identification of diagenetic artifacts in foraminiferal shells using carbon and oxygen isotopes abstract we have analyzed carbon and oxygen isotopes of two groups of planktonic foraminiferal shells from sediments near the pliocene pleistocene p p and the miocene pliocene m p boundaries in the lower gutingkeng formation in southwestern taiwan the p p shells display heavier isotopic compositions 18 o 1 5 13 c 1 5 over a narrow range suggesting a pristine environmental signature on the other hand the m p shells are much lighter 18 o 3 to 7 13 c 1 to 1 5 and more scattered associated with secondary carbonate diagenesis our detailed sem examination confirms this proposition the p p shells display a clean micro texture and are free from carbonate recrystallization however there are abundant secondary calcite crystals in the m p shells therefore the extreme shift of 18o and 13c in foraminiferal shells provides a guideline for evaluation of diagenetic artifacts of deeply buried sediments that have been uplifted on land

evolution and distribution of the conodonts sweetognathus and iranognathus and related genera during the permian and their implications for climate change abstract the conodont genus sweetognathus which is characterized by pustulose ornamentation on a wide flat topped carina originated in the earliest permian as s expansus from diplognathodus edentulus the asselian through artinskian part of the sweetognathus lineage is well represented in kansas by the successive evolution of s expansus s merrilli s aff s merrilli s whitei and s bucaramangus sweetognathus and iranognathus lineages were mainly confined to tropical areas from the kungurian onward the kungurian and guadalupian part of the sweetognathus lineage is well represented in south china by the successive evolution of s whitei artinskian s guizhouensis lower kungurian s subsymmetricus upper kungurian s iranicus hanzhongensis roadian and s fengshanensis capitanian an additional lineage in west texas is represented by the evolution of s sulcatus to s aff adjunctus to s adjunctus and to s bicarinum in the urals and northwestern pangea the late part of the sweetognathus lineage is represented by rare specimens of s bogoslovskajae upper artinskian lower kungurian during the late artinskian s whitei radiated into s toriyamai and s bucaramangus and also gave rise to neostreptognathodus pequopensis and probably pseudosweetognathus costatus neostreptognathodus exsculptus may have evolved from adetognathus paralautus through adetognathus telfordi sp nov iranognathus characterized by a narrow carina with poorly developed denticles and bearing subtle and smaller pustulose micro ornament replaced sweetognathus at or near the guadalupian lopingian boundary it probably also evolved from diplognathodus in the topmost guadalupian a lineage of iranognathus sp nov a to i erwini can be recognized for the guadalupian and lopingian boundary interval a lineage of iranognathus sp nov a to i movschovithschi to i sosioensis to i tarazi is found throughout the guadalupian and lopingian boundary interval and the wuchiapingian of south china sweetognathus and iranognathus tend to develop homeomorphic accessory nodes iteratively during lowstand periods of global sea level near the artinskian kungurian and guadalupian lopingian boundaries and in the late wuchiapingian sweetognathus and iranognathus seem to be equatorial warm water inhabitants distribution patterns reflect glaciation in gondwana during the asselian and sakmarian a warm climate during the artinskian cooling in north pangea during the kungurian and later permian slight amelioration during the guadalupian warming during the wuchiapingian and cooling during the changhsingian in the peri gondwana region definitions for most of the important sweetognathus species are refined three new species and subspecies iranognathus sp nov a adetognathus telfordi sp nov gullodus duani sp nov are described

llandovery silurian conodont provincialism an update based on quantitative analysis abstract the llandovery conodont provincialism is reassessed based on a larger dataset than that which was available in 1990 the study interval is divided into two time units the pre telychian and telychian three quantitative methods are adopted in the biogeographic analysis including cluster analysis non metric multidimensional scaling and minimum spanning tree in the pre telychian interval four provinces can be recognized i e the north american baltic siberian timan severnaya zemlya australian and yangtze provinces however only three provinces can be recognized in the subsequent telychian interval the timan severnaya zemlya province existed also in this time interval but austria and australia are combined with the pre telychian north american baltic siberian province and form a new province the baltic austrian siberian australian north american province basan province while tibet and the pre telychian yangtze province form the chinese province the conodont richness shows a latitudinal or temperature dependent gradient the conodont fauna was most diverse in the lower latitudes tropical arid and partly warm temperate climatic zones however the provincialism of the llandovery conodont faunas demonstrates a longitudinal pattern which cannot be the result of any latitudinal factors such as temperature but could be controlled by longitudinal factors probably by the circulation of ocean currents the circulation pattern can also explain the formation of the telychian basan province which probably resulted from the rheic and panthalassa ocean gyres according to the conodont provincialism and the distribution of taxa five types of conodont species can be recognized including limitedly distributed species basan species equatorial species shallow sea realm species and cosmopolitan species the conodont fauna showed a significant change in provincialism from the ordovician to the silurian i e from a latitudinal pattern to a longitudinal pattern the hirnantian glaciation may be one of the controlling factors which resulted in the reorganization of the conodont faunas and the change of their living habits and ecological requirement

