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

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

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

middle late permian mass extinction on land the end permian mass extinction has been envisaged as the nadir of biodiversity decline due to increasing volcanic gas emissions over some 9 million years we propose a different tempo and mechanism of extinction because we recognize two separate but geologically abrupt mass extinctions on land one terminating the middle permian guadalupian at 260 4 ma and a later one ending the permian period at 251 ma our evidence comes from new paleobotanical paleopedological and carbon isotopic studies of portal mountain antarctica and comparable studies in the karoo basin south africa extinctions have long been apparent among marine invertebrates at both the end of the guadalupian and end of the permian which were also times of warm wet greenhouse climatic transients marked soil erosion transition from high to low sinuosity and braided streams soil stagnation in wetlands and profound negative carbon isotope anomalies both mass extinctions may have resulted from catastrophic methane outbursts to the atmosphere from coal intruded by feeder dikes to flood basalts such as the end guadalupian emeishan basalt and end permian siberian traps

a review and synthesis of glendonites pseudomorphs after ikaite with new data assessing applicability as recorders of ancient coldwater conditions abstract calcite pseudomorphs after ikaite glendonite are associated with coldwater depositional systems including glaciomarine and deepwater settings as dictated by the limited stability field of ikaite ikaite precipitation is favored by elevated alkalinity and dissolved phosphate conditions encountered commonly in association with organic rich marine sediments where methane oxidation is occurring the rapid recrystallization of ikaite to calcite during slight warming or pressure release results in considerable solid volume loss producing a highly porous crystal mesh preservation of the original ikaite crystal form requires precipitation of diagenetic calcite cement during early burial to prevent compaction and collapse of pseudomorph structures during later burial diagenesis remaining pore space may be filled with deeper burial calcite cement glendonites from the permian of the sydney basin occur in subtidal shelf facies containing glacial dropstones and a normal marine fauna stable oxygen isotope signatures of modern ikaite suggest carbonate precipitation in equilibrium with ambient seawater carbon signatures are usually strongly negative relative to normal marine carbonate consistent with derivation of carbonate from methane oxidation review of published data suggests that while holocene glendonite may provide reliable isotopic records of the conditions of ikaite precipitation precipitation of later calcite cement within the glendonite structure reduces the significance of the isotopic signature as an indicator of primary depositional conditions bulk glendonite samples from the permian sydney basin australia have a broad range of 18 o and 13c 18opdb 5 to 15 13c 8 to 16 in contrast to the narrow range for brachiopod carbonate 18opdb 1 to 5 13c 5 to 7 from the same strata handpicked separates of primary glendonite and secondary calcite also have a wide range of stable isotope values the data from sydney basin glendonites indicate that diagenetic precipitation of calcite has blurred the isotopic signature of primary ikaite replacement calcite at the scale of micosampling done in this study

on using carbon and oxygen isotope data from glendonites as paleoenvironmental proxies a case study from the permian system of eastern australia abstract glendonites calcite pseudomorphs after ikaite caco3 6h2o feature prominently in fine grained glacially influenced permian marine strata of eastern australia which accumulated in a series of extensional basins that occupied polar to temperate latitudes along the southeastern margin of gondwana because ikaite formation in the marine environment requires near freezing temperatures high alkalinity and elevated concentrations of orthophosphate the presence of glendonites in ancient strata implies a particular array of paleoenvironmental conditions a petrographic and geochemical study was carried out to assess the veracity of isotopic data from glendonites as proxy indicators of ancient ocean chemistry sea floor temperature and diagenesis in thin section glendonites consist of inclusion zoned equant to bladed calcite crystals interpreted as the ikaite replacement phase enclosed in a matrix of calcite and minor chalcedony and pyrite cements carbon and oxygen isotope data show a negative covariance with 18o values ranging from 22 5 to 0 3 and 13c values from 27 7 to 4 5 v pdb of the calcite phases examined the ikaite replacement phase is the most enriched in 18o and most depleted in 13c enclosing cements possess lower 18o and higher 13c values and are interpreted to have formed during later stages of burial diagenesis the 18o values of the ikaite replacement phase do not correspond to formation with permian seawater at near freezing temperatures unless isotopic disequilibrium is assumed the 13c values are similar to the carbon isotope composition of bulk organic matter in the host sediment and suggest that the alkalinity and orthophosphate necessary for ikaite stability were generated in the zone of suboxic to anoxic diagenesis results indicate that although 18o and 13c values from glendonites are useful for understanding early to late diagenetic processes they are not ideal proxies for seawater chemistry and temperature

multiple early triassic greenhouse crises impeded recovery from late permian mass extinction the late permian mass extinction was not only the most catastrophic known loss of biodiversity but was followed by unusually prolonged recovery through the early triassic opinion has been divided on whether delayed recovery was a legacy of especially profound ecological disruption or due to additional environmental perturbations new records from the sydney basin in southeastern australia now reveal five successive late permian and early triassic spikes of unusually high atmospheric co2 and profound chemical weathering these successive atmospheric co2 greenhouse crises coincided with unusually warm and wet paleoclimates for a paleolatitude of 61 s successive transient greenhouse crises punctuated long term cool dry and low co2 conditions and may account for the persistence of low diversity and small size in early triassic plants and animals

