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

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

lithospheric thermal structure and rheology of the eastern china abstract temperature distributions of the lithosphere beneath the eastern china were estimated by local isostasy equilibrium constrained geothermal calculation in this study maps of the lateral temperature variation at depths of 50 and 100 km as well as moho boundary are presented for the eastern china continent and the 600 c and 1100 c isotherm depth maps are also given meanwhile the thermal thickness of lithosphere is calculated as the depth of 1350 c isotherm the rheological strength of lithosphere is calculated based on a four layer model which consists of the upper lower lowermost crust layers and a wet lithospheric mantle layer the results show that the lithosphere of 160 180 km thick exists under sichuan basin in the western part of yangtze craton but keel is absent beneath the entire north china craton it is notable that the lithospheric thickness is only 130 140 km beneath ordos basin in the western part of north china craton accordingly there is no lithospheric keel beneath ordos basin these geothermal modeling results are in good agreement with those of seismic tomography and other geothermal studies the temperatures in the lower crust of the north china craton estimated are in range of 500 600 c consequently the composition of lower crust of the north china craton should be more mafic than that of previous estimation based on much cooler geotherms the spatial variation of lithospheric rheology in the eastern china is influenced by local geotherms and crustal compositions the creme brulee model which is represent by a strong crust portion but a weak lithospheric mantle portion in vertical strength profile approximates the lithospheric rheological layering for the regions of the western half of north china craton and the northern part of ne china which has thicker crust or moderate to high geotherm on the other hand the jelly sandwich model demonstrates the rheological layering of the western part of the yangtze craton and the eastern half of the north china craton which has low to moderate geotherm and or thinner crust in general thermal age of the tectonic province controls the present day thermal structure and rheology of the lithosphere of the eastern china

timing of mammal like reptile extinctions across the permian triassic boundary in south africa the rate timing and pattern of change in different regions and paleoenvironments are critical for distinguishing among potential causes for the permian triassic p t extinction carbon isotopic stratigraphy can provide global chronostratigraphic control we report a large 13 c excursion at the p t boundary and no long term permian 13 c trends for samples from the interior of pangea stratigraphic gaps between available samples limit the resolution of our 13 c curve but the excursion is within a 15 m thick zone of overlap between permian and triassic taxa sedimentological and taphonomic observations demonstrate that this 15 m interval does not represent geologically instantaneous deposition together these data support a rapid and globally synchronous p t event but suggest that it occurred over a geologically resolvable interval of time

low oxygen levels in earliest triassic soils an earliest triassic methane postapocalyptic greenhouse following the permian triassic p t extinction event was proposed on the basis of evidence of deeply weathered paleosols at high latitudes with features of low latitude soils and low stomatal index values of seed fern leaves reexamination of distinctive phyllosilicates unique to a single stratigraphic level in paleosols located just above the isotopically defined permian triassic boundary in australia and antarctica furnishes additional tests of this hypothesis illite is the dominant clay mineral in earliest triassic paleosols from antarctica but the paleosols also contain conspicuous green nodules of coarsely crystalline berthierine examples from the geologic record and from experimental studies indicate that the formation of berthierine is restricted to reducing conditions the occurrence of this unusual mineral in soils may indicate soil oxygen consumption by the influx of atmospheric methane to form carbon dioxide which in turn warmed the earliest triassic giving rise to a postapocalyptic greenhouse

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

low oxygen levels in earliest triassic soils comment and reply reply we thank huggett and hesselbo for their interest in our work and substantial agreement with our conclusions when they state we do not dispute the possibility of a postapocalyptic greenhouse nor that this could explain the existence at high latitudes of a mineral normally associated with low