wuchiapingian early lopingian permian global brachiopod palaeobiogeography a quantitative approach abstract a global presence absence database of 212 wuchiapingian early lopingian permian brachiopod genera from 30 stations is analysed by cluster analysis nonmetric multidimensional scaling and minimum spanning tree to document the global palaeobiogeographical patterns five core groups are revealed by the quantitative analysis and interpreted as representing five marine biotic provinces they are the cathaysian tropical western tethyan tropical himalayan warm temperate austrazean cold temperate and greenland svalbard provinces cold temperate the cathaysian province is composed of many isolated or semi isolated islands situated in the palaeotethys whereas the other four provinces occurred mainly on the continental shelves of pangea the western tethyan province along the western coast of the palaeotethys the himalayan province on the northern margin of gondwanaland the austrazean province along the southeastern margin of gondwanaland and the greenland svalbard province on the northern margin of pangea in addition nonmetric multidimensional scaling helped to identify key biogeographic determinants latitude related thermal gradient appears to have accounted for most of the variance in the data geographic distance and ocean circulation may have also played a major but subordinate role in the delineation and or enhancement of some of the provinces comparison with early and middle permian global marine provincialism indicates that marine biotic provinces had significantly reduced during the lopingian late permian in the lead up to the end permian mass extinction

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

early permian location of western north american terranes based on brachiopod fusulinid and coral biogeography abstract brachiopod rugose coral and fusulinid faunas present in early permian rocks along northern and western margins of north america in both cratonal localities and accreted terranes have been compared statistically allowing refinement in placement of these terranes relative to the north american continental margin at that time statistical tests including conventional and probabilistic indices of similarity as well as multivariate analysis show that the faunas of wrangellia alexander are most similar to those of stikinia and quesnellia and to the yukon canadian rocky mountains part of the continental margin they also show that faunas of the eastern klamath terrane are most similar to those of stikinia quesnellia and the central cordilleran part of the continental margin these results suggest that during the early permian wrangellia alexander was the northernmost of these terranes lying west of the yukon canadian rocky mountains region and the eastern klamath terrane was the southernmost lying west of the central cordillera stikinia and quesnellia were in intermediate positions these relative latitudes are compatible with latitudinal determinations based on paleomagnetic data faunal diversity in the eastern klamath and stikine terranes is similar to that at similar latitudes on the craton whereas diversity in the wrangellia alexander terrane is considerably lower than that of the latitudinally similar yukon canadian rocky mountains area as diversity is in part a function of temperature this may suggest water around the wrangellia alexander terrane was cooler than that along the continental margin therefore we suggest that warm water currents bathed the southern terranes and the southern and central parts of coastal north america whereas cool water currents influenced the northernmost terrane wrangellia alexander revised otsuka similarity coefficients for corals show higher similarities between western north american terranes and the western continental margin than previously published but they still are relatively low this and the overall patterns of similarity and limits on distribution of tethyan corals and fusulinids in the eastern panthalassa suggest that wrangellia alexander stikinia and the eastern klamath terranes were at approximately the same distance estimated at 2000 3000 km from their latitudinally equivalent segments of the north american craton

kurosegawa terrane in southwest japan disrupted remnants of a gondwana derived terrane abstract the kurosegawa terrane is an anomalous disrupted paleozoic and mesozoic lithotectonic assemblage characterized by fragments of continent and continental margins it is located in southwest japan where it lies between two mesozoic subduction complex terranes the kurosegawa terrane is an exotic and far travelled geologic entity with respect to its present position limestones of the kurosegawa terrane formed along a continental margin yield fusulinacean fossils cancellina colania and lepidolina accordingly the kurosegawa terrane was once situated within the colania lepidolina territory in the east tethys panthalassa region at a palaeo equatorial latitude possibly close to the eastern margin of the south china and or indochina east malaya continental blocks these blocks had rifted from gondwana by late devonian they drifted northwards passing through the colania lepidolina territory in mid permian time and amalgamated with the proto asian continent during the late triassic subsequently during the cretaceous parts of the allochthonous continental blocks and their associated tectonic collage were transpressed dispersed and displaced from the southeastern periphery of asia towards the north as a result the kurosegawa terrane is formed as a disrupted allochthonous terrane characterized by a serpentinite melange zone lying between the adjoining mesozoic subduction complex terranes