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

global coal gap between permian triassic extinction and middle triassic recovery of peat forming plants early triassic coals are unknown and middle triassic coals are rare and thin the early triassic coal gap began with extinction of peat forming plants at the end of the permian ca 250 ma with no coal known anywhere until middle triassic 243 ma permian levels of plant diversity and peat thickness were not recovered until late triassic 230 ma tectonic and climatic explanations for the coal gap fail because deposits of fluctuating sea levels and sedimentary facies and paleosols commonly found in coal bearing sequences are present also in early triassic rocks nor do we favor explanations involving evolutionary advances in the effectiveness of fungal decomposers insects or tetrapod herbivores which became cosmopolitan and much reduced in diversity across the permian triassic boundary instead we favor explanations involving extinction of peat forming plants at the permian triassic boundary followed by a hiatus of some 10 m y until newly evolved peat forming plants developed tolerance to the acidic dysaerobic conditions of wetlands this view is compatible not only with the paleobotanical record of extinction of swamp plants but also with indications of a terminal permian productivity crash from delta sup 13 c sub org and total organic carbon of both nonmarine and shallow marine shales 205 refs 3 figs more 3 tabs less

orientation relative age and extent of the tharsis plateau ridge system the tharsis ridge system is roughly circumferential to the regional topographic high of northern syria planum and the major tharsis volcanoes however many of the ridges have orientations that deviate from the regional trends normals to vector means of ridge orientations calculated in 10 boxes of latitude and longitude show that the tharsis ridges are not purely circumferential intersections of vector mean orientations plotted as great circles on a stereographic net show that the ridges are not concentric to a single point but to three broad zones these data indicate either that the tharsis ridge system did not form in response to a single regional compressional event with a single stress center or that the majority of the ridge system did form in a single event but with locally controlled deflections in the generally radially oriented stress field superposition relationships and relative ages suggest that the compressional stresses that produced the ridges occurred after the emplacement of the ridged plains volcanic units early in the hesperian period but did not extend beyond the time of emplacement of the syria planum formation units or the basal units of the tharsis montes formation during the latter half of the hesperian period comparison of topographic data with the locations of ridges demonstrates a good correlation between the topographic edge of the tharsis rise and outer extent of ridge occurrence compressional deformation related to tharsis is present out to about 5100 km from the regional topographic center located near northern syria planum the innermost extent cannot be determined because the ridged plains units have been buried by more recent volcanic units although ridge formation appears to have extended farther inward than is presently observed models involving a combination of isostatic stresses and stresses resulting from flexural loading appear to explain best the observed tensional features topography gravity and to a first approximation the locations and orientations of the compressional ridges

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 co2 increases the freezing sensitivity of plants implications for paleoclimatic reconstructions from fossil floras reconstructions of coldest month mean temperature cmmt in the geologic past are important for understanding the dynamics of the climate system operating at that time a common method for estimating cmmt involves applying the climatic tolerances of modern plant species to close analogues in the fossil record the so called nearest living relative nlr approach here we show that the leaves of seven modern species commonly used as nlrs to reconstruct cmmt from the fossil record freeze at warmer temperatures when grown at high co2 800 vs 400 ppmv this co2 effect was found across all tested plant groups including palms taxodiaceous conifers and two southern hemisphere evergreen species this pervasive response indicates that many nlr derived estimates of cmmt for times of high co2 should be adjusted by at least 11 5 to 13 8c a revision of cmmt estimates toward warmer values further increases the disparity in continental interiors between cmmt indicators from the fossil record and the colder predictions from general circulation models

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

biogeochemical controls on photic zone euxinia during the end permian mass extinction geochemical biomarker and isotopic evidence suggests that the end permian was characterized by extreme oceanic anoxia that may have led to hydrogen sulfide buildup and mass extinction we use an earth system model to quantify the biogeochemical and physical conditions necessary for widespread oceanic euxinia and hydrogen sulfide release to the atmosphere greater than threefold increases in ocean nutrient content combined with nutrient trapping ocean circulation cause surface water h 2 s accumulation in the paleo tethys ocean and in areas of strong upwelling accounting for the presence of sulfide oxidizing phototrophs in the model suppresses but does not prevent widespread release of h 2 s to the atmosphere evidence from the geologic record is consistent with modeled geochemical distributions of widespread nutrient induced euxinia during the end permian suggesting h 2 s toxicity and hypercapnia may have provided the kill mechanism for extinction

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

equability continentality and tertiary climate the crocodilian perspective the distributions of fossil crocodilians are used to examine north american continental paleoclimates for four time periods in the cenozoic control groups provide a qualitative means of examining the completeness of the record and thus the validity of crocodilian patterns by analogy with the range of the extant american alligator alligator mississippiensis the patterns imply that mid to high latitude continental interiors during the eocene and miocene did not undergo seasonal temperature extremes as great as those observed in such areas today this is compatible with the paleobotanical data during both the late oligocene and the pleistocene times of major glaciation crocodilians were restricted to more maritime localities

greenhouse crises of the past 300 million years proxies of past co 2 and climate over the past 300 m y now reveal multiple global climate change events in unprecedented detail evidence for past co 2 spikes comes from expanded and refined data on stomatal index of fossil ginkgo and related leaves new evidence for synchronous climatic change comes from paleosols in montana utah and neighboring states each co 2 spike was coeval with unusually clayey red and decalcified paleosols which can be traced throughout the colorado plateau spikes in atmospheric co 2 also were coeval with increases in paleosol alkali depletion as an indication of high temperature and spikes in paleosol base depletion and depth to calcic horizons as indications of high precipitation in the colorado plateau times of warmer climate were also more humid perhaps due to greater moisture potential of warmer air seasonality of climate did not increase during warm wet spikes the mesozoic greenhouse was not persistently hot with cool spells but warm with hot flashes these data furnish power laws predicting the sensitivity and magnitude of change in mean annual temperature mat and mean annual precipitation map due to rising co 2 in a mid latitude mid continental region the magnitude of the coming anthropogenic greenhouse pales in comparison with past greenhouse spikes at times of global mass extinctions

stomatal response of swordfern to volcanogenic co2 and so2 from kilauea volcano 1 the experimentally determined relationship between atmospheric pco2 and plant stomata has been used to interpret large but transient changes in atmospheric composition such as may have resulted from the eruptions of flood basalt however this relationship has not been tested in the field i e in the vicinity of active volcanoes to examine the specific effects of volcanogenic emissions moreover the interpretation of paleoatmospheric pco2 from fossil stomatal data assumes that the stomatal response resulted solely from variation in pco2 and ignores the potential effect of outgassed so2 we hypothesize that volcanogenic so2 also has a significant effect on leaf stomata and test this hypothesis by measuring the stomatal index of the common swordfern nephrolepis exaltata in the plumes of the actively outgassing vents of kilauea volcano we find that compared to control locations stomatal index is lowest at sample sites in the plume of halema uma u crater where concentrations of both co2 and so2 are much higher than background however sites located directly in the plume of pu u o o where so2 levels are high but co2 levels are not also yield low values of stomatal index we propose that shifts in the stomatal index of fossil leaves may record transient atmospheric increases in both so2 and co2 such as may be caused by eruptions of flood basalts calculations of pco2 based on stomatal frequency are likely to be exaggerated

