calibrating the end permian mass extinction the end permian mass extinction was the most severe biodiversity crisis in earth history to better constrain the timing and ultimately the causes of this event we collected a suite of geochronologic isotopic and biostratigraphic data on several well preserved sedimentary sections in south china high precision u pb dating reveals that the extinction peak occurred just before 252 28 0 08 million years ago after a decline of 2 per mil in 13c over 90 000 years and coincided with a 13c excursion of 5 that is estimated to have lasted 20 000 years the extinction interval was less than 200 000 years and synchronous in marine and terrestrial realms associated charcoal rich and soot bearing layers indicate widespread wildfires on land a massive release of thermogenic carbon dioxide and or methane may have caused the catastrophic extinction

the terrestrial end permian mass extinction in south china abstract the end permian mass extinction reflects the most severe life crisis during the phanerozoic and was associated with major global environmental changes however the consistency of the time and pattern of the terrestrial and marine extinctions remains controversial in this paper we presented detailed analyses of the high resolution biostratigraphical and geochemical data from terrestrial sections in south china our analyses show that the transitional kayitou formation actually recorded the process of terrestrial mass extinction as evidenced by the mass disappearance of the gigantopteris megaflora in the lower part the dramatic reduction in abundance of palynomorphs in the middle and the last occurrences of plant remains and abundant charcoal fossils in the uppermost part it is associated with a distinct negative shift of 13corg beginning in the middle part of the formation which is correlative with that in the top of bed 26 at the marine meishan section in addition the kayitou formation is characterized by a distinct shift of lithofacies of fresh lake swamp or river flat environment from olive grey black mudstone siltstone fine to coarse sandstone in the lower part to gradually increasing maroon rocks to purely maroon mudrocks with poorly sorted breccia calcic palaeosols and calcareous nodules in the lowest part of the dongchuan formation which indicates a dramatic collapse of soil system associated with rapid deforestation and climatic warming and drying in the coastal area the kayitou formation contains marine beds with the typical permian triassic mixed faunas and floras which are correlative with the latest changhsingian marine mixed fauna 1 at meishan the kayitou formation also recorded a distinct transgression that began in the latest changhsingian all above phenomena suggest that the kayitou formation is actually the witness of the terrestrial end permian mass extinction and it is mostly or entirely of latest changhsingian permian rather than triassic age

high thermal maturity in the lower saxony basin intrusion or deep burial abstract the lower saxony basin lsb is situated at the southern rim of the northern permian basin the most important hydrocarbon bearing province in europe in its southern part areas of high thermal maturation up to 6 rr occur which were previously explained as being caused by magmatic intrusions of turonian to santonian age that affected carboniferous to lower cretaceous rocks in this area 2d numerical basin modelling was carried out in order to reconstruct the temperature histories along two parallel n s trending seismic sections along these sections new data about maturity distribution and temperature history were obtained by vitrinite reflectance measurements and apatite fission track analysis for the areas with highest maturity values low coalification gradients were established which agree well with earlier published data on wells further towards the west this new information does not support previous hypotheses on high heat flows from magmatic intrusions even if lateral heat transport is taken into account instead comparisons with a recently published map of the subsurface structure of the lsb indicate that maturity distribution may be closely related to major tectonic structures deep burial of individual structures of the lsb which are bordered by deep e w to ese wnw trending faults is further suggested by a rapidly increasing thicknesses of preserved cretaceous strata towards the south and b structural restoration of one of the seismic sections to achieve a fit between measured and calculated palaeo temperature and vitrinite reflectance data deep burial of carboniferous source rocks during cretaceous time has to be assumed due to an inversion phase in the early and middle upper cretaceous major amounts of sediment were removed and further uplift occurred in tertiary times in contrast the northern part of the lsb experienced maximum burial and temperatures during tertiary times

carbon isotope stratigraphy across the permian triassic boundary a review abstract the palaeozoic mesozoic transition is marked by distinct perturbations in the global carbon cycle resulting in a prominent negative carbon isotope excursion at the permian triassic p t boundary well known from a plethora of marine and continental sediments potential causes for this negative 13 c trend and their links to the latest permian mass extinction have been intensively debated in the literature in order to draw conclusions regarding causation a general 13 c curve was defined after consideration of all available datasets and with due reference to the biostratigraphic background the most important features of the p t carbon isotope trend are the following the 4 7 13 c decline lasting 500 000 years is gradual and began in the changhsingian at the stratigraphic level of the c bachmanni zone the decreasing trend is interrupted by a short term positive event that starts at about the latest permian low latitude marine main extinction event horizon eh indicating that the extinction itself cannot have caused the negative carbon isotope excursion after this short term positive excursion the 13 c decline continues to a first minimum at about the p t boundary a subsequent slight increase is followed by a second occasionally two peaked minimum in the lower and middle i isarcica zone the negative carbon isotope excursion was most likely a consequence of a combination of different causes that may include 1 direct and indirect effects of the siberian trap and contemporaneous volcanism and 2 anoxic deep waters occasionally reaching very shallow sea levels a sudden release of isotopically light methane from oceanic sediment piles or permafrost soils as a source for the negative carbon isotope trend is questionable at least for the time span a little below the eh and somewhat above the p t boundary

changing fluvial environments across the permian triassic boundary in the karoo basin south africa and possible causes of tetrapod extinctions abstract the karoo supergroup is a 12 km thick succession of sedimentary rocks that accumulated in a large intracratonic retroarc foreland basin in southwestern gondwana the strata record 100 million years of almost continuous sediment accumulation from the permo carboniferous 300 ma through to the early jurassic 190 ma under a range of climatic regimes and within several tectonically controlled sub basins alluvial sediments dominate the succession from the late permian onwards fossils of synapsid reptiles and early dinosaurs are sufficiently common to be used in a ten fold biostratigraphic subdivision of these strata the permian triassic boundary in the karoo succession is marked by a major extinction of the herbivorous dicynodonts which co incides with a rapid change in fluvial facies this study uses field observations of the sedimentary facies palaeosols and in situ fossils of well exposed p tr boundary sequences in the southern karoo basin to provide evidence of environmental changes that may have caused the tetrapod extinctions in the main karoo basin below the p tr boundary sequence the sediments comprise drab greenish grey mudrocks with a few thick 3 12 m multistoried laterally accreted fine grained sandstone bodies the mudrocks host hydromorphic palaeosols with palustrine carbonate horizons and mostly disarticulated skeletal remains of dicynodon assemblage zone fauna above a transition zone of approximately 20 m thickness these strata change into reddish brown mudrocks with numerous thin 0 5 5 m ribbon sandstone bodies and more continuous sheet sandstones calcic palaeosols with rhizocretions nodular horizons and pervasive calcareous encrustation of articulated skeletons of lystrosaurus and associated fauna of the lystrosaurus assemblage zone within a 20 m thick interval of the transitional strata fossils of dicynodon and lystrosaurus occur together the facies transition that co incides with the latest permian dicynodont extinction is interpreted as a change in fluvial style from meandering to low sinuosity channels with general drying of the floodplain habitats and redistribution of vegetation belts the horsetails in particular became significantly reduced in areal distribution the changes in fluvial style in the karoo basin at the end of the permian were triggered by a pulse of thrusting in the southerly source area dated at 247 ma 2 ma which brought about rapid progradation of a large sandy braided fan system the katberg sandstone fm into the central parts of the basin a concomitant basinward migration of depositional environments allowed the lystrosaurus communities that were adapted to dry floodplains to colonise the entire basin to the detriment of most of the wet floodplain dicynodon fauna that lived there

permo carboniferous magmatism of the northeast german basin abstract variscan continent continent collision in central europe was followed by a period of syn to late tectonic magmatism involving the extrusion of large volumes of permosilesian age volcanic rocks particularly in the northeast german basin the volcanic suite up to ca 2000 m thick comprises rhyolites acid and basic andesites and tholeiitic and alkali basalts tectono geochemical analysis in conjunction with volume calculations and petrography reveals changes in volcanic activity over time a total of five eruptive stages are recognised beginning in the stephanian and extending up into the upper rotliegend permian these include the stephanian late carboniferous andesite pre ignimbrite stage i lower rotliegend permian age explosive ignimbrite stage ii post ignimbrite stage iii late rhyolite stage iv and upper rotliegend permian age late basalt stage v in addition several volcanic centres including at least two large caldera like structures are recognised the total calculated volume for the northeast german basin volcanics is ca 48 000 km3 comprising rhyolitic rocks and ignimbrites ca 70 andesitic rocks ca 26 and basalts with cogenetic dolerites ca 4 regional variations in composition and geochemistry are related to diverse crust mantle regimes which correlate with differing positions relative to the heterogeneous basement of the variscan foredeep or within the rhenohercynian orogenic zone the crustal thickening and increasing generation depth of the mafic magmas from north to south may reflect the presence of a pre existing subduction influenced basaltic magma source

