end permian catastrophe by a bolide impact evidence of a gigantic release of sulfur from the mantle our studies in southern china have revealed a remarkable sulfur and strontium isotope excursion at the end of the permian along with a coincident concentration of impact metamorphosed grains and kaolinite and a significant decrease in manganese phosphorous calcium and microfossils foraminifera these data suggest that an asteroid or a comet hit the ocean at the end of permian time and caused a rapid and massive release of sulfur from the mantle to the ocean atmosphere system leading to significant oxygen consumption acid rain and the most severe biotic crisis in the history of life on earth

the end permian mass extinction a rapid volcanic co2 and ch4 climatic catastrophe abstract the end of the permian was a time of crisis that culminated in the earth s greatest mass extinction there is much speculation as to the cause for this catastrophe here we provide a full suite of high resolution and coeval geochemical results trace and rare earth elements carbon oxygen strontium and clumped isotopes reflecting ambient seawater chemistry and water quality parameters leading up to the end permian crisis preserved brachiopod low mg calcite based seawater chemistry supplemented by data from various localities documents a sequence of interrelated primary events such as coeval flows of siberian trap continental flood basalts and emission of carbon dioxide leading to warm and extreme greenhouse conditions with sea surface temperatures sst of 36 c for the late permian although anoxia has been advanced as a cause for the mass extinction most biotic and geochemical evidence suggest that it was briefly relevant during the early phase of the event and only in areas of upwelling but not a general cause instead we suggest that renewed and increased end permian siberian trap volcanic activity about 2000 years prior to the extinction event released massive amounts of carbon dioxide and coupled with thermogenic methane emissions triggered extreme global warming and increased continental weathering eventually these rapidly discharged greenhouse gas emissions less than 1000 years before the event ushered in a global hothouse period leading to extreme tropical ssts of 39 c and higher based on these sea surface temperatures atmospheric co 2 concentrations were about 1400 ppmv and 3000 ppmv for the late and end permian respectively leading up to the mass extinction there was a brief interruption of the global warming trend when sst dropped concurrent with a slight but significant recovery in biodiversity in the western tethys it is possible that emission of volcanic sulfate aerosols resulted in brief cooling just after the onset of intensified warming during the end of the permian after aerosol deposition global warming resumed and the biotic decline proceeded and was accompanied by suboxia in places of the surface ocean which culminated in the greatest mass extinction in earth history

evidence for abrupt latest permian mass extinction of foraminifera results of tests for the signor lipps effect we used published biostratigraphic data on ranges of fusulinids and other foraminifera from permian triassic boundary sections in the southern alps italy to test the effects of sampling and species abundance on the record of the timing of the latest permian extinction the number of last occurrences of taxa reaches a maximum close to the local base of the tesero horizon of the werfen formation taxa that have 15 stratigraphic abundance percent of sample intervals in which a taxon occurs show last occurrences well before that level whereas taxa with more complete records tend to disappear at or close to that level these results are in agreement with simulations for abrupt extinctions as opposed to gradual or steplike extinction scenarios and support predictions of the signor lipps effect that errors in the end points of biostratigraphic ranges can produce range truncations and apparent gradual decline preceding a sudden extinction boundary on the basis of estimated sedimentation rates for the italian sections the end permian extinctions could have been very sudden 30 k y and the disappearance of most latest permian foraminifers was most likely coincident with a worldwide ecological stress event identified by a global negative 13 c anomaly that occurs in italy near the base or within the time transgressive tesero horizon

early triassic seawater sulfate drawdown abstract the marine sulfur cycle is intimately linked to global carbon fluxes atmospheric composition and climate yet relatively little is known about how it responded to the end permian biocrisis the largest mass extinction of the phanerozoic here we analyze carbonate associated sulfate cas from three permo triassic sections in south china in order to document the behavior of the c s cycle and its relationship to marine environmental changes during the mass extinction and its aftermath we find that 34 s cas varied from 9 to 44 at rates up to 100 myr 1 during the griesbachian smithian substages of the early triassic we model the marine sulfur cycle to demonstrate that such rapid variation required drawdown of seawater sulfate concentrations to 4 mm and a reduction in its residence time to 200 kyr this shorter residence time resulted in positive covariation with 13 c carb due to strong coupling of the organic carbon and pyrite burial fluxes carbon and sulfur isotopic shifts were associated with contemporaneous changes in climate marine productivity and microbial sulfate reduction rates with negative shifts in 13 c carb and 34 s cas linked to warming decreased productivity and reduced sulfate reduction sustained cooling during the spathian re invigorated oceanic overturning circulation reduced marine anoxia and limited pyrite burial as seawater sulfate built to higher concentrations during the spathian the coupling of the marine c and s cycles came to an end and a general amelioration of marine environmental conditions set the stage for a recovery of invertebrate faunas variation in seawater sulfate during the early triassic was probably controlled by climate change possibly linked to major eruptive phases of the siberian traps

