the guadalupian permian kamura event in european tethys article i nfo in order to document paleoenvironmental conditions of the equatorial western paleo tethys during the late middle permian prior to the end guadalupian mass extinction chemostratigraphic analysis using stable carbon isotopes was conducted for the guadalupian rocks at brusane in the velebit mtn central croatia by analyzing 72 carbonate samples of the capitanian upper guadalupian velebit formation we found an interval with unusually high 13 ccarb values 4 to 6 in the ca 150 m thick yabeina fusuline zone the present find clarifies that the primary productivity and burial rate into the sediments were considerably high during the capitanian in westernmost paleo tethys this chemostratigraphic signal is properly correlated with the kamura event detected in a mid panthalassan paleo atoll limestone in japan the present results identify the capitanian kamura event for the first time in european paleo tethys on the opposite side of the globe from the mid panthalassan paleo seamount and prove the global context of the event as well as its utility in chemostratigraphic correlation in order to enhance bioproductivity on a global scale the increase in nutrient supply is inevitable in addition to riverine run off from pangea active oceanic circulation in particular upwelling of deep sea water enriched in nutrients was likely vital both in panthalassa and paleo tethys the extinction of some guadalupian fauna in particular photosymbiotic community large tested fusulines large bivalves rugose corals was likely related to a temporary cooling coupled with eutrophication in low latitude shallow marine environments of paleo tethys and panthalassa

palaeobiogeography and palaeogeographical implications of permian marine bivalve faunas in northeast asia kolyma omolon and verkhoyansk okhotsk regions northeastern russia abstract the paper considers the biogeography and palaeogeographic implications of the permian marine bivalve faunas of northeast asia with a focus on the dynamic relationships between biotic similarities and palaeogeographic distance through an interval of ca 50 million years a stage by stage time series analysis of the biotic similarities between two previously recognized biochores in northeast asia the kolyma omolon and verkhoyan okhotsk provinces has been carried out using both the jaccard and dice similarity indices based on the spatio temporal distributions of 355 permian marine bivalve species in northeast asia the outcome of this analysis combined with other empirical data and previously published tectonic sedimentological and palaeontological information suggests that 1 the bivalve faunas from these two provinces were distinctive from one another as two separate biochores throughout all but the earliest asselian permian stages and 2 the biotic similarities between the verkhoyan okhotsk and kolyma omolon provinces remained consistently low since sakmarian all falling well below the minimum threshold of the jaccard index of 0 42 required for distinguishing marine biotic provinces we interpret these below threshold jaccard biotic similarities as an indication of significant palaeogeographic separation between the verkhoyan okhotsk and kolyma omolon provinces which is in turn considered to indicate rifting and sea floor spreading of the omolon microcontinent and associated terranes and island arcs away from the north asian craton at least from the sakmarian to the beginning of the late permian palaeo distance separation appears to be the primary and most significant biogeographic determinant in accounting for the differences in the spatial distribution of most permian bivalve species in northeast asia several other variables also appear to have played a significant role including regional climate conditions ocean currents and merged island chains as geographic barriers in particular the relatively high biotic similarity between the verkhoyan okhotsk and kolyma omolon provinces during the late wuchiapingian and changhsingian may have been related to the shallowing of the deep water basins oimyakon ayan yuryakh balygychan and sugoi basins that had previously separated the two provinces and the flooding submergence of the okhotsk taigonos volcanic arc system thus allowing the invasion of lower latitude warm water palaeotethyan and even gondwanan species into northeast asia

quasi lagrangian large eddy simulations of cross equatorial flow in the east pacific atmospheric boundary layer using a large eddy simulation les the atmospheric boundary layer abl is numerically modeled along 958w from 88 st o 48n during boreal autumn and compared to observations from the east pacific investigation of climate processes in the coupled ocean atmosphere system epic 2001 since the local abl winds are predominantly southerly in this season a quasi lagrangian forcing is used in which the abl air column is forced as if it were advecting northward with the mean september october 2001 meridional wind across the equatorial cold tongue and the rapidly warming ssts to the north pressure gradients and large scale zonal advective tendencies are prescribed as a function of latitude where possible observations from the epic 2001 experiment are used for forcing and for comparison with model results the abl s modeled vertical structure accords with the conceptual model of wallace et al and agrees well with observations surface stability accounts for the minimum in surface wind over the equatorial cold tongue and the maximum over the warm water to the north stability of the lower abl over the cold tongue allows a jet to accelerate at about 500 m height relatively uncoupled to the frictional surface layer vertical mixing over the warm water to the north distributes this momentum to the surface additional simulations were performed to explore the modeled abl s sensitivity to pressure gradients zonal advection free tropospheric humidity and initial conditions the model abl was robust changing the forcings resulted in little change in the modeled structure the strongest sensitivity was of stratocumulus clouds over the cold tongue to cloud top radiative cooling once formed at the southern edge of the cold tongue modeled stratocumulus clouds demonstrate a remarkable ability to maintain themselves over the cold tongue in the absence of surface fluxes by radiative cooling at their tops the persistence of thin stratocumulus clouds in this lagrangian model suggests that horizontal advection of condensate might be an important process in determining cloudiness over the cold tongue

highly productive polar forests from the permian of antarctica abstract two stratigraphically closely spaced bedding planes exposed at lamping peak in the upper buckley formation beardmore glacier area antarctica contain abundant in situ stumps n 53 n 21 and other plant fossils that allow reconstruction of forest structure and biomass of glossopteris forests that thrived at 75 s paleolatitude in the permian mean trunk diameter is 14 and 25 cm corresponding to estimated mean maximum heights of 12 and 19 m basal areas are 65 and 80 m 2 ha 1 the above ground biomass was calculated using allometric equations for ginkgo biloba yielding biomasses of 147 and 178 mg ha 1 biomass estimates based on comparison with biomass of modern forests with equivalent basal areas are higher 225 400 mg ha 1 the amount of above ground biomass added each year annual net primary productivity based on biomass estimates and growth rings in silicified plant material from the buckley formation nearby is poorly constrained ranging from 100 2000 g m 2 yr 1 compared to modern forests at all latitudes the permian forests have high basal areas and high biomass exceeded in both only by forests of the u s pacific northwest and sequoia forests the estimated range of productivity anpp is within that of many very productive modern forests the lamping peak forests basal areas and calculated biomass are also larger than younger high paleolatitude fossil forests except for arctic cenozoic forests the presence of these highly productive fossil forests at high paleolatitude is consistent with hothouse conditions during the late permian prior to the eruption of the siberian flood basalts

a comparison of shear and buoyancy driven planetary boundary layer flows abstract planetary boundary layer pbl flows are known to exhibit fundamental differences depending on the relative combination of wind shear and buoyancy forces these differences are not unexpected in that shear instabilities occur locally while buoyancy force sets up vigorous thermals which result in nonlocal transport of heat and momentum at the same time these two forces can act together to modify the flow field in this study four large eddy simulations less spanning the shear and buoyancy flow regimes were generated two correspond to the extreme cases of shear and buoyancy driven pbls while the other two represent intermediate pbls where both forces are important the extreme cases are used to highlight and quantify the basic differences between shear and convective pbls in 1 flow structures 2 overall statistics and 3 turbulent kinetic energy tke budget distributions results from the two intermediate les cases are used to develop and verify a velocity scaling and a tke budget mode

derivation of isotope ratios errors and error correlations for u pb geochronology using 205pb 235u 233u spiked isotope dilution thermal ionization mass spectrometric data a comprehensive treatment of the derivation of u pb isotope ratios and their corresponding uncertainties from isotope dilution thermal ionization mass spectrometric measurements is presented standard parametric statistical methods of error propagation are utilized to convolve uncertainties associated with instrumental mass fractionation tracer subtraction blank pb and u subtraction and initial common pb correction derivations include errors and error correlations for total sample u pb and pb isotope ratios including radiogenic and initial common pb for two and three dimensional isochron calculations radiogenic u pb and pb isotope ratios for concordia and radiogenic model age calculations and the propagation of model age errors from radiogenic isotope ratios

atmospheric pressure response to mesoscale sea surface temperature variations in the kuroshio extension region in situ evidence several research cruises were conducted across the kuroshio extension front to examine the low level atmospheric responses to mesoscale variations in sea surface temperature sst surface meteorological observations including sea level pressure slp and sst were collected at two moored buoys that were located on either side of the kuroshio extension and from a research vessel as it moved between the two buoys during the various cruises spatial perturbations in slp along the ship transects calculated by subtracting moored buoy slp from that of the moving ship tend to be positive negative where sst is lower higher on spatial scales of about 100 km and the magnitude of these slp perturbations near the sst front can exceed 1 0 hpa radiosonde data also show that the atmospheric boundary layer thins thickens over lower higher sst although the contribution of across track component in the wind cannot be calculated the along track component of divergence suggests low level convergence over higher sst the thermally induced pressure gradient is important in the momentum budget suggesting that sea breeze like local circulations formed over the sst fronts indeed the pressure adjustment mechanism can sometimes dominate even on a scale of 100 km although it is not always observed the time scale in which the boundary layer thickness adjusted to sst is estimated to be 1 day or less

ice keel scour marks in the geological record evidence from carboniferous soft sediment striated surfaces in the parana basin southern brazil abstract soft sediment glacially striated surfaces are common structures in ancient glacial successions such as the gondwanic paleozoic record and document ice erosion on non lithified beds in most cases they have been interpreted as the product of subglacial erosion beneath advancing marine or terrestrial glaciers although direct evidence for glacial sedimentation in associated strata is infrequent in this paper we document soft sediment striated surfaces of carboniferous age occurring in cross laminated sandstones of the lower itarare group southern parana basin brazil and interpret them as scour marks generated by keels of floating ice striated surfaces occur in closely spaced multiple stratigraphic horizons in the lower half of a deglacial sequence whose facies characteristics indicate sedimentation in subaqueous outwash and deltaic settings surfaces are laterally discontinuous commonly bordered by marginal berms and in some cases capped by mudstones with dropstones they have orientations that deviate from the regional paleo ice flow indicated by glacial grooves carved on the pre glacial basement the characteristics observed are consistent with modern and pleistocene ice keel scour marks in addition soft sediment striated surfaces from other gondwanic localities have similar attributes suggesting that ice keel scour marks may be more common in the geological record than previously considered and that vertically repeated striated surfaces do not necessarily indicate multiple ice sheet advances therefore paleo ice flow reconstructions based on soft sediment striated surfaces need to be revaluated considering that the movement of free floating ice masses is controlled by phenomena other than glacier advance

