify intervals of intermittent benthic meiofaunal recolonization events that we attribute to small transient increases in do availability the mechanism controlling these fluctuations remains speculative but given the possible centennial to millennial scale frequency of these changes we hypothesise that the mid latitude setting of fiskegrav during the late permian was sensitive to changes in atmospheric circulation patterns which may have influenced local precipitation and intermittently modulated some of the processes promoting anoxia

the palaeoenvironmental context of the palaeolithic of java a brief review abstract the earliest palaeolithic implements found in java island are older than 1 ma postdating the oldest homo erectus fossils the archaeological record subsequently documents acheulean like tools in early middle pleistocene deposits a diversity of flake tools assemblages found in late middle early upper pleistocene sites and the conspicuous development of cave occupations during the end of the pleistocene and the early holocene the environment mostly forested during the lower pleistocene underwent important changes during the setup of mid pleistocene climatic conditions then at the beginning of the upper pleistocene and at the boundary between mis 2 and 1 its reconstructions must also consider more local factors e g the repetitive effects of the tectonic and volcanic activities which had severe consequences on local climate on the palaeogeography and the vegetal formations or even isolation of faunistic and floristic groups examples presented here broach the context of ancient human settlements and adaptation from a multidisciplinary viewpoint that includes the study of the vegetal cover and the availability of lithic raw material the associated vertebrate faunas considered both as an environmental proxy and as a subsistence resource reflect the contrasts between periods of contact with the mainland increased biodiversity and periods of isolation favouring endemism and also the impact of local environmental constraints

the triassic timescale new constraints and a review of geochronological data a review of geochronological data underlying the geological time scale for the triassic yields a significantly different time scale calibration than that published in the most recent compi lation geologic time scale 2004 this is partly due to the availability of new radio isotopic data but mostly because strict selection criteria are applied and complications arising from biases both systematic and random are accounted for in this contribution the ages for the base and the top of the triassic are constrained by u pb ages to 252 3 and 201 5 ma respectively these dates also constrain the ages of major extinction events at the permian triassic and triassic jurassic bound aries and are statistically indistinguishable from ages obtained for the siberian traps and volcanic products from the central atlantic magmatic province respectively suggesting a causal link ages for these continental volcanics however are mostly from the k ar 40 ar 39 ar system which requires accounting and correcting for a systematic bias of c 1 between u pb and 40 ar 39 ar isotopic ages the 40 ar 39 ar ages being younger robust age constraints also exist for the induan olenekian boundary 251 2 ma and the early middle triassic olenekian anisian boundary 247 2 ma resulting in a surprisingly short dur ation of the early triassic which has implications for the timing of biotic recovery and major changes in ocean chemistry during this time furthermore the anisian ladinian boundary is con strained to 242 0 ma by new u pb and 40 ar 39 ar ages radio isotopic ages for the late triassic are scarce and the only reliable and biostratigraphically controlled age is from an upper carnian tuff dated to 230 9 ma yielding a duration of more than 35 ma for the late triassic all of these ages are from u pb analyses applied to zircons with uncertainties at the permil level or better the resulting compilation can only serve as a guideline and must be considered a snapshot resolving some of the issues mainly associated with inaccurate and misinterpreted data in previous publi cations however further advances will require revision of some of the data presented here

monsoonal precipitation in the paleo tethys warm pool during the latest permian abstract simulations of the late permian 251 ma are analyzed with respect to the northern hemispheric pangean monsoon we find that the presence and spatial distribution of the warm pool and not land sea temperature differences are the primary forcing agents for the monsoon the land sea temperature gradient as a monsoonal mechanism is tested by eliminating the cathyasian peninsula and is found to have little impact on the spatial character of the monsoon furthermore the response of the monsoon to the warm pool was tested by removing all paleo tethys equatorial islands which allows the warm pool to expand and migrate westward thus shifting the pattern of monsoonal precipitation given that paleogeography changes through time these results have important implications for the migration and strength of the tropical monsoon over geologic time additionally different co2 regimes are presented in which a 10 fold change in forcing produces diverging climates and therefore different warm pool and monsoon locales tropical and equatorial ocean currents impact the seasonal progression and location of the warm pool and atmospheric mass flux for the monsoonal regime is characterized and shown to change with warm pool movement experiments were conducted using the low resolution version of community climate system model version 3 ccsm3 in both coupled and fixed sea surface temperature sst context for validation purposes a modern control is briefly presented with observations and is shown to represent both the spatial and seasonal progression of the indian monsoon