oceanic primary productivity and dissolved oxygen levels at the cretaceous tertiary boundary their decrease subsequent warming and recovery thirty six different geochemical and foraminiferal analyses were conducted on samples collected at closely spaced intervals across the cretaceous tertiary k t boundary exposed at caravaca spain a rapid reduction in the gradient between 13c values in fine fraction carbonate and benthic foraminiferal calcite and a decrease in the abundance of phosphorus a proxy for organic carbon and calcium were recorded in sediments 0 0 5 cm above the k t boundary these trends imply that an abrupt mass mortality occurred among pelagic organisms leading to a significant reduction in the flux of organic carbon to the seafloor in addition variations in sulfur isotope ratios the hydrocarbon generating potential of kerogen measured as the hydrogen index and foraminiferal indices of dissolved oxygen level all imply that a rapid decrease in dissolved oxygen was coincident with the 13c event evidence of the low oxygen event has also been recognized in japan and new zealand suggesting that intermediate water oxygen minima were widely developed during earliest danian time a threefold increase in the kaolinite illite ratio and a 1 2 decrease in 18o carbonate fine fraction were recorded in the basal 0 1 2 cm of danian age sediments these trends suggest that atmospheric warming and an increase in surface water temperature occurred 0 3 kyr after the 13c event recovery in the difference between 13c values in the carbonate fine fraction and in benthic foraminiferal calcite as well as increases in phosphorus and calcium contents occur at the base of planktonic foraminiferal zone pla implying that an increase in primary productivity commenced some 13 kyr after the k t boundary tables a1 a3 are available on diskette or via anonymous ftp from kosmos agu org directory apeno username anonymous password guest diskette may be ordered from american geophysical union 2000 florida avenue n w washington dc 20009 or by phone at 800 966 2481 15 00 payment must accompany order

early triassic recovery of the brachiopod faunas from the end permian mass extinction a global review abstract brachiopod faunas in lower triassic deposits from spitzbergen primorye of russia japan mangyslak of kazakhstan alpine europe the caucasus the middle east the himalaya south china new zealand and western usa are taxonomically and stratigraphically reviewed they comprise survivors of the end permian extinction and taxa originating in the early triassic origination of the mesozoic type taxa represents the recovery of early triassic brachiopods the initial recovery of brachiopod faunas began in the late griesbachian and the time interval between the end of extinction and the onset of the recovery of brachiopods is much shorter than previously suspected the early triassic recovery of brachiopod faunas is characterized by widespread brachiopod dispersal multiprovincialism and the presence of rare lazarus genera at that time taxonomic selectivity of the recovery brachiopod faunas favors the rhynchonellids the re population of post extinction brachiopods varies geographically there is a preference for regions either previously barren of latest permian taxa or regions where the pre extinction changhsingian and surviving brachiopods are very rare this unique biogeographic selectivity is probably partly responsible for the impoverished nature of brachiopod faunas in the triassic even mesozoic oceans five intervals of extinction survival survival recovery recovery dispersal and radiation are recognized based on variations in brachiopod faunas from the latest permian to the early triassic a dramatic reduction in brachiopod diversity at the end permian mass extinction is followed by several stepwise declines in diversity in the survival interval the time during which the surviving brachiopods are dominated by geographically widespread generalist faunas that adapted to a wide variety of environments the survival interval was followed by a slow re population of new lineages dominated by progenitor taxa

u pb zircon geochronology and tempo of the end permian mass extinction the mass extinction at the end of the permian was the most profound in the history of life fundamental to understanding its cause is determining the tempo and duration of the extinction uranium lead zircon data from late permian and early triassic rocks from south china place the permian triassic boundary at 251 4 0 3 million years ago biostratigraphic controls from strata intercalated with ash beds below the boundary indicate that the changhsingian pulse of the end permian extinction corresponding to the disappearance of about 85 percent of marine species lasted less than 1 million years at meishan a negative excursion in 13 c at the boundary had a duration of 165 000 years or less suggesting a catastrophic addition of light carbon

evidence for a fungal event methane hydrate release and soil erosion at the permian triassic boundary in southern israel abstract the transition between the permian and the triassic systems in israel is evident only in the subsurface two cores from the makhtesh qatan 2 core 9 and avedat 1 core 5 drillholes in which the permian triassic boundary was found marked by a fungal event were sampled at close intervals and analysed for palynological petrographical mineralogical chemical and isotopic properties three palynozones were recorded lueckisporites virkkia zone late permian fungal event and endosporites papillatus zone early triassic the fungul event occurs in a narrow interval of 1 m and contains almost exclusively fungal remains and recycled woody particles the two cores consist of laminated sediments mainly siliciclastic that were deposited in very shallow to restricted marine environments with a minor presence of evaporites and no bioturbation green glauconitic material and framboidal pyrite suggest suboxic conditions even in the shallow waters reddish brown particles and plant fragments derived from nearby soils now outcropping on the northeast side of the dead sea these materials as well as recycled brown glauconitic grains suggest a drop in sea level and intense erosion before sedimentation which was apparently continuous major and trace element compositions including rare earth elements do not exhibit any particular pattern that might be related to the fungul event or to other core intervals the rare earth element patterns are basically normal and their concentration correlates with the clay content reflecting the provenance of the arabo nubian massif and its sedimentary rims iridium results were mostly at the background level and therefore the two distinct anomalous values are inconclusive microspherules mainly of 2 m size and al si composition were observed in a few samples in both cores their origin could not be determined though they are considered to be natural there was no evidence for shocked quartz 13corg excursion exhibits a marked negative shift in both cores just below the fungal event the lowest values 37 and 42 are among the lowest ever recorded near the permian triassic boundary and suggest large scale release of methane hydrates