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

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

triassic climates state of the art and perspectives abstract the climate of the triassic period was characterized by a non zonal pattern dictated by a strong global monsoon system with effects that are most evident in the tethys realm this strong monsoonal regime is related to the aggregation of the pangaean supercontinent which by triassic time was already completed climate oscillations existed within this framework the harsh hot house climatic conditions that characterized the late permian and perhaps precipitated the end permian mass extinction were probably maintained during the early triassic and may account for the impoverished but distinctive faunal and floral lower triassic associations although metazoan reef builders were probably the most affected group carbonate production remained high at least in the western tethys realm the middle triassic was characterized locally by humid episodes although their geographical distribution has yet to be clarified the carnian pluvial event marks an episode of increased rainfall documented worldwide was the most distinctive climate change within the triassic different hypotheses have been proposed for its causes changes of atmospheric or ocean circulation driven by plate tectonics a peak of the global monsoon due to maximum continent aggregation or triggering by the eruption of a large igneous province subsequently the late carnian and norian seem to have been climatically stable although minor climatic changes have recently been described even from this time period finally the end triassic extinction event is also associated with climate change specifically warming and increased rainfall but this evidence comes mostly from the northern parts of the central atlantic magmatic province and the global pattern of climate change at the triassic jurassic boundary has still to be resolved many facets of triassic climate are intriguing and deserve further research however palaeoclimate studies on the triassic have so far been carried out only locally with different proxies those proxies will require inter calibration in order to depict correctly the temporal and geographical patterns of triassic climate

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

late permian continental sediments in the se iberian ranges eastern spain petrological and mineralogical characteristics and palaeoenvironmental significance abstract a detailed mineralogical and petrological study and the analysis of paleosol profiles in continental alluvial sediments of the late permian in the se iberian ranges spain allow us to infer the significant environmental changes that occurred during this time period three parts have been distinguished in the late permian sediments alcotas formation the lower part includes abundant and well preserved carbonate paleosol profiles and fine grained sediments made up by quartz feldspar hematite and illite with scarce kaolinite the preservation of dolomicrite in some paleosols suggests that they originally developed as dolocretes in an arid to semi arid climate with marked seasonality a change towards more humid and acid conditions can be deduced from the presence of siderite and goethite in paleosols in the middle part of the alcotas formation moreover the presence of plant remains coal beds and or carbonaceous shales at the top of the middle part and the lack of carbonate paleosols in the upper part of the formation would indicate a further step towards acid conditions these conditions would increase until the early triassic as indicated by the lack of carbonates and the presence of sr rich aluminium phosphate sulphates aps minerals at the base of the triassic canizar formation which clearly indicates extreme acid conditions during the permian triassic transition of the study area

gas emissions due to magma sediment interactions during flood magmatism at the siberian traps gas dispersion and environmental consequences we estimate the fluxes of extremely reduced gas emissions produced during the emplacement of the siberian traps large igneous province due to magma intrusion in the coaliferous sediments of the tunguska basin using the results of a companion paper iacono marziano et al submitted to epsl and a recent work about low temperature interaction between magma and organic matter svensen et al 2009 we calculate co ch4 dominated gas emission rates of 7 1015 2 1016 g yr for a single magmatic volcanic event these fluxes are 7 to 20 times higher than those calculated for purely magmatic gas emissions in the absence of interaction with organic matter rich sediments we investigate by means of atmospheric modelling employing present geography of siberia the short and mid term dispersion of these gas emissions into the atmosphere the lateral propagation of co and ch4 leads to an important perturbation of the atmosphere chemistry consisting in a strong reduction of the radical oh concentration as a consequence both co and ch4 lifetimes in the lower atmosphere are enhanced by a factor of at least 3 at the continental scale as a consequence of 30 days of magmatic activity the short term effect of the injection of carbon monoxide and methane into the atmosphere is therefore to increase the residence times of these two species and in turn their capacity of geographic expansion the estimated co and ch4 volume mixing ratios i e the number of molecules of co or ch4 per cm3 divided by the total number of molecules per cm3 in the low atmosphere are 2 5 ppmv at the continental scale and locally higher than 50 ppmv the dimension of the area affected by these high volume mixing ratios decreases in the presence of a lava flow accompanying magma intrusion at depth complementary calculations for a 10 year duration of the magmatic activity suggest i an increase in the mean ch4 volume mixing ratio of the whole atmosphere up to values 3 to 15 times higher than the current one and ii recovery times of 100 years to bring back the atmospheric volume mixing ratio of ch4 to the pre magmatic value thermogenic methane emissions from the siberian traps has already been proposed to crucially contribute to end permian early triassic global warming and to the negative carbon isotopic shift observed globally in both marine and terrestrial sediments our results corroborate these hypotheses and suggest that concurrent high temperature co emissions also played a key role by contributing to increase i the radiative forcing of methane and therefore in its global warming potential and ii the input of isotopically light carbon into the atmosphere that generated the isotopic excursion we also speculate a poisoning effect of high carbon monoxide concentrations on end permian fauna at a local scale