a remarkable sea level drop and relevant biotic responses across the guadalupian lopingian permian boundary in low latitude mid panthalassa irreversible changes recorded in accreted paleo atoll limestones in akasaka and ishiyama japan abstract the capitanian upper guadalupian to wuchiapingian lower lopingian shallow marine limestones at akasaka and ishiyama in central japan record unique aspects of the extinction related guadalupian lopingian boundary g lb interval the ca 140 m thick akasaka limestone consists of the capitanian black limestone unit b 112 m and the wuchiapingian light gray dolomitic limestone unit w 21 m with a black white striped limestone unit s 9 m between them the g lb horizon is assigned at the base of unit w on the basis of the first occurrence of the wuchiapingian fusulines the capitanian unit b and the wuchiapingian unit w were deposited mostly in the subtidal zone of a lagoon whereas the intervened unit s and the lowermost unit w were in the intertidal zone a hiatus with a remarkable erosional feature was newly identified at the top of unit s these records indicate that the sea level has dropped significantly around the g lb to have exposed the top of the atoll complex above the sea level the ishiyama limestone located ca 10 km to the north of the akasaka limestone retains almost the same depositional records the extinction of large tested fusuline yabeina and large bivalves alatoconchidae occurred in the upper part of unit b and the overlying 20 m thick limestone the uppermost unit b and unit s below the hiatus represents a unique barren interval the upper half of the barren interval is more depleted in fossils than the lower half and this likely represents a duration of the severest environmental stress es for the shallow marine protists animals on the mid oceanic paleo atoll complex small tested fusulines re appeared at the base of unit w above the hiatus these facts prove that the elimination of shallow marine biota occurred during the capitanian shallowing of akasaka paleo atoll before the subaerial exposure erosion across the g lb the overall shallowing and the development of such a clear hiatus at the top of a mid oceanic seamount in accordance with the contemporary sea level curve based on continental shelf records indicates that a remarkable sea level drop has occurred globally during the latest capitanian this further suggests that a cool climate likely has appeared even in the low latitude domains in panthalassa to cause the decline of the middle permian shallow water protists animals that adapted to warmer seawater the wuchiapingian biota first appeared immediately after this erosional episode i e during the onset of warming after the g lb

a new perspective on southern hemisphere storm tracks abstract a detailed view of southern hemisphere storm tracks is obtained based on the application of filtered variance and modern feature tracking techniques to a wide range of 45 yr european centre for medium range weather forecasts ecmwf re analysis era 40 data it has been checked that the conclusions drawn in this study are valid even if data from only the satellite era are used the emphasis of the paper is on the winter season but results for the four seasons are also discussed both upper and lower tropospheric fields are used the tracking analysis focuses on systems that last longer than 2 days and are mobile move more than 1000 km many of the results support previous ideas about the storm tracks but some new insights are also obtained in the summer there is a rather circular strong deep high latitude storm track in winter the high latitude storm track is more asymmetric with a spiral from the atlantic and indian oceans in toward antarctica and a subtropical jet related lower latitu

air sea interaction at the southern brazilian continental shelf in situ observations the influence of the cross shelf oceanographic front occurring between the brazil current bc and the brazilian coastal current bcc on the local marine atmospheric boundary layer mabl is investigated here this front is typical of wintertime in the southern brazilian continental shelf sbcs and this is the first time that its effects are investigated over the above mabl here we analyze variability vertical structure and stability of mabl as well as heat fluxes at air sea interface across five oceanographic transects in the sbcs made during a winter 2012 cruise local thermal gradients associated with mixing between distinct water masses play an essential role on mabl modulation and stability although weaker when compared with other frontal regions the cross shelf thermal gradients reproduce exactly what is expected for open ocean regions stronger weaker winds lower higher sea level pressure and a more unstable stable mabl are found over the warm cold side of the oceanographic front between the bc warm and coastal cold waters our findings strongly support the coexistence of both known mabl modulation mechanisms the static and hydrostatic mabl stability this is the first time that these modulation mechanisms are documented for this region turbulent fluxes were found to be markedly dependent on the cross shelf sst gradients resulting in differences of up to 100 w m 2 especially in the southernmost region where the gradients were more intense

the influence of sea surface temperature on surface wind in the eastern equatorial pacific weekly to monthly variability abstract temporal correlations between near equatorial surface wind and sea surface temperatures sst at 11 w in the eastern pacific ocean are investigated using data from an array of moored sensors between 5 n and 5 s the signature of tropical instability waves with periods of 20 30 days is apparent in time series of sst and both the meridional and zonal wind components results indicate the existence of a band of pronounced horizontal divergence in the surface wind field associated with the large meridional sst gradient equatorial front normally located just north of the equator perturbations of the equatorial front by the instability waves induce fluctuations in the overlying winds evidence of the air sea coupling is stronger in time series of the meridional gradients of wind and sst than between time series of the variables themselves the meridional differencing serves as a high pass filter in the space domain which removes planetary scale wind fluctuations that are unrelated to the local sst

quantitative radiometric and biostratigraphic calibration of the pennsylvanian early permian cisuralian time scale and pan euramerican chronostratigraphic correlation a quantitative biostratigraphic and radiometric calibration is presented for the pennsylvanian through early permian global time scale based upon high precision isotope dilution thermal ionization mass spectrometer id tims u pb zircon ages for interstratified ash beds in the parastratotype sections of the southern urals of russia twenty four ash bed ages in three outer ramp and basinal sections of the pre uralian foredeep bracket the biotic definitions of global stages and regional substages from the base of the upper pennsylvanian kasimovian stage to the base of the lower permian artinskian stage four additional ash bed ages in two sections of the eastern slope of the urals constrain the global bashkirian and serpukhovian stages quantitative stratigraphic methods conop9 are applied to a compilation of over 2000 bioevents in 22 stratigraphic sections supplemented by our dated volcanic horizons to refine the pennsylvanian early permian global time scale significant shifts in the duration of several stages are demonstrated ranging from one to six million years compared with prior estimates the unprecedented density of radiometric calibration points for the pennsylvanian permian transition provides a high resolution 0 1 ma global chronostratigraphic standard for testing and improving biostratigraphic correlations across euramerica we integrate radiometric ages biostratigraphic correlation and cyclostratigraphic tuning of major cyclothems to the long period 404 ka eccentricity cycle to elucidate the tempo magnitude and forcing of eustatic changes and cyclothemic deposition associated with the waxing and waning of gondwanan ice sheets and establish a pan euramerican chronostratigraphic framework for most of pennsylvanian and early permian time

prevailing anoxia in the kungurian permian of south china possible response to divergent climate trends between the tropics and gondwana the kungurian ocean climate system has received little attention but a new compilation of geochemical and paleoclimatic proxies suggest more complex climate dynamics during the late paleozoic icehouse greenhouse transition than previously considered here integrated carbon isotope stratigraphical sedimentological and geochemical data across two early middle permian successions in the youjiang basin south china is presented these proxies indicate widespread anoxia below or near the water sediment interface in south china during the kungurian high primary productivity high sedimentation rate and a relative sea level rise are here proposed as being responsible for this process in the late kungurian but cannot account for the remaining anoxia at cycle boundaries we put forward a hypothesis that divergent climate trends between the tropics and gondwana might have played an important role in ocean stagnation and prevailing o2 deficient conditions in and probably outside south china during the kungurian the termination of anoxia in this region during the latest kungurian is attributed to an intensification of oceanic circulation a rise in atmospheric po2 concentrations a sea level drop depressed primary productivity and low sedimentation rates this study calls for further high resolution sedimentological and geochemical investigations on the paleotropics outside south china in order to elucidate the icehouse greenhouse transition at the global scale

bimodal character of the late paleozoic glaciations in argentina and bipolarity of climatic changes abstract the upper paleozoic sedimentary rock sequences of argentina show an outstanding record of climatic fluctuations during this interval and the complexity and rapidity of the climatic changes there were two distinct events of cooling or glacial periods the older in the middle carboniferous late visean bashkirian and the younger in the early permian asselian tastubian and these were separated by a long lasting interval of warming during the late pennsylvanian it is postulated that climatic fluctuations in the northern paleotemperate realm may have had the same causes as in argentina and that these periods of cooling and warming probably occurred at the same time in both hemispheres in western argentina and central patagonia the occurrence of the early permian glacial phase and the absence of the younger phases like those present in eastern argentina and south africa suggest that during the final deglaciation in gondwana thawing gradually progressed to the east then located closer to the paleopolar region

climatic and hydrologic controls on upper paleozoic bauxite deposits in south china abstract the late paleozoic era was an interval of major tectonic and climatic changes including formation of the supercontinent pangea and the 60 myr long late paleozoic ice age lpia although bauxite formation declined globally from the carboniferous to the permian in conjunction with global cooling it was an interval of widespread bauxite formation in china in south china 1 the jiujialu formation bauxite deposits in central and northern guizhou zunyi area are of early middle visean age 2 the dazhuyaun formation bauxite deposits in northern guizhou wuchuan zheng an daozheng area to southern chongqing nanchuan area and southeastern guizhou fuquan kaili area are of late pennsylvanian early permian age and 3 the heshan formation bauxite deposits in western guangxi to yunnan are of middle late permian age in north china the benxi formation bauxite deposits are of late mississippian middle pennsylvanian age the contrasting trends in bauxite metallogenesis between china and the rest of the world imply different climatic patterns in the eastern tethys high annual humidity with seasonal dryness and pangea aridification this hypothesis is further supported by differences in the chemical index of alteration or cia 80 in the eastern tethys vs 50 in western pangea and in paleotemperatures mean annual temperature or mat 20 c in the eastern tethys vs 4 c in western pangea determined from permo carboniferous siliciclastic deposits permo carboniferous bauxite deposits in south china formed in coastal plain and coastal karstic depression environments in which the position of the groundwater table was related to sea level changes during the late paleozoic high frequency eustatic fluctuations caused by waxing and waning of gondwana icesheets controlled sedimentation in these coastal depositional systems leading to cyclic accumulation of coal and bauxite deposits and cycles of vadose and phreatic type bauxite formation the results of the present study show that during interglacial stages lateritization resulted from high pco2 high sea level and groundwater table elevations low precipitation and limited vegetation cover whereas during glacial stages bauxitization of these ferralitic weathering products was promoted by low pco2 low sea level and groundwater table elevations high precipitation and more extensive vegetation cover thus a unique combination of geographic climatic and eustatic factors accounted for widespread formation of bauxite in south china during the lpia

multiyear measurements of the oceanic and atmospheric boundary layers at the brazil malvinas confluence region 1 this study analyzes and discusses data taken from oceanic and atmospheric measurements performed simultaneously at the brazil malvinas confluence bmc region in the southwestern atlantic ocean this area is one of the most dynamical frontal regions of the world ocean data were collected during four research cruises in the region once a year in consecutive years between 2004 and 2007 very few studies have addressed the importance of studying the air sea coupling at the bmc region lateral temperature gradients at the study region were as high as 0 3 c km 1 at the surface and subsurface in the oceanic boundary layer the vertical temperature gradient reached 0 08 c m 1 at 500 m depth our results show that the marine atmospheric boundary layer mabl at the bmc region is modulated by the strong sea surface temperature sst gradients present at the sea surface the mean mabl structure is thicker over the warmside of the bmc where brazil current bc waters predominate the opposite occurs over the coldside of the confluence where waters from the malvinas falkland current mc are found the warmside of the confluence presented systematically higher mabl top height compared to the coldside this type of modulation at the synoptic scale is consistent to what happens in other frontal regions of the world ocean where the mabl adjusts itself to modifications along the sst gradients over warm waters at the bmc region the mabl static instability and turbulence were increased while winds at the lower portion of the mabl were strong over the coldside of the bc mc front an opposite behavior is found the mabl is thinner and more stable our results suggest that the sea level pressure slp was also modulated locally together with static stability vertical mixing mechanism by the surface condition during all cruises sst gradients at the bmc region modulate the synoptic atmospheric pressure gradient postfrontal and prefrontal conditions produce opposite thermal advections in the mabl that lead to different pressure intensification patterns across the confluence