a sulfur isotope event at the end of the permian abstract a hypothesis of light sulfur injection to the ocean atmosphere system at the end of the permian was presented by kaiho et al kaiho k kajiwara y nakano t miura y kawahata h tazaki k ueshima m chen z q shi g r 2001 end permian catastrophe by a bolide impact evidence of a gigantic release of sulfur from the mantle geology 29 815 818 based on a negative shift of 34 s 32 s ratio of carbonate associated sulfate in south china this hypothesis was discussed in some papers with additional data in other areas however the cause and distribution of the negative shift has not been clarified here we show that a significant decrease in the 34 s 32 s ratio of carbonate associated sulfate occurred simultaneously in south china and hungary at the end of the permian coincident with the end permian mass extinction the cause of the abrupt negative shift of 34 s 32 s in these two distant sites is the injection of light sulfur to the surface ocean from the deep ocean rich in h 2 s or deposits rich in sulfide or the mantle this sulfur isotope event was likely caused by either an abrupt warming a bolide impact to the ocean mantle plume induced volcanism or a harmonizing of these possible direct causes are 1 massive release of h 2 s gas from the euxinic surface and intermediate waters due to abrupt warming by volcanic co 2 or impact shock wave in the ocean 2 a huge volcanism penetrated sediments or ore rich in sulfide 3 an extraterrestrial impact to sulfide rich sediments or ore deposit and 4 release of mantle origin sulfur by an impact of 70 km asteroid to the ocean these are four possible causes for a mass extinction there is also a possibility of a local oceanic event only in the tethys

catastrophic extinction of planktonic foraminifera at the cretaceous tertiary boundary evidenced by stable isotopes and foraminiferal abundance at caravaca spain we present data demonstrating constant 13c values in 12 common planktonic foraminiferal species which constitute 99 of the total specimens 63 mu m in assemblages collected across the cretaceous tertiary k t boundary at caravaca spain these latter values are in contrast to a rapid reduction in 13c in samples of the fine fraction of carbonate at the k t boundary and a subsequent negative shift of 13c of a benthic foraminiferal species these results indicate that the post k t occurrences of cretaceous planktonic species in lower danian sediments at caravaca are the result of reworking rapid decreases in the percentage abundance of well preserved specimens and in the number of specimens per gram of carbonate for the same 12 species at the k t boundary also suggest reworking and abrupt extinction at the k t boundary our data imply that sudden changes occurred within the pelagic ecosystem during the k t boundary event

the permo triassic extinction the end permian mass extinction brought the palaeozoic great experiment in marine life to a close during an interval of intense climatic tectonic and geochemical change improved knowledge of latest permian faunas coupled with recent advances in isotopic studies and biostratigraphy have greatly enhanced our understanding of the events of 250 million years ago and have begun to provide answers to many questions about the causes of extinction

the parental magma for some rocks from the norite 1 subzone of the stillwater complex a lunar analog study the interpretation of single lunar highlands igneous samples is hindered not only by their brecciation but also by a lack of similar intensive work on terrestrial plutonic rocks terrestrial studies of cumulate rocks are more extensive and have a well developed stratigraphic context in an attempt to establish how much can be learned about the parent magma from single plutonic hand samples single samples from three successive homogeneous but contrasting layers anorthosite anorthositic norite norite in the stillwater complex norite 1 subzone were subjected to detailed petrographic and major and trace element chemical analyses the chemical data show that although the calculated parent magma for each layer is similar a model of liquidus phases plus trapped magma model is not simultaneously quite consistent with petrography and chemistry further calculated eu anomalies and the fe content of the plagioclases provide evidence that the oxidation of the magma was different for each layer such oxidation changes can explain qualitatively the mg fe variations otherwise attributed to trapped liquid however it would appear that a reasonable estimate of the parent composition can be made even for single hand samples such as lunar plutonic highlands rocks there are uncertainties and a better understanding of crystallization mechanisms for basic plutonic rocks is needed without such understanding lunar samples can never be fully interpreted the calculated parent for the stillwater complex norite 1 subzone rocks considered is chemically similar to some primitive continental tholeiites except for its high normative orthopyroxene and negative eu anomaly both of which are major differences published data show that the eu anomaly existed in parental magmas even for the lower ultramafic zone and that most ree data are consistent with common or closely related parents for all rocks of the stillwater at least radically different magmas for different parts of the intrusion do not seem likely

origins of microspherules from the permian triassic boundary event layers in south china abstract volcanism and impact scenarios are two of the most plausible ways of interpreting the causes of the largest biological mass extinction at the end permian microspherules have previously been widely reported from tens of different permian triassic boundary ptb sections in south china and some other regions these microspherules have been interpreted as either the product of volcanic eruptions or an impact event in order to test these scenarios we collected 60 samples from 12 intensively studied ptb sections in south china in addition four soil samples close to these ptb layers were also collected for comparison our investigation indicates that abundant microspherules with mosaic or dot shape crystals on rounded surface are present in the surface samples in the ptb layers at meishan meili and shatian sections and most soil background samples in south china those microspherules consist of four different types based on their main chemical composition surface features and internal structure including iron magnetite silicate glassy pyrite microspherules and framboids in contrast microspherules have not been found in a few sections in remote areas such as the selong xishan section in tibet and the dalongkou section in xinjiang northwest china in the deeply excavated samples at the shangsi section and the hard tuff layers around the ptb at the xiaochehe section in guiyang microspherules decrease in abundance with depth in ptb clay beds all these microspherules except the pyrite microspherules and framboids are found in both the ptb layers and the nearby soil background samples the iron microspherules are pure iron oxides such as magnetite hematite or maghemite and contain low concentrations of nickel and chromium and lack an ni fe core and general extraterrestrial mineral wustite all these external and chemical characteristics suggest that most of iron microspherules previously reported from ptb sections in south china are modern industrial fly ashes a low ratio of fe 3 fe total in crystals of magnetite silicate microspherules and high zno contents can identify them as industrial contaminants the pyrite microspherules and framboidal pyrite found from bed 24e and bed 26 at the meishan sections are of depositional or and diagenetic origins and only the rounded quartz and the fragments containing extremely high sio 2 and tio 2 are possibly of volcanic origin