the carbon isotope excursion on gssp candidate section of lopingian guadalupian boundary an isotopic stratigraphically well documented outcrop in penglaitan guangxi province south china has been proposed as a candidate gssp for the lopingian guadalupian boundary correlatable outcrops from the west wing tieqiao section and east wing penglaitan section of the laibin syncline exhibit synchronous excursions in carbon isotopes the isotopic excursions 13c show the best placement of the boundary may lie at the base of bed 6k which coincides with the clarkina postbitteri conodont zone and with eustatic change 13c increases during the uppermost guadalupian jinogondolella granti conodont zone from the top of 3c to the base of 6i a 13c peak value of 5 is located at the transition between these two conodont zones and is suggested as a proxy for the transition from transgression to regression a gradual depletion of carbon isotopes occurs in the c postbitteri zone from bed 6e to 7b and this gradual 13c excursion also suggests the sequences around the guadalupian lopingian boundary at the candidate section are conformable during the middle later c postbitteri zone a 3 5 dramatic 13c depletion is recorded at the tieqiao section but only a 2 depletion at the deeper facies penglaitan section synchronous with conodont zones that mark eustatic changes

the carbon and sulfur cycles and atmospheric oxygen from middle permian to middle triassic the results of a theoretical isotope mass balance model are presented for the time dependence of burial and weathering plus degassing fluxes within the combined long term carbon and sulfur cycles averaged data for oceanic 13c and 34s were entered for every million years from 270 to 240 ma middle permian to middle triassic to study general trends across the permian triassic boundary results show a drop in the rate of global organic matter burial during the late permian and a predominance of low values during the early to middle triassic this overall decrease with time is ascribed mainly to epochs of conversion of high biomass forests to low biomass herbaceous vegetation resulting in a decrease in the production of terrestrially derived organic debris additional contributions to lessened terrestrial carbon burial were increased aridity and a drop in sea level during the late permian which led to smaller areas of low lying coastal wetlands suitable for coal and peat deposition mirroring the drop in organic matter deposition was an increase in the burial of sedimentary pyrite and a dramatic increase in the calculated global mean ratio of pyrite s to organic c high s c values resulted from an increase of deposition in marine euxinic basins combined with a decrease in the burial of low pyrite associated terrestrial organic matter the prediction of increased oceanic anoxia during the late permian and early triassic agrees with independent studies of the composition of sedimentary rocks weathering plus burial fluxes for organic carbon and pyrite sulfur were used to calculate changes in atmospheric oxygen the striking result is a continuous drop in o2 concentration from 30 to 13 over a twenty million year period this drop was brought about mainly by a decrease in the burial of terrestrially derived organic matter but with a possible contribution from the weathering of older organic matter on land it must have exerted a considerable influence on animal evolution because of the role of o2 in respiration some examples are the extinction of many vertebrates loss of giant insects and amphibians and the restriction of animals to low elevations it is concluded that the extinction of plants may have contributed to the extinction of animals

eocene continental climates and latitudinal temperature gradients global climate during the mesozoic and early cenozoic is thought to have been warmer than at present but there is debate about winter temperatures paleontological data indicate mild temperatures even at high latitudes and in mid latitude continental interiors whereas computer simulations of continental paleoclimates produce winter temperatures closer to modern levels foliar physiognomy and floristic composition of 23 eocene floras from the interior of north america and australia indicate cold month means generally 2 c even where the mean annual temperature mat was

origin and correlation of tuffs in the permian newcastle and wollombi coal measures nsw australia using chemical fingerprinting abstract felsic tuffs are common throughout the late permian newcastle and wollombi coal measures ncm wcm of the northern sydney basin petrographic studies reveal that they are composed of fragmented crystals of plagioclase quartz and less common degraded biotite and k feldspar together with lithic fragments and relict altered glass shards alteration during burial at t 62 78 kaolinite siderite ankerite and in extreme circumstances tonsteins dominated by i s the latter is formed by the alteration of vitric tuffs zr tio 2 and nb y ratios and rock primordial and chondrite normalised ree patterns la yb 4 05 to 11 37 indicate that the tuffs have been derived from rhyodacitic to dacitic continental arc calc alkaline magmas the accuracy of a recent lithostratigraphic correlations between the ncm and the wcm has been tested by determining the chemical composition of four stratigraphically well defined tuffs in the ncm and comparing them with those obtained from tuffs of the wcm which are thought to be stratigraphically equivalent the comparison was carried out using multivariate statistical analysis the analysis revealed that two of the tuffs awaba nobbys in the ncm could be distinguished the others mt hutton warners bay showed considerable scatter this contrasted with the tonsteins formed from the tuffs which apart from the mt hutton tuff were able to be separated in the wcm three of the tuffs nalleen unnamed tuff equivalent to the mt hutton tuff monkey place creek could be separated however the fourth unnamed tuff equivalent to the warners bay tuff exhibited some scatter treating tuffs in the wcm separately as unknowns in the discriminant model to determine possible correlatives in the ncm revealed that the nalleen tuff is equivalent to the awaba tuff in the ncm confirming the lithostratigraphic correlation the remainder of the tuffs in the wcm however show moderate to poor correlation with the proposed stratigraphically equivalents in the ncm thus the analysis shows that correlation based on lithostratigraphic grounds may be incorrect