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

current perspectives on the permian triassic boundary and end permian mass extinction preface abstract the end permian mass extinction is now robustly dated at 252 6 0 2 ma u pb and the permian triassic p t gssp level is dated by interpolation at 252 5 ma an isotopic geochronological timescale for the late permian early triassic based on recent accurate high precision u pb single zircon dating of volcanic ashes together with calibrated conodont zonation schemes is presented the duration of the early triassic induan olenekian stages is estimated at only 5 5 million years the duration of the induan stage griesbachian dienerian sub stages is estimated at ca one million years and the early olenekian smithian sub stage at 0 7 million years duration considering this timescale the delayed recovery following the end permian mass extinction may not in fact have been particularly protracted in the light of the severity of the extinction conodonts evolved rapidly in the first 1 million years following the mass extinction leading to recognition of high resolution conodont zones continued episodic global environmental and climatic stress following the extinction is recognized by multiple carbon isotope excursions further faunal turnover and peculiar sedimentary and biotic facies e g microbialites the end permian mass extinction is interpreted to be synchronous globally and between marine and non marine environments the nature of the double phased late permian extinction at the guadalupian lopingian boundary and the p t boundary linked to large igneous provinces suggests a primary role for superplume activity that involved geomagnetic polarity change and massive volcanism

multiple climatic changes around the permian triassic boundary event revealed by an expanded palynological record from mid norway here we present the palynological record from two shallow core holes 6611 09 u 01 and 02 from the trondelag platform offshore mid norway consisting of 750 m of upper permian and lower triassic sediments the relatively homogeneous assemblages recovered from the upper permian deposits are dominated by gymnosperm pollen mainly pteridosperms at the base of the griesbachian numerous spore species appear in the record leading to an increased diversity the change at this boundary is also marked by the massive reduction of one group of pteridosperm pollen vittatina together with other typical permian elements e g lueckisporites virkkiae this group is rare but consistently present in the lower part of the griesbachian and it gradually disappears in its upper part the distribution of other groups such as taeniate and non taeniate bisaccate gymnosperm pollen pteridosperms and conifers shows no significant change across the boundary whereas spores and other gymnosperm pollen increase in diversity and abundance these changes coincide with the formational change between the schuchert dal formation upper permian and the wordie creek formation griesbachian equivalents late permian and griesbachian palynomorph assemblages display different patterns the former show a homogeneous composition of low diversity whereas the latter reflect diverse and variably composed floras the data suggest that the arid phase of the late permian was followed by a humid phase at the base of the griesbachian in the griesbachian section a succession of six distinct palynological assemblages phase ii vii can be inferred comparable changes have been described from east greenland the variations in the palynological record are interpreted to reflect changing ecological conditions e g changing humidity comparable variations in the distribution of 13 c isotope values reported from various sections from greenland and china showing stable values during the late permian and highly variable values during the griesbachian suggest common causes for the observed fluctuations multiphase volcanic activity of the siberian traps seems to be the most likely candidate to have caused the variations in the 13 c isotope as well as in the palynological record in contrast to the common claim that marine and terrestrial biota both suffered a mass extinction related to the permian triassic boundary event the studied material from the norwegian midlatitudinal sites shows no evidence for destruction of plant ecosystems the presence of diverse microfloras of griesbachian age supports the idea that the climate in this area allowed most plants to survive the permian triassic boundary event

early triassic conodont palynological biostratigraphy of the meishan d section in changxing zhejiang province south china the lower triassic consisting of the yinkeng fm helongshan fm and the lower part of the nanlinghu fm is well developed at the meishan d section of changxing county zhejiang province south china based on detailed study of the conodont biostratigraphy from the interval of the permian triassic boundary and the lower triassic in the meishan d section 8 conodont zones are recognized in ascending order as follows the neogondolella changxingensis yini hindeodus praeparvus zone beds 24a 24e top of the changxing fm the neogondolella meishanensis meishanensis hindeodus eurypyge zone beds 25 27b base of the yinkeng fm the hindeodus parvus zone beds 27c 27d first conodont zone of triassic the global index for the base of triassic the isarcicella staeschei zone beds 28 29a lower part of the yinkeng fm i isarcica zone beds 29b 51 lower part of the yinkeng fm the neogondolella tulongensis n planata zone beds 52 72 from upper part of the yinkeng fm to lower part of the helongshan fm the neospathodus kummeli zone beds 73 92 middle part of the helongshan fm and the neospathodus cristagalli n dieneri zone beds 93 111 from upper part of the helongshan fm to the base of the nanlinghu fm at the meishan d section the palynological biostratigraphy is also studied herein the palynological assemblage of lundbladispora taeniaesporites equisetosporites is found in the intervals which contain the conodont isarcicella isarcica zone and the lower part of the neogondolella tulongensis n planata zone

conodont biostratigraphic control on transitional marine to non marine permian triassic boundary sequences in yunnan guizhou china the recovery of conodonts associated with ash beds and magnetostratigraphy in the key zhongzhai section near langdai liuzhi guizhou province provides precise and definitive control on the position of the permian triassic boundary in the transition from marine to non marine facies of western guizhou and eastern yunnan provinces of southwestern china in the zhongzhai section the boundary interval consists of a lower limestone 20 cm thick that contains fragments of hindeodus sp and clarkina sp this is overlain by a 50 cm thick black shale bed containing an abundant brachiopod fauna but only a single conodont fragment this bed is in turn overlain by a 23 cm thick limestone that contains clarkina meishanensis merrillina ultima hindeodus changxingensis h praeparvus and h eurypyge directly over this limestone is a 5 cm thick ash bed followed by a 10 cm thick black shale which is overlain by a second upper ash bed that is 3 cm thick on top of the upper ash bed is a 20 cm thick silty limestone containing an abundant dwarf conodont fauna dominated by hindeodus and containing h parvus but also including clarkina tulongensis the permian triassic boundary is placed at the level of the black shale located between the two ash beds 2007 elsevier b v all rights reserved

environmental perturbations during the latest permian evidence from organic carbon and mercury isotopes of a coal bearing section in yunnan province southwestern china abstract the end permian mass extinction epme is sudden but prior to which the ecological resilience has diminished the late permian is an important geologic period for coal formation associated with extensive volcanic activities in south china and adjacent regions here we present a systematic analysis of organic carbon and mercury isotopes as well as elemental geochemistry and mineralogy of a coal bearing section from the lianying coalfield in yunnan province south china the data show that organic carbon 13c values are negatively shifted by 25 22 to 25 99 in pyroclastic tonstein partings which are near synchronous with the negative eu anomaly 0 48 0 52 significant hg enrichment 130 352 ppb and near zero 199hg 0 08 0 07 these c and hg isotope anomalies and associated geochemical signatures which are manifested by characteristic al2o3 tio2 zr tio2 and nb yb ratios are likely caused by subduction or collision related volcanism our study provides evidence for the occurrences of volcanism before the advent of epme which played a significant role in stressing the environment and consequently diminishing the ecological resilience in the latest permian

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

sources of sr and s in aluminum phosphate sulfate minerals in early middle triassic sandstones iberian ranges spain and paleoenvironmental implications for the west tethys aluminum phosphate sulfate aps minerals formed during early diagenesis in relation to acid meteoric waters are the main host of sr and s in the early middle triassic continental sandstones of the iberian ranges east of the iberian peninsula the sources of these elements and the effects of paleoenvironmetal changes on these sources and on the formation of aps minerals during early middle triassic times were established on the basis of sr and s isotopic analyses the s and sr data d34s v cdt 11 to 14 and 87sr 86sr 0 7099 0 7247 respectively can be interpreted as resulting from mixing of different sources strontium was sourced from the dissolution of pre existing minerals like k feldspar and clay minerals inherited from the source areas causing high radiogenic values however the isotopic signal must also be influenced by other sources such as marine or volcanic aerosol that decreased the total 87sr 86sr ratios marine and volcanic aerosols were also sources of sulfur but the d34s was lowered by dissolution of pre existing sulfides mainly pyrite pyrite dissolution and volcanic aerosols would also trigger the acid conditions required for the precipitation of aps minerals aps minerals in the study area are found mainly in the canizar formation olenekian aegian which has the lowest 87sr 86sr ratios the lower abundance of aps minerals in the eslida formation aegian pelsonian may indicate change in the acidity of pore water towards more alkaline conditions while the increased 87sr 86sr ratios imply decreased sr input from volcanic activity and or marine aerosol inputs during anisian times therefore the decrease in abundance of aps minerals from the early to middle triassic and the variations in the sources of sr and s are indicative of changes in paleoenvironmental conditions during the beginning of the triassic period these changes from acid to more alkaline conditions are also coincident with the first appearance of carbonate paleosols trace fossils and plant fossils in the upper part of the canizar formation and more in the overlying eslida formation and mark the beginning of biotic recovery in this area the presence of aps minerals in other european basins of the western tethys such as the german basin the paris basin and the southeastern france and sardinia basins could thus also indicate that unfavorable environmental conditions caused delay in biotic recovery in those areas in general the presence of aps minerals may be used as an indicator of arid acidic conditions unfavorable to biotic colonization

crustal memory and basin evolution in the central european basin system new insights from a 3d structural model abstract the central european basin system cebs is composed of a series of subbasins the largest of which are 1 the norwegian danish basin 2 the north german basin extending westward into the southern north sea and 3 the polish basin a 3d structural model of the cebs is presented which integrates the thickness of the crust below the permian and five layers representing the permian cenozoic sediments structural interpretations derived from the 3d model and from backstripping are discussed with respect to published seismic data the analysis of structural relationships across the cebs suggests that basin evolution was controlled to a large degree by the presence of major zones of crustal weakness the nw se striking tornquist zone the ringkobing fyn high rfh and the elbe fault system efs provided the borders for the large permo mesozoic basins which developed along axes parallel to these fault systems the tornquist zone as the most prominent of these zones limited the area affected by permian cenozoic subsidence to the north movements along the tornquist zone the margins of the ringkobing fyn high and the elbe fault system could have influenced basin initiation thermal destabilization of the crust between the major nw se striking fault systems however was a second factor controlling the initiation and subsidence in the permo mesozoic basins in the triassic a change of the regional stress field caused the formation of large grabens central graben horn graben gluckstadt graben perpendicular to the tornquist zone the ringkobing fyn high and the elbe fault system the resulting subsidence pattern can be explained by a superposition of declining thermal subsidence and regional extension this led to a dissection of the ringkobing fyn high resulting in offsets of the older nw se elements by the younger n s elements in the late cretaceous the nw se elements were reactivated during compression the direction of which was such that it did not favour inversion of n s elements a distinct change in subsidence controlling factors led to a shift of the main depocentre to the central north sea in the cenozoic in this last phase n s striking structures in the north sea and nw se striking structures in the netherlands are reactivated as subsidence areas which are in line with the direction of present maximum compression the moho topography below the cebs varies over a wide range below the n s trending cenozoic depocentre in the north sea the crust is only 20 km thick compared to about 30 km below the largest part of the cebs the crust is up to 40 km thick below the ringkobing fyn high and up to 45 km along the teisseyre tornquist zone crustal thickness gradients are present across the tornquist zone and across the borders of the ringkobing fyn high but not across the elbe fault system the n s striking structural elements are generally underlain by a thinner crust than the other parts of the cebs the main fault systems in the permian to cenozoic sediment fill of the cebs are located above zones in the deeper crust across which a change in geophysical properties as p wave velocities or gravimetric response is observed this indicates that these structures served as templates in the crustal memory and that the prerift configuration of the continental crust is a major controlling factor for the subsequent basin evolution

structure and quantification of processes controlling the evolution of the inverted ne german basin abstract a ne sw reflection seismic transect crossing the entire ne german basin negb was investigated in detail to study the interaction between tectonics and sedimentation during the multiphase evolution of the region by restoring a geological section across the post rotliegend the kinematic evolution was reconstructed and rates of important geological processes such as erosion or basin shortening were quantified the present day structural style of the negb is the result of several major deformation events 1 regional subsidence accompanied by local thin skinned e w extension during the permo triassic jurassic was followed by basin inversions at the 2 jurassic cretaceous and at the 3 cretaceous tertiary boundary zechstein salt played an important role since mobile zechstein evaporites decoupled the supra salt from the sub salt succession and allowed the transmission of deformation over a large distance of major significance to the late cretaceous structural development was the crustal scale upthrusting of the calfoerde block along the gardelegen fault at the southern basin margin the accompanying horizontal shortening has a minimum value of 9 km and led to the development of thrusts and folds within the post zechstein succession