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

dynamic variation of middle to late ordovician cephalopod provincialism in the northeastern peri gondwana region and its implications abstract middle to late ordovician cephalopod occurrence data from south china and adjacent terranes in the northeastern peri gondwana region are used to define biogeographic provinces several multivariate methods are adopted for biogeographic analysis including cluster analysis non metric multidimensional scaling and network analysis during the middle ordovician three biogeographic provinces in this region are recognized the australia the north china tibet sibumasu nts and the south china altun sa provinces in the late ordovician three provinces with modified geographic ranges may also be recognized as the cephalopods of the tibetan region and sibumasu terrane changed significantly and accordingly they have been included with south china altun to form a south china tarim tibet sibumasu province stts while the other two late ordovician provinces are the australia and the north china provinces the dynamic variation of cephalopod provincialism in the northeastern peri gondwana region may have been controlled by the changing palaeolatitude and differentiated movement of these plates or terranes from the middle through late ordovician

distribution and characteristics of mixed transitional mid permian late artinskian ufimian marine faunas in asia and their palaeogeographical implications abstract the permian marine biogeography of the asian region is characterised by the development of three broad realms boreal tethyan and gondwanan in the early early permian asselian to early artinskian there seems to have existed sharp biogeographical boundaries with no transitional zones between the realms presumably due to the effect of gondwanan glaciation and sharp climatic zonation the mid permian late artinskian to ufimian of the asian region is distinguished by the rise of two broad transitional zones in which mixed marine faunas flourished the northern transitional zone north and northeast china sikhote alin central and northeast japan is characterised by an admixture of both warm water cathaysian and cold temperate boreal genera the southern transitional zone arabian peninsula iran afghanistan the karakorum southeast and central pamir salt range central and northwest tibet shan thai terrane timor and western irian jaya on the other hand is distinguished by incorporating faunal elements of both gondwanan and cathaysian origin the mixed faunas of both transitional zones share several antitropically distributed genera e g monodiexodina lytvolasma and spiriferella and are succeeded by palaeotropical tethyan faunas of late permian age it has been postulated that the mixed mid permian fauna of the northern transitional zone was probably formed in an epicontinental sea which was connected to both the asian tethys and the arctic which facilitated the migration of cathaysian and boreal forms into the epicontinental sea and subsequent faunal mixing the formation of the mixed faunas of the southern transitional zone on the other hand is probably related to the breaking off of the cimmerian blocks from northern gondwana and subsequent drifting into a lower latitudinal zone with geographical proximity to both gondwana and cathaysia during the mid permian

the early triassic ammonoid recovery paleoclimatic significance of diversity gradients ammonoids recovered much faster than other marine shelly invertebrates after the end permian mass extinction based on a refined global data set at the basin level we investigate the paleobiogeographical global latitudinal and longitudinal diversity patterns in terms of climatic changes during the early triassic such analysis differs from already published qualitative or quantitative studies in that it estimates faunal patterns and endemicity at an ecologically meaningful level of spatial resolution i e at the basin level during the early triassic the global first order trend in increasing ammonoid diversity was accompanied by a progressive change from cosmopolitan to latitudinally restricted distributions this led to the emergence of a clear latitudinal diversity gradient during most of the smithian and spathian stages which entails increased steepness of the sea surface temperature gradient during the late early triassic however two brief episodes of ammonoid cosmopolitanism combined with low global diversity interrupted the first order increasing trend at the very beginning of the smithian and at its very end the longitudinal analysis of smithian distributions indicates a westward decrease of diversity within the tethys which faded away during the spathian analysis of endemicity indicates a rapid biogeographical maturing and structuring of faunas concomitant with the edification of the latitudinal diversity gradient