a major fire event recorded in the mesofossils and petrology of the late permian lower whybrow coal seam sydney basin australia abstract petrographic and mesofossil analyses of plies from the late permian lower whybrow coal new south wales australia have revealed a significant fire event in both the swamp setting and the hinterland the fire event is characterised by a change in the maceral composition the seam during this interval being dominated by inertinite especially semifusinite following the fire event the mineral matter content of the coal increases this may be the result of increased run off and erosion in the hinterland due to destruction of vegetation this major fire event is also reflected in a change in the vegetation as represented by the mesofossil content of the seam prior to the fire event the seam contains abundant bisaccate taeniate pollen sporangia and seed like bodies of possible glossopterid affinity these are lost at the ply in which the fire event is recorded though seed like bodies become important again later the fire event also corresponds to a change in the megaspore content of the coal a new species appearing perhaps as a result of hydrological change following this major fire event a mineral rich ply was deposited which contains miospore masses of spores from fern like plants possibly representing a re colonisation event by rhizomorphs after vegetation death this evidence for a major fire and its implications for the origin of inertinites leads to the conclusion that throughout this and other permian gondwana coals fire was an integral part of the temperate mid high latitude southern hemisphere swamp ecosystem

large perturbations of the carbon cycle during recovery from the end permian extinction high resolution carbon isotope measurements of multiple stratigraphic sections in south china demonstrate that the pronounced carbon isotopic excursion at the permian triassic boundary was not an isolated event but the first in a series of large fluctuations that continued throughout the early triassic before ending abruptly early in the middle triassic the unusual behavior of the carbon cycle coincides with the delayed recovery from end permian extinction recorded by fossils suggesting a direct relationship between earth system function and biological rediversification in the aftermath of earth s most devastating mass extinction

relative sea level control of deposition in the late permian newcastle coal measures of the sydney basin australia abstract accumulation of the 400 m thick late permian newcastle coal measures of the sydney basin was controlled by changes in relative sea level three 3rd order sequences which constitute the coal measures consist of 4th order depositional sequences of fluvial conglomerate coal and small paralic lacustrine deltas crevasse splays deposited on a coastal plain landward of a marine shoreline each 4th order sequence was deposited during a single 4th order relative sea level cycle following falls in relative sea level alluvial conglomerates derived from the new england orogen filled incised valleys above sequence boundaries forming lowstand systems tracts sigmoidal conglomerates with giant crossbeds were deposited as alluvial fill in compactional moats formed at the toes of abandoned paralic deltas alluvial sediments passed through the coastal plain directly to the marine shoreline causing the shoreface to prograde rising relative sea level caused siliciclastic sedimentation to wane during these hiatuses in the transgressive systems tract a rising water table stimulated peat mire growth blanketing the entire non marine area when the vertical accumulation of peat was outpaced by increasing rates of rising relative sea level transgressing lagoons interdistributary bays and lakes inundated the mires above maximum flooding surfaces continuing relative sea level rise in the highstand systems tracts caused paralic lacustrine crevasse splays crevasse subdeltas and small deltas to prograde westwards into the newcastle half graben from a volcanic source on the offshore uplift at this time of rising base levels sediments were trapped on the coastal plain while the marine shoreface was starved falling relative sea level terminated paralic lacustrine delta progradation and initiated exposure and erosion to repeat the cycle and initiate another 4th order sequence two source areas supplied sediment into the newcastle half graben an easterly source on the offshore uplift shed volcanic detritus into the newcastle coalfield via paralic lacustrine deltas and the new england orogen shed volcano lithic detritus via braided streams the supply from the new england orogen was switched on or increased by a fall in relative sea level while supply from the offshore uplift was switched off reduced or diverted and vice versa during a rise in relative sea level increasing rates of 2nd order falling relative sea level resulted in an upward change from predominantly marine shoreface and coastal plain sedimentation to predominantly fluvial sedimentation in the upper newcastle coal measures

ptb mass extinction and earliest triassic recovery overlooked new evidence for a marine origin of lower triassic mixed carbonate siliciclastic sediments rogenstein member germany abstract the central european permo triassic basin was land locked with occasional connections to the north pangaea shelf and tethys a thick sequence of siliciclastic fluvial and floodplain sediments separates the late permian marine carbonate evaporite cycles of the zechstein basin from marine middle triassic marls and carbonates of the germanic basin within this latest permian middle triassic siliciclastic interval the location of the permian triassic boundary ptb is difficult to recognize the first limestones after the ptb are induan mixed carbonate siliciclastic oolites and microbialites of the bernburg and calvorde formations untere buntsandstein group consensus emerged after a long lasting controversy that the carbonates of the so called rogensteine are the relics of an alkaline playa lake the idea of the marine genesis was finally rejected because of the obvious lack of calcified metazoans the existing depositional playa lake model will be tested using previously unconsidered data such as currently discussed early triassic recovery scenarios of marine benthic communities after the permian triassic mass extinction global patterns of early triassic carbonate production permian triassic tectono sedimentary evolution of northern pangaea and stable oxygen and carbon isotope data the rogenstein is interpreted as marine carbonate showing the characteristic features of marine carbonates of the early triassic recovery period calcified invertebrates are rare in many marine settings during the aftermath of the permian triassic mass extinction thin shells of the oolites resemble opportunistic bivalves flourishing in marine early triassic oceans the oolites and microbialites are the product of abiotic and biotically induced carbonate precipitation following the permian triassic mass extinction while biomineralisation is insignificant rogenstein microbialites look like marine early triassic microbial reefs the extraordinary size of the rogenstein ooids resembles marine neoproterozoic ooids the term anachronistic has been used in the literature to describe the similarities in the fabric and composition of early triassic and early palaeozoic neoproterozoic marine carbonates stable carbon isotopes of least altered rogenstein ooids and stromatolites exhibit trends similar to the composition of triassic seawater the presence of flat pebble conglomerates and sediment structures similar to herring bone cross stratification confirm the marine genesis i propose that cool seawater transgressed during a global rise of late permian early triassic base level from the barents shelf southward along reactivated extensional graben structures and flooded the central european permo triassic basin there the extremely hot and arid climate of the megacontinent pangaea caused increased evaporation of seawater and subsequent supersaturation with respect to calcium carbonate insignificant biomineralisation and high water energy in the shallow sea give rise to largely abiotic and biotically induced carbonate precipitation which resembles lake sediments at first sight benthic tropical carbonate production started with the next transgression during the rot formation leading to the sedimentation of marls and limestones during the spathian late olenekian