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

evolution of the lower saxony basin abstract the lower saxony basin is a 300 km long and 65 km wide late jurassic and early cretaceous trough which parallels the northern margin of the rhenish massif this basin became inverted during the senonian and paleocene the lower saxony basin is the most important oil province of germany past production amounts to 200 10 6 t of oil 1 5 10 9 bbl the lower saxony basin is superimposed on the late carboniferous variscan foredeep basin and the frontal structures of the variscan fold belt during the permian to middle jurassic the area formed part of the northwest european basin differential subsidence of the lower saxony basin was initiated during the late jurassic and persisted till albian time this involved reactivation of permo carboniferous fracture systems by divergent wrenching a major aptian deep seated laccolith is evident in the western part of the lower saxony basin during the senonian and paleocene sinistral convergent wrenching induced uplift of the basin floor and folding of its sedimentary fill the margins of the inverted lower saxony basin are thrust over the adjacent stable platform areas the differential subsidence of the lower saxony basin can be related to a period of major crustal extension in the north sea rift basin inversion coincides with important orogenic events in the alpine system and is thought to have been induced by intra plate compressional stresses

variscan to alpine heterogeneous palaeo stress field above a major palaeozoic suture in the carpathian foreland southeastern poland abstract the tectonic evolution of the region adjacent to the sw border of the east european craton is crucial for understanding the palaeozoic amalgamation of europe and its later evolution we present a structural analysis of the brittle deformation fault slip data inversion and folding carried out in the cambrian to cenozoic rocks of the european platform in se poland to characterize the late palaeozoic maastrichtian palaeocene and miocene tectonics of this region the variscan late carboniferous palaeo stress pattern was characterized by n s to nne ssw oriented compression as inferred from the folding of the palaeozoic mainly devonian rocks the compression was associated with the northwesterly present day coordinates motion of gondwana towards the northerly situated laurussia subsequently the mid polish trough mpt developed in an extensional regime the stress regime changed to compressional at the maastrichtian palaeocene transition in response to the africa europe plate kinematics the compressional regime induced the tectonic inversion of the mid polish trough the stress pattern was characterized by ne sw oriented compression in the holy cross mts hcm area and in the radomsko high folds and faults in the mesozoic cover revealed a sinistral reactivation of the holy cross fault hcf and of nw se trending faults the alpine stress patterns were related to the subduction of the european platform beneath the carpathian orogen the flexural bending of the subducted lithosphere induced a homogeneous middle miocene n s extension in the carpathian foreland subsequently the northward propagation of the carpathian front resulted in late middle miocene n s compression restricted to the proximal area of the frontal thrusts implied by a strain partitioning at a low friction contact between the carpathian nappes and the european platform since the palaeozoic the teisseyre tornquist zone ttz behaved as lithospheric weak zone which has been reactivated during the maastrichtian palaeocene change in stress regime it resulted in the tectonic inversion of the polish trough inherited faults conditioned superficial stress perturbations and focused the deformation

tectonic subsidence modelling of the polish basin in the light of new data on crustal structure and magnitude of inversion abstract the polish basin pb is one of a set of basins developed on the paleozoic platform of western europe in the late paleozoic between the variscan orogen and the east european craton eec its main depocentral axis the mid polish trough mpt was active during most of the basin development as a maximum subsidence zone with almost uninterrupted sedimentation the present base of the permian in the mpt ranges in depth from ca 3000 to 3500 m near the baltic coast to up to 8000 m to the southeast the mpt lies parallel and adjacent to the edge of the eec and appears to be related to a distinct structural zone within the crust the tornquist teisseyre zone ttz subsidence of the mpt can be explained in terms of crustal extension transtension and related lithosphere cooling coupled with the structural predetermination of the underlying ttz tectonic subsidence analysis of the preserved and reconstructed stratigraphic record suggests the occurrence of a late permian early triassic rifting phase however there is a deficit of geologically observable extensional features faulting of this age implying an important relationship between this phase of apparent basin subsidence and earlier post variscan late carboniferous early permian tectonism the match between crustal structure implied by basin modelling studies and available deep seismic sounding dds data is not always clear this is probably related to the heterogeneous basement which comprises the outer zone of the variscan belt in the southwest eec crust in the northeast and a complex of caledonian reworked precambrian crustal blocks in the central part of the basin changes to crustal architecture as a result of alpine tectonics may also play a role increased tectonic subsidence rates during oxfordian kimmeridgian times late jurassic correlate with intensified rifting and wrench activity within the arctic north atlantic rift system and along the northern tethyan margin in contrast accelerating tectonic subsidence beginning in the cenomanian is a precursor of compressional deformations in the basin that culminated in alpine related basin inversion during the latest late cretaceous and earliest tertiary taking inversion into account the maximum depth of the base zechstein structural surface at the end of the cretaceous is estimated to have been as much as 5000 m near the baltic sea to more than 10 000 m in the southeasternmost part of the basin because of the erosion of these sediments however constraints on cretaceous subsidence and in turn the magnitude and exact timing of late cretaceous paleogene inversion are poor

evolution of the northeast german basin inferences from a 3d structural model and subsidence analysis abstract a 3d structural model of the northeast german basin was evaluated with special emphasis on its evolution as an intracontinental depression the study includes investigations on subsidence history and structural setting of the basin thickness evolution and calculated tectonic subsidence volumes of permian to quaternary sediments in the northeast german basin indicate that the subsidence history was related to five stages of basin evolution which differ in their subsidence mechanisms for the initial rift phase in the late carboniferous to early permian a dominant thermal event and subordinate horizontal stresses were indicated by thickness variation evolution and by structural evidence the main part of basin subsidence occurred in a nw se oriented basin in the subsequent phase of thermal relaxation with maximum subsidence from early permian rotliegend to middle triassic muschelkalk from middle triassic the thermal subsidence pattern was superposed by further tectonic events in the middle triassic regional extension led to a reconfiguration of the southern part of the basin where new nne ssw trending troughs rheinsberg and gifhorn troughs developed in the jurassic the northwestern part of the basin was uplifted while in the south the keuper subsiding areas continued to sink and nw se trending depressions related to salt margins became important differentiation continued into cretaceous times when regional compression caused uplift of the southeastern part of the basin and basin margins a final subsidence phase occurred in the cenozoic this was accompanied by intensive salt movement recent basin configuration reflects the superposition of structural elements resulting from different evolution stages the main structural characteristics of the basin are 1 a vertical tectonic zonation in a pre zechstein succession which lacks significant internal structures and a strongly deformed post zechstein succession which was decoupled due to the thick zechstein salt and 2 a marked asymmetry of the basin with a shallow northern slope and a steep bounding fault at the southern margin elbe fault system the northwestern part of the basin shows the structural properties of an intracratonic sag basin with persisting subsidence and with minor salt mobilisation in contrast initial structures in the southeastern part are strongly overprinted by younger tectonic events including middle triassic to jurassic extension late cretaceous inversion and late to post cretaceous salt movements tectonic elements that deform the whole sedimentary succession are restricted to the basin s southern eastern and northeastern margins where salt thickness decreases combined volumetric and backstripping investigations show that 2 3 of the total subsidence was induced by the sediment load and 1 3 was caused by tectonics the tectonic subsidence history varies laterally across the basin while tectonic subsidence curves in the northwestern part of the basin show fast subsidence during the permian and early triassic decreasing exponentially with time subsidence curves in the southeastern part indicate repeated tectonic activity however the tectonic subsidence volume created during permian to late triassic is significantly higher than the tectonic subsidence during younger phases of basin history

pattern of vertebrate extinctions across an event bed at the permian triassic boundary in the karoo basin of south africa the extinction of vertebrates around the time of the permian triassic boundary has long been regarded as a gradual event occurring over millions of years our new field investigations of fluvial strata in the central and southern karoo basin of south africa have revealed the presence of an event bed coinciding with a mass extinction of terrestrial fauna and flora the bed is in a sedimentary sequence that is marked by a reddening of flood plain mud rocks and a change from high to low sinuosity river channel systems here we show that the pattern of vertebrate taxa disappearing below this boundary and the subsequent appearance of new taxa above the boundary are consistent with a relatively sudden possibly catastrophic event perhaps of 50 000 yr duration or less

a brachiopod calcite record of the oceanic carbon and oxygen isotope shifts at the permian triassic transition the permian triassic p t mass extinction was the most dramatic of all such events but its cause has thus far remained elusive1 3 carbon and oxygen isotope analyses may offer clues to this puzzle because their results identify major changes in the earth s exosystem4 5 several studies have already dealt with carbon and oxygen isotope records at the p t transition2 6 11 but we present here empirical data derived from the brachiopod shell calcite whose isotope composition generally corresponds to that of the sea water in which the animals lived originally12 15 these data allow us to assess quantitatively the magnitude of changes in the earth s exosystem during that critical time interval