direct observations of atmospheric boundary layer response to sst variations associated with tropical instability waves over the eastern equatorial pacific tropical instability waves tiws with a typical wavelength of 1000 km and period of 30 days cause the equatorial front to meander and result in sst variations on the order of 18 28c vertical soundings of temperature humidity and wind velocity were obtained on board a japanese research vessel which sailed through three fully developed sst waves from 1408 to 1108w along 28n during 21 28 september 1999 a strong temperature inversion is observed throughout the cruise along 28n capping the planetary boundary layer pbl that is 1 1 5 km deep temperature response to tiw induced sst changes penetrates the whole depth of the pbl in response to an sst increase air temperature rises in the lowest kilometer and shows a strong cooling at the mean inversion height as a result this temperature dipole is associated with little tiw signal in the observed sea level pressure slp the cruise mean vertical profiles show a speed maximum at 400 500 m for both zonal and meridional velocities sst based composite profiles of zonal wind velocity show weakened intensified vertical shear within the pbl that is consistent with enhanced reduced vertical mixing causing surface wind to accelerate decelerate over warm cold ssts taken together the temperature and wind soundings indicate the dominance of the vertical mixing over the slp driving mechanism based on the authors measurements a physical interpretation of the widely used pbl model proposed by lindzen and nigam is presented

the marine permian of east and northeast asia an overview of biostratigraphy palaeobiogeography and palaeogeographical implications abstract the permian marine biostratigraphy faunal successions and mutual correlations where possible throughout east and northeast asia are synthesized region by region based on both published literature and the author s field observations in certain parts of the region the correlation of the permian marine successions of ne asia with the permian international timescale and in particular with gondwanan permian marine sequences remains a major challenge due to profound marine provincialism during the permian however by employing biogeographically mixed faunas from east asia se mongolia ne china south primorye of far east russia and the south kitakami terrane of japan as biostratigraphic gateways coupled with some bipolarly and bi temperately shared permian marine taxa and faunas it has been possible to correlate with reasonable confidence some of the high palaeolatitude permian marine rock units and faunas of ne asia with those of the tethyan region and gondwana palaeobiogeographically the permian marine faunas of east and ne asia are assigned to four major provinces verkolyman sino mongolian japanese cathaysian and panthalassan provinces on the basis of their palaeogeographical distribution patterns and characteristics of faunal assemblages of these the sino mongolian japanese province has considerable significance for regional palaeogeographical plate tectonic and palaeoceanographical reconstructions during the middle permian because of its conspicuously mixed cool and warm water marine biota the origin of this biogeographically mixed marine biota is interpreted to have resulted from a combination of some key factors including the increased tectonic convergence between the bureya jiamusi terrane and the sino korean platform during the permian and the intermingling of both warm and cold water ocean currents off the eastern coastal areas of the bureya jiamusi terrane and the sino korean platform during the middle permian

late paleozoic ice age glaciers shaped east antarctica landscape abstract the erosion history of antarctica is fundamental to our understanding of interlinks between climate and glacier dynamics however because of the vast polar ice sheet covering more than 99 of antarctica land mass the continental surface response to glacial erosion remains largely unknown over the last decade the subglacial topography of antarctica has been imaged by airborne radar surveys these studies revealed high and complex sub glacial relief in the core of the east antarctic shield interpreted as resulting from rifting episodes and low long term erosion rates or repeated large scale glacial retreats and advances in east antarctica thermochronology studies have revealed a spatially localized cenozoic erosion starting after 34 ma with a maximum denudation of 2 km in the lambert trough low pre glacial erosion rates before 34 ma have been inferred since the permian period following a phase of significant 2 km erosion during the late paleozoic between 350 and 250 ma however the exact extent magnitude and significance of this late paleozoic erosion phase remain elusive here we show that homogeneous exhumation occurred at the scale of the terre adelie margin of east antarctica in response to major glacial erosion during the late paleozoic ice age lpia our data require homogeneous exhumation and 4 km erosion between 340 and 300 ma along a 600 km profile along the terre adelie george v land coast the data are inconsistent with either exhumation during permian rifting or with significant 1 5 km cenozoic glacial erosion which requires lpia glaciers to have been temperate promoting glacial sliding erosion and sediment transfer even at high latitudes unlike in the present situation

the permian antitropical fusulinoidean genus monodiexodina distribution taxonomy paleobiogeography and paleoecology all the documented occurrences with illustration of specimens of the permian fusulinoidean genus monodiexodina from a total of 33 areas in 11 regions are reviewed and their taxonomic positions are reexamined in this paper among 17 species including two subspecies of monodiexodina in the current taxonomy the following 10 species are recognized as valid m kattaensis m wanneri m caracorumensis m sutchanica m shiptoni m kumensis m wanganensis m neimongolensis m delicata and m rhaphidoformis in addition species once referred to monodiexodina but now should be excluded from the genus are also investigated in terms of their generic positions in reconstructed mid permian paleomap monodiexodina bearing areas can be restored to either northern or southern middle latitudes between high latitudinal cool cold water climatic realm and paleo tropical warm water realm these two middle latitudinal areas each corresponding to the northern and southern transitional zones respectively can be best interpreted climatologically as mesothermal warm temperate belts in both hemispheres thus suggesting the genus to be a paleobiogeographically typical antitropical fusulinoidean taxon moreover the genus is generally found in a monotypic crowded manner in sandy sediments with their shells being often aligned uni directionally this mode of occurrence of monodiexodina strongly suggests that it was adapted to shallow marine high energy environments which would probably be essentially maintained by the acquisition of highly elongated fusiform subcylindrical shells with well developed polar torsion this morphological feature is adapted to increase septal pores per unit area in polar regions thus increasing possibility to develop more pseudopodia on both sides of test it probably has a functional significance for not only locomotion but also anchoring their tests on the surface of bottom sediments in agitated water conditions the genus itself is considered to be a rather long ranging taxon from the late yakhtashian artinskian to the early midian capitanian it is therefore concluded that monodiexodina had an opportunistic character occurring repeatedly only when favorable high energy conditions such as sand shoal appeared in warm temperate climatic belts in both hemispheres monodiexodina originated in the southern transitional zone from an elongated eoparafusulina stock at late early permian around late artinskian time it flourished in southern middle latitudinal areas in latest early and early middle permian time the genus then migrated to the northern hemisphere northern transitional zone by some dispersion mechanism at around the early middle permian and prevailed there during the remaining period of the middle permian

a direct measurement of the distribution in depth of 26al in the estacado meteorite abstract the two dimensional distribution of 26al across a slice of the estacado meteorite was measured using non destructive coincidence counting the maximum activity was found to be 60 2 dpm kg 1 and the variation across the slice rather small the intensity and distribution are in moderate agreement with existing theoretical models if the pre atmospheric shape of the meteorite had been a sphere of radius 0 35 0 05 m but it was more likely to have been slightly non spherical

middle permian u pb zircon ages of the glacial deposits of the atkan formation ayan yuryakh anticlinorium magadan province ne russia their significance for global climatic interpretations abstract the atkan formation in the ayan yuryakh anticlinorium magadan province northeastern russia is of great interest because of the occurrence of deposits of apparent dropstones and ice rafted debris that have been previously interpreted as glacial two high precision u pb zircon ages one for an intercalated volcanic tuff 262 5 0 2 ma and the other for a boulder clast 269 8 0 1 ma within a diamictite of the atkan formation constrain the age of the atkan formation as guadalupian middle permian sedimentologic study of the atkan formation casts doubt on the glacial nature of the diamictites deposition of rocks of the atkan formation temporally correlates with the capitanian interglacial event in the southern hemisphere that recently was calibrated with high precision ca tims the previously proposed climate proxy record based upon warm water foraminifera which corresponds closely to global climate fluctuations is compared with the glacial record of eastern australia and indicates that the capitanian was a time of globally warm climate the sedimentology of atkan formation the record of diversification of both fusulinids and rugosa corals global sea water temperature and sea level fluctuations agree well with high latitude paleoclimate records in northeastern russia and eastern australia major components of the atkan formation the volcanic rocks are syngenetic with the sedimentation process the volcanic activity in the nearby regions during middle late permian was quite extensive

the permian biostratigraphy of the kolyma omolon region northeast asia the main features of the tectonics permian paleogeography biota structural facies zonation of the kolyma omolon region are analysed the characteristics of the permian regional stratigraphic scale of the kolyma omolon region are described the permian deposits of the kolyma omolon region are divided into four regional stratigraphic subdivisions ranked as superhorizons which in turn are subdivided into nine horizons these horizons are further subdivided into 18 provincial zones lones in accordance with russian stratigraphical nomenclature most of the lones distinguished have dual index species representing the dominant brachiopod and bivalve species the chosen nominal species of these lones are as a rule related to each other phylogenetically and as such they represent key stages in the evolution of their respective taxonomic groups through the permian the resultant biostratigraphic scale is adopted as a regional one for the kolyma omolon chukotka and southeastern part of the verkhoyan okhotsk regions almost all the lones distinguished can also be recognized in the verkhoyansk region and many of the lones are also traceable outside northeast asia q 2006 elsevier ltd all rights reserved

atmospheric boundary layer adjustment to the synoptic cycle at the brazil malvinas confluence south atlantic ocean 1 this study analyzes and discusses atmospheric boundary layer vertical profiles of potential temperature specific humidity and wind speed at each of the sides of the brazil malvinas confluence in the southwestern atlantic ocean such confluence is characterized by the meeting of water masses with very different characteristics the southern waters of the malvinas current can be several degrees colder and appreciably less salty than the northern brazil current waters at the same time a synoptic cycle can be identified at the region marked by the successive passages of frontal systems and extratropical cyclones the different phases of the synoptic cycle lead to different thermal advections at the confluence causing respective different patterns of atmospheric boundary layer adjustment to the surface heterogeneity induced by the confluence in the present study this adjustment along the synoptic cycle is analyzed using data from five experiments performed across the confluence from 2003 to 2008 in each of the campaigns a number of soundings were launched from a ship at both sides of the confluence a climatological analysis with respect to the closest frontal passage is presented and it suggests that the observations collected at each of the years analyzed are referent to a different day of the synoptic cycle the average profiles at each side of the confluence are in agreement with previous modeling studies of warm and cold thermal advection patterns over an oceanic front furthermore our study shows that peculiar transitional characteristics are also observed between the conditions of well established warm and cold advection at many phases of the synoptic cycle a strongly stratified boundary layer occurs at one or both sides of the confluence some of the observed characteristics such as a large moisture accumulation near the surface suggest that existing sensible and latent heat fluxes parameterizations fail under very strong stratifications and the consequences of this deficiency are analyzed