permian gondwana boreal antitropicality with special reference to brachiopod faunas in a reconstructed global permian marine biogeographic framework antitropicality is defined as a biogeographic phenomenon whereby a taxon occurs only in the boreal and gondwanan realms and is lacking completely or nearly so in the intervening palaeoequatorial realm we recognise three types of antitropical distributions bipolar high latitude generally 50 latitude in each hemisphere bitemperate approximately between 30 and 50 latitudes in each hemisphere and a combination of both evidence of permian antitropicality has been reported from almost all major marine invertebrate groups both pelagic or benthic forms and is best known at the generic level although an increasing number of antitropical species have also been recognised antitropicality appears to have occurred throughout most of the permian but its strength varied from stage to stage judging by the number of brachiopod genera shared between the two hemispheres the phenomenon manifests itself most strongly from the sakmarian to the kazanian wordian suggesting a prolonged interval of enhanced biotic interchanges between the gondwanan and boreal realms possible migration pathways and mechanisms are reviewed and discussed among a number of existing scenarios invoked to explain the origin of both modern and geological antitropicality we here present data particularly supporting 1 a south to north stepping stone migratory mechanism via island terranes scattered in the eastern palaeotethys 2 a vicariance model exemplified by the spatio temporal distribution of tomiopsis and 3 a shelf north to south migration along the western coast of the palaeotethys as suggested by sowerbina in addition we also consider dispersal along the western coast of pangea facilitated at times by upwelling systems as an additional migration pathway for intercontinental biotic exchanges during the permian although corroborating data are required at present

palaeomagnetism and palaeogeography of mongolia in the cretaceous permian and carboniferous preliminary data abstract the paper reports on the results of palaeomagnetic stability tests of oriented samples of lithologically different types of cretaceous permian and carboniferous rocks from northern and southern mongolia the permian andesites and tuffites from three localities barun buren tel tin gol and chulut tsagan del have yielded interesting results groups of normally and reversely polarized andesite tuffs were found even within a single outcrop by means of thermal field demagnetization and multicomponent analysis of the magnetization with a view to the number of samples 177 suitable for analysis and the number of localities 9 the reported palaeomagnetic data should be considered as preliminary the interpreted results indicate a different palaeogeographic evolution of northern and southern mongolia relative to the siberian platform and north china in the permian and carboniferous on the other hand similar apparent polar wander paths for north china lin et al 1985 and the studied regions of northern and southern mongolia indicate similar palaeogeographic evolution in the permian to carboniferous

tectonic evolution of the qiangtang block northern tibet during the late cisuralian late early permian evidence from fusuline fossil records abstract the tectonic evolution of the qiangtang block in the qinghai tibetan plateau has been a controversial subject for a long time in this paper the discovery of new stratigraphic and fusuline fossil evidence from the permian sequences qudi and lugu formations of the qiangtang block is reported and the palaeogeographical position and tectonic history of this block during the late cisuralian late early permian are discussed the qudi formation is typified by thick turbidite deposits and contains artinskian fusulines such as pseudofusulina and chalaroschwagerina the fusulines were deposited as grains involved in debris flow deposits suggesting a synchronicity with the depositional time of the turbidites the subsequent lugu formation is dominated by seamount type carbonates with an irregular basalt base fusulines cancellina pseudodoliolina and parafusulina in the base of the carbonates confirm its age as middle kungurian the transition from the turbidite qudi formation to the seamount lugu formation is here interpreted to be a continuous depositional process recording the qiangtang block s separation from the indian plate this separation signaled the opening of the neotethys ocean between the qiangtang block and the indian plate palaeogeographically the qiangtang block s separation is comparable with the baoshan block s separation in the east and central pamir s separation in the west by contrast the ultimate opening of the neotethys ocean by the separation of india pakistan and northern oman is apparently much later than this event recorded in the qiangtang block consequently it is interpreted that the opening of the neotethys ocean in the whole northern gondwanan margin is a diachronous series of events