restudy of conodont biostratigraphy of the permian triassic boundary section in zhongzhai southwestern guizhou province south china abstract new conodont samples have been systematically collected at high stratigraphic resolution from the upper part of the longtan formation through to the lower part of the yelang formation at the zhongzhai section southwestern guizhou province south china in an effort to verify the first local occurrence of hindeodus parvus in relation to the permian triassic boundary at this section the resampled conodont fauna from the permian triassic boundary interval comprises five identified species and two undetermined species in hindeodus and clarkina most importantly the first local occurrence of hindeodus parvus is found for the first time from the bottom of bed 28a 18 cm lower than the previously reported first local occurrence of this species at this section considering the previously accepted ptb at the zhongzhai section well calibrated by conodont biostratigraphy geochronology and carbon isotope chemostratigraphy this lower earlier occurrence of h parvus suggests that this critical species could occur below the permian triassic boundary as such this paper provides evidence that 1 the first local occurrences of h parvus are diachronous in different sections with respect to the ptb defined by the first appearance datum fad of this species at its gssp section in meishan china and that 2 the lower stratigraphic range of h parvus should now be extended to latest permian

mass extinction of peat forming plants and the effect on fluvial styles across the permian triassic boundary northern bowen basin australia abstract the most spectacular extinction event in earth s history occurred across the permian triassic boundary in the northern bowen basin a major coal bearing sedimentary basin in eastern australia a long lived c 9 myr cold climate peat mire ecosystem collapsed at the permian triassic boundary when the vast majority c 95 of peat producing plants became extinct the environmental change marked by the permian triassic boundary is expressed as an abrupt and sharp change in sedimentary regime at the contact between the rangal coal measures and the sagittarius sandstone the stratigraphic record shows no diminution in the thickness lateral extent or spatial distribution of coal seams prior to the boundary event the abrupt ecological shift at the permian triassic boundary was coincident with and interrelated to a change in landscape attributes and fluvial style the boundary shift is considered to reflect a short period radical atmospheric change accompanied by an abrupt change in plant ecosystems however palynological data indicate that it was preceded by a more gradual gross taxonomic progression in the floral succession the boundary shift is unlikely to reflect change in the tectonic setting of the northern bowen basin because the detrital character of clastic sediment supply shows no provenance change within the boundary sequence the late permian fluvial style is characterised by large scale up to 1 km wide sandstone dominated low sinuosity trunk river channel deposits the trunk river channels were flanked by extensive levee composite crevasse splay systems channel tracts were relatively stationary in position over enduring periods and developed stacked sediment accumulations up to 30 m thick the constrained character of the late permian trunk river systems was most likely due to progressive compaction of thick tracts of peat substrate and the stabilising effect of vegetation adjacent to the channel complex the well developed crevasse splays coupled with the low sinuosity style of the fluvial channels might suggest a perennial fluvial system characterised by short discharge periods as common in high latitude settings the fluvial architecture of the sagittarius sandstone the basal formation of the lower triassic rewan group is characterised by sheet like elements suggestive of broad shallow channels in a deforested braid plain setting the channel deposits are considered to represent highly mobile sandy systems dominated by a flashy runoff regime the mass extinction of plants in the northern bowen basin at the permian triassic boundary thus had a significant impact on the early triassic landscape and fluvial architecture

different modes of the late cretaceous early tertiary inversion in the north german and polish basins several selected seismic lines are used to show and compare the modes of late cretaceous early tertiary inversion within the north german and polish basins these seismic data illustrate an important difference in the allocation of major zones of basement thick skinned deformation and maximum uplift within both basins the most important inversion related uplift of the polish basin was localised in its axial part the mid polish trough whereas the basement in the axial part of the north german basin remained virtually flat the latter was uplifted along the sw and to a smaller degree the ne margins of the north german basin presently defined by the elbe fault system and the grimmen high respectively the different location of the basement inversion and uplift within the north german and polish basins is interpreted to reflect the position of major zones of crustal weakness represented by the wnw ese trending elbe fault system and by the nw se striking teisseyre tornquist zone the latter underlying the mid polish trough therefore the inversion of the polish and north german basins demonstrates the significance of an inherited basement structure regardless of its relationship to the position of the basin axis the inversion of the mid polish trough was connected with the reactivation of normal basement fault zones responsible for its permo mesozoic subsidence these faults zones inverted as reverse faults facilitated the uplift of the mid polish trough in the order of 1 3 km in contrast inversion of the north german basin rarely re used structures active during its subsidence basement inversion and uplift in the range of 3 4 km was focused at the elbe fault system which has remained quiescent in the triassic and jurassic but reproduced the direction of an earlier variscan structural grain in contrast n s oriented mesozoic grabens and troughs in the central part of the north german basin avoided significant inversion as they were oriented parallel to the direction of the inferred late cretaceous early tertiary compression the comparison of the north german and polish basins shows that inversion structures can follow an earlier subsidence pattern only under a favourable orientation of the stress field a thick zechstein salt layer in the central parts of the north german basin and the mid polish trough caused mechanical decoupling between the sub salt basement and the supra salt sedimentary cover resultant thin skinned inversion was manifested by the formation of various structures developed entirely in the supra salt mesozoic cenozoic succession the zechstein salt provided a mechanical buffer accommodating compressional stress and responding to the inversion through salt mobilisation and redistribution only in parts of the ngb and mpt characterised by either thin or missing zechstein evaporites thick skinned inversion directly controlled inversion related deformations of the sedimentary cover inversion of the permo mesozoic fill within the mid polish trough was achieved by a regional elevation above uplifted basement blocks conversely in the north german basin horizontal stress must have been transferred into the salt cover across the basin from its sw margin towards the basins centre this must be the case since compressional deformations are concentrated mostly above the salt and no significant inversion related basement faults are seismically detected apart from the basin margins this strain decoupling in the interior of the north german basin was enhanced by the presence of the elbe fault system which allowed strain localization in the basin floor due to its orientation perpendicular to the inferred late cretaceous early tertiary far field compression

accretionary history and crustal evolution of the variscan belt in western europe abstract the variscan belt of western europe is part of a large intra paleozoic belt extending on both sides of the atlantic from the ouachitas in the us and the mauritanides in west africa to the bohemian massif in czechoslovakia and poland the belt was constructed between 500 and 250 ma as a result of convergence and collision between two main continents laurentia baltica and africa after the closure of various oceanic basins iapetus rheic and galicia massif central now recorded as discrete in part cryptic sutures which form the roots of large crystalline nappes in which are found dismembered remnants of oceanic crust and mantle the accretionary history of the variscan belt in western europe is related to the progressive closure of probably two oceanic basins the rheic in the north and another the galicia massif central in the south by respectively southward and northward intraoceanic subduction followed by obduction and intracontinental lithospheric subduction the result is a broad 700 800 km fan like divergent belt which must be considered as a classical obduction collision orogen with a long intracontinental history of about 100 150 ma its arcuate shape is probably due to the northwestward impingement of a promontory of the african continent into laurentia baltica

the terminal paleozoic fungal event evidence of terrestrial ecosystem destabilization and collapse because of its prominent role in global biomass storage land vegetation is the most obvious biota to be investigated for records of dramatic ecologic crisis in earth history there is accumulating evidence that throughout the world sedimentary organic matter preserved in latest permian deposits is characterized by unparalleled abundances of fungal remains irrespective of depositional environment marine lacustrine fluviatile floral provinciality and climatic zonation this fungal event can be considered to reflect excessive dieback of arboreous vegetation effecting destabilization and subsequent collapse of terrestrial ecosystems with concomitant loss of standing biomass such a scenario is in harmony with predictions that the permian triassic ecologic crisis was triggered by the effects of severe changes in atmospheric chemistry arising from the rapid eruption of the siberian traps flood basalts

late cretaceous and cenozoic intra plate compressional deformations in the alpine foreland a geodynamic model abstract the mesozoic grabens and wrench induced troughs of western and central europe developed in response to triassic early cretaceous intra plate tensional stresses which affected the arctic north atlantic and the tethys borderlands during the rifting phase preceding the opening of the respective oceans this resulted in the fragmentation of the continental crust of the alpine foreland during the late cretaceous and tertiary alpine orogeny collision related compressive stresses exerted on the foreland induced the reactivation of these fracture systems causing the inversion of mesozoic grabens and the uplifting of major basement blocks at distances up to 1300 km to the north of the present alpine deformation front the structural style of these inverted basins and basement uplifts is indicative of compressional and transpressional deformations the total amount of crustal shortening associated with these deformations is unlikely to exceed a few tens of kilometres these displacements require a coupling between the foreland and the orogen at the alpine a subduction zones and within the foreland a decoupling at intra crustal levels between the crust and mantle and or at deeper lithospheric levels the example of the alpine foreland indicates that compressive stresses inducing major deformations can be transmitted from a collisional plate boundary through continental lithosphere over distances of up to 1300 km circumstantial evidence suggests that collision related compressive stresses not large enough to give rise to significant deformations can be transmitted through continental lithosphere over even greater distances

heterogeneous tectonic inversion of the mid polish trough related to crustal architecture sedimentary patterns and structural inheritance abstract using a 3 d structural model we performed a basin scale analysis of the tectonically inverted mid polish swell which developed above the nw se oriented teisseyre tornquist zone the later separates the paleozoic west european platform from the precambrian east european craton the model permits a comparison between the present depths and sedimentary thicknesses of five layers within the permian mesozoic and cenozoic successions the inversion of the nw se trending mid polish trough during the late cretaceous paleogene resulted in uplift of a central horst the mid polish swell bounded by two lateral troughs these structural features are induced by squeezing of a weak crust along the teisseyre tornquist zone the swell is characterized by an inherited segmentation which is due to ne sw transversal faults having crustal roots from nw to se we distinguish the pomeranian kujavian and malopolska segments that are separated by two transversal faults during the inversion the zechstein salt occurring in the pomeranian and kujavian segments in the nw acted as decoupling level between the basement and the post salt cover leading to disharmonic deformation conversely because no salt occurs in the se both basement and cover were jointly deformed the vertical tectonic uplift at the surface is estimated to amount to 3 km in the malopolska segment the structural inheritance of the basement is expressed by the heterogeneous geometry of the swell and tectonic instability during mesozoic sedimentation the reasons for the inheritance are seen in the mosaic type paleozoic basement sw of the teisseyre tornquist zone contrasting the precambrian east european craton which acted as a stable buttress in the ne the horst and trough geometry of cenozoic sediments blanketing the mid polish swell reveals the ongoing intracontinental compressional stress in poland