the sedimentary record of drifting ice early wisconsin sunnybrook deposit in an ancestral ice dammed lake ontario canada abstract outcrops of pebbly mud diamict at scarborough in southern ontario canada the so called sunnybrook till are associated with the earliest incursion of the laurentide ice sheet lis into mid continent north america some 45 000 years ago the sunnybrook is a blanket like deposit containing deepwater ostracodes and occurs conformably within a thick 100 m succession of deltaic and glaciolacustrine facies that record water depth changes in a large proglacial lake contextual evidence associated facies sedimentary structures deposit geometry and landforms indicates a low energy depositional setting in an ice dammed ancestral lake ontario in which scouring by floating ice masses was an important process u shaped iceberg cut scours with lateral berms up to 7 m deep occur on the upper surface of the sunnybrook and are underlain by sub scour structures that extend several meters below the scour base ice rafted concentrations of clasts clast layers grooved surfaces formed by floating ice glissading over a muddy lake floor soft sediment striations and melanges of sand and mud mixed by grounding ice keels ice keel turbates are present and are all well known from modern cold environments the wider significance of this depositional model is that the lis margin lay east of scarborough and did not overrun southern ontario this finding is in agreement with recent data from the erie basin of canada ohio and indiana where deposits formerly correlated with the sunnybrook and thus implying an extensive early wisconsin ice sheet are now regarded as illinoian a speculative hypothesis is proposed that relates deposition of the sunnybrook and two younger deposits of similar sedimentology to surge like instabilities of the southern lis margin

till as a glacial tectomict its internal architecture and the development of a typing method for till differentiation abstract till has been studied for over a century yet still a clear understanding of the mechanics of deposition and or emplacement of till eludes us tills in the past have been generally subdivided into sediments formed in various sub environments of the glacial system as such it has been generally agreed that tills can be separated in terms of these types based on various attributes such as clast fabric increasingly such separation into various sub types of till has become however highly debatable and tenuous based upon the use of micromorphology and a greater in depth appreciation of the internal architecture of till it has become apparent that previously established classifications of till are erroneous micromorphology reveals that deposition and or emplacement of tills is a complex tectonic process such that lodgement melt out and flow tills as previously defined do not appear to exist rather a new term better describes tills as glacial tectomicts by using micromorphology in establishing the presence of sets of microstructures a statistical method is introduced that permits differentiation of tills from other diamictons the implications for this new understanding of tills allied to statistical typing is considerable in terms of till formation glacial stratigraphy and understanding glacial environments in terms of stress histories porewater transmission subglacial deformation mechanics till rheological phase changes and the timeline of till formation

linked debrites in sand rich turbidite systems origin and significance abstract the outer parts of a number of small late jurassic sandy deep water fans in the northern north sea are dominated by the stacked deposits of co genetic sandy and muddy gravity flows sharp based structureless and dewatered sandstone beds are directly overlain by mudclast breccias that are often rich in terrestrial plant fragments and capped by thin laminated sandstones pseudonodular siltstones and mudstones the contacts between the clast rich breccias and the underlying sandstones are typically highly irregular with evidence for liquefaction and upward sand injection the breccias contain fragments up to metre scale of exotic lithologies surrounded by a matrix that is extremely heterogeneous and strewn with multiphase and variably sheared sand injections and scattered coarse and very coarse sand grains often coarser than in the immediately underlying sand bed markov chain analysis establishes that the breccias consistently overlie sandstones and the character of the breccias and their external contacts rule out a post depositional origin via in situ liquefaction intrastratal flowage or bed amalgamation and disruption the breccias are interpreted as debrites that rode on a water rich sand bed just deposited by a co genetic concentrated gravity current as such they are referred to as linked debrites to distinguish them from debrites emplaced in the absence of a precursor sand bed the distinction is important because these linked debris flows can achieve significant mobility through entrainment of both water and sediment from beneath and they ride on a low friction carpet of liquefied sand this explains the paradox presented by fan fringes in which there are common debrites when conventional thinking might predict that deposits of low concentration gravity currents should be more important here in fact evidence for transport by low concentration turbidity currents is rare in these systems several possible mechanisms might explain the formation of linked flows but the ultimate source of both sandy and clast rich flow components must be in shallower water on the basin margin the debrites are not triggered from distal slopes flow partitioning may have occurred by upslope erosion and retardation of the mudclast charged portion of an erosional sandy density current partial flow transformation of a precursor debris flow and or hydraulic segregation and reconcentration of the flaky clasts and carbonaceous matter during transport linked debrites are not restricted to small sand rich fans and similar mechanisms may be responsible for the long runout of debris flows in other systems the recognition of a distinct class of linked debrites is of wider importance for facies prediction reservoir heterogeneity and even carbon fluxes and sequestration on continental margins

evolution of marine atmospheric boundary layer structure across the cold tongue itcz complex the structure of the marine atmospheric boundary layer mabl over the tropical eastern pacific ocean is influenced by spatial variations of sea surface temperature sst in the region as the mabl air is advected across a strong sst gradient associated with the cold tongue itcz complex ctic substantial changes occur in the thermodynamic structure surface fluxes and cloud properties this study attempts to define and explain the variability in the mabl structure and clouds over the ctic using data collected on research cruises from the fall seasons of 1999 2001 composite soundings were created for both the cold and warm sides of the sst front to describe the mean atmospheric boundary layer abl structure and its evolution across this front the average difference in sst across this front was 6 c much of this difference was concentrated in a band only 50 km wide during the fall seasons on the cold side of the gradient a well defined inversion exists in all years below this inversion both fair weather cumulus and stratiform clouds are observed as the mabl air moves over the sst front to warmer waters the inversion weakens and increases in height the mabl also moistens and eventually supports deeper convection over the itcz both the latent and sensible heat fluxes increase dramatically across the sst front because of both an increase in sst and surface wind speed cloudiness is variable on the cold side of the sst front ranging from 0 2 to 0 9 coverage on the warm side cloud fraction was quite constant in time with values generally greater than 0 8 the highest cloud top heights 3 km are found well north of the sst front indicating areas of deeper convection an analysis using energy and moisture budgets identifies the roles of various physical processes in the mabl evolution

structure and formation of the highly stable marine boundary layer over the gulf of maine 1 a shallow stable boundary layer is ubiquitous over the cool waters of the gulf of maine in summer this layer affects pollutant transport throughout the region by isolating overlying flow from the surface in this paper we explore how the stable boundary layer is formed and describe its characteristics the temperature profile of the lowest 1 2 km of the atmosphere over the gulf of maine is remarkably similar regardless of transport time over water or the time of day when the flow left the land provided only that the flow is offshore this similarity is forced by the roughly constant water temperature and the roughly constant temperature of the free troposphere over the continent however the processes leading to the similar profiles are quite different depending on the time of day when the flow crosses the coast air leaving the coast at night already has a stable profile whereas air leaving the coast at midday or afternoon has a deep mixed layer in the latter case the stable layer formation over the water is of interest using observations of surface fluxes profiles and winds on the noaa research vessel ronald h brown from the 2004 international consortium for atmospheric research in transport and transformation icartt new england air quality study we show that the formation of the stable layer which involves cooling a roughly 50 to 100 m deep layer by 5 15 k occurs within 10 km and a half hour after leaving the coast the internal boundary layer near shore is deeper than predicted by standard relationships historical data are explored and also show deeper internal boundary layers than predicted we also describe one exceptional case where a 200 m deep neutral layer was observed and discuss the degree of isolation of the stable boundary layer and its duration

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

multi sensor satellite and in situ measurements of a warm core ocean eddy south of the brazil malvinas confluence region abstract a warm core eddy was detected south of the brazil malvinas falkland confluence bmc region in satellite images of the southwestern atlantic ocean in late 2002 the structure was also sampled by in situ instruments deployed by a ship in 2 days of november 2002 an analysis of satellite data was performed to account for the lifecycle dimension surface temperature surface chlorophyll concentration surface height anomaly and displacement of the eddy since it was detached from the brazil current in september 2002 satellite data were derived from several sources such as the amsr e modis and radar altimeter the structure lasted 64 days at south of the brazil malvinas confluence region later being re assimilated by the brazil current return flow in situ data collected during 2 days showed that the eddy was about 150 m deep 5 5 c warmer and 1 practical salinity unit saltier than adjacent waters the salt anomaly associated to the eddy was estimated as 1 37 10 12 kg while its heat content was 4 24 10 18 j these are typical estimates for eddies present at the bmc region sea surface temperature sst chlorophyll concentration and sea surface height anomaly time series were analyzed for the eddy s center along its trajectory path throughout its lifetime mean translational velocities for the eddy during its lifetime were computed from visual interpretation and by using an adaptation of the maximum cross correlation mcc method on amsr e sst images the overall deviation between the two methods was 26 this suggests that the mcc method has a potential to be applied in monitoring programs to automatically account for the translational velocities of eddies in the bmc region

iceberg drop dump and grounding structures from pleistocene glacio lacustrine sediments scotland abstract dropstone dump and grounding structures resulting from the melt out of debris contained in floating and grounded icebergs are described from a pleistocene ice marginal glacio lacustrine sequence in scotland dropstones display bending penetration rucking and complete rupture of stratum occurring beneath them and onlap above them with the degree of deformation varying as a function of the size shape and axial disposition of the clast and of the sediment type into which they fell dump structures are conical mounds of gravel or diamict formed by the break up and overturning of dirt laden icebergs and the consequent release of large quantities of debris to the lake floor grounding structures are caused by the grounding of icebergs the down warping of underlying lake floor se iment and the subsequent in situ melt out of contained debris to form isolated troughs of diamict

the middle permian capitanian mass extinction on land and in the oceans abstract a middle permian mass extinction first discovered in 1994 has become known as the end guadalupian event in the literature however recent studies of foraminifera and brachiopod range truncations in conodont dated sections on the south china block have shown that the losses occur below this level in the middle of the capitanian stage extinctions were suffered by several other groups notably the corals whilst the mollusc record is more enigmatic a major bivalve crisis has been reported in some studies the giant alatoconchids being notable victims but not others gastropods were unaffected by the crisis whilst a roughly contemporaneous ammonoid mass extinction may have occurred in the early wuchiapingian a few million years after the main marine losses compilation of data from plant species in south china reveals a significant 24 loss suggesting that the capitanian crisis also occurred on land an intra capitanian extinction of 56 of plant species in north china block sequences may also have coincided with these losses correlation of these marine and terrestrial extinction events using the palaeomagnetic record provides two alternatives either turnover amongst plant species is contemporaneous with the marine extinction and the eruption of the emeishan flood basalt province in southwest china or plant losses post date the marine extinction and instead coincide with the waning phase of the igneous province current understanding of the major dinocephalian extinction suggests this event occurred during the preceding stage the wordian but future improvements in both sampling and dating this tetrapod crisis may reveal a synchronicity of plant animal and marine invertebrate extinctions the clear temporal link of the capitanian marine extinction with emeishan volcanism suggests that these flood basalt eruptions triggered the crisis a contemporaneous major negative c isotope excursion suggests that like many other mass extinction events methane release from hydrates may also be implicated however in the best dated chinese sections the main excursion is found to slightly post date the extinction which occurs at the end of an unusual and unexplained interval of exceptionally heavy 13c values other usual suspects for mass extinctions either lack geological and palaeontological evidence e g marine anoxia and global cooling or do not precisely correlate with the extinction e g major eustatic regression