survival brachiopod faunas of the end permian mass extinction from the southern alps italy and south china eight brachiopod species in seven genera are described from the permian triassic boundary beds of south china and northern italy the brachiopods from northern italy are described for the first time and include two new species orbicoelia dolomitensis chen and spirigerella teseroi chen the permian affinity of these brachiopods and their stratigraphical position above the extinction horizon demonstrate that they are survivors from the end permian mass extinction the surviving brachiopods from south china which was located at the eastern margin of the palaeo tethys ocean are considerably abundant and diverse and are dominated by geographically widespread generalist elements adapted to a wide variety of environments they were mostly limited to the upper permian to lowest griesbachian in contrast the survivors in northern italy which was situated at the western margin of the palaeo tethys comprise elements ranging from the carboniferous to permian or widespread tethyan genera these survivors did not occur in the pre extinction western tethyan oceans but migrated into this region after the end permian extinction event disaster taxon lingula proliferated slightly earlier in western tethyan oceans than in eastern tethyan regions following the event survival brachiopods from both regions appear to have a generic affinity although they do not share any species both south chinese and italian survival faunas support the view that the survival interval is the duration when survivors are dominated by geographically widespread generalist organisms adapted to a wide variety of ecological conditions

87sr 86sr ratios in permo carboniferous sea water from the analyses of well preserved brachiopod shells abstract sr isotopic analyses of well preserved portions of permo carboniferous brachiopods distributed globally confirm the general shape of the sr isotope age curve established by previous workers for this time interval there is little variation between the sr isotopic composition of unaltered portions of brachiopods and that of portions of the same shell interpreted to be diagenetically altered based on cathodoluminescence elemental and stable isotopic data however the sr isotopic composition in diagenetically altered micritic matrix adjacent to the shell is more radiogenic the sr isotopic composition in the unaltered portions of calcitic megafossils has potential as a stratigraphie tool

land plant diversity and the end permian mass extinction the permian and triassic represent a time of major global climate change from icehouse to hothouse conditions and significant 25 northward motion of landmasses amalgamated in essentially one supercontinent pangea the greatest of all mass extinctions occurred around the permian triassic boundary 251 ma although there is no consensus regarding the cause s recent studies have suggested a meteor impact and worldwide die off of vegetation on the basis of sparse local observations however new analyses of global permian and triassic plant data in a paleogeographic context show that the scale and timing of effects varied markedly between regions the patterns are best explained by differences in geography climate and fossil preservation not by catastrophic events caution should be exercised when extrapolating local observations to global scale interpretations at the other extreme global compilations of biotic change through time can be misleading if the effects of geography climate and preservation bias are not considered

a negative carbon isotope anomaly associated with the earliest lopingian late permian mass extinction abstract palaeozoic life was severely affected in a pair of mass extinction events at the beginning earliest lopingian 260 million years ago and the end 251 million years ago of the late permian however the biological and geochemical record of the earliest lopingian crisis remains poorly constrained we present analyses of strata in south china showing that a negative anomaly of stable carbon isotope ratios accompanied an abrupt extinction of marine faunas at the beginning of the late permian similar to patterns observed at the end permian and the end cretaceous 65 million years ago extinction events

survival strategies of brachiopod faunas from the end permian mass extinction abstract global reviews reveal that 102 brachiopod species including 40 indeterminate species belonging to 43 genera within 27 families survived the end permian mass extinction in south china the himalayan regions southern tibet nepal salt range and kashmir southern alps italy arctic canada western usa and western australia of these the surviving brachiopods are most abundant and widespread in south china where they occur in 32 of the 42 permian triassic p t boundary sections around the world brachiopod faunas are the most abundant and diverse post extinction survivors and their appearance above the end permian mass extinction horizon somewhat masks recognition of the end permian extinction these surviving brachiopods occur in three stratal intervals corresponding to the mixed fauna beds mfb hereafter 1 3 of the p t boundary beds a sharp drop in diversity of the brachiopod faunas coincides with the widely accepted end permian mass extinction horizon the post extinction brachiopods were also affected by a subsequent crisis corresponding to the boundary between mfb 2 and mfb 3 so that most survivors were extinct approximately 0 7 ma after the end permian mass extinction the surviving brachiopods were mainly productida followed by spiriferida in particular small chonetids chonetid like productellids and smooth thin shelled ambocollid spiriferids are most abundant lingula is extraordinarily abundant and widespread approximately 0 7 ma after the greatest extinction when many regions became devoid of articulate brachiopods widespread broadly adapted and small sized taxa preferentially survived frequent intrageneric speciation of widespread widely adapted generalist genera enabled survival brachiopods to occupy rapidly and efficiently vacant ecospace in the aftermath of the end permian extinction the ecological habitats of the post extinction brachiopods are subdivided into nearshore epeiric sea restricted carbonate platform open carbonate platform ramp and outer shelf environments of these the survival brachiopods are most diverse in the open platform environments the nearshore zone provided ideal habitats for the nonarticulated brachiopods to occupy whereas the survivors in the outer shelf are predominantly chonetids and chonetid like productellids the most successful survivors the productid brachiopods are widely distributed in six types of ecological habitats and thus have no apparent preference for specific environments the end permian extinction resulted in the movement of biogeographical provinces towards the palaeo equator the brachiopods survived mostly in the palaeo equatorial provinces and along the southern margins of the palaeo tethys ocean