terrestrial permian triassic boundary in southern china new stratigraphic structural and palaeoenvironment considerations the permian triassic boundary is located above the main phanerozoic terrestrial and marine biotic crisis southwest china eastern yunnan and western guizhou is considered as an ideal place in asia to study the terrestrial permian triassic boundary its correlation with the stratigraphically equivalent marine deposits and to discuss the contemporaneity between the marine and terrestrial extinctions the chahe and zhejue sections which have already been studied in detail especially using 13c isotopic analyses for both sections and geochronology for the chahe section are considered to be the reference terrestrial sections to discuss changes both through time and space in macroflora pollen diversity and paleoenvironment based on new structural analyses of these sections we demonstrate that they have been strongly affected by polyphase deformations and are therefore not suitable to discuss the vertical and or lateral evolutions of the depositional environments within the permian triassic succession the use of the chahe and zhejue sections to study the contemporaneity between marine and terrestrial extinction events at the end of the permian in southern china as well as the stratigraphic correlations and the palaeoenvironment reconstitution of western guizhou and eastern yunnan therefore must be reconsidered

the elbe fault system in north central europe a basement controlled zone of crustal weakness abstract the elbe fault system efs is a wnw striking zone extending from the southeastern north sea to southwestern poland along the present southern margin of the north german basin and the northern margin of the sudetes mountains although details are still under debate geological and geophysical data reveal that upper crustal deformation along the elbe fault system has taken place repeatedly since late carboniferous times with changing kinematic activity in response to variation in the stress regime in late carboniferous to early permian times the elbe fault system was part of a post variscan wrench fault system and acted as the southern boundary fault during the formation of the permian basins along the trans european suture zone sensu geol mag 134 5 1997 585 the teisseyre tornquist zone ttz most probably provided the northern counterpart in a pull apart scenario at that time further strain localisation took place during late mesozoic transtension when local shear within the elbe fault system caused subsidence and basin formation along and parallel to the fault system the most intense deformation took place along the system during late cretaceous early cenozoic time when the elbe fault system responded to regional compression with up to 4 km of uplift and formation of internal flexural highs compressional deformation continued during early cenozoic time and actually may be ongoing the upper crust of the elbe fault system which itself reacted in a more or less ductile fashion is underlain by a lower crust characterised by low p wave velocities low densities and a weak rheology structural seismic and gravimetric data as well as rheology models support the assumption that a weak stress sensitive zone in the lower crust is the reason for the high mobility of the area and repeated strain localisation along the elbe fault system

salt redistribution during extension and inversion inferred from 3d backstripping abstract a 3d backstripping approach considering salt flow as a consequence of spatially changing overburden load distribution isostatic rebound and sedimentary compaction for each backstripping step is used to reconstruct the subsidence history in the northeast german basin the method allows to determine basin subsidence and the salt related deformation during late cretaceous early cenozoic inversion and during late triassic jurassic extension in the northeast german basin the deformation is thin skinned in the basinal part but thick skinned at the basin margins the salt cover is deformed due to late triassic jurassic extension and late cretaceous early cenozoic inversion whereas the salt basement remained largely stable in the basin area in contrast the basin margins suffered strong deformation especially during late cretaceous early cenozoic inversion as a main question we address the role of salt during the thin skinned extension and inversion of the basin in our modelling approach we assume that the salt behaves like a viscous fluid on the geological time scale that salt and overburden are in hydrostatical near equilibrium at all times and that the volume of salt is constant because the basement of the salt is not deformed due to decoupling in the basin area we consider the base of the salt as a reference surface where the load pressure must be equilibrated our results indicate that major salt movements took place during late triassic to jurassic e w directed extension and during late cretaceous early cenozoic nne ssw directed compression moreover the study outcome suggests that horizontal strain propagation in the salt cover could have triggered passive salt movements which balanced the cover deformation by viscous flow in the late triassic strain transfer from the large graben systems in west central europe to the east could have caused the subsidence of the rheinsberg trough above the salt layer in this context the effective regional stress did not exceed the yield strength of the basement below the rheinsberg trough but was high enough to provoke deformation of the viscous salt layer and its cover during the late cretaceous early cenozoic phase of inversion horizontal strain propagation from the southern basin margin into the basin can explain the intensive thin skinned compressive deformation of the salt cover in the basin the thick skinned compressive deformation along the southern basin margin may have propagated into the salt cover of the basin where the resulting folding again was balanced by viscous salt flow into the anticlines of folds the huge vertical offset of the pre zechstein basement along the southern basin margin and the amount of shortening in the folded salt cover of the basin indicate that the tectonic forces responsible for this inversion event have been of a considerable magnitude

permian triassic extinction organic δ13c evidence from british columbia canada the permian triassic p t extinction is documented geochemically in a marine sequence deposited in a basinal setting at williston lake northeastern british columbia by using elemental and isotopic organic geochemical data from well preserved sedimentary rocks the 13 c values of kerogens in the rocks exhibit a sudden shift at the p t boundary from latest permian values of 29 1 pdb to a minimum of 32 6 2 m above the p t boundary and then back to the permian value 4 m above the p t boundary after considering various factors we conclude that reduced surface water primary productivity following the p t mass extinction is largely responsible for the observed 13 c shift the abruptness of the 13 c shift in a sequence of continuous deposition argues that the strong pulse of extinction at the p t boundary was sudden rather than gradual marine primary productivity did not recover until at least 50 to 100 ka after the time of the p t boundary so a higher atmospheric p co 2 in the earliest triassic may have resulted from buildup of dissolved co 2 owing to reduced photosynthetic carbon demand in the surface water

taxonomic and ecological variations of permian triassic transitional bivalve communities from the littoral clastic facies in southwestern china abstract immediately after the latest permian mass extinction bivalve faunas colonized the permian triassic transitional beds pttb especially in littoral clastic facies of south china the permian triassic p tr transitional bivalve fauna is composed of holdovers long term survivors and newly evolved taxa and characterized by moderate diversity and high dominance however the taxonomy and ecology of this bivalve fauna of littoral clastic facies have not been well understood especially in comparison with offshore marine records this paper presents a study on a p tr transitional bivalve fauna from five sections of littoral clastic facies in southwestern china and as such it contributes to a better knowledge of the ecological processes of benthic communities during the p tr transition in total 20 species in 13 genera of bivalves are identified from the pttb in the lower part of the kayitou formation and the basal part of the feixianguan formation of the five sections cluster analysis suggests that the transitional bivalve fauna could be further divided into two successive communities early and late communities and each is composed of five assemblages promyalina neoschizodus community early community is characterized by presence of holdover taxa high taxonomic diversity and evenness and more abundant shallow infaunal suspension feeders in pteria community late community taxonomic diversity and evenness are much lower and stationary epifaunal suspension feeders boost at the expense of shallow infaunal suspension feeders compared with the promyalina neoschizodus community furthermore the promyalina neoschizodus community shows a clear spatial variation along environmental gradient from brackish lagoon to shallow marine settings while the pteria community is more uniform and homogeneous laterally the promyalina neoschizodus community in the studied region is of latest permian age while the pteria community should belong to the earliest triassic consequently a significant taxonomical and ecological turnover of bivalve communities occurred between the promyalina neoschizodus community and the pteria community during the extinction interval in southwestern china

tracing tectonic deformation using the sedimentary record the study of sediments and sedimentary basins in terms of their tectonic environment requires a multidisciplinary approach and has increasingly drawn both techniques and objectives from fields outside sedimentology the application of different theoretical experimental and empirical resources provided by structural geology geochemistry geophysics scale modelling and field geology complement sedimentological methods with the combined aim of achieving a deeper understanding of the origins evolution and significance of sedimentary sequences in terms of their tectonic history studies presented in this volume range across a wide spectrum from the analysis of sedimentary sequence architecture at basin scale down to the chemical properties of individual grains and include studies from a range of tectonic settings the volume will be of interest to those involved with or contemplating studies involving the linkages between tectonics and sedimentation as well as a wider audience to whom the results of such studies may provide fresh insight

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

the interplay between massive volcanism and the local environment geochemistry of the late permian mass extinction across the sydney basin australia abstract the isotopic geochemical and physical characteristics of the late permian mass extinction have been identified and assessed from terrestrial sections across the sydney basin eastern australia these new data are used to both correlate the extinction event across the basin and elucidate its cause two stratigraphically well constrained cores were examined one each from the northern and southern regions of the sydney basin both sections show uninterrupted transitions from the last permian coal to a carbonaceous shale overlain by siltstones mudstones sandstones and shales whose mineralogical and physical characteristics are consistent with non marine origins these non marine origins are also broadly supported by elemental data carbon isotopic data were the primary means for identifying the stratigraphic position of the late permian mass extinction across the basin the data show that the mass extinction occurred as an interval with the form of a closely spaced double negative 13corg excursion within 1 m of the top of the last permian coal a feature previously unrecognised in the basin this result is supported by coincident excursions in 15n and 34spyrite the first measurements of their kind for the late permian mass extinction in the sydney basin the interrelationships between the c n and s isotopic data concentrations and elemental ratios together with major trace and rare earth element concentrations ratios and statistical analyses show severe environmental disruption occurred at the time of the extinction event with die off of terrestrial vegetation and the injection of sulphate into the water column consistent with massive volcanism geochemical evidence also shows however that local conditions have the potential to disrupt the late permian mass extinction signature and hence the data need to be interpreted carefully

successive episodes of normal faulting and fracturing resulting from progressive extension during the uplift of the holy cross mountains poland conjugate normal faults extension fractures and mesh fracture structures were investigated in devonian carbonate rocks from the southern part of the holy cross mountains hcm central poland strata folded during variscan deformations were later subject to uplift resulting in increasing extension in the upper part of the rock mass at a relatively shallow depth faults and fractures developed in an orderly vertical succession first mesh fracture structures and conjugate normal fault sets enclosing acute dihedral angles 2 of over 45 were formed next conjugate normal faults with 2 less than 45 and sub vertical extension fractures developed the occurrences of conjugate normal sets enclosing different dihedral acute angles and extension fractures with similar strikes juxtaposed with each other at the same stratigraphic level point to the fact that the uplifted rock mass underwent successive changes in a stress regime leading to the formation of these structures the first sets of conjugate normal faults and fractures developed when the hcm were uplifted during a late stage of variscan deformations the next sets of extension fractures and conjugate normal faults developed during the following uplift events interrupted by periods of sedimentation of the mesozoic and younger strata