evolution of permian conodont provincialism and its significance in global correlation and paleoclimate implication the main components of asselian through artinskian conodont faunas found around the world are basically the same and the provincialism is indicated only by less common endemic elements such as gondolelloides and new genus a henderson in north pangea sweetognathus bucaramangus around the equator and vjalovognathus in eastern gondwana provincialism is marked by differences at the species level of mesogondolella neostreptognathodus and sweetognathus during the kungurian and becomes very distinct with differences at the genus level during the guadalupian and lopingian three provinces of permian conodonts referred to as the north cool water province ncwp the equatorial warm water province ewwp and the peri gondwana cool water province gcwp are recognized the ncwp is marked by gondolelloides in the early cisuralian dominance of neostreptognathodus and no or rare sweetognathus in the late cisuralian dominance of merrillina and mesogondolella and absence of sweetognathus in the guadalupian and dominance of merrillina and mesogondolella and absence of iranognathus in the lopingian the ewwp is characterized by the absence of gondolelloides and vjalovognathus in the cisuralian abundance of sweetognathus and pseudosweetognathus in the kungurian late cisuralian jinogondolella and sweetognathus in the guadalupian and clarkina and iranognathus in the lopingian the gcwp is marked by vjalovognathus merrillina in the cisuralian vjalovognathus merrillina and mesogondolella in the guadalupian and vjalovognathus and merrillina in the lopingian mixed faunas are recognized in regions bordering between the ewwp and gcwp including western timor during the artinskian pamirs during the kungurian and the salt range during the guadalupian and lopingian three different conodont zonations are proposed one for each of the three conodont provinces four potential horizons for inter provincial correlation of permian conodonts are recognized they are in ascending order 1 the first appearance of sweetognathus whitei which is closely related to the last occurrence of carboniferous type conodonts such as streptognathodus and adetognathus 2 the first appearance of neostreptognathodus pequopensis 3 the base of the jinogondolella nankingensis zone and 4 the base of the clarkina postbitteri iranognathus erwini zone the spatial and temporal distribution pattern of permian conodonts suggests that temperature is the primary controlling factor evolution of permian conodont provincialism reveals a glaciation during the asselian and sakmarian a global warming during the artinskian a climate cooling in north pangea during the kungurian a continuation of kungurian climate trends in the guadalupian a relatively minor warming during the wuchiapingian a returned cooling in the changhsingian and lower and middle griesbachian and a global warming in the late griesbachian which ended the permian conodont lineage

capitanian late guadalupian permian global brachiopod palaeobiogeography and latitudinal diversity pattern a global database containing 3365 occurrences 821 species and 251 genera of the capitanian late guadalupian permian brachiopod faunas from 24 stations has been analyzed by cluster analysis using the jaccard and otsuka coefficients and the probabilistic index of similarity nonmetric multidimensional scaling and minimum spanning tree two supergroups three groups and six subgroups are revealed and interpreted as representing respectively two biotic realms the palaeoequatorial and gondwanan realms two regions and six provinces an additional realm the boreal realm based on the fauna from spitsbergen also appears recognizable although it also shows considerable similarities with southwestern north america and the northern margin of gondwana as revealed by the statistical analysis the palaeoequatorial realm can be further subdivided into the north america region and the asian tethyan region the six biotic provinces are the cathaysian province in the palaeotethys and mesotethys the greenland svalbard province in the arctic region the austrazean province in eastern australia and new zealand the grandian province in western north america and the two transitional zones the himalayan province in the southern temperate zone and the sino mongolian japanese province in the northern temperate zone polynomial regression analysis and rarefaction analysis indicate that the generic diversities of brachiopod faunas during the capitanian peaked in the palaeoequatorial cathaysian province and the two transitional zones himalayan province and sino mongolian japanese province but fell dramatically in the polar regions the generic diversity of the palaeoequatorial grandian province is apparently lower than in the two transitional zones of temperate palaeolatitudes suggesting that the generic diversity of capitanian brachiopod faunas does not exhibit a strict negative correlation with palaeolatitudes this in turn would suggest that biogeographical determinants such as geographical barriers inhabitable area and ocean currents other than latitude related temperature control may also have played an important role in the dispersal of some brachiopods and the characterization of some local provinces and high diversities the capitanian global brachiopod palaeobiogeography is generally comparable with those in the wuchiapingian and changhsingian but with some notable differences these include 1 that the grandian province of the capitanian in western north america vanished after the end guadalupian regression 2 that the western tethyan province of the lopingian could not be distinguished in the capitanian and 3 that the austrazean province was larger in area than either in the wuchiapingian or in the changhsingian