phanerozoic large igneous provinces lips heatt haline euxinic acidic thermal transgression episodes and mass extinctions abstract the phanerozoic consists of three mutually exclusive climate states icehouse greenhouse and hothouse the greenhouse is the default state representing 70 of the phanerozoic it is characterized by a weak thermal mode pole driven deep water formation with little or no continental sea ice and weakly oxic cool water sinking near the poles nitrogen limitation characterizes greenhouse oceans in which ammonium may be the dominant bioavailable form of nitrogen the steady state greenhouse default must be forced to produce either of the other two states continent continent collision produces the intense chemical weathering that draws down atmospheric co2 and results in the icehouse state that comprises 20 25 of the phanerozoic icehouses have ice caps in contact with the ocean that produce icebergs and foster sea ice formation sea ice formation fills the ocean with highly oxic phosphorus limited icewater except for a thin layer of warm surface water in the tropics of the 23 most conspicuous mass extinctions of the phanerozoic including the late ediacaran 4 are associated with ice volume related regressions and 3 are problematic we suggest that the other 16 mass extinctions occurred when greenhouse climate was forced to hothouse climate large igneous provinces lips can trigger the heatt haline euxinic acidic thermal transgression mechanism which can force greenhouse climate to a hothouse climate state the rapid voluminous co2 emissions of lips cause a series of events that result in very slow but pronounced haline mode circulation mid latitude driven deep water formation that produces warm saline bottom water at very dry hot subtropical and middle latitudes this water upwells at the poles causing warm and moist equable climate hothouse development promotes deep sea anoxia that is generated in concert with co2 buildup and warming the spread of anoxia favors reduced nitrogen over nitrate and limited iron dust curtails nitrogen fixation this leads to dominance of primary productivity by primitive green algae and or cyanobacteria progression to euxinia that reaches the photic zone severely curtails primary productivity via poisoning even as availability of usable nitrogen plummets the result is eukaryotic mass extinction we suggest that the 16 phanerozoic mass extinctions referred to above resulted at least in part from the heatt process evidence for this relationship at 11 of the most severe extinctions is convincing data sets for the other 5 are strongly suggestive of heatt related mass extinction but do not yet have enough documentation to reliably characterize them as heatt episodes

surface rupture morphology and vertical slip distribution of the 1959 m w 7 2 hebgen lake montana earthquake from airborne lidar topography

detailed correlation and age of continental late changhsingian and earliest triassic beds implications for the role of the siberian trap in the permian triassic biotic crisis abstract conchostracan rich beds between the siberian trap flood basalts and within the thick underlying hungtukun tuffs of the tunguska basin can be closely correlated with conchostracan faunas of dalongkou nw china and the germanic basin the germanic basin faunas in turn can be closely correlated with the marine international stratigraphic time scale and the accuracy of the biostratigraphic correlation of the permian triassic boundary ptb is confirmed by a minimum in 13ccarb values at this level these high resolution correlations demonstrate conclusively that the ptb is located within the temporally brief but thick siberian trap flood basalt sequence the ptb lies slightly above the level of the main permo triassic extinction event in low latitude marine beds which occurred at the base of the c meishanensis h praeparvus conodont zone and correlates with the beginning of the siberian trap flood basalt event the main end permian continental extinction event was somewhat earlier within the middle of the c changxingensis c deflecta conodont zone this horizon marks a mass extinction that devastated a diverse conchostracan fauna and left only low diversity faunas at low and high latitudes this continental extinction event horizon lies within the middle of the hungtukun tuffs of the tunguska basin and 107 m above the base of the guodikeng formation at dalongkou nw china a triassic type pioneer flora with numerous lycopod spores appears immediately above this level severe high northern and southern latitude marine extinctions occurred concurrently with this continental event but low latitude marine biota was not then affected this earlier event is best explained by global warming the main low latitude extinction event in marine warm water faunas occurred somewhat later and left no signature in high latitude marine faunas or in continental faunas but it does coincide with a rapid collapse of tropical rain forest environments disappearance of the highly diverse gigantopteris flora this collapse likely was caused by global cooling due to a volcanic winter event