high resolution terrestrial permian triassic eventostratigraphic boundary in western guizhou and eastern yunnan southwestern china the adjoining area of western guizhou and eastern yunnan provinces in southwest china is an ideal place to investigate the feasibility of correlating marine and nonmarine permian triassic boundary ptb sequences as it contains outcrop sections of shallow marine marginal marine or paralic and terrestrial ptb sections all in close geographic proximity this paper documents for the first time multiple stratigraphic data from several well preserved terrestrial ptb sections in the area and attempts to use these data to define locate and correlate the ptb in the area a study of the spores and pollen and vegetation types across the terrestrial ptb sections in the study area suggests three distinct evolutionary stages across the boundary stage 1 xuanwei formation is characterised by late permian or paleozoic type ferns and pteridosperms 85 0 with a few gymnosperms 15 0 stage 2 is marked by an abrupt drop of sporopollen elements of late permian aspects coupled with the appearance of fungal spores and limited early triassic palynomorphs stage 3 top xuanwei formation and kayitou formation is dominated by gymnosperm pollen 58 8 of clearly early triassic aspect although still retaining limited ferns and pteridosperms the three biotic stages seem to well correspond with the changing trend of the 13corg curves from the same sections which is characterized by a sharp drop just before the ptb followed by a short term partial recovery across the boundary and then succeeded by a gradual decline after the ptb in the early triassic combining evidence from eventostratigraphic i e the succession of boundary clay beds biostratigraphic using both macroplants and palynomorphs and chemostratigraphic i e organic carbon isotope excursion signals we propose that a high resolution ptb succession closely correlatable to its marine counterpart at the meishan section in eastern china is recognisable at the terrestrial ptb sections in the western guizhou eastern yunnan area in southwest china

geochemical consequences of the permian triassic mass extinction in a non marine succession sydney basin australia abstract the identification of the permian triassic boundary ptb and permian triassic mass extinction event ptme in eastern australia is based primarily on palynological and plant fossil evidence with limited 13 c org data from the northern part of the sydney basin consequently the ptb in the sydney basin has been placed at the top of the last permian coal measures here we report carbon and nitrogen isotopic data together with major element trace element and mineralogical data for a continuous non marine permian triassic p tr section from the southern sydney basin the ptme is identified by a negative shift in 13 c org of 3 8 occurring approximately 1 m above the bulli coal seam lack of correlation between 13 c org and toc indicates that the isotopic signature has not been affected by contamination or diagenetic processes the interrelationships between c n and s data indicate severe environmental disruption and increased weathering at the time of the extinction event with die off of terrestrial vegetation and the injection of sulphuric acid into the water column positive excursions in ni cr and co are coincident with the negative 13 c org shift and are most consistent with a reduction in oxygen availability due to a major volcanic eruption

the glueckstadt graben a sedimentary record between the north and baltic sea in north central europe abstract the glueckstadt graben is one of the deepest post permian structures within the central european basin system and is located right at its heart at the transition from the north sea to the baltic sea and from the lower saxony basin to the rynkoebing fyn high the mesozoic to recent evolution is investigated by use of selected seismic lines seismic flattening and a 3d structural model a major tectonic event in the latest middle late triassic keuper was accompanied by strong salt tectonics within the glueckstadt graben at that time a rapid subsidence took place within the central part which provides the core of the glueckstadt graben the post triassic tectonic evolution of the area does not follow the typical scheme of thermal subsidence in contrast it seems that there is a slow progressive activation of salt movements triggered by the initial triassic event starting with the jurassic the subsidence centre partitioned into two parts located adjacent to the triassic core in comparison with other areas of the central european basin system the glueckstadt graben was not strongly affected by additional jurassic and cretaceous events during the late jurassic to early cretaceous the area around the glueckstadt graben was affected by relative uplift with regional erosion of the elevated relief however subsidence was reactivated and accelerated during the cenozoic when a strong subsidence centre developed in the north sea during paleogene and quaternary neogene the two centres of sedimentation moved gradually towards the flanks of the basin the data indeed point toward a control of post permian evolution by gradual withdrawal of salt triggered by the initial exhaustion along the triassic subsidence centre in this sense the glueckstadt graben was formed at least partially as basin scale rim syncline during post permian times the present day hamburger east and westholstein troughs are the actual final state of this long term process which still may continue and may play a role in terms of young processes and e g for coastal protection

the spatial nearshore offshore distribution of latest permian phytoplankton from the yangtze block south china abstract in order to analyze the spatial paleoecological distribution of the organic walled microphytoplankton in the late permian five sections from the yangtze block south china displaying different sediment facies types from neritic to offshore paleoenvironments including basinal facies have been investigated palynologically based on the diversity and relative abundance of acritarch species and genera the new data from the permian provide similar patterns as those described from other geological periods 1 low diversities with 2 to 4 acritarch species occur in nearshore environments whereas the higher diversities more than ten acritarch species appear in the offshore environments 2 at the generic level the genera leiosphaeridia reduviasporonites and micrhystridium are distributed widely from nearshore facies corresponding to shallow water environments to offshore facies corresponding to deeper water settings whereas some genera such as dictyotidium and veryhachium have a narrower distribution occurring on the continental shelf and towards the basin indicating open marine environments 3 the genus schizosporis only occurs around the permian triassic boundary ptb when the sea level declined probably indicating nearshore environments with shallow water settings 4 at the specific level the species micrhystridium breve displaying short spines and leiosphaeridia minutissima are indicative of neritic facies whereas the other species of micrhystridium and veryhachium with longer spines e g micrhystridium stellatum and veryhachium hyalodermum and leiosphaeridia microgranifera indicate more open marine environments big spherical acritarch species over 80 m in diameter such as dictyotidium reticulatum indicate shallow water environments and 5 in the ptb strata the relative abundance of the enigmatic reduviasporonites interpreted by some authors as a fungal spore is not higher than 14 in every sample indicating that a spike of reduviasporonites does not occur in the yangtze area reduviasporonites chalastus 40 m in length obviously dominates in shelf environments of shallow water whereas the smaller reduviasporonites catenulatus 15 m in length are more common in deeper water

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

style and evolution of salt pillows and related structures in the northern part of the northeast german basin the northern part of the northeast german basin contains a large number of late permian zechstein salt pillows whereas diapiric structures are almost completely absent this lack of diapirs facilitated the study of early stages of salt movement in the basin salt pillows and related structures were investigated in terms of distribution geometry and time of initiation of salt flow within the regional geological context the primary zechstein thickness in the study area was reconstructed to gain more insight into the relationship between the geometry of the salt layer and the style of the salt related structures in this study no clear spatial relationship between the salt structures and basement faults has been found and the location of the salt structures in this area appears to be highly independent of the underlying structural grain the overburden is affected by minor faulting we propose that buckling of the overburden due to regional compression significantly contributed to the initiation of the late jurassic to early cretaceous salt structures in the basin reverse faulting of the gardelegen and haldensleben faults is related to inversion tectonics and exerted a compression on the basin fill during the deformation the late permian salt layer acted as an efficient detachment and led to a marked decoupling of the mesozoic overburden from the underlying pre zechstein rocks

compressional intra plate deformations in the alpine foreland an introduction abstract the recognition of the basin inversion phenomenon dates back to the 1920 s and 1930 s the true scope of the latest cretaceous and cenozoic basin inversions became apparent only in the 1970 s it is proposed that these intra plate deformations are related to compressional stresses exerted on the foreland during the alpine orogeny

rapid and synchronous collapse of marine and terrestrial ecosystems during the end permian biotic crisis a newly studied permian triassic p tr boundary section in jameson land east greenland contains an abundant and well preserved marine fauna as well as terrestrial palynomorphs for the first time it is possible to compare the biotic crises of the marine and terrestrial realms using the same samples from the same section the sediments record a negative excursion in 13 c carb values of 8 9 and in 13 c org values of 10 11 the presence of the conodont hindeodus parvus combined with the 13 c carb record enables correlation with the proposed global stratotype section at meishan this shows that the greenland section is the most expanded p tr section known collapse of the marine and terrestrial ecosystems took between 10 and 60 k y it took a further few hundred thousand years for the final disappearance of permian floral elements collapse of the terrestrial and marine ecosystems began at the same stratigraphic level and preceded the sharp negative excursion in the 13 c record

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

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

terrestrial paleoenvironment characterization across the permian triassic boundary in south china well preserved marine fossils in carbonate rocks permit detailed studies of the end permian extinction event in the marine realm however the rarity of fossils in terrestrial depositional environments makes it more challenging to attain a satisfactory degree of resolution to describe the biotic turnover on land here we present new sedimentological paleontological and geochemical x ray fluorescence analysis from the study of four terrestrial sections chahe zhejue mide and jiucaichong in western guizhou and eastern yunnan yangtze platform south china to evaluate paleoenvironmental changes through the permian triassic transition our results show major differences in the depositional environments between the permian xuanwei and the triassic kayitou formations with a change from fluvial lacustrine to coastal marine settings this change is associated with a drastic modification of the preservation mode of the fossil plants from large compressions to small comminuted debris plant fossils spanning the permian triassic boundary show the existence of two distinct assemblages in the xuanwei formation a late permian changhsingian assemblage with characteristic cathaysian wetland plants mainly gigantopteris dictyophylloides gigantonoclea guizhouensis g nicotianaefolia g plumosa g hallei lobatannularia heinanensis l cathaysiana l multifolia annularia pingloensis a shirakii paracalamites stenocostatus cordaites sp is identified in the lowermost kayitou formation an early triassic induan annalepis peltaspermum assemblage is shown associated with very rare relictual gigantopterids palynological samples are poor and low yield samples show assemblages almost exclusively represented by spores a similar to 1 m thick zone enriched in putative fungal spores was identified near the top of the xuanwei formation including diverse multicellular forms such as reduviasporonites sp this interval likely corresponds to the ptb fungal spike conventionally associated with land denudation and ecosystem collapse while the floral turnover is evident further studies based on plant diversity would be required in order to assess contribution linked to the end permian mass extinction versus local paleoenvironmental changes associated with the transition between the xuanwei and kayitou formations c 2014 elsevier ltd all rights reserved less