a review of indian phanerozoic palaeomagnetism implications for the india asia collision abstract an overview is presented of the indian apparent polar wander path apwp for the phanerozoic and in particular for post late palaeozoic times this apwp is compiled on basis of data available at october 1981 from peninsular and extrapeninsular indo pakistan and from dsdp cores from the indian plate one of the more important and newly recognized features of this apwp is a large scale triassic jurassic loop this loop indicates a changeover from a late palaeozoic early mesozoic northwards and counter clockwise rotational movement with greater india reaching moderately low southern latitudes into a southwards and clockwise rotational movement during the early to middle jurassic recognizable likewise in apwp s from other gondwana continents this loop reflects the opening of the neotethys studies of extrapeninsular regions up to and north of the indus tsangpo suture zone have shown wide spread presence of magnetic overprints which delineate two regionally confined age groups younger overprints 20 40 m y predominate in the more external thrust zones older overprints 50 60 m y in contrast are found in the more internal zones both north and south of the indus tsangpo suture zone the latter are interpreted to reflect a late phase of relaxation in the early tertiary collision of greater india with south central asia or off shore island arcs which occurred at equatorial to low northern palaeolatitudes 0 10 n subsequent northwards movement over 2500 3000 km or more and impingement of greater india into southern asia resulted into large scale underthrusting of greater india along the main central thrust beneath southern tibet and to clockwise rotation of thrust units in the western himalaya a discrepancy between indian palaeomagnetic data and results available todate from southern tibet is discussed

late paleozoic middle latitude gondwana environment stable isotope records from western australia abstract one hundred and twelve permian fossil brachiopod samples from two western australian basins carnarvon and canning basins have been analyzed for oxygen and carbon isotopes to study the middle paleolatitude environment in the permian all samples were thin sectioned and examined using petrography and cathodoluminescence microscopy for evaluating shell preservation a total of 249 isotopic analyses from the best preserved portion non luminescent nl of shells were found useful for inferring paleoenvironments for the carnarvon basin average 13 c values of nl shells were between 4 2 and 4 5 for the callytharra formation n 123 late sakmarian early artinskian jimba jimba calcarenite n 7 early artinskian coyrie madeline formations n 71 both late artinskian early kungurian and wandagee formation n 18 late kungurian average 13 c values of nl shells were 5 0 0 4 n 9 for the quinnanie shale cundlego formations both kungurian for the canning basin mean 13 c values of nl shells were 5 1 1 1 n 11 5 3 0 2 n 4 and 4 8 0 5 n 6 for the noonkanbah formation artinskian kungurian lightjack formation roadian capitanian and hardman formation wuchiapingian respectively within the uncertainty of the stratigraphical correlation the carbon isotope values spanning late sakmarian to kungurian in middle latitude western australia are comparable to those of coeval low latitude urals average 18 o values of nl shells were about 0 0 1 to 0 1 for the callytharra formation jimba jimba calcarenite coyrie madeline formations quinnanie shale cundlego formations noonkanbah formation and hardman formation and were 0 5 0 7 and 0 3 0 7 for the wandagee formation and lightjack formation respectively these oxygen isotope values are overall higher than the coeval values reported for low latitude regions and for eastern australia the positive oxygen isotope values are here interpreted to indicate a cool temperature and or a possibly moderately high salinity condition for the two studied basins in western australia during the permian

the capitanian guadalupian middle permian mass extinction in nw pangea borup fiord arctic canada a global crisis driven by volcanism and anoxia until recently the biotic crisis that occurred within the capitanian stage middle permian ca 262 ma was known only from equatorial tethyan latitudes and its global extent was poorly resolved the discovery of a boreal capitanian crisis in spitsbergen with losses of similar magnitude to those in low latitudes indicated that the event was geographically widespread but further non tethyan records are needed to confirm this as a true mass extinction the cause of this crisis is similarly controversial whilst the temporal coincidence of the extinction and the onset of volcanism in the emeishan large igneous province in china provides a clear link between those phenomena the proximal kill mechanism is unclear here we present an integrated fossil pyrite framboid and geochemical study of the middle to late permian of the sverdrup basin at borup fiord ellesmere island arctic canada as in spitsbergen the capitanian extinction is recorded by brachiopods in a chert limestone succession 30 40 m below the permian triassic boundary the extinction level sees elevated concentrations of redox sensitive trace metals mo v u mn and contemporary pyrite framboid populations are dominated by small individuals suggestive of a causal role for anoxia in the wider boreal crisis mercury concentrations a proxy for volcanism are generally low throughout the succession but are elevated at the extinction level and this spike withstands normalization to total organic carbon total sulfur and aluminum we suggest this is the smoking gun of eruptions in the distant emeishan large igneous province which drove high latitude anoxia via global warming although the global capitanian extinction might have had different regional mechanisms like the more famous extinction at the end of the permian each had its roots in large igneous province volcanism

carbon and oxygen isotope records of permian brachiopods from relatively low and high palaeolatitudes climatic seasonality and evaporation