neotethys seawater chemistry and temperature at the dawn of the end permian mass extinction abstract the end of the permian was a time of great death and massive upheaval in the biosphere atmosphere and hydrosphere over the last decades many causes have been suggested to be responsible for that catastrophe such as global warming anoxia and acidification the gyanyima limestone block was an open ocean seamount in the southern neotethys at subtropical latitude and it affords us insight into open ocean oceanographic changes during the end of the permian after careful screening using multiple tests we reconstructed carbonate seawater curves from the geochemical data stored in pristine brachiopod shell archives from the shallow water limestone of the changhsingian gyanyima formation of tibet the reconstructed strontium isotope curve and data for the late changhsingian are relatively invariant about 0 707013 but in the upper part of the succession the values become more radiogenic climaxing at about 0 707244 the 87 sr 86 sr curve and trend are similar to those observed for the upper permian succession in northern italy but dissimilar less radiogenic to whole rock results from austria iran china and spitsbergen the ce ce anomaly results ranging from 0 310 to 0 577 for the brachiopods and from 0 237 to 0 655 for the coeval whole rock before the event and of 0 276 for whole rock during the extinction event suggest normal redox conditions these ce values are typical of normal open ocean oxic water quality conditions observed in modern and other ancient counterparts the biota and ce information clearly discounts global anoxia as a primary cause for the end permian biotic crisis carbon isotopes from brachiopod shells and whole rock are relatively invariant for most of the latest permian interval which is in stark contrast to the distinct negative carbon isotope excursion observed near and about the event estimates of seawater temperature at shallow depth fluctuated from 22 2 to 29 0 c up to unit 8 2 and then gradually rise from 29 7 c in unit 8 13 to values exceeding 35 c at a stratigraphic level about 120 ky before the permian triassic boundary and just before the onset of the extinction interval this dramatic increase in seawater temperature has been observed in global successions from tropical to mid latitude and from restricted to open ocean localities e g northern italy iran the brachiopod archive and its geochemical proxies from tibet support the paradigm that global warming must have been an important factor of the biotic crisis for the terrestrial and marine faunas and floras of the late paleozoic world

massive volcanism at the permian triassic boundary and its impact on the isotopic composition of the ocean and atmosphere abstract bulk carbonate and conodonts from three permian triassic p t boundary sections at guryul ravine kashmir abadeh central iran and pufels bula bulla italy were investigated for 13 c and 18 o carbon isotope data highlight environmental changes across the p t boundary and show the following features 1 a gradual decrease of 4 to more than 7 starting in the late permian changhsingian c bachmanni zone with two superimposed transient positive excursions in the c meishanensis h praeparvus and the m ultima s mostleri zones 2 two 13 c minima the first at the p t boundary and a higher occasionally double minimum in the lower i isarcica zone it is unlikely that the short lived phenomena such as a breakdown in biological productivity due to catastrophic mass extinction a sudden release of oceanic methane hydrates or meteorite impact s could have been the main control on the latest permian carbon isotope curve because of its prolonged 0 5 ma duration gradual decrease and the existence of a 1 positive shift at the main extinction horizon the p t boundary 13 c trend matches in time and magnitude the eruption of the siberian traps and other contemporaneous volcanism suggesting that volcanogenic effects such as outgassed co 2 from volcanism and even more thermal metamorphism of organic rich sediments as the likely cause of the negative trend

palaeosol stratigraphy across the permian triassic boundary bogda mountains nw china implications for palaeoenvironmental transition through earth s largest mass extinction abstract upper permian and lower triassic palaeosols from northeastern tethyan localities exposed within the bogda mountains nw china provide a wealth of information regarding long term palaeoclimatic and palaeoenvironmental variations wuchiapingian palaeosols are characterized by intense redoximorphy accumulation of vascular plant matter accumulation of clay minerals and fe oxides slickensides and clastic dikes suggesting a soil moisture regime that ranged from perennially wet to distinctly seasonal in soil moisture budget changsinghian to early induan palaeosols include subsurface accumulations of clay and carbonate as well as surficial accumulations of organic matter indicative of sub humid to sub arid soil moisture and variable soil moisture regimes induan to olenekian palaeosols contain pedogenic caco 3 accumulations and gypsum pseudomorphs indicating a drier environment characterized by net soil moisture deficiency elemental composition of palaeosol matrix was used to estimate palaeoprecipitation through the chemical index of alteration minus potassium cia k proxy estimates from various wuchiapingian strata indicate relatively stable palaeoprecipitation during the late changsinghian and early induan palaeoprecipitation appears to have decreased from 1100 to 230 180 mm year over less than 100 m of vertical stratigraphic section in the induan and olenekian palaeoprecipitation appears much less stable than in wuchiapingian with values vacillating from 290 to 1014 mm year the transition to a relatively unstable precipitation state coincides generally with the permian triassic boundary and may reflect climatic disturbances associated with the end permian extinction event in addition to altered atmospheric circulation patterns resulting from regional tectonics moisture availability and expansion of the subtropical high pressure belt