age and timing of the permian mass extinctions u pb dating of closed system zircons the age and timing of the permian triassic mass extinction have been difficult to determine because zircon populations from the type sections are typically affected by pervasive lead loss and contamination by indistinguishable older xenocrysts zircons from nine ash beds within the shangsi and meishan sections china pretreated by annealing followed by partial attack with hydrofluoric acid result in suites of consistent and concordant uranium lead u pb ages eliminating the effects of lead loss the u pb age of the main pulse of the extinction is 252 6 0 2 million years synchronous with the siberian flood volcanism and it occurred within the quoted uncertainty

elevated atmospheric co2 and the delayed biotic recovery from the end permian mass extinction excessive co2 in the earth ocean atmosphere system may have been a significant factor in causing the end permian mass extinction co2 injected into the atmosphere by the siberian traps has been postulated as a major factor leading to the end permian mass extinction by facilitating global warming widespread ocean stratification and development of anoxic euxinic and co2 rich deep waters a broad incursion of this toxic deep water into the surface ocean may have caused this mass extinction although previous studies of the role of excessive co2 have focused on these bottom up effects emanating from the deep ocean top down effects of increasing atmosphere co2 concentrations on ocean surface waters and biota have not previously been explored passive diffusion of atmospheric co2 into ocean surface waters decreases the ph and caco3 saturation state of seawater causing a physiological and biocalcification crisis for many marine invertebrates while both bottom up and top down mechanisms may have contributed to the relatively short term biotic devastation of the end permian mass extinction such a top down physiological and biocalcification crisis would have had long term effects and might have contributed to the protracted 5 to 6 million year long delay in biotic recovery following this mass extinction earth s modern marine biota may experience similar top down co2 stresses if anthropogenic input of atmosphere ocean co2 continues to rise

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

the permian triassic boundary in the continental series of eurasia abstract the most important eurasian sections where the transitional permian triassic boundary beds are characterized palaeontologically are found in the germanic basin west european platform moscow basin east european platform tungusska basin siberian platform jimsar basin dalongkou area tianshan mountains and noyan somon depression mongolia usually the permian and triassic continental formations formed under distinct palaeogeographic especially climatic and palaeotectonic conditions so the lithological and sedimentological differences between them are pronounced difficult problems appear in those regions where the sedimentation at this level proceeded under very similar conditions tungusska basin jimsar basin across the permo triassic boundary ptb among palaeontological data the most important for correlation of these continental beds is the tetrapod fauna broad interchange between the tetrapod fauna of the old world continents resulted in the wide distribution during the late permian and early triassic of common or closely related forms which enables distant correlations the ptb is marked by the change of the late permian tetrapod communities dominated by the large herbivore dicynodon or closely allied forms to assemblages that include lystrosaurus as the most common form this is recorded in lower triassic beds of eastern europe china mongolia india and siberia the upper permian sporomorph associations sa are dominated by striate bissacate pollen whereas the early lower triassic ones are distinguished by the very important role of spores primarily by cavate trilete lundbladispora densoisporites and also by non striate dissacate klausipollenites and teniate pollen lunatisporites in the oldest horizons of the triassic very distinctive species of conchostracans falsisca eotriassica kozur or the closely related form f verhojanica molin appear the ptb is within a normal polarity zone formerly considered the lowest palaeomagnetic zone of the triassic the boundary beds of two sections moscow basin and jimsar basin may be equally worthy as candidates for the ptb gssp in the continental series the preference should be given to the section better characterized and internationally accessible to scientists the ptb generally accepted for the continental series coincides more or less with the base of the otoceras concavum ammonite zone of the boreal province and with the base of the boundary clay in tethys at the same time it lies clearly below the traditionally adopted ptb in marine sequences at the base of the otoceras woodwardi zone and also below the first appearance datum fad of i parva in the meishan section proposed now as the ptb gssp yin 1996 the palaeozoic mesozoic boundary candidate of global stratotype section and point of the permian triassic boundary china university geoscience press wuhan 137 pp this demonstrates that the fad of i parva can be asynchronous see baud 1996 albertiana 18 pp 6 9 that is why in the choice of the ptb gssp in the marine series it is necessary to take into consideration the generally accepted point of view on the position of ptb in the continental series

late early triassic microbial reefs of the western united states a description and model for their deposition in the aftermath of the end permian mass extinction abstract research in the western united states to reinvestigate and characterize the previously reported stromatolites of the latest early triassic spathian virgin limestone member of the moenkopi formation has shown that these microbial build ups formed patch reef mounds detailed field analysis of these reef mounds and the surrounding beds has established that they attained 1 2 m of topographic relief above the seafloor a petrographic study of these microbial mounds illustrates that they consisted of microbial fabrics as well as voids with early marine cements and formed in the absence of in situ metazoans these reef mounds formed during the aftermath of the end permian mass extinction that spanned the early triassic due to the devastation of marine metazoans at this extinction the early triassic has often been deemed a reef gap because no metazoan reefs are found at this time whereas colonial metazoan reefs are globally absent from lower triassic strata microbial build ups similar to these described from the western united states have been found in south china armenia southern turkey and greenland a regional early permian to late early triassic unconformity exists in the study region however analysis of these microbial reefs within a global context suggests that conditions favouring microbial reef development must have existed as long as 4 8 m y after the end permian mass extinction a depositional model of these microbial mounds indicates that flooding of the shelf with anoxic and or co2 rich deep waters may have fostered their occurrence