the changing maltese soil environment evidence from the ancient cart tracks at san pawl tat tarġa naxxar the historic cart ruts of malta are incised into the underlying bedrock topography anomalous relationships between their routeways and the uneven terrain beneath suggest that they originated on a land surface different from that of today an exposure close to a cart rut location near naxxar reveals evidence of limestone terrain development and its role in the evolution of the cart rut patterns specifically it reveals that cart trackways were most probably superimposed from a soil cover onto an underlying bedrock surface topographically different from the former soil surface a model is developed demonstrating likely relationships between human activity soil erosion and trackway evolution leading to the incision of the trackways into the bedrock

the palaeomagnetism of late permian early triassic and late triassic deposits on timor an australian origin summary studies have been carried out on sediments from two formations in western timor a red crinoid bearing limestones of the maubisse formation of late permian early triassic age and b reddish calcilutites and red shales of the aituto formation of late triassic age the crinoid bearing limestones occur in both a non recrystallized and a recrystallized slightly marmorized facies natural remanent magnetization nrm was analysed by means of progressive demagnetization both using alternating magnetic fields and by heating the determination of acquisition remanence and remanent coercive force demonstrated that in a large number of sites high temperature volcanic haematite is the main carrier of remanence a few sites from the non recrystallized maubisse limestones revealed magnetite as the main remanence carrier the recrystallized maubisse limestones were found to have a secondary remanence with a very high coercivity and a high blocking temperature characteristic remanent magnetization chrm directions could be obtained both from the non recrystallized limestones of the maubisse formation and from the aituto formation for the plate tectonic interpretation of the data only the chrm inclination values have been used because of the complicated often chaotic tectonism on timor palaeolatitudinal positions of 39 and 33 have been derived from the late permian early triassic maubisse formation and the late triassic aituto formation respectively this points to the presence on the island of timor of a displaced terrane of australian origin

marine faunal realms of the mesozoic review and revision under the new guidelines for biogeographic classification and nomenclature consensus among the friends of paleobiogeography produced tentative guidelines to the classification and nomenclature of marine biogeographic units i e biochores based on these loose rules the present paper is a critical review of all published mesozoic marine realms subrealms and superrealms formerly called climatic belts biochores are defined by the overall endemism within geographic and time envelopes that include choro and chrono types without consideration of facies or climate the hierarchy of ranks or tiers is superrealm realm subrealm province subprovince only ranks in italics are obligatory region is informal these ranks scale with endemism geographic range and persistence in time biochores are named geographically following nomenclatural guidelines not strict rules of synonymy and homonymy with priority beginning with uhlig s paper of 1911 uhlig s two climatic belts are tentatively accepted as optional top ranking superrealms for times of exceptional global endemism available names for them are euroboreal or panboreal new and tethys panthalassa the validity of the 29 existing names for realm group biochores realms subrealms and superrealms in the marine mesozoic is discussed 19 names are rejected for a variety of reasons including synonymy homonymy and usefulness the most important realm group biochores are arctic and boreal atlantic in the boreal euroboreal realm or superrealm and tethyan mediterran caucasian indo pacific jurassic early cretaceous and austral middle late cretaceous in the tethys panthalassa superrealm

paleogeographic reconstruction of accreted oceanic rocks akiyoshi southwest japan the depositional setting of an accreted oceanic rock succession of limestone chert and greenstone is reconstructed by using the stratigraphy age and lithologic features in the akiyoshi terrane southwest japan stratigraphic and radiolarian paleontological results identify four coeval oceanic rock units ranging in age from late early carboniferous to late middle permian sediments on the top the upper flank the lower flank and the foot of the seamount and on the surrounding ocean floor are represented by reef limestone detrital limestone with spicular chert spicular chert with displaced limestone and radiolaria bearing chert respectively all units rest on greenstone radiolaria bearing chert is interpreted as a more distal facies than spicular chert these rocks are interpreted as sediments deposited on and around a basaltic seamount formed in an open ocean realm that had no input of terrigenous materials