magnetostratigraphic correlations of permian triassic marine to terrestrial sections from china abstract we have studied three permian triassic pt localities from china as part of a combined magnetostratigraphic 40ar 39ar and u pb radioisotopic and biostratigraphic study aimed at resolving the temporal relations between terrestrial and marine records across the permo triassic boundary as well as the rate of the biotic recovery in the early triassic the studied sections from shangsi sichuan province langdai guihzou province and the junggar basin xinjiang province span marine paralic and terrestrial pt environments respectively each of these sections was logged in detail in order to place geochronologic paleomagnetic geochemical conodont and palynologic samples within a common stratigraphic context here we present rock magnetic paleomagnetic and magnetostratigraphic results from the three localities at shangsi northern sichuan province we sampled three sections spanning permo triassic marine carbonates magnetostratigraphic results from the three sections indicate that the composite section contains at least eight polarity chrons and that the pt boundary occurs within a normal polarity chron a short distance above the mass extinction level and a reversed to normal r n polarity reversal furthermore the onset of the illawarra mixed interval lies below the sampled section indicating that the uppermost permian changhsingian and at least part of the wuchiapingian stages postdate the end of the kiaman permo carboniferous reversed superchron at langdai guizhou province we studied magnetostratigraphy of pt paralic mudstone and carbonate sediments in two sections the composite section spans an r n polarity sequence section mean directions pass a fold test at the 95 confidence level and the section mean poles are close to the mean pt pole for the south china block based on biostratigraphic constraints the r n transition recorded at langdai is consistent with that at shangsi and demonstrates that the pt boundary occurred within a normal polarity chron a short distance above the mass extinction level in the southern junggar basin xinjiang province in northwest china we determined the magnetostratigraphy of three sections of a terrestrial sequence normal and reversed polarity directions are roughly antipodal and magnetostratigraphies from the three sections are highly consistent combined bio and magneto stratigraphy used to correlate this sequence to other pt sequences suggests that the previously proposed biostratigraphic pt boundary in the junggar sections was most likely misplaced by earlier workers suggesting that further work is necessary to confidently place the pt boundary there

the permian triassic palynological transition in the guryul ravine section kashmir india implications for tethyan gondwanan correlations this first palynological study of the permian triassic succession in the guryul ravine kashmir india reveals impoverished latest permian spore pollen assemblages in the uppermost zewan formation a rich palynoassemblage from the basal khunamuh formation characteristic of the permian triassic transition zone and depleted triassic assemblages from higher in the khunamuh formation the collective assemblages can be broadly correlated to the densipollenites magnicorpus and klausipollenites decipiens palynozones of peninsular india and to palynofloras spanning the permian triassic boundary elsewhere in gondwana generally low spore pollen yields and poor preservational quality of the studied assemblages hinder more precise correlations and are inferred to be a function of an offshore marine depositional setting on the margin of the neotethys ocean and thermal alteration associated with cenozoic collisional tectonism between india and asia

sulfur geochemistry across a terrestrial permian triassic boundary section in the karoo basin south africa concentrations of sulfur and carbon and isotopic compositions of sulfur were determined in sedimentary rocks from a section across the terrestrial permian triassic p tr boundary in the northern karoo basin south africa high concentrations of sulfide produced by sulfate reducing bacteria were found in the sedimentary rocks at and just below the perceived p tr boundary the ratios of organic carbon to sulfide of the sedimentary rocks with high concentrations of sulfide are relatively constant and similar to those of marine environments this means that the enhanced accumulation of sulfide is a result of the enrichment of sulfate in the water as the sulfide concentrations do not correlate with concentrations of any major elements indicative of weathering intensity the supply of sulfate was independent of environmental factors such as temperature and co2 concentrations in the atmosphere which control weathering intensity therefore it is reasonable to consider that the sulfate might have been supplied to the freshwater directly as acid rain by an event such as a bolide impact or a volcanic eruption the absence of evidence for an impact event in the geological record though favors volcanic input as the cause of the acid rain

quantifying sand provenance and erosion marsyandi river nepal himalaya we use petrographic and mineralogical data on modern sediments to investigate erosion patterns in the marsyandi basin of the central himalaya a privileged natural laboratory in which a series of multidisciplinary geomorphological sedimentological geochemical and geochronological studies have been recently carried out to unravel the interrelationships between tectonic climatic and sedimentary processes in high relief orogenic belts although relative erosion patterns are effectively constrained by analyses of replicate samples along six successive tracts of the marsyandi river uncertainties are caused by potential compositional variation between the monsoon and post monsoon season estimates of erosion rates are significantly affected by poor knowledge of total sediment flux through the basin ourresults support focusederosion of the southern tectonically lower part of the greater himalayain the hangingwall of the mct zone where thesummer monsoon reachesitspeak intensity up to 5 m a andsediment yieldsanderosion ratesreach14 100 3400t km 2 and 5 1 1 2 mm a erosion rates sharply decrease southward in low relief lesser himalayan units 1 6 0 6 mm a and also progressivelydecreasenorthwardsinthehigh altitude tectonically upperpartofthegreaterhimalaya whererainfalldecreasesrapidly to b2 m a even areas of extreme topography such as the manaslu granite are characterized by relatively low erosion rates 2 4 0 9 mm a because precipitations become too scarce to feed significant ice flux and glacial activity monsoonal rainfall decreases further tob0 5 m a in the tethys himalayan zone farther north where erosion rates are 1 mm a coupling between erosion and peak monsoonal rainfall along the southern front of the greater himalaya is consistent with both channel flow models of tectonic extrusion

pattern of marine mass extinction near the permian triassic boundary in south china the meishan section across the permian triassic boundary in south china is the most thoroughly investigated in the world a statistical analysis of the occurrences of 162 genera and 333 species confirms a sudden extinction event at 251 4 million years ago coincident with a dramatic depletion of 13ccarbonate and an increase in microspherules

late permian limestones and the permain triassic boundary new biostratigraphic palaeobiogeographical and geochemical data in caucasus and eastern europe

permian strontium isotope stratigraphy cvu acknowledges funding from the leopoldina german national academy of sciences grant no lpds 2014 08

dinosaur abundance was not declining in a 3 m gap at the top of the hell creek formation montana and north dakota an 3 m stratigraphic interval that entirely lacks dinosaur fossils or has very few fossils has been reported at the top of the hell creek formation in the upper great plains of north america the presence of the 3 m gap in fossil distribution has been cited as evidence that dinosaurs had either become extinct or were on the verge of extinction prior to the bolide impact at the end of the cretaceous period a survey in two areas of north dakota and montana reveals that dinosaur fossils in the upper 3 m of the hell creek formation occur in numbers that are comparable to their abundance in other levels of the formation evidence for a gradual extinction is absent and data are consistent with an abrupt extinction associated with an impact