ocean stagnation and end permian anoxia ocean stagnation has been invoked to explain the widespread occurrence of organic carbon rich laminated sediments interpreted to have been deposited under anoxic bottom waters at the time of the end permian mass extinction however to a first approximation stagnation would severely reduce the upwelling supply of nutrients to the photic zone reducing productivity moreover it is not obvious that ocean stagnation can be achieved numerical experiments performed with a three dimensional global ocean model linked to a biogeochemical model of phosphate and oxygen cycling indicate that a low equator to pole temperature gradient could have produced weak oceanic circulation and widespread anoxia in the late permian ocean we find that polar warming and tropical cooling of sea surface temperatures cause anoxia throughout the deep ocean as a result of both lower dissolved oxygen in bottom source waters and increased nutrient utilization buildup of quantities of h2s and co2 in the late permian ocean sufficient to directly cause a mass extinction however would have required large increases in the oceanic nutrient inventory

quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols abstract paleosols fossil soils are preserved throughout the geologic record in depositional settings ranging from alluvial systems to between basalt flows until recently paleosols were studied using primarily qualitative methods in recent years paleopedology has shifted from a largely qualitative field based on comparisons with modern analogues to an increasingly quantitative endeavor some of this change has been a result of applying existing techniques to new materials but many of the innovations have been the result of applying new techniques to new materials including thermodynamic modeling of soil formation isotope geochemistry and applications of empirical relationships derived from modern soils a variety of semi quantitative and quantitative tools has been developed to examine past weathering and pedogenesis and to reconstruct both paleoenvironmental and paleoclimatic conditions at the time that the paleosols formed though it is often not possible to achieve the same temporal resolution as with marine records for paleoclimatic reconstructions proxies based on paleosols are potentially a much more direct means of making paleoclimatic reconstructions because soils form at the earth s surface in direct contact with the atmospheric and climatic conditions at the time of their formation paleoclimatic and environmental properties that may be reconstructed using the new proxies include provenance weathering intensity mean annual precipitation and temperature during pedogenesis nutrient fluxes into and out of the paleosols the atmospheric composition of important gases including co2 and o2 the moisture balance during pedogenesis the soil gas composition reconstructed vegetative covering and paleo altitude

organic geochemistry across the permian triassic transition at the idrijca valley western slovenia abstract bulk and molecular stable c isotopic compositions and biomarker distributions provide evidence for a diverse community of algal and bacterial organisms in the sedimentary organic matter of a carbonate section throughout the permian triassic p tr transition at the idrijca valley western slovenia the input of algae and bacteria in all the upper permian and lower scythian samples is represented by the predominance of c15 c22 n alkanes odd c number alkylcyclohexanes c27 steranes and substantial contents of c21 c30 acyclic isoprenoids the occurrence of odd long chain n alkanes c22 c30 and c29 steranes in all the samples indicate a contribution of continental material the decrease of corg and ccarb contents increase of rock eval oxygen indices and 13c enrichment of the kerogen suggest a decrease in anoxia of the uppermost permian bottom water the predominance of odd c number alkylcycloalkanes c27 steranes and c17 n alkanes with 13c values 30 and 13c enrichment of the kerogens in the lowermost scythian samples are evidence of greater algal productivity this increased productivity was probably sustained by a high nutrient availability and changes of dissolved co2 speciation associated to the earliest triassic transgression a decrease of corg content in the uppermost scythian samples associated to a 13c depletetion in the carbonates up to 4 and individual n alkanes up to 3 4 compared to the upper permian samples indicate lowering of the primary productivity algae cyanobacteria and or higher degradation of the organic matter

evolutionary dynamics of the permian triassic foraminifer size evidence for lilliput effect in the end permian mass extinction and its aftermath abstract there is growing evidence of the lilliput effect in the end permian mass extinction and its aftermath however very little has been published on assessing the lilliput effect on protozoans in the early triassic based on quantitative analysis of a great quantity of samples from outcrop sections this study investigates foraminiferal test size variations through the changhsingian to the olenekian based on fossil records from three outcrop sections in south china the sharp reduction in foraminifer sizes coincides with the first or main episode of the end permian mass extinction foraminifers remained small in sizes in the early induan their body sizes increased slowly in the late induan to olenekian but never recovered to the pre extinction test size levels the lilliput effect on foraminifera in the aftermath of the end permian crisis is indicated by the extinction of large taxa decrease in size for surviving taxa and rise of small sized new forms physiological reactions of various foraminifer groups reveal that several defaunation events such as anoxia ocean acidification and global warming that prevailed through the permian triassic interval may be responsible for both the end permian crisis and the lilliput effect