δ13c depth profiles from paleosols across the permian triassic boundary evidence for methane release stable carbon isotopic analyses of organic carbon 13 c in individual paleosol profiles from permian triassic sequences of antarctica reveal systematic isotopic variations with profile depth these variations are in many cases analogous to those in modern soils which are functions of redox conditions soil development and degree and type of microbial decay in modern soils these isotopic depth functions develop independently from vegetation changes c 3 versus c 4 vegetation and can be diagnostic of soil orders this study shows that soil intrinsic functions can be preserved in the 13 c values of paleosols as old as 260 ma and constitute valuable data for paleoecological interpretations a large carbon isotopic offset of as much as 10 in whole paleosol profiles across the permian triassic boundary indicates significant changes in the soil biogeochemistry and the soil atmosphere system early triassic paleosols are distinctive in their extremely low 13 c values to 42 and often show an anomalous 13 c depth distribution compared to both permian paleosols and modern soils highly depleted 13 c values as the ones in early triassic paleosols are suggested to be associated with microbial methane oxidation methanotrophy this hypothesis implies increased methane concentrations in the early triassic soil atmosphere system increased atmospheric methane was probably partly responsible for the global carbon isotopic shift documented in marine and terrestrial sediments across the permian triassic boundary

origin alteration and geochemical correlation of late permian airfall tuffs in coal measures sydney basin australia abstract the late permian illawarra coal measures of the southern sydney basin contain tuffs derived from altered pyroclastic airfall material these units represent ideal stratigraphic time planes because as the products of airfall volcanic ashes they are distributed over wide areas in short periods of geological time geochemical correlation of the tuffs of the illawarra coal measures with similar units in the stratigraphically equivalent newcastle coal measures offers a unique opportunity to understand the temporal and spatial relations during deposition of coal bearing units in the sydney basin thirty five core samples comprising 12 samples from each of the burragorang and farmborough claystone members and 11 samples from the huntley claystone member were analysed for major and trace elements by x ray fluorescence and instrumental neutron activation and the results were subjected to stepwise discriminant analysis the elements that served as the best discriminators between tuffs were in order of atomic number ti v sn hf and th samples for basin wide correlation were taken from thick interseam tuffs of the newcastle coal measures and treated as unknowns in the discriminant model the burragorang claystone member shows a strong geochemical correlation with the awaba tuff and the farmborough claystone member correlates with the warners bay tuff the huntley claystone member however has proved difficult to correlate with the nobby s tuff the proposed stratigraphic equivalent in the newcastle coal measures petrographic data for tuffs of the illawarra coal measures indicate that they were deposited by airfall mechanisms and consist mainly of kaolinite and mixed layer illite smectite clays quartz and plagioclase crystal fragments lithic fragments and secondary calcite and siderite zr tio2 and nb y ratios tectonic discrimination diagrams and chondrite normalised ree patterns la yb 3 3 to 11 9 are identical to those for tuffs of the newcastle coal measures and are interpreted as being derived from magma that was calc alkaline rhyodacitic to rhyolitic in composition and derived from a continental volcanic arc tectonic setting the source of the tuffs is interpreted to be an active volcanic arc to the east of the present coastline currarong orogen but a lack of evidence from below the continental shelf makes it difficult to make concrete conclusions on its likely extent and composition

timing and magnitude of tetrapod extinctions across the permo triassic boundary a review of the tetrapod amphibian and amniote record across the permo triassic boundary ptb indicates a global evolutionary turnover of tetrapods close to the ptb there is also a within guadalupian tetrapod extinction here called the dinocephalian extinction event probably of global extent the dinocephalian extinction event is a late wordian or early capitanian extinction based on biostratigraphic data and magnetostratigraphy the extinction precedes the illawara reversal so it is not synchronous with the end guadalupian marine extinction the russian ptb section documents two tetrapod extinction events one just before the dinocephalian extinction event and the other at the base of the lystrosaurus assemblage however generic diversity across the latter extinction remains essentially the same despite a total evolutionary turnover of tetrapod genera the chinese and south african sections document the stratigraphic overlap of dicynodon and lystrosaurus in the karoo basin the lowest occurrence of lystrosaurus is in a stratigraphic interval of reversed magnetic polarity which indicates it predates the marine defined ptb so as previously suggested by some workers the lowest occurrence of lystrosaurus cannot be used to identify the ptb in nonmarine strata correlation of the marine ptb section at meishan southern china to the karoo basin based primarily on magnetostratigraphy indicates that the main marine extinction preceded the ptb tetrapod extinction event the ecological severity of the ptb tetrapod extinction event has generally been overstated and the major change in tetrapod assemblages that took place across the ptb was the prolonged and complex replacement of therapsids by archosaurs that began before the end of the permian and was not complete until well into the triassic the tetrapod extinctions are not synchronous with the major marine extinctions at the end of the guadalupian and just before the end of the permian so the idea of catastrophic causes of synchronous ptb extinctions on land and sea should be reconsidered

global aridity during the early miocene a terrestrial paleoclimate record from the ebro basin spain abstract paleosols are an important tool in the paleoclimatic and paleoenvironmental interpretation of continental deposits and can provide a high resolution proxy for paleoclimate results from geochemical climofunctions applied to early miocene strata exposed in the ebro basin spain demonstrate that mean annual precipitation was the dominant control on paleosol type and indicate that the paleoclimate was considerably wetter during the early miocene by up to 1150 mm yr 1 in comparison to modern values placing it in a subhumid climatic regime rather than an arid semiarid regime as previously suggested by sedimentological and paleontological approaches by making comparisons with published data on paleoclimate during the early miocene this article stresses the importance of regional climatic changes in global paleoclimatic interpretation

methane release from igneous intrusion of coal during late permian extinction events abstract unusually large and locally variable carbon isotope excursions coincident with mass extinctions at the end of the permian period 253 ma and guadalupian epoch 260 ma can be attributed to methane outbursts to the atmosphere methane has isotopic values 13c low enough to reduce to feasible amounts the carbon required for isotopic mass balance the duration of the carbon isotopic excursions and inferred methane releases are here constrained to 10 000 yr by counting annual varves in lake deposits and by estimating peat accumulation rates on paleogeographic maps the most marked carbon isotope excursions form linear arrays back to plausible methane sources end permian siberian traps and longwood bluff intrusions of new zealand and end guadalupian emeishan traps of china intrusion of coal seams by feeder dikes to flood basalts could create successive thermogenic methane outbursts of the observed timing and magnitude but these are unreasonably short times for replenishment of marine or permaf