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

end permian catastrophe by bolide impact evidence of a gigantic release of sulfur from the mantle comment and reply kaiho et al report sulfur isotope and chemical data for samples from the meishan china permo triassic p tr boundary section they interpret the s isotope data as well as the occurrence of fe and ni rich particles as evidence for a large scale impact event that penetrated the earth s mantle and formed a crater 1000 km in diameter we disagree with their interpretation in all major points

synchrony and causal relations between permian triassic boundary crises and siberian flood volcanism the permian triassic boundary records the most severe mass extinctions in earth9s history siberian flood volcanism the most profuse known such subaerial event produced 2 million to 3 million cubic kilometers of volcanic ejecta in approximately 1 million years or less analysis of 40 ar 39 ar data from two tuffs in southern china yielded a date of 250 0 0 2 million years ago for the permian triassic boundary which is comparable to the inception of main stage siberian flood volcanism at 250 0 0 3 million years ago volcanogenic sulfate aerosols and the dynamic effects of the siberian plume likely contributed to environmental extrema that led to the mass extinctions

deev jahi model of the permian triassic boundary mass extinction a case for gas hydrates as the main cause of biological crisis on earth the smoking gun revealing the secrets of the end permian mass mortality is a unique 1 2 m thick layer consisting of 5 20 cm long crystals of calcite that occurs precisely at the permian triassic boundary ptb in iran armenia turkey and china this layer is interpreted as synsedimentary abiotic seafloor cement indicative of precipitation from a highly carbonate supersaturated seawater its 13 c composition 13 c 0 pdb is 4 to 5 pdb lower than the typical upper permian values 4 to 5 pdb suggesting the involvement of massive amounts of gas hydrate ch 4 13 c 60 pdb the temporal coincidence of the cement layer with the ptb suggests that the process that promoted seafloor cementation was also responsible for the biological crisis a cementation model is developed based on accumulation dissociation cycle of gas hydrates which also explains the mass extinction at the ptb the upper permian accumulation period of gas hydrates ended abruptly adjacent to the ptb and the dissociation event began releasing 3 2 to 4 7 10 18 g ch 4 into the ocean oxidation of ch 4 in the water column created a seawater that was charged with co 2 an oceanic acid bath and had lower than normal o 2 content but not anoxic this oceanic acid bath first dissolved suspended fine grained carbonate particles and small calcareous organisms followed by extensive dissolution of platform carbonates raising ca 2 and hco 3 concentrations of seawater when the release of ch 4 declined the acid bath ocean became a soda ocean precipitating massive amount of seafloor cements observed globally at the ptb the study suggests that prior to cement precipitation the ptb ocean was charged with co 2 warm had low oxygen high ca 2 and high hco 3 concentrations these conditions collectively created stressful conditions causing the marine mass mortality the leakage of ch 4 to the atmosphere produced a super hot climate resulting in the biological devastation on land the proposed kill mechanism is developed on the basis of the physical clue the cement layer left behind by the killing process the change in ocean chemistry the accumulation dissociation cycles of gas hydrates also explain the 13 c pattern of marine carbonates and the periodicity of mass extinction events during the phanerozoic accumulation periods were long 5 to 20 my providing favorable conditions for ecosystem development pardeess phase the dissociation events were short and catastrophic 10 to 500 ky causing low oxygenation super hot climate and biological devastation doozakh phase it appears that most mass extinctions of the phanerozoic have been related to the internal working of the earth system during the phanerozoic methane has played the role of the deev jahi a female demon in persian mythology whose task is to attack the earth every so often to kill life on land and in sea

permian triassic boundary in the central transantarctic mountains antarctica the permian triassic boundary occurs within a relatively complete terrestrial sequence in the shackleton glacier area of the central transantarctic mountains the boundary is within a 7 to 10 m thick interval between the permian glossopteris flora and the lower triassic lystrosaurus fauna this interval representing on the order of 200 k y records some of the events that occurred in the transition from the permian to triassic in the best documented section at graphite peak in the beardmore glacier region protohaploxypinus microcorpus zone palynomorphs which we assign to the latest permian record the declining glossopteris flora and occur near the top of the buckley coal measures just below a previously reported major negative 13c excursion in the shackleton glacier area the permian glossopteris flora including fossil wood roots and leaves occurs within the lower part of the fremouw formation the antarctic lystrosaurus assemblage of early triassic age has several species in common with the south african fauna that lived 20 to 35 closer to the equator the migration of vertebrates from southern africa into antarctica in the early triassic supports hypotheses of runaway greenhouse warming possibly related to co2 emissions from siberian flood basalts and large methane gas releases changes in flora bracketing the first of the major negative 13c anomalies near the boundary in antarctica and in east greenland support the hypothesis that a global event perhaps through mutations caused by enhanced ultraviolet radiation may have played a role in the destruction of floras