permian diamictites in northeastern asia their significance concerning the bipolarity of the late paleozoic ice age despite a lack of detailed sedimentologic analyses diamictites in the middle permian atkan formation were previously interpreted as glaciomarine and glacially influenced marine deposits this interpretation allowed this unit to play a prominent role in paleoclimatic and biogeographical reconstructions associated with presumed bipolar glaciation during the late paleozoic ice age lpia in this sense the lpia is considered to be a close analog to bipolar glaciation and climate change during the cenozoic here results are presented that challenge the glacigenic interpretation for these strata and negate interpretations of the bipolar nature of the lpia the 400 to 1500 m thick atkan formation was deposited in back arc basins associated with activity of the okhotsk taigonos volcanic arc along the leading edge of pangea as it drifted across the north polar circle the occurrence of tuffs volcanic clasts and glass shards indicate derivation from a nearby arc cooling and solidification of some clasts during sedimentation is suggested by the occurrence of clasts with embayments and protrusions that extend into the surrounding matrix clasts with columnar like jointing and alteration of the matrix surrounding some clasts ca tims dating of tuff zircons indicate a late capitanian age which is consistent with fossils within the strata bedded diamictites deposited as debrites dominate these diamictites which occur as tens of m thick downlapping packages that thicken then thin upward were deposited as prograding and abandoning sediment gravity flow fans chaotic and folded strata formed as slumps graded sandstones and conglomerates were deposited as turbidites and mudstones were deposited as mudflows low density turbidites and hemipelagic deposits striated clasts and outsized clasts piercing bedding were not observed in the study area strata above and below the atkan formation contain abundant graded beds and deep water trace fossils indicating deposition as turbidites the combination of debrites turbidites slumps volcanic grains clasts glass and tuffs and an absence of glacigenic indicators suggest that atkan strata were deposited in deep water basins associated with the development of the volcanic arc rather than due to glacial activity these findings are significant as they require reconsideration of current views of lpia glaciation and suggest that ice sheets were limited to gondwana

the permian of the transbaikal region eastern russia biostratigraphy correlation and biogeography abstract permian deposits in the transbaikal region within the mongol okhotsk belt and adjacent areas have been studied the characteristics of the permian marine and continental formations are documented and our present understanding of the stratigraphy is presented the constitution of the regional stratigraphic units or horizons is specified and their paleontological characteristics are stated the correlation of the horizons with the permian global chronostratigraphical scale is rather tentative and has been made possible only by comparison with the well characterized sections of northeast russia incomplete faunal distribution in the sections of the transbaikal region makes it difficult to distinguish uninterrupted zonal sequences however the presence of characteristic associations and often of index species of biozones recognized outside the transbaikal region makes it possible to trace and date these biostratigraphic units the contradiction between paleobiogeographic and paleomagnetic evidence is noted the permian biota being represented by boreal faunas and angaran floras suggestive of temperate latitudes while paleomagnetic data seem to indicate tropical latitudes for the transbaikal region during the permian

permian ice volume and palaeoclimate history oxygen isotope proxies revisited abstract a high resolution oxygen isotope record based on 356 measurements of conodont apatite from several low latitudinal sections in south china usa and iran was composed in order to unravel permian palaeotemperature and ice volume history the conodont apatite 18 o record is compared to published brachiopod calcite 18 o records brachiopods and conodonts from different palaeocontinents show significantly different 18 o values suggesting differences in local climatic conditions e g evaporation precipitation ratio as a consequence secular changes in palaeotemperature and oxygen isotope composition of permian sea water cannot be reconstructed from records combined from different areas but have to be based on records from a specific area oxygen isotope analyses of different conodont taxa suggest that streptognathodus and hindeodus lived in near surface seawater and recorded surface water temperature whereas the habitat of gondolellid genera was variable depending on sea level with both near surface and deeper waters as potential life habitat the oxygen isotope record measured on conodonts from south china exhibits relative high values between 22 and 23 vsmow during the glaciated early permian translating into warm seawater temperature between 26 and 30 c assuming that the late palaeozoic ice volumes were comparable to the pleistocene glacial maxima in contrast to the earlier view that the late palaeozoic ice age lpia terminated in the late sakmarian the south china conodont apatite oxygen isotope record suggests waning of the ice sheets in the kungurian ice melting is indicated by a pronounced decrease in 18 o of 2 vsmow which is interpreted as reflecting the combined effect of climatic warming and glacial ice melting significant temperature fluctuations 4 c warming succeeded by 6 to 8 c cooling are observed during the guadalupian lopingian transition interpreted as combined climate changes induced by emeishan volcanism and changes in habitat depth of gondolellid conodonts oxygen isotope values increase to 22 vsmow in the changhsingian which suggests climate cooling and clarkina moving to deeper waters because of the changhsingian sea level rise across the permian triassic boundary 18 o values decrease from 22 to 19 vsmow parallel to the significant negative carbon isotope excursion and the eruption of the siberian traps the latter is pointing to a cause effect relationship as a consequence of the massive release of volcanic greenhouse gases derived from the siberian volcanism and related processes

an early permian fusuline fauna from southernmost peninsular thailand discovery of early permian warming spikes in the peri gondwanan sibumasu block abstract an early permian fusuline fauna is reported from the tarn to formation of the yala area in southernmost peninsular thailand which geotectonically belongs to the peri gondwanan sibumasu block the fauna consists of pseudofusulina and praeskinnerella species including forms closely resembling tethyan and panthalassan pseudofusulina fusiformis and pseudofusulina ex gr kraffti a yakhtashian bolorian age is estimated for this fauna in sibumasu shallow marine biotas showing similar tethyan affinities such as the fusulines misellina and alatoconchid bivalves also occur in the early permian succession of the kinta valley area in western peninsular malaysia these unusual tethyan faunas within early permian peri gondwanan fossil records suggest episodic influences from paleo tropical tethyan biotas they are here interpreted as showing short term warming spikes during the late yakhtashian bolorian transgression which would facilitate sporadic migration and temporal inhabitation of warm water dwellers into the eastern cimmerian areas the yala and kinta valley fusuline and other invertebrate faunas would give us a new insight for the permian geohistory and environmental change of the peri gondwanan sibumasu block

high precision u pb zircon age constraints on the guadalupian in west texas usa abstract the guadalupian epoch was characterized by major changes in paleogeography paleoclimate and biodiversity yet the paucity of precise and accurate radioisotopic dates from the guadalupian stages in their type area guadalupe mountains national park in west texas has rendered their calibration inadequate in this study we report high precision u pb zircon geochronology by the ca id tims method from three ash beds 2 internal errors only in the rader member of the bell canyon formation at the back ridge section 262 127 0 097 ma mswd 0 89 n 3 the lower pinery member of the bell canyon formation at the frijole section 264 23 0 13 ma mswd 0 89 n 8 and the basal south wells member of the cherry canyon formation at the monolith canyon section 266 525 0 078 ma mswd 0 62 n 5 the bayesian interpolation statistics method is used to establish an age stratigraphy model that estimates the base of the capitanian to be 264 28 0 16 ma serving as the best age estimate for the capitanian stage at present in addition we review the existing geochronology from the guadalupian series in west texas and seek to propose more precise temporal estimates of guadalupian geological and biological events these data constrain the high frequency sequences of the cherry canyon and bell canyon formations in the guadalupe mountains national park area accordingly the base of the wordian is estimated at 266 9 0 4 ma and the illawarra geomagnetic polarity reversal in west texas at 267 4 0 4 ma to 266 5 0 3 ma the global end guadalupian extinction began in the conodont zone of jinogondolella altudaensis above the base of the reef trail member of the bell canyon formation and might continue to the clarkina postbitteri postbitteri zone in the earliest wuchiapingian the conodonts display a rapid evolutionary rate during this interval this constrains the biotic crisis from ca 260 ma to 259 ma based on our conodont age estimation the emplacement of the emeishan large igneous province elip in south china has been constrained to ca 260 ma to 257 4 ma based on zircon u pb geochronology by the ca id tims method overlapping with the end guadalupian extinction which provides support for the temporal relationship between them additionally the elip persisted into the early wuchiapingian and may have hampered ecosystem restoration during the post extinction interval

structure of offshore flow abstract the horizontal and vertical structure of the mean flow and turbulent fluxes are examined using aircraft observations taken near a barrier island on the east coast of the united states during offshore flow periods the spatial structure is strongly influenced by the surface roughness and surface temperature discontinuities at the coast with offshore flow of warm air over cool water the sea surface momentum flux is large near the coast and decreases rapidly with increasing offshore distance or travel time the decrease is attributed to advection and decay of turbulence from land the rate of decrease is dependent on the characteristic timescale of the eddies in the upstream land based boundary layer that are advected over the ocean as a consequence the air sea momentum exchange near the coast is influenced by upstream conditions and similarity theory is not adequate to predict the flux the vertical structure reveals an elevated layer of downward momentum flux and turbulence energy maxima over

new u pb constraints identify the end guadalupian and possibly end lopingian extinction events conceivably preserved in the passive margin of north america implication for regional tectonics the discovery and dating of a volcanic ash bed within the upper phosphoria formation in se idaho usa is reported the ash occurs 11 m below the top of the phosphatic meade peak member and yielded a 206 pb 238 u date of 260 57 0 07 0 14 0 31 ma i e latest capitanian guadalupian the stratigraphic position of this ash near the top of the meade peak phosphatic member of phosphoria formation indicates plausible completeness of the sedimentation within the guadalupian lopingian and probably at the permo triassic p t transitions the new radiometric age reveals that the regional biostratigraphy and palaeontology of phosphoria and park city formations requires serious reconsideration particularly in cool water conodonts bryozoans and brachiopods the new age proposes that the guadalupian lopingian boundary glb coincides with the meade peak rex contact and consequently with the end guadalupian extinction event the lack of a major unconformity at the p t transition suggests that the effects of the sonoma orogeny were not as extensive as has been assumed

sst induced surface wind variations over the brazil malvinas confluence satellite and in situ observations abstract the confluence of the brazil malvinas currents maintains strong sea surface temperature sst fronts in the midlatitude southwestern atlantic year round sst effects on near surface stability and surface wind variations are examined in this region using satellite and in situ datasets satellite observations show strong weak surface wind speeds over the warm brazil cold malvinas current a novel feature of this study is the construction of a high resolution surface meteorological dataset that is based on historical ship observations analysis of this new in situ dataset reveals an increased reduced sea air temperature difference over the brazil malvinas current indicating destabilization stabilization in the atmospheric boundary layer these results are consistent with the sst induced vertical mixing mechanism for wind adjustment the sst effect on the near surface atmosphere is observed both in the climatology and on interannual time scales in the brazil malvinas confluence along a zo