terrestrial record of methane hydrate dissociation in the early cretaceous reconstruction of changing c isotopic composition of early cretaceous atmospheric co2 from fossilized c3 vascular land plant tissue revealed a brief and striking negative excursion d 25 in atmospheric d 13 c followed by a rapid positive compensation d 15 during the aptian ca 117 ma mass balance calculations show that dissociation of a small amount of methane gas hydrate is the most tenable cause of the negative excursion this would also result in an increased co2 o2 mixing ratio as o2 is consumed during ch4 oxidation to co2 spurring the exponential phase of angiosperm biogeographic expansion

carbon isotope fractionation during decomposition of organic matter in soils and paleosols implications for paleoecological interpretations of paleosols abstract stable isotope ratios reported as 13c of organic carbon preserved in paleosols have potential utility as a valuable paleoecological indicator if the isotopic composition of paleobiomass is preserved in the paleosol organic carbon without fractionation however soil organic matter is in a constant state of decomposition in an open system and frequently decomposes further during alteration after burial of the paleosol during this decomposition kinetic fractionation of 13c 12c in an open system results in concentration of 13c in the residual organic matter preserved in the soil and paleosol this paper summarizes studies of modern soils which show that this 13c enrichment follows a rayleigh distillation process whereby the 13c 12c ratio is a function of the natural logarithm of the fraction of remaining soil organic carbon leaving soil organic carbon 13c enriched by up to 6 with respect to the original biomass if the fraction of original biomass carbon remaining during these decomposition processes deviates significantly from 1 the soil organic carbon can be 13c enriched by several per mil and thus not a good paleoecological indicator of the 13c value of the original biomass therefore effective paleoecological studies of 13c preserved in paleosol organic carbon must therefore demonstrate that the measured concentration of organic carbon in the paleosol is near its maximum concentration during soil formation or that the paleosol organic matter does not include the 13c enriched products of microbial decomposition suggestions are made for interpreting the effects of carbon isotope fractionation of organic matter and for materials and methods most useful for paleoecological studies from bulk paleosol organic carbon

carbon isotopic evidence for chemocline upward excursions during the end permian event abstract a negative shift in marine inorganic carbon isotope composition 13 c carb during the end permian mass extinction has been used as evidence for several different extinction mechanisms changes to the 13 c of organic matter and the difference between it and 13 c carb 13 c 13 c carb 13 c org have been examined at few locations with conflicting interpretations we examine the changes to both organic and inorganic carbon isotopes across the permian triassic boundary at two marine sections from south china meishan and shangsi and compare these to data from other previously published sections through these analyses we demonstrate that a decrease in 13 c occurred during the extinction event throughout the paleo tethys ocean the extent and intensity of the decrease varies by location averaging a negative shift of 5 several possibilities as to the cause of this shift exist including siberian trap volcanism a change in the terrestrial marine organic carbon input to the system or a change in the dominant marine biota brought about through environmental changes such as widespread ocean anoxia euxinia the decrease in 13 c observed at many of these sections across the event horizon is here interpreted to represent a shift from algae cyanobacteria to less fractionating phototrophic sulfur bacteria in marine shelf environments resulting from upward excursions of the chemocline these chemocline upward excursions would release euxinic water to the photic zone allowing phototrophic sulfur bacteria to thrive the limited available biomarker data are consistent with this interpretation

coupled carbon isotopic and sedimentological records from the permian system of eastern australia reveal the response of atmospheric carbon dioxide to glacial growth and decay during the late palaeozoic ice age abstract proxy geochemical records from high latitude ice proximal deposits have the potential to provide key insights into past icehouse climates but such records are rare the permian system of eastern australia contains a rich record of environmental and climatic changes that occurred in areas proximal to glaciation during the acme and waning stages of the late palaeozoic ice age within this succession a wealth of fine grained organic matter rich facies provides an opportunity to construct a bulk 13corg record that records changes in atmospheric co2 through the permian fluctuations in 13corg track changes in climate determined independently on the basis of sedimentological criteria in the same strata these patterns are also broadly consistent with multiple proxy records derived from palaeoequatorial sites the results of this geochemical investigation 1 support recent studies using the high latitude ice proximal sedimentologic and stratigraphic record and palaeoequatorial geochemical proxies that document highly variable climatic conditions within the overall permian icehouse to greenhouse transition and 2 confirms that the sedimentary record of glaciation from eastern australia reflects global changes in atmospheric co2 on several m y order timescales

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

volcanism mass extinction and carbon isotope fluctuations in the middle permian of china the 260 million year old emeishan volcanic province of southwest china overlies and is interbedded with middle permian carbonates that contain a record of the guadalupian mass extinction sections in the region thus provide an opportunity to directly monitor the relative timing of extinction and volcanism within the same locations these show that the onset of volcanism was marked by both large phreatomagmatic eruptions and extinctions amongst fusulinacean foraminifers and calcareous algae the temporal coincidence of these two phenomena supports the idea of a cause and effect relationship the crisis predates the onset of a major negative carbon isotope excursion that points to subsequent severe disturbance of the ocean atmosphere carbon cycle

cool climate or warm spike lateritic bauxites at high latitudes abstractlaterites and bauxites and their associated ultisols and oxisols are widespread in warm wet climates today and their spread to high latitudes has been attributed to episodes of past global warming bauxitic paleosols from the early eocene monaro volcanics of southeastern australia have been claimed as exceptions formed in a cool wet climate reexamination and chemical analysis of a sequence of intrabasaltic paleosols in the bega no 7 core of radiometrically dated monaro volcanics now show highly variable paleotemperature and precipitation the core includes 53 successive paleosols mostly nonbauxitic but bauxitic paleosols reveal local spikes in warmth and precipitation coincident with early eocene 55 52 51 and 48 ma global spikes of warmth precipitation and high atmospheric co2 these bauxitic paleosols thus formed in warm wet not cool dry climates and their poleward spread coincided with global greenhouse spikes