intensified chemical weathering during the permian triassic transition recorded in terrestrial and marine successions abstract global warming is inferred to have been one of the main causes of the permian triassic p tr boundary mass extinction although a strong temperature rise in tropical sea surface temperatures during the latest permian has been documented coeval climate changes in terrestrial sections are less well known here we analyzed multiple weathering indexes including cia ciw and pia for two terrestrial sections in north china shichuanhe and yima all of which show a major excursion toward higher values greater weathering intensity around the end permian plant extinction eppe at shichuanhe the cia chemical index of alteration increases from 70 to 75 over the interval of 11 36 m which straddles the eppe at 33 m and then decreases from 75 to 71 in the overlying strata at yima cia increases from 63 to 79 over the interval of 57 68 m extending up to the eppe at 68 m and then gradually decreases from 78 to 72 in the overlying strata these results imply a strong warming event coupled with intense chemical weathering in soil environments leading up to the end permian plant extinction the decline in cia values following the eppe may reflect loss of weathered soils through physical erosion rather than climatic cooling estimation of atmospheric temperatures from the cia data indicate rapid rises at shichuanhe from 11 6 c to 16 5 c and yima from 9 3 c to 18 4 c during the end permian crisis the findings in this study are consistent with the hypothesis that a sharp temperature rise caused the extinction of terrestrial organisms during the end permian crisis

tectonic evolution of the mid polish trough modelling implications and significance for central european geology abstract the polish basin forms the easternmost part of the permian mesozoic northwest european basin the depocentral axis of the polish basin the mid polish trough mpt is superimposed on the boundary between the west european phanerozoic and east european proterozoic crustal domains within the trans european suture zone the presence of this fundamental crustal boundary may be paramount in structurally controlling the position of the mpt concentrating stresses during post variscan wrench and extensional tectonics in central europe tectonic subsidence analysis of the preserved and reconstructed stratigraphic record of the polish basin indicates the occurrence of an initial late permian early triassic 255 241 ma rifting phase that was followed by subsequent episodes of increased tectonic subsidence during the oxfordian kimmeridgian 157 152 ma and beginning in the cenomanian 97 ma the oxfordian kimmeridgian episode is interpreted as corresponding to a second extensional event which correlated with intersified rifting and wrench activity within the arctic north atlantic rift system and along the northern tethyan margin while the cenomanian may be considered a precursor of compressional deformations in the basin which culminated in basin inversion in the latest cretaceous and paleocene forward modelling results in view of existing geophysical interpretations which show the presence of a deep moho and a very velocity lower crustal layer beneath thempt suggest that permo mesozoic basic development may be related at least in part to the intrusion of mantle material into and densification of the lower crust rather than exclusively to crustal extension and thinning

salt flow and diapirism related to extension at crustal scale abstract the analysis of the structure and history of salt diapirs in large ancient evaporitic basins such as the southeastern north sea basin suggests that diapirism is controlled by crustal scale extension laboratory experiments on small scale models designed to simulate configurations comparable to the southeastern north sea basin show that diapirs which grow in a sedimentary cover during basement extension can develop close to basement normal faults or at a significant distance from them if the displacement on the basement faults is transfered horizontally along the salt layer for given values of salt viscosity strain rate and friction coefficient in brittle rocks the pattern of salt diapirism in a particular area depends on the ratio of cover thickness to salt thickness as well as the absolute thicknesses of cover and salt layers the experiments give criteria for identifying different types of diapirs and provide models of horizontal flow in a salt layer undergoing extension and diapir development some dynamic implications of the experiments are applied to the southeastern north sea basin

comments on terrestrial permian triassic boundary in southern china new stratigraphic structural and palaeoenvironment considerations by bourquin et al 2018 abstract the terrestrial permian triassic transitional section at chahe in western guizhou province south china has served as a key reference section for the study of terrestrial ptb as well as the end permian mass extinction on land in south china however bourquin et al 2018 recently reported that the ptb interval at chahe has undergone serious tectonic deformation and thus is not suitable for studying the ptb transition or the terrestrial end permian extinction due to an unknown amount of stratigraphy removed displaced by faulting in order to clarify the observations of bourquin et al 2018 we re surveyed the chahe section in further detail recently and our observations suggest that the interpreted deformation by bourquin et al 2018 cannot be verified and it also contradicts the regional litho and bio stratigraphic and chemostratigraphic results we provide detailed outcrop imagery and data for all colleagues who are interested in this section to check our observations

mixed continental marine biotas following the permian triassic mass extinction in south and north china abstract correlation between marine and continental permian triassic p tr strata is crucial for full understanding of the nature of this global extinction event but it has proved difficult to achieve here we show that two sections in south china and north china record similar mixed continental marine biota in the post extinction stratigraphic interval including conchostracans plants insects marine bivalves and lingulid brachiopods in addition the continental p tr mass extinction was represented by a sharp decrease in the diversity and abundance of the gigantopteris flora in south china but eliminated the palaeozoic type conifer flora and herbivorous pareiasaurs in north china these mixed continental marine biota provide the biological evidence for stratigraphic correlation between marine and continental p tr transitional beds in south china and north china especially the co occurrence of the pteria towapteria eumorphotis bivalve assemblage and the euestheria gutta bearing conchostracan fauna or euestheria gutta magniestheria mangaliensis palaeolimnadiopsis vilujensis conchostracan assemblage we propose that these specific marine bivalve and continental conchostracan assemblages could be considered as markers of p tr transitional beds in marine continental siliciclastic settings

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

vegetation changeover across the permian triassic boundary in southwest china extinction survival recovery and palaeoclimate a critical review abstract this paper reviews critically the permian triassic p tr fossil plants and microflora recorded in three well studied terrestrial permian triassic boundary ptb sections namely chahe zhejue and jiucaichong and two marine terrestrial transitional ptb sections namely mide and tucheng in western guizhou province and eastern yunnan province wgey southwest china distinct floral composition abundance and diversity across the ptb allow the establishment of two terrestrial macrofloral assemblages the lobatannularia multifolia gigantoclea guiyangensis l g assemblage was recognized from the upper xuanwei formation while the annalepis peltaspermum a p assemblage from the lower kayitou formation the former flora comprises 105 species in 39 genera and is late changhsingian in age the latter assemblage includes 18 species in 14 genera and is induan in age the changhsingian assemblage is characterized by the loss of many wuchiapingian elements of the gigantopteris flora and an increase of the gymnosperms most of the permian type plant taxa were wiped out in the ptb crisis on land with only few relicts persisting into the early triassic which saw the flourishing of annalepis and common presence of peltaspermum and permian relicts of the gigantopterids during the permian triassic transition some rare gigantopterids elements as well as some peltaspermum representatives survived the biocrisis annalepis a pioneering lycopsid genus in the recovery of the triassic land plants and its proliferation marks the recovery of land plants after the ptb crisis on land in wgey accordingly vegetation changeover across the ptb is marked by a dramatic turnover of plants on land from the permian gigantopteris flora to the triassic annalepis dominated assemblage palynofloras are characterized by a dramatic drop of palynomorphs in both abundance and diversity and show a stepwise extinction pattern moreover macro and microfloras of the wgey region indicate that humid and warm climate regime prevailed through the p tr transition in southwest china the coal forming swamps gradually migrated westward due to marine transgressions throughout the late permian the gigantopteris flora also migrated from east to west and a few species can survive into the earliest triassic in the wgey region but disappeared soon after

the observed dispersion relationship for north pacific rossby wave motions abstract the phase speeds of ocean surface height variability obtained by analyzing the time longitude sections of altimetric anomalies have been widely reported as being generally faster than those of free first baroclinic linear mode flat bottom rossby planetary waves in contrast to previous analyses extraction of the different signals in the time longitude domain is performed here by array processing methods better able to separate different frequency and wavenumber bands although an incomplete description of oceanic variability in the north pacific real oceanic motions with energy levels varying from about 10 to 40 of the total in each frequency band are indistinguishable from the simplest theoretical description at higher latitudes as the linear waves slow they disappear altogether nonequatorial latitudes display some energy with frequencies too high for consistency with linear theory this energy produces a positive bias if a lumped average westward phase speed is computed for all the m

strike slip tectonics within the sw baltic sea and its relationship to the inversion of the mid polish trough evidence from high resolution seismic data abstract the sw baltic sea occupies an area where crustal scale regional tectonic zones of different age merge and overlap creating a complex tectonic pattern this pattern influenced the evolution of the mesozoic sedimentary basin in this area we present an interpretation of new high resolution seismic data from the sw baltic sea which provided new information both on modes of the late cretaceous inversion of this part of the danish polish mesozoic basin system as well as on relationship between tectonic processes and syn tectonic depositional systems within the bornholm darlowo fault zone located between the koszalin fault and christianso block both strike slip and reverse faulting took place during the inversion related activity the faulting was related to reactivation of extensional pre permian fault system syn tectonic sedimentary features include a prominent generally s and se directed progradational depositional system with the major source area provided by uplifted basement blocks in particular by the bornholm block sediment progradation was enhanced by downfaulting along a strike slip fault zone and related expansion of accommodation space closer to the christianso block some syn tectonic deposition also took place and resulted in subtle thickness changes within the hinge zones of inversion related growth folds lack of significant sediment supply from the inverted and uplifted offshore part of the mid polish trough suggests that in this area nw se located marginal trough parallel to the inversion axis of the mid polish trough did not form and that uplifted bornholm block played by far more prominent role for development of syn inversion depositional successions