stable carbon isotope stratigraphy across the permian triassic boundary in shallow marine carbonate platforms nanpanjiang basin south china a distinct negative 13c excursion is documented in two permian triassic sections heping and taiping in shallow marine carbonate platform deposits in the nanpanjiang basin south china these sections span from the changhsingian to the dienerian and are characterized by a distinct marine boundary facies change from massive skeletal lime packstone in the changhsingian to distinctive calcimicrobial framestone in the griesbachian hindeodus parvus zone the 13corg and 13ccarb excursions occur directly after the onset of the calcimicrobial framestone herein termed the permian triassic boundary event and before the first occurrence of h parvus the isotope shifts are associated with a sharp drop in species abundance and diversity and coincide with a decrease in total organic carbon toc content the shift towards depleted values in 13corg and 13ccarb at the permian triassic boundary event together with low toc contents persists throughout the griesbachian h parvus zone these data document a corresponding negative shift of 13corg and 13ccarb values and low toc contents with the onset of growth of calcified microbial framestones a postextinction disaster facies immediately below the base of the griesbachian h parvus zone based on paleontological evidence the first occurrence of the disaster facies follows the extinction event which implies that the 13c depleted values above this facies postdate the event this suggests that two separate events had to account for the initiation of the extinction and the 13c excursion however the consequences that led to the negative isotopic shift might be linked to the intriguing recovery lag of early triassic ecosystems based on data from ptb sections worldwide of a greater 13c offset in high compared with low latitudes we propose that methane eruptions from thermal destabilization of high latitude clathrate deposits may have led to the negative 13c shift and may have caused long term adverse ecological conditions

fungal event and palynological record of ecological crisis and recovery across the permian triassic boundary the end of the permian period was marked by the most severe mass extinction in the geologic record detailed quantitative study of pollen and spores from shallow marine deposits spanning the permian triassic p tr boundary in israel reveals a sequence of palynological ecological stages reflecting a major crisis among land plants the disappearance of the gymnosperm dominated palynoflora of the late permian lueckisporites virkkiae zone is recorded at a claystone horizon containing almost exclusively abundant fungal remains and carbonized terrestrial plant debris this fungal spike is followed by a zone dominated by marine acritarchs and a succession showing ecological recovery with abundantlycopodsporesandeventualreappearanceofbisaccategymnospermpolleninthe earlytriassic thelatestpermianproliferationoffungiisrecognizableworldwideandcan be correlated with other paleontological and geochemical markers of a global ecological disaster

permian triassic extinction pattern revealed by foraminifers and geochemical records in the central persian gulf southern iran abstract permian triassic boundary ptb foraminifers are studied from the upper part of the dalan formation and the base of the kangan formation in four wells a b e f on and near the qatar arc persian gulf iran isotope studies including 13c and 18o values from wells b and e and 87sr 86sr ratios in wells b e and f have also been carried out to possibly provide a high resolution extinction pattern of foraminifers in the ptb interval the latter has been thoroughly investigated in iran turkey south china vietnam slovenia carnic alps and bukk mountains kashmir greenland and serbia the distribution of the last appearance of foraminiferal genera from the ptb interval in all of the wells is very similar featuring a stepwise extinction from 3 to 2 m before the boundary and compares to that observed in some of the sections from elsewhere i e south china vietnam slovenia and serbia the 13c value in wells b and e shows a negative shift at the base of a thrombolite unit immediately after the considered ptb and another negative shift at about 11 m below it in well e the thrombolite unit is assumed as earliest triassic but questionable with no supportive conodonts the 18o isotope values in wells b and e demonstrate the same negative upward trend due to dysoxic or anoxic conditions in the end permian oceans the uniform reduction without any sharp incline in the 18o profile suggests concurrent global warming the highest 87sr 86sr ratio fluctuations in wells b e and f coincide with the appearance of thrombolites changes in the profiles of carbon oxygen and strontium isotopes close to the ptb in wells b e and f seem to correspond to lithofacies variations from limestone to dolostone and a reduction in foraminiferal diversity these changes substantiate a clear perturbation in the marine environmental and global geochemistry elements through the ptb interval the 13c 18o and 87sr 86sr values obtained from the studied wells are comparable to those in other ptb stratigraphic sections in the paleo tethyan region

bolide impacts acid rain and biospheric traumas at the cretaceous tertiary boundary abstract large projectiles impacting the earth will cause severe shock heating and chemical reprocessing of the earth s atmosphere this occurs during atmospheric entry and more importantly as a result of the supersonic plume ejected on impact in particular very large amounts of nitric oxide would result from the impact of the putative cretaceous tertiary bolide s we present models of the shock chemistry the conversion of no to no2 and thence to nitrous and nitric acids and the global dispersion of the no2 and acids two plausible projectiles are considered an ice rich long period comet and a much smaller rock metal asteroid the comet produces semi global atmospheric no2 mixing ratios of 0 1 while the asteroid produces these high mixing ratios only in the immediate region of the impact the comet produces concentrated nitrous and nitric acid rain with aph 0 1 5 globally the asteroid produces rain with aph 0 1 near the impact and 4 5 globally immediate environmental effects of these nitrogen species include inhibition of photosynthesis due to extinction of solar radiation by no2 foliage damage due to exposure to no2 and hno3 toxicosis resulting from massive mobilization of soil trace metals and respiratory damage due to exposure to no2 the acid rain decreases the ph of the oceanic mixed layer affecting the stability of calcite with important implications for the survival of calcareous shelled organisms and for exhalation of co2 from the mixed layer to the atmosphere longer term environmental effects perhaps 1000years in duration include a global warming due to the sudden co2 injection and the simultaneous extinction of the ocean micro organisms which normally help remove co2 from the atmosphere mixed layer system havens for survival include carbonate buffered lakes and burrows this acid rain theory therefore serves to explain the peculiar selectivity of the extinctions seen at the cretaceous tertiary boundary the first few years of acid rain will lead to massive weathering rates of continental soils characterized by large ratios of the relatively insoluble metals e g be2 al3 hg2 cu fe2 fe3 tl3 pb2 cd2 mn2 sr2 to the more soluble metals ca2 mg2 which should have left a clear signal in the fossils of neritic organisms and in unperturbed neritic sediments near river deltas if such sediments still exist for the cretaceous tertiary time frame