high precision u pb zircon age calibration of the global carboniferous time scale and milankovitch band cyclicity in the donets basin eastern ukraine 1 high precision id tims u pb zircon ages for 12 interstratified tuffs and tonsteins are used to radiometrically calibrate the detailed lithostratigraphic cyclostratigraphic and biostratigraphic framework of the carboniferous donets basin of eastern europe chemical abrasion of zircons use of the internationally calibrated earthtime mixed u pb isotope dilution tracer and improved mass spectrometry guided by detailed error analysis have resulted in an age resolution of 0 05 or 100 ka for these carboniferous volcanics this precision allows the resolution of time in the milankovitch band and confirms the long standing hypothesis that individual high frequency pennsylvanian cyclothems and bundles of cyclothems into fourth order sequences are the eustatic response to orbital eccentricity 100 and 400 ka forcing tuning of the fourth order sequences in the donets basin to the long period eccentricity cycle results in a continuous age model for the middle to late pennsylvanian moscovian kasimovian ghzelian strata of the basin and their record of biological and climatic changes through the latter portion of the late paleozoic ice age detailed fusulinid and conodont zonations allow the export of this age model to sections throughout euramerica additional ages for mississippian strata provide among the first robust radiometric calibration points within this subperiod and result in variable lowering of the base ages of its constituent stages compared to recent global time scale compilations

end guadalupian extinction of the permian gigantic bivalve alatoconchidae end of gigantism in tropical seas by cooling abstract the unique permian bivalve family alatoconchidae has aberrant shell forms and extraordinary size up to 1 m representing the largest bivalve group in the paleozoic their occurrence is reported sporadically from lower middle permian shallow marine carbonates in 9 areas in the world tunisia croatia oman iran afghanistan thailand malaysia the philippines and japan that cover low latitudes of both the tethyan and panthalassan domains alatoconchids almost always occurred in close association with large tested fusulines verbeekinidae and or rugose corals waagenophyllidae of the typical tethyan assemblage suggesting their preferential adaptation to shallow warm water tropical environments this tropical trio alatoconchidae verbeekinidae and waagenophyllidae became extinct either during the late guadalupian or around the guadalupian lopingian boundary g lb their intimate association and occurrence range suggest that these 3 taxonomically distinct clades may have shared not only a common habit but also a common cause of extinction the shell structure of alatoconchids suggests their symbiosis with photosynthetic organisms algae cyanobacteria in order to maintain their large body size that required high energy consuming metabolism in contrast to smaller forms the alatoconchidae attained their largest size in the wordian middle guadalupian probably maximizing the benefits of photosymbiosis the subsequent extinction of the warm water adapted tropical trio both in tethys and panthalassa positively supports the explanation that a critical cooling took place on a global scale including low latitude oceans the end of the gigantism in fusulines and bivalves in the capitanian late guadalupian was likely caused by the collapse of photosymbiotic systems during a temporary temperature drop of seawater kamura cooling event coupled with eutrophication that was detrimental to the tropical fauna adapted particularly to oligotrophic conditions gigantism of bivalves occurred several times in the phanerozoic e g siluro devonian permian triassic early jurassic and jurassic creataceous mostly in warm periods the sea level change in the phanerozoic apparently synchronized with the intermittent rise and decline of bivalve gigantism suggesting that the photosymbiosis related gigantism in low latitudes may serve as a potential monitor of global warming cooling in the past

warm water benthic foraminifera document the pennsylvanian permian warming and cooling events the record from the western pangea tropical shelves abstract shallow warm water benthic foraminifera swwbf including all larger fusulinids symbiont bearing benthic foraminifera are among the best indicators of paleoclimate and paleogeography in the carboniferous and permian the distribution of benthic foraminifera in space and time constrain important tectonic paleogeographic and climatic events at a global scale the north american shelves during pennsylvanian and permian time though geographically within the tropical belt are characterized by temperate environments with significantly lower foraminifera diversification and rare occurrences of warm water tethyan forms that are in general appear in the region as a migration entities such environments allow documentation of warming episodes associated with sudden immigration of warm water and exotic forms of swwbf that evolved elsewhere into the area first occurrence datum fod of the forms exotic to north america during warming episodes are always delayed in respect of their first appearance datum fad elsewhere the time of delay and taxonomic diversity of fusulinids in north america shelves depended on the scale and intensity of the warming episodes cooling events on the other hand are associated with decreased taxonomic diversity and appearances of endemic forms characteristic only of temperate water provinces the occurrence of these forms in boreal and north american provinces appears to be isochronous as their environments are uniform and induce their uniform and isochronous distribution several warming and cooling episodes during pennsylvanian permian time are recognized the differences between taxonomic variations in each event could potentially be used for provisional estimation of the degree of climatic change a strong link between biotic and climatic events in north american province and the similarity of biotic changes in the north american and other provinces suggests that paleoclimatic events in north american province were controlled by global factors

discovery of shallow marine biofacies conodonts in a bioherm within the carboniferous permian transition in the omolon massif ne russia near the north paleo pole correlation with a warming spike in the southern hemisphere the conodont genera hindeodus and streptognathodus are reported for the first time within the carboniferous permian transition in the northern high latitudes of the paren river omolon massif ne russia several fossil groups including brachiopods bivalves scaphopods and microgastropods were found to be prolific in the invertebrate dominated bioherms these bioherms occur within predominantly siliciclastic sequences with extremely poor fauna whereas in the studied bioherms the diversity of the bivalves and brachiopods exceeded observed diversity elsewhere in coeval facies in ne russia the bioherms are biostratigraphically constrained as uppermost pennsylvanian to lowermost cisuralian based on ammonoids the very unusual peak of bivalve and brachiopod diversity and the occurrence of conodonts that require minimum sea water temperatures of at least 10 12 c indicate a short lived but significant warming event at that time at least of provincial significance this event most likely corresponds with a short lived warming event recently discovered in the east of the southern hemisphere in timor and australia thus the event is possibly of global significance

permian carbon isotope and clay mineral records from the xikou section zhen an shaanxi province central china climatological implications for the easternmost paleo tethys abstract permian carbon isotopic and clay mineralogical records were recovered from the carbonates in the xikou section a complete and uninterrupted upper carboniferous to lower triassic carbonate dominated succession exposed in zhen an shaanxi province central china which were used to document carbon isotopic signatures and climatic changes affecting the easternmost paleo tethys region during the permian both carbon isotope and clay mineralogical data suggest fluctuating climatic conditions and trends that can be approximately correlated with eastern australian glaciations and north american craton during the artinskian to capitanian stages two global carbon isotopic anomalies across the permian triassic boundary and the guadalupian lopingian series boundary were detected for the first time in the stratigraphic record of the south qinling micro continental block the capitanian stage comprises an early phase of climatic warming followed by a later phase of climatic cooling the kungurian stage represents a climatic warming interval and the main phase of deglaciation during the late paleozoic ice age lpia a 13c positive shift across the boundary of the artinskian to kungurian stages together with the following negative excursion recorded in the early kungurian stage can be used as an indicator for the boundary between the artinskian and kungurian stage

on the role of sea surface temperature gradients in forcing low level winds and convergence in the tropics abstract we examine the importance of pressure gradients due to surface temperature gradients to low level p 700 mb flow and convergence in the tropics over time scales 1 month the latter plays a crucial role in determining the distribution of cumulonimbus convection and rainfall our approach is to consider a simple one layer model of the trade cumulus boundary layer wherein surface temperature gradients are mixed vertically consistent with ecmwf analyzed data the top of the layer is taken at 700 mb the influence from higher levels is intentionally suppressed by setting horizontal pressure gradients and frictional stresses to zero at the top of the layer horizontal convergence within the layer is taken up by cumulonimbus mass flux however the development of the cumulonimbus mass flux is associated with a short relaxation time o hr roughly the development time for such convection during this short time horizontal convergence acts to redistribute mass so as to reduce horizontal pressur

paleoenvironmental setting mechanism and consequence of massive organic carbon burial in the permian junggar basin nw china abstract the junggar basin in northwestern china is a typical walled sedimentary basin that has a prolonged basin evolution history from the paleozoic to cenozoic and is rich in petroleum resources permian strata reach thousands of meters in thickness and have been intensively studied for their record of regional tectonics and paleoenvironments they have also been exploited for oil and gas for the past several decades in this paper we summarize perspectives on tectonic evolution stratigraphic framework sedimentary environments and the paleoclimate of the permian junggar basin and the adjacent turpan basin further we discuss the mechanism and consequences of massive organic carbon burial based on a compilation of published radiometric dating datasets an updated chronostratigraphic framework was proposed for the junggar basin this framework constrains the ages of two main petroleum source intervals the fengcheng formation and the lucaogou and equivalent formations as early permian and middle permian respectively although a global warming and drying trend was present throughout the permian period the regional climate over the junggar basin was drier in early permian and more humid in the middle late permian with short term climatic fluctuations during the deposition of the two petroleum source intervals dry and temperate climate prevailed and evaporative lacustrine environment dominated organic matter enrichment was promoted by stable salinity stratification and limited dilution by inorganic sediments leading to one of the richest lacustrine source rock deposits in the world the average organic carbon burial rates were 11 2 gc m2 yr for the lucaogou formation and 3 5 gc m2 yr for the fengcheng formation lower than the average organic carbon burial rate in modern lakes however considering the large areas of global tectonic lakes in the permian period organic carbon burial in lacustrine environments could act as a significant carbon sink and impact the global carbon cycle and climate evolution

high precision radioisotopic ages for the lower midian upper wordian stage of the tethyan time scale shigeyasu quarry yamaguchi prefecture japan abstract global correlation of strata to the guadalupian series permian period of the international geologic time scale remains provisional due to a lack of the sufficient biostratigraphically constrained radioisotopic ages five new high precision u pb radioisotopic ages were obtained from tuffs in the lower midian upper wordian volcano siliciclastic succession of the akiyoshi plateau southwestern japan two undisturbed and continuous tuffs occur within fusulinid bearing laminated limestone turbidites with precise biostratigraphic control the colania douvillei and lepidolina shiraiwensis fusulinid zones in the akiyoshi succession provide an early midian age in the tethyan provincial time scale the range of ages 267 46 0 04 ma to 265 76 0 03 ma over 25 m of section including the limestone turbiditic beds suggest that this lower midian stage of the tethyan time scale is correlated with the upper wordian stage of the international geologic time scale the sedimentologic bio and geochronologic data affirm the effectively conformable nature of the siliciclastic carbonate succession of the tsunemori formation at the shigeyasu quarry and the presence of acidic volcanic tuffs are consistent with a forearc basin or trench slope basin depocenter for the tsunemori formation