vertebrate extinction across permian triassic boundary in karoo basin south africa distinct assemblages of paleosols above and below the permian triassic boundary in the karoo basin of south africa are evidence for reorganization of ecosystems following this greatest of all mass extinctions the permian triassic boundary is recognized from the last appearance of dicynodon and from a series of negative excursions in the isotopic composition of carbon within therapsid tusks pedogenic carbonate nodules and organic matter the boundary is also marked by laminated beds with very weakly developed paleosols a change from purple 10r to brownish red 2 5yr paleosols and a thin 10 cm claystone breccia of reworked soil clasts paleoclimatic changes include a shift from arid and highly seasonal paleoclimate inferred from diffuse and shallow calcareous nodules in permian paleosols to semiarid and less seasonal paleoclimate inferred from deep and well focused calcic horizons in triassic paleosols an earliest triassic shift to warmer and wetter paleoclimate is also indicated by increased chemical weathering abundance of lycopsids and diversity of labyrinthodonts permian paleosols have root traces comparable to those of open shrubland and riparian woodland whereas triassic paleosols have root traces and profile forms like soils of open woodland this is a significant paleoenvironmental change but not as dramatic a change as would be expected from the devastating extinctions of 88 of fossil vertebrate genera latest permian therapsid reptiles were diverse and ecologically specialized in contrast the principal earliest triassic therapsid lystrosaurus was a burrower with no specific habitat preference its short internal nares barrel chest and high neural spines would have given it greater aerobic scope than preexisting therapsids and may have been an advantage under conditions of hypercapnia and hypoxia these adaptations and associated ecosystem changes are compatible with widespread vertebrate mortality by acidosis and pulmonary edema in a post apocalyptic greenhouse created by the voluminous release of methane from shallow marine and permafrost clathrates

palaeomagnetic data for permian and triassic rocks from drill holes in the southern sydney basin new south wales abstract a section 300 m thick across the permian triassic boundary has been sampled in the southern coalfield of the sydney basin new south wales 55 samples mainly grey to drab sandstones were collected from 9 diamond drill holes which penetrated the entire narrabeen group and the upper part of the conformably underlying illawarra coal measures as well as a sill emplaced into the coal measures the samples included fully oriented cores additional reconnaissance samples from two further drill holes were also studied partial alternating field demagnetization and petrography indicate the magnetic remanence to be a stable drm partial thermal demagnetization above 300 c or 400 c caused large increases in magnetic susceptibility partial chemical demagnetization did not cause significant changes in remanence directions for the coal cliff sandstone basal narrabeen group triassic the palaeomagnetic pole position normal was calculated to be at 59 n 322 e dp 27 dm 29 which agrees with previously published data for the uppermost coal measures permian the pole position was calculated as 58 n 340 e dp 09 dm 10 data for samples from the lower to middle coal measures yield a pole position which is between the new permian triassic pole position and that for the underlying middle permian igneous rocks the top of the reversed kiaman magnetic interval permian may be near the tongarra coal and appin formation boundary early late permian

late oligocene early miocene paleosols of distal fluvial systems ebro basin spain abstract the study of paleosols can be a vital tool in the paleoenvironmental interpretation of continental deposits because their physical and chemical characteristics are a reflection of variations in aspects of soil formation changes in paleosol characteristics can be used to determine the architecture and nature of parent material paleosol maturity topography climate and soil forming organisms including vegetation cover on the ancient floodplain and can be utilized to recreate a palaeocatena furthermore paleosols can provide quantitative data on paleoclimate where other sources such as organic matter and pedogenic carbonate are absent late oligocene early miocene strata exposed in the ebro basin spain have been identified as proximal alluvial fan fluvial and lacustrine continental facies in parts of the distal fluvial system pedogenically altered channel and overbank deposits interfinger with ephemeral lacustrine facies three main paleosol types developed in these sediments and have been described and compared to modern soils entisol like early successional soils inceptisol like young soils and alfisol like open woodland soils paleoenvironmental reconstructions suggest a mosaic of ecotypes with areas of open woodland composed of shrubs herbs and small trees and other plants of low stature and with each ecotype being controlled primarily by fluctuating paleohydrological conditions from field observations and geochemical analysis the climate was found to be humid continental mean annual temperature mat 10 14 c 4 c mean annual precipitation map 450 830 mm yr 1 200 mm yr 1 these results indicate that climatic conditions were wetter than the present day ebro basin mat 14 c map 320 mm yr 1 and differ from previous interpretations of an arid to semi arid environment based on sedimentological criteria alone

δ13c values of carbonate nodules across the permian triassic boundary in the karoo supergroup south africa reflect a stinking sulfurous swamp not atmospheric co2 abstract paleosol macromorphology petrography and stable isotope geochemistry of carbonate nodules from permo triassic p t boundary strata of the central karoo basin south africa are presented in order to evaluate their utility as geochemical archives of permian triassic paleoatmospheric chemistry and their potential to provide a terrestrial carbon isotope chemostratigraphy for correlation with contemporaneous global marine 13 c records paleosol morphologies across p t boundary strata of the central karoo basin indicate the region was a poorly drained seasonally to continuously flooded bottomland radiaxial calcite microspar and micrite microtextures are observed in the calcite nodules associated with p t paleosol profiles micritic calcite is typical of soil carbonate that forms in well drained soils characterized by open system gaseous diffusion between the soil and global atmosphere whereas more coarsely crystalline textures and radiaxial calcite are more typical of crystallization in phreatic environments with limited gaseous diffusion between the soil and global atmosphere in this regard only those nodules composed of micritic calcite can be considered as a potentially reliable source of proxy information for paleoatmospheric 13 c values across the p t boundary the 13 c values of all carbonate nodules from two overlapping measured sections near carlton heights south africa range from 24 4 to 1 8 whereas micritic calcite nodule 13 c values range from 7 0 to 21 3 comparison of calcite 13 c values with penecontemporaneous organic matter 13 c values indicate that calcite 13 c values 13 c values rather these more negative carbonate nodule 13 c values likely reflect calcite crystallization under poorly drained swampy conditions characterized by a semi closed chemical system that evolved independently of earth s troposphere therefore previously reported negative carbon isotope shift s measured from carbonate nodules in the karoo basin p t strata do not provide a record of atmospheric 13 c and probably do not provide a viable carbon isotope stratigraphy that can be realistically correlated with global p t marine carbon isotope stratigraphies