an integrated study of the ne german basin abstract the ne german basin is part of the southern permian basin south of the transeuropean suture zone tesz here we report an attempt to integrate a variety of geological and geophysical data in order to reveal the present day deep crustal structure of the ne german basin special focus is taken on detailed geological information available reflection seismic data wide angle refraction seismic data and gravity data based on this integrative approach a concise crustal model is developed which can be subject to further evaluation furthermore it is shown that the ne german basin is an outstanding feature quite different from classical basin types as the moho is flat below the basin neither a simple shear nor a pure shear extension model can be applied instead a thick high velocity lower crustal layer is present below the basin centre this high velocity lower crust is also observed in the western part of the basin and can be taken as characteristic for east avalonia results of gravity modelling indicate the presence of a high density lower crust thus supporting the wide angle data furthermore changes in crustal structure can be derived from changes in reflectivity pattern and from the gravimetric signature along the elbe fault system indicating the presence of different crustal domains north and south of the fault system an elastic plate model where the forces applied are the sediment load a vertical load at the southern margin accounting for the harz moutains and a nne ssw directed compression indicates a buckling of the crust during late cretaceous to tertiary inversion however the correlation between the observed crustal structure and the tectonic events that have affected the area remains a subject of discussion a permian thermal event affected the upper mantle and the lower crust and therefore may have modified the crustal memory with regard to caledonian and variscan events additional tectonic events affected the area during the mesozoic in conclusion it remains an open question whether the high velocity and high density lower crustal structure represents a remnant of east avalonia whether it is related to the formation of the permo triassic basin or is the cumulative result of a series of events during the palaeozoic and mesozoic

parallel trends in organic and inorganic carbon isotopes across the permian triassic boundary stable carbon isotope ratios in both inorganic and organic reservoirs have been widely applied to model environmental and sedimentological changes on a global scale most studies dealing with major extinction events have used the record of inorganic carbon in this paper the authors report the relation between shifts in carbon 13 content of organic matter and coexisting carbonate fractions at a major extinction event the permian triassic boundary they found that both delta sup 13 c sub carb and delta sup 13 c sub org of the surface ocean varied dramatically across the boundary but the fractionation delta sup 13 c between organic matter and carbonate remained constant this result appreciably restricts the interpretation of changes in the carbon cycle during this critical interval the new data are best explained by a combination of two mechanisms for variation in delta sup 13 c sub carb 1 burial and erosion of organic carbon with a long time constant and 2 sequestration of organic carbon into shallow and deep oceanic reservoirs with a shorter time constant for application to their case the first mechanism is limited by possible buildup of marine pco sub 2 which would increase the isotopic fractionation factor the second mechanism is limited in application to short term transient variations in delta sup 13 c modelingmore of the carbon cycle and its variations of delta sup 13 c must take both mechanisms into account less

palynological assemblages of non marine rocks at the permian triassic boundary western guizhou and eastern yunnan south china abstract marine and non marine facies of the permian triassic boundary stratigraphic set ptbst are well developed in south china palynological assemblages enable subdivision and correlation of the permian triassic boundary ptb rocks three palynological assemblages are recognized across the ptbst in two terrestrial ptb sections in western guizhou and eastern yunnan south china assemblage 1 xuanwei formation is a late permian palynological assemblage dominated by ferns and pteridosperms with minor gymnosperms most taxa are typical long ranging paleozoic forms but the appearance of lueckisporites confirms a late permian age for this assemblage assemblage 2 ptbst is marked by an abrupt decrease in palynomorph abundance and diversity and thriving fungal algal spores assemblage 2 is still dominated by ferns and pteridosperms with a few gymnosperms but is characterized by a mixed palynoflora containing both late permian and early triassic elements most taxa are typical late permian ones also found in assemblage 1 however some taxa of early triassic aspect e g lundbladispora and taeniaesporites appeared for the first time in assemblage 3 top xuanwei formation and kayitou formation the proportion of gymnosperm pollen increases rapidly exceeding that of ferns and pteridosperms but the abundance of palynomorphs is still low typical early triassic taxa such as lundbladispora aratrisporites and taeniaesporites are present in greater abundance and confirms an early triassic age for this assemblage

reply to the comment on terrestrial permian triassic boundary in southern china new stratigraphic structural and palaeoenvironment considerations by h zhang z feng j ramezanik s z shen abstract in their comment zhang et al 2018 question the existence of the deformation structures that we report for the upper part of the chahe permian triassic boundary reference section these authors further suggest that this deformation contradicts the regional litho bio and chemostratigraphic results here again and based on the outcrop picture provided by zhang et al 2018 we present new arguments attesting for a major tectonic deformation in the upper part of the chahe section we argue that the color pattern of the outcrop the flora description the 13corg isotope profile showing a negative excursion and the lack of coal bed in the upper part of series cannot be used as definitive arguments for a continuous succession in consequence we maintain that above bed 66 the succession is affected by numerous fold accommodation faults preventing any continuous logging and coherent stratigraphic analysis in the kayitou and dongchuan formations along that section

carbon isotope and iridium event markers near the permian triassic boundary in the meishan section zhejiang province china abstract systematic investigations for carbon isotopes and iridium of the meishan section were carried out using very narrow sampling intervals the high resolution results demonstrate the following characteristics 1 a large drop in 13c 7 cm above the base of the triassic with a magnitude of about 6 2 a sharp ir peak of 2 02 ppb 10 cm above the base of the triassic whereas the ir mean of six samples equals 0 4 ppb the large negative carbon isotope shift the ir anomaly within a thin sublayer and microspherules all occur within a 20 cm thick section above the base of the triassic which has been defined to coincide with an abrupt facies change from carbonate to clay the geochemical results and the microspherules suggest that the permian triassic boundary event was catastrophic and probably caused by an extraterrestrial impact

characteristics of claystones across the terrestrial permian triassic boundary evidence from the chahe section western guizhou south china abstract x ray diffraction xrd scanning electronic microscopy sem and x ray fluorescence spectroscopy xfs studies were undertaken for claystones and or mudstones from the chahe section a terrestrial permian triassic boundary tptb section our results indicate that the compositions of claystones in the permian triassic boundary ptb interval beds 66f 68 outlined by biostratigraphy are different from claystones and or mudstones found either below or above the interval of the same section the clay minerals in the claystones of the ptb interval are mainly composed of illite montmorillonite interlayers with a few montmorillonites and chlorites the other claystones and or mudstones underlying and overlying the ptb consist of chlorites and or kaolinites some authigenic clastic minerals such as hexagonal dipyramid quartz and zircons are only found in claystones in the ptb interval from the chahe section and some marine ptb sections in western guizhou and eastern yunnan southwestern china in addition some elements are present in abnormal concentrations in the claystones of the ptb interval as well most important is that we found no spherules in all the claystones studied indicating no evidence of an extraterrestrial impact during the permian triassic transition the particular characteristics of the tptb claystones at the chahe section indicate their volcanic origin and thus provide a reliable auxiliary event marker for high resolution demarcation of the tptb in south china they are also indicative in the marine ptb claystones in south china thus the ptb claystones can be used as auxiliary markers for high resolution correlation of the ptb from marine facies to land in south china when direct fossil evidence in the ptb sequence is lacking

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

inversion related features along the southeastern margin of the north german basin elbe fault system abstract a seismostratigraphic approach constrained by well data is used for the interpretation of the deformation style along the central elbe fault system efs within the sedimentary succession structural analysis allows to qualify to quantify and to date tectonic events the stratigraphic interpretation is complicated by the mobilized upper permian zechstein salt and by erosional events a first order quantification of the inversion related uplift is estimated from vertical fault offsets that reach up to 4 km the main uplift occurred during the maastrichtian paleocene amounts of erosion inferred from comparing the strata thickness on top of the flechtingen high with the surrounding basinal areas range from 3 to 4 km the data indicate a changing deformation style thick skinned deformation with southwest dipping thrusts that vertically offset the pre permian basement is observed along the flechtingen high in the central part of the efs thin skinned deformation occurs in the north german basin where salt detaches the post permian cover from the barely faulted basement it is concluded that during the late cretaceous early tertiary inversion the efs responded to regional compression with uplift and formation of an internal high the flechtingen high a stress sensitive crustal weak zone beneath the efs could be the reason for the repeated strain localization in the area

records of terrestrial sulfur deposition from the latest permian coals in sw china abstract different sulfur fractions of low sulfur average 0 11 coals from the latest permian in southwestern china were analyzed isotopically at a high vertical resolution to examine the ramifications for potential terrestrial extinction mechanisms at the permo triassic boundary s org organic sulfur accounts for 87 of the total sulfur content on average while s py pyritic sulfur is very low 13 of the total sulfur content and ca 0 01 of the whole sample weight and relatively constant throughout the profile except for some insignificant additions in clay rich layers these indicate the possible differential contribution of local diagenesis during the early stages of peat accumulation the 34 s org values have a relatively narrow range from 1 5 to 7 6 while the 34 s py values have a wider range from 0 8 to 34 1 suggesting that pyrite was possibly formed in different stages and that there was negligible bacterial contribution to the primary organic sulfur fraction thus the organic sulfur signal in the coal is largely sourced from the original plant material and records temporal variations in the isotopic composition of the sulfur input to the coal forming environment the stratigraphically lower coal b3 has 34 s org values around 4 while the stratigraphically higher coal b2 which is closer to the permian triassic boundary has clearly higher 34 s org values ranging from 5 3 to 7 6 this change is most likely due to increased marine sulfate aerosol inputs into the coal forming peatland caused by coastline retreat during late permian transgression importantly there is no evidence in these discrete intervals of coal formation to indicate a dominant role of atmospheric inputs of isotopically lighter sulfur from either h 2 s released from euxinic oceans or volcanic so 2 this militates against theories that implicate such sources of sulfur in terrestrial extinction mechanisms at the end permian

geometry of thin skinned tectonic systems in relation to detachment layer thickness in sedimentary basins characterizing features of both extensional and compressional thin skinned systems may be controlled by the thickness of the underlying mobile material within extensional fault arrays detachment layer thickness in conjunction with detachment dip controls variations in fault spacing and polarity because rigid fault blocks are only free to rotate as long as there is enough underlying mobile material to redistribute between the fault block keels different styles of extensional fault array range from single polarity arrays with closely spaced faults thin detachment to arrays where the fault blocks rotate until the fault blocks separate from one another thick detachment departure from this relationship depends on the amount of internal deformation that can be sustained by the domino fault blocks within contractional zones detachment folds occur where the amount of mobile material can fill the evolving fold core via redistribution thrusts occur where there is insufficient mobile material to sustain detachment fold growth the variations in extensional and contractional style that are described here in relation to mobile layer thickness can be combined to give an idealized model of regional variation in structural style in relation to regional variation in stratigraphy applying this model to a salt basin an allochthon in the area of thickest salt may be characterized by updip raft tectonics and downdip detachment fold belts this style would be laterally transitional toward areas of thinner or lower net salt to updip domino fault arrays and downdip thrust systems