permian bivalve mollusks of northeast asia abstract bivalve mollusks are very important in the permian biota of northeast asia during the permian the bivalves had different distribution patterns both in space and time and their occurrence was governed by many factors related to water depth and geodynamic conditions in northeast asia there were two main bivalve paleocommunities shallow and deep sea bivalves through the permian the bivalves began to dominate benthic assemblages there are five major stages in their developmental history asselian artinskian kungurian roadian wordian capitanian early wuchiapingian and late changhsingian the mid kungurian stage was characterized by a maximum in bivalve diversity whereas the late kungurian early capitanian and latest permian had the lowest bivalve diversity

the permian of the verkhoyansk okhotsk region ne russia abstract this report summarizes data on the permian deposits of the verkhoyansk okhotsk region tectonics paleogeography fauna flora and stratigraphy the verkhoyansk okhotsk region covers the area of the verkhoyansk fold and thrust belt the permian deposits of this region were formed on the passive continental margin of the angarida continent the ancient siberian continent situated within the siberian platform this continental margin developed as the result of continental break up in the late precambrian late precambrian to jurassic including permian sediments were deposited on a passive margin with a continental shelf extending out into an ocean towards the northeast during the permian exclusively terrigenous sediments were deposited over a vast territory in the verkhoyansk paleobasin forming part of this continental margin the permian deposits are divided into six regional stratigraphic units ranked as horizons regional stages which in turn are subdivided into faunal zones and beds serving as the basis for intra regional correlation in the late jurassic cretaceous the continental margin sediments were converted into a foreland fold and thrust belt due to the collision of the siberian platform with the kolyma omolon and okhotsk continental blocks

sedimentological record of the late paleozoic glaciation in queensland australia although much is known of the timing geographical extent and character of the late paleozoic gondwanan glaciation its rec ord in eastern australia is poorly resolved some previous investigations have asserted that large parts of australia were covered by a cold based continental ice sheet during the pennsylvanian late carboniferous new data from queensland in northeast australia reported herein however suggest that the glaciation there was restricted to discrete short lived periods in the namurian 315 ma westphalian 311 ma and sakmarian 289 293 ma thick successions in three widely separated areas indicate that the glaciation was confined in each case to local valley or mountain glaciers and that the mainly proglacial sediments were enclosed in every case by substantial intervals of fluvial lacustrine and shallow marine strata deposited under nonglacial conditions accordingly we submit that the cessation of glacial sediment deposition elsewhere in gondwana during the pennsylvanian to earliest permian was due to the decay of glaciers rather than to a transition to a cold based ice sheet or sheets as has been previously suggested the interpretations presented herein make a significant contribution toward constraining the size and extent of glaciation in gondwana which has major implications for late paleozoic world climate and sea level fluctuations

evolution and extinction of permian fusulinid fauna in the khao tham yai limestone in ne thailand abstract the first detailed biostratigraphic investigation of a single limestone unit within the khao tham yai limestone shows it was deposited continuously in a shelf setting without any intercalation of clastic beds it ranges from the wordian middle middle permian up to the wuchiapingian lower upper permian the limestone unit is divided in ascending order into three fusulinid zones i e colania lepidolina and codonofusiella zones the middle zone is characterized by an abundance of large tested fusulinids characteristic of the lepidolina zone shell sizes of the fusulinid species in this zone display continuous rapid morphological change along a one way evolutionary path from small primitive species with simple structure to large highly evolved species having a complicated wall structure fusulinid biostratigraphy in a single limestone unit elucidates evolution and extinction patterns of permian fusulinids of the shallow water tethyan shelf area in the indochina block our study reveals that the boundary between the guadalupian middle permian and lopingian upper permian in the khao tham yai limestone is clearly defined as an abrupt change in the fusulinid assemblages from the elimination of large tested verbeekinids and schwagerinids to the domination of small shelled schubertellids the schubertellids underwent slower evolutionary morphological change than earlier fusulinids and were decreasingly dominant through the permian a similar pattern of fusulinid evolution and extinction at the guadalupian lopingian boundary occurs in shallow water tethyan shelf areas and mid oceanic shallow water environments in mid panthalassa eventually even smaller fusulinids abruptly become extinct clastic deposits finally replace previous carbonate formations characterized by algae foraminifera biota it starts in the upper middle permian in the southern parts and spreads throughout the whole area in the lower upper permian in ne thailand these observations suggest possible correlation between the turning points of fusulinid evolution and global environmental change such as worldwide sea level drop and its consequent effects

acme and demise of the late palaeozoic ice age a view from the southeastern margin of gondwana abstract palaeoenvironmental reconstructions from across the globe indicate that the climatic and oceanographic changes that accompanied the permian transition from deep icehouse to greenhouse conditions were uneven and asynchronous because of a paucity of well constrained data environmental changes in gondwana remain poorly understood relative to tropical pangaea in this regard the permian system of eastern australia provides a unique record of this transition along a high latitude open marine shelf not only was glaciation protracted here relative to other regions of gondwana but the record also spans temperate to polar palaeolatitudes providing an opportunity to examine environmental changes along a latitudinal transect we integrate proxies for 18oseawater palaeotemperature pco2 and depositional environment to assess the evolution of nearshore conditions through the permian glaciation was not continuous but rather focused into four discrete glacial epochs p1 p4 each several million years in length which alternated with nonglacial intervals of similar duration during the asselian mid artinskian p1 p2 time uniform conditions along the full extent of the margin were maintained by a cold boundary current coupled with oceanic upwelling increased spatiotemporal variability is evident at the end of glacial p2 mid artinskian perhaps due to tectonic changes that impacted the palaeogeography of the margin although glaciers had disappeared by this time elsewhere in gondwana eastern australia saw two additional periods of glaciation p3 roadian earliest captianian and p4 early wuchiagingian continued albeit intermittent glaciation was facilitated by drift toward higher palaeolatitudes orogenic activity that led to the development of areas of high elevation that could serve as nucleation points for glaciers and transient drops in atmospheric pco2 variations in meltwater input exerted a strong effect on local 18oseawater values complicating attempts to reconstruct latitudinal gradients in palaeotemperature results point to atmospheric co2 as the primary driver responsible for the dynamic climate variations evident in the record

cosmic ray effects in the antarctic meteorite allan hills a 78084 abstract in the antarctic h4 chondrite alha 78084 measurements of 26 al 53 mn noble gases and cosmic ray tracks have been performed on documented samples to investigate depth dependences of cosmic ray induced effects 26 al activities vary between 224 and 246 dpm kg si equ 53 mn activities range from 299 to 359 dpm kg fe in agreement with the kohman and bender model 1 22 ne 21 ne ratios between 1 145 and 1 176 are observed the 3 he 21 ne vs 22 ne 21 ne correlation shows a trend line similar to those found for st severin and keyes track data indicate ablation depths between 1 3 and 6 5 cm with a mean ablation of 3 8 cm this leads to a preatmospheric mass of about 40 kg and an ablation loss of about 66 by mass preatmospheric size and shielding calculated from measured 22 ne 21 ne ratios using the semi empirical curves of bhandari and potdar 2 agree with those derived from track measurements the combined data of spallation nuclides and cosmic ray tracks indicate a simple one stage irradiation as a small object with a preatmospheric radius of 14 1 cm for about 32 m y and a terrestrial age of less than 170 000 years

imprint of the late palaeozoic ice age on stratigraphic and carbon isotopic patterns in marine carbonates of the orogrande basin new mexico usa the permian records one of the most extreme climate transitions of the phanerozoic yet the climatic and environmental dynamics of this interval and their effects on neritic carbonate systems remain poorly constrained new stratigraphic and carbon isotope records from uppermost pennsylvanian to lower permian strata of the orogrande basin in south central new mexico usa provide fresh insights into the response of palaeotropical carbonate systems to the growth and demise of ice sheets on gondwana the earliest permian acme of glaciation is recorded in the orogrande basin as a series of subaerial exposure surfaces marked by highly variable 13c values that tend toward values as low as 6 these stratigraphic and isotopic patterns are interpreted to reflect the retreat of the sea from the basin during glacial expansion younger lower sakmarian to kungurian strata deposited during the long decline of the late paleozoic ice age are characterized overall by higher and more uniform 13c values 2 to 5 and show no evidence of long term subaerial exposure however these strata record two short lived excursions toward more negative 13c values these excursions occur through intervals that record shifts toward shallower and more restricted conditions in the orogrande basin the timing of these shifts corresponds to two periods of glacial expansion across eastern australia during late sakmarian to early artinskian and kungurian time these relationships suggest that pulses of glacial expansion in eastern gondwana were of sufficient magnitude to have caused relative sea level fall and possibly environmental change in the orogrande basin the results from this study suggest that marine chemistry depositional environments and sea level in the orogrande basin were profoundly influenced by epochs of gondwanan glaciation these inferences help improve the understanding of how palaeotropical carbonate systems responded to the effects of cryospheric changes during the acme and waning stages of the late palaeozoic ice age

oxygen isotope values from high latitudes clues for permian sea surface temperature gradients and late palaeozoic deglaciation abstract the permian was a period of waning large scale continental glaciations in the southern hemisphere the waning of these ice sheets during the early permian led to discharge of 18o depleted ice melt water into the oceans this coupled with rising seawater temperatures resulted in a concomitant decline of about 2 5 in the 18o of seawater as recorded by brachiopod shells from low latitude

cosmic ray records in the ll chondrite dhurmsala abstract the radionuclides 10be 26al and 53mn the noble gas isotopic composition of he ne and xe and cosmic ray particle track densities were determined in six documented samples of a large fragment of the dhurmsala meteorite fall using the 22 ne 21 ne ratios and the 21ne concentrations the cosmic ray exposure age of dhurmsala is deduced to be 13 0 1 0 my the results suggest a simple exposure history the six samples covering a distance of 13 cm do not show any significant isotopic variations due to depth effects as expected in a large meteorite consistent with the model calculations of reedy 1985 and bhandari and potdar 1982 the results obtained in this study indicate that the dhurmsala samples investigated here originate at a depth of 20 to 24 cm in a meteoroid with a preatmospheric radius of r 50 cm

evolution in a cold climate abstract a brief appraisal of marine fossils from high latitudes and episodically cold climate especially in east australia and new zealand during late palaeozoic and early mesozoic times shows patterns of evolution and survival that differ from those adduced for the palaeotropics and northern hemisphere examples taken from amongst phyla scyphozoa bryozoa brachiopoda and classes bivalvia and class cephalopoda suggest these attributes 1 evolution and demise of species and genera proceeded at a rate close to that known for palaeotropical and northern hemisphere macro invertebrates but involved fewer families and orders 2 possibly intraspecific variation was greater amongst southern palaeohemisphere permian species than in those of the permian palaeotropics 3 there was no proven diminution of life at the end of the guadalupian middle permian at southern high latitudes where however the fossil record is meagre for this interval younger wuchiapingian and changhsingian faunas were moderately diverse 4 there is no evidence for a high latitude southern hemisphere anoxic event in the early triassic despite claims of a world wide anoxic interval nor has any substantial volcanic eruption or bolide impact left any marked traces in the sedimentary record 5 as a consequence some major groups such as bryozoa and conulariida staurozoa survived the end permian extinction shock in the southern hemisphere 6 other major groups appear to have survived better in the south than in the north notably mollusc bivalvia and cephalopoda it therefore appears likely that triassic seas were restocked substantially from the southern hemisphere and that the permian extinction shock was asymmetric with respect to latitudes in its distribution and affect