palaeogeographic constraints on the tectonic evolution of the maizuru terrane of southwest japan to the eastern continental margin of south china during the permian and triassic abstract the maizuru terrane in the inner zone of southwest japan consists of weakly metamorphosed ophiolitic complexes and permian and triassic strata the permian maizuru group is 1500 3000 m thick and consists mainly of mudstone sandstone and alternating beds of sandstone and mudstone it is subdivided into lower middle and upper formations and is overlain with angular unconformity by the lower middle triassic yakuno group the maizuru group is characterised by the occurrence of the capitanian lepidolina kumaensis fauna in conglomerates of the middle and upper formations and the wuchiapingian codonofusiella colaniella and changhsingian palaeofusulina colaniella faunas in lenticular limestones and conglomerates of the upper formation pre capitanian foraminifera are contained in limestone clasts of conglomerates of the upper formation and the basal part of the yakuno group examination on the stratigraphy lithology foraminiferal fauna and late palaeozoic to mesozoic tectonics in and around the maizuru terrane leads to the following conclusions capitanian and lopingian limestone blocks and clasts were originally deposited on the continental shelf and were subsequently redeposited on the deeper continental slope almost all of the pre capitanian limestone clasts were derived from the akiyoshi seamount accreted by the early late permian except for those containing verella prolixa and pseudostaffella praegorski which were reworked from the shallow continental shelf the maizuru terrane originated on the active continental margin located close to south china during permian triassic time but the depositional environment of the permian and triassic strata rapidly changed from deeper continental slope to shallow continental shelf

progress problems and prospects an overview of the guadalupian series of south china and north america abstract the guadalupian epoch is marked by the formation of the pangean supercontinent global sea level change rifting and drifting of the cimmerian continents formation of large igneous provinces and dramatic biotic changes a high resolution biostratigraphic chemostratigraphic and high precision geochronologic framework of this critical transition is fundamental to understanding these events extensive studies of the latest cisuralian and guadalupian series in both south china and north america reveal the same conodont lineages but the conodont interval zones based on jinogondolella within the guadalupian series are slightly diachronous high precision u pb geochronological studies ca id tims method calibrate the base of the guadalupian series base roadian at 273 01 0 14 ma a previously reported age from an ash bed overlying the emeishan flood basalts 259 51 0 21 ma is adopted for the guadalupian lopingian boundary glb based on recently published geochronology and bayesian age modeling from the guadalupian series the base of the capitanian is constrained at 264 28 0 16 ma and the base of the wordian is interpolated to be 266 9 0 4 ma the illawarra reversal is of early middle wordian age both north america and south china possess a distinct negative 13ccarb excursion of 3 5 at the latest kungurian and early roadian lk er cie which coincides with the early stages of a significant 3rd order sea level rise the large end guadalupian 13ccarb negative excursion may have been affected by post depositional diagenesis or a warming event associated with the emeishan volcanism the 87sr 86sr ratios in both regions declined from the latest kungurian to the late capitanian but have different ratios and reveal several fluctuations in the middle guadalupian measured 18oapatite values suggest that the delaware basin was 3 4 c cooler than the eastern yangtze block analysis of a new high resolution database of marine taxa indicates only a minor pre lopingian diversity drop from 261 04 ma to 259 98 ma which coincides with the peak emeishan volcanism the widely perceived end guadalupian mass extinction in north america is evidently masked by and possibly an artefact of a stratigraphic truncation effect due to rapid lithofacies changes from limestone to laminated evaporites with the closure of the west texas basins

climatic implications from the sequential changes in diversity and biogeographic affinities for brachiopods and bivalves in the permian of eastern australia and new zealand abstract brachiopoda and bivalvia of successive macro invertebrate zones of eastern australia and new zealand are analysed to demonstrate a sequence of climatic change throughout the permian period reflecting glacial episodes separated by warmer intervals three such glacial intervals are indicated for the early cisuralian permian a long asselian episode a brief artinskian episode and a substantial kungurian interval followed by a cold roadian interval middle permian guadalupian and a very late permian lopingian episode markedly warmer intervals developed in the possibly late asselian baigendzinian and much of the lopingian in addition relatively long cool times allowed the flourishing and comparative diversification of eastern australian faunas at several stages

middle permian brachiopods from central peninsular malaysia faunal affinities between malaysia and west cambodia a moderately diverse permian brachiopod fauna is described from a new rock unit the bera formation in the bera district central pahang peninsular malaysia the fauna consists of 19 taxa including 14 genera and 17 both identified and unidentified typically tethyan species the fauna appears to be correlative on the basis of brachiopods with the neoschwagerina yabeina fusulinid zones in indochina and south china in particular it has strong linkage to member c yabeina beds of the sisophon limestone west cambodia this is indicated by three of the bera species urushtenoidea chaoi ching spyridiophora gubleri termier and termier and transennatia termierorum sp nov being shared with the cambodian fauna a possible early capitanian middle permian age is proposed for the bera brachiopod fauna