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

calcium and calcium isotope changes during carbon cycle perturbations at the end permian negative carbon and calcium isotope excursions as well as climate shifts took place during the most severe mass extinction event in earth s history the end permian 252 ma investigating the connection between carbon and calcium cycles during transient carbon cycle perturbation events such as the end permian may help resolve the intricacies between the coupled calcium carbon cycles as well as provide a tool for constraining the causes of mass extinction here we identify the deficiencies of a simplified calcium model employed in several previous studies and we demonstrate the importance of a fully coupled carbon cycle model when investigating the dynamics of carbon and calcium cycling simulations with a modified version of the long term ocean atmosphere sediment carbon cycle reservoir model which includes a fully coupled carbon calcium cycle indicate that increased weathering rates and ocean acidification potentially caused by siberian trap volcanism are not capable of producing trends observed in the record as previously claimed our model results suggest that combined effects of carbon input via siberian trap volcanism 12 000 pg c the cessation of biological carbon export and variable calcium isotope fractionation due to a change in the seawater carbonate ion concentration represents a more plausible scenario this scenario successfully reconciles 13c and 44ca trends observed in the sediment record as well as the proposed warming of 6 c

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

early triassic early olenekian life in the interior of east gondwana mixed marine terrestrial biota from the kockatea shale western australia abstract a new terrestrial marine assemblage from the lower beds of a thin outcrop section of the kockatea shale in the northern perth basin western australia contains a range of fossil groups most of which are rare or poorly known from the lower triassic of the region to date the collection includes spinose acritarchs organic cemented agglutinated foraminifera lingulids minute bivalves and gastropods ammonoids spinicaudatans insects austriocaridid crustaceans actinopterygians a temnospondyl like mandible plant remains and spores and pollen of these groups the insects crustaceans and macroplant remains are recorded for the first time from this unit palynomorphs permit correlation to nearby sections where conodonts indicate an early olenekian smithian age the locality likely represents the margin of an early triassic shallow interior sea with variable estuarine like water conditions at the southwestern end of an elongate embayment within the east gondwana interior rift sag system preserved along the western australian margin monospecific spinose acritarch assemblages intertwined with amorphous organic matter may represent phytoplankton blooms that accumulated as mats and suggest potentially eutrophic surface waters the assemblage represents a mixure of marine and terrestrial taxa suggesting variations in water conditions or that fresh brackish water and terrestrial organisms were transported from adjacent biotopes some of the lower dark shaly beds are dominated by spinicaudatans likely indicating periods when the depositional water body was ephemeral isolated or subjected to other difficult environmental conditions the biota of the kockatea shale is insufficiently known to estimate biotic diversity and relationships of individual taxa to their permian progenitors and triassic successors but provides a glimpse into a coastal zone from the interior of eastern gondwana specialist collecting is needed to clarify the taxonomy of many groups and comparisons to other lower triassic sites are required to provide insights into the pattern of biotic decline and recovery at the end permian crisis

carbon isotope excursions and microfacies changes in marine permian triassic boundary sections in hungary abstract several permian triassic boundary sections occur in various structural units within hungary these sections represent different facies zones of the western palaeotethys margin the gardony core in the ne part of the transdanubian range typically represents the inner ramp while the balvany section in the bukk mountains of northern hungary represents an outer ramp setting the two sections have different patterns for their 13 c values the balvany section shows a continuous change towards more negative 13 c values starting at the first biotic decline followed by a sharp quasi symmetric negative peak at the second decline the appearance of the 13 c peak has no relationship to the lithology and occurs within a shale with low overall carbonate content indicating that the peak is not related to diagenesis or other secondary influences instead the shift and the peak reflect primary processes related to changes in environmental conditions the continuous shift in 13 c values is most probably related to a decrease in bioproductivity whereas the sharp peak can be attributed to an addition of c strongly depleted in 13 c to the ocean atmosphere system the most plausible model is a massive release of methane hydrate the quasi symmetric pattern suggests a rapid warming cooling cycle or physical unroofing of sediments through slope failure and releasing methane hydrate the gardony 1 core shows a continuous negative 13 c shift starting below the p t boundary however the detailed analyses revealed a sharp 13 c peak in the boundary interval just below the major biotic decline although its magnitude doesn t reach that observed in the balvany section based on careful textural examination and high resolution stable isotope microanalyses we suggest that the suppression of the 13 c peak that is common in the oolitic boundary sections is due to combined effects of condensed sedimentation sediment reworking and erosion as well as perhaps diagenesis