late palaeozoic global changes affecting high latitude environments and biotas an introduction abstract the late palaeozoic ice age lpia spanning approximately from 320 ma serpukhovian late mississippian to 290 ma mid sakmarian early permian represents the vegetated earth s largest and most long lasting regime of severe and multiple glaciations involving processes and patterns probably comparable to those of the last ice age accompanying the lpia occurred a number of broadly synchronous global environmental and biotic changes these global changes as briefly reviewed and summarized in this introductory paper comprised but are not limited to the following massive continental reorganization in the lead up to the final assembly of pangea resulting in profound changes in global palaeogeography palaeoceanography and palaeobiogeogarphy substantially lowered global atmospheric carbon dioxide concentrations p co 2 coupled with an unprecedented increase in atmospheric oxygen concentrations reaching earth s all time high in its last 600 million year history sharp global temperature and sea level drops albeit with considerable spatial and temporal variability throughout the ice age and apparently a prolonged period of global sluggish macro evolution with both low extinction and origination rates compared to other times in the aftermath of the lpia the world s climate entered into a transitional climate phase through the late early to middle permian before its transformation into a greenhouse state towards the end permian in recent years considerable amount of data and interpretations have been published concerning the physical evidence in support of the lpia its broad timeframe and eustatic and ecosystem responses from the lower latitudes but relatively less attention has been drawn to the impact of the ice age on late palaeozoic high latitude environments and biotas it is with this mission in mind that we have organized this special issue with the central focus on late palaeozoic high latitude regions of both hemispheres that is gondwana and northern eurasia our aim is to gather a set of papers that not only document the physical environmental changes that had occurred in the polar regions of gondwana and northern eurasia during the lpia but also review on the biotic responses at different taxonomic ecological and spatial scales to these physical changes in a refined chronological timeframe this introductory paper is designed to provide a global context for the special issue with a brief review of key late palaeozoic global environmental changes including changes in global land sea configurations atmospheric chemistry global climate regimes global ocean circulation patterns and sea levels and large scale biotic biogeographic and evolutionary responses followed by a summary of what we see as unresolved scientific issues and various working hypotheses concerning late palaeozoic global changes and in particular the lpia as a possible reference to future research

fusuline biotic turnover across the guadalupian lopingian middle upper permian boundary in mid oceanic carbonate buildups biostratigraphy of accreted limestone in japan abstract two sections in upper middle to lower upper permian shallow water limestones at kamura and akasaka in southwest japan were analyzed for detailed lithostratigraphy and biostratigraphy both sections represent ancient seamount capping carbonate buildups developed on a basaltic basement in a mid oceanic environment the occurrence of abundant tethyan fusulines allows the recognition of well defined biostratigraphic zonation in both sections and their mutual correlation the upper guadalupian middle permian lepidolina yabeina zone is overlain conformably by the lower lopingian upper permian codonofusiella reichelina zone with a 13 m thick transitional interval barren of index taxa the guadalupian lopingian g l boundary is marked by the first appearance datum fad of the lopingian codonofusiella reichelina assemblage in both sections this study recognizes for the first time the g l boundary horizon in a mid oceanic shallow water environment in addition the shallow water carbonates in the study sections record the extinction of the middle permian large sized fusuline family verbeekinidae at the g l boundary in mid panthalassa as well as in shallow water tethyan shelf areas demonstrating positively that the g l boundary mass extinction occurred on a global scale the abrupt elimination of large shelled fusulines followed by the domination of small shelled fusulines may indicate that environmental stress occurred at the end of guadalupian the dying out of symbiotic algae may have caused the selective extinction of the large shelled fusulines

discriminating glacier thermal and dynamic regimes in the sedimentary record abstract this paper provides a description and evaluation of the sedimentary facies and environments associated with a range of glacier thermal and dynamic regimes with additional consideration given to the tectonic context new and previously published data are evaluated together and are presented from modern terrestrial and marine glacial sedimentary environments in order to identify a set of criteria that can be used to discriminate between different glacier thermal regimes and dynamic styles in the sedimentary record sedimentological data are presented from a total of 28 glaciers in 11 geographical areas that represent a wide range of contemporary thermal dynamic and topographic regimes in the context of landsystems representatives from terrestrial environments include temperate glaciers in the european alps patagonia new zealand the cordillera blanca peru cold glaciers in the dry valleys of antarctica and the antarctic peninsula region and polythermal valley glaciers in svalbard northern sweden the yukon and the khumbu himal nepal the glaciomarine environment is illustrated by data from cold and polythermal glacier margins on the east antarctic continental shelf and from a polythermal tidewater glacier in svalbard along with general observations from temperate glaciers in alaska these data show that temperate glacial systems particularly in high relief areas are dominated by rockfall and avalanche processes although sediments are largely reworked by glaciofluvial processes debris in polythermal glaciers is both thermally and topographically influenced in areas of moderate relief debris is mainly of basal glacial origin and the resulting facies association is dominated by diamicton in high relief areas such as the himalaya the debris load in polythermal glaciers is dominated by rockfall and avalanche inputs resulting in extensive accumulations of sandy boulder gravel cold glaciers are dominated by basal debris entrainment but sediments are little modified from the source materials which are typically sandy boulder gravel from older till and sand from glaciofluvial glaciolacustrine and aeolian sources similar facies associations but with different facies geometry and thickness occur in equivalent glaciomarine settings application of these concepts can aid the interpretation of glacier thermal regime and hence palaeoclimate in quaternary and ancient glacial systems

modulation mechanisms of marine atmospheric boundary layer at the brazil malvinas confluence region 1 the influence of the brazil malvinas confluence bmc region on the marine atmospheric boundary layer mabl is investigated through in situ data analysis of five different cruises 2004 to 2008 and numerical experiments with a regional atmospheric model two different groups of numerical experiments were performed in order to evaluate the relevance of static stability and hydrostatic balance physical mechanisms for the mabl instability the first group used monthly climatological sea surface temperature sst as bottom boundary condition while the second used daily updated advanced microwave scanning radiometer eos sst data together with radiosondes and surface data assimilation a reasonable agreement between numerical results and quikscat wind data was observed through correlation coefficients and mean square error values in terms of the horizontal structure of the mabl stronger winds were found over the warm side of the bmc region as well as over the thermal front itself which supports the coexistence of both modulation mechanisms the analyzed patterns of surface atmospheric thermal advection showed a clear interaction between the synoptic and regional scales the signature of the oceanic thermal front almost meridionally oriented on the air temperature at 2 m makes the temperature advection strongly determined by the zonal component of the wind the analysis of momentum budget terms did not show a clear and reasonable explanation of the existence or predominance of the modulation mechanisms and it also suggested the relevance of other effects such as the idea based on unbalanced coriolis force and turbulence friction effects

radioisotopic calibration of the guadalupian middle permian series review and updates abstract four high precision u pb ca idtims dates for the roadian lower guadalupian of 274 0 0 12 and 273 1 0 1 ma and for the wuchiapingian lower lopingian of 260 16 0 39 and 258 14 0 20 ma were obtained from permian tuff beds in the periphery of the okhotsk massif n e russia the beds are well constrained within the local lithostratigraphic and regional biostratigraphic framework besides regional bivalves and brachiopod faunas the ammonoid sverdrupites harkeri occurs close to the recovered roadian tuffs this ammonoid provides direct correlation of the tuffs with the kazanian stage on the russian platform and the roadian stage in the canadian arctic where the conodont index species of the roadian stage jinogondolella nankingensis gracilis and sverdrupites harkeri and other roadian ammonoids are documented from the assistant formation our review of the kungurian roadian wordian successions in the main well studied regions suggests that the base of the roadian stage should be extended down to approximately 277 ma and the roadian wordian boundary should be placed at approximately 271 ma the new calibration of the roadian stage reduces the duration of the enormously long kungurian stage from about 10 myr approximately to 6 0 6 5 myr if the proposed calibration is correct the duration of guadalupian series would be almost twice as great as in the previous estimates our results also suggest a possible correlation of the p3 alpine glacial event in the eastern australia with the wordian and possible uppermost roadian stages this p3 event corresponds with the disappearance of ammonoids and conodonts in the upper roadian and wordian in high latitudes regions i e n e russia russian and canadian arctic and australia perhaps due to extreme cooling of these areas the new radioisotopic ages in the okhotsk massif and surrounding regions improve the numerical calibration of the palynological zonation in the eastern australia and provide a direct correlation of the regional biostratigraphic brachiopod and bivalve zonation of n e russia with the international geologic time scale this zonation becomes a solid and reliable regional correlation tool within the vast territory from taymyr and east siberia to entire n e russia and transbaikalia

epic 95 w observations of the eastern pacific atmospheric boundary layer from the cold tongue to the itcz abstract the atmospheric boundary layer abl along 95 w in the eastern equatorial pacific during boreal autumn is described using data from the east pacific investigation of climate epic 2001 with an emphasis on the evolution of the thermodynamic abl properties from the cold tongue to the cold advection region north of the sea surface temperature sst front surface sensible and latent heat fluxes and wind stresses between 1 s and 12 n are calculated from data from eight ncar c 130 research aircraft flights and from tropical atmosphere ocean tao buoys reduced surface wind speed and a 10 m s 1 jet at a height of 500 m are found over the equatorial cold tongue demonstrating the dependence of the surface wind speed on surface stability the abl exhibits a maximum in cloud cover on the north downwind side of the warm sst front at 1 3 n turbulent mixing driven by both surface buoyancy flux and radiative cooling at the cloud tops plays a significant role in maintaining the depth and structure of t

permian ammonoid associations of the verkhoyansk region northeast russia abstract on the basis of a study of the majority of permian ammonoids known in verkhoyansk region and an analysis of their age distribution seven associations and four subassociations are established these ammonoid associations are the khorokyt arkachan endybal mysovy orol takamkyt delendzha and post sverdrupites associations in ascending order the majority of these associations and subassociations include some complementary ammonoid beds the ammonoid associations and subassociations are considered as biostratigraphic divisions of regional stratigraphic extent and are useful for dating and correlating the permian sedimentary sequences of the verkhoyansk region the geographical and stratigraphic distributions of 360 permian ammonoid shells in the verkhoyansk region permits us to not only diagnose each ammonoid association with specific index species but also to elucidate the biogeographic connections and migration patterns of the verkhoyansk ammonoid faunas in relation to these spreading throughout the entire boreal realm

end guadalupian extinction of larger fusulinids in central iran and implications for the global biotic crisis abstract the end guadalupian capitanian biotic crisis was less intense than its end permian counterpart but highly selective against certain groups of tropical organisms such as rugose corals and keriothecal walled fusulinid foraminifera the causes of this event remain debated in part due to apparent disagreement among stratigraphic sections in the timing of taxonomic losses in order to further constrain the timing of extinction and assess the broader pattern of change in benthic marine ecosystems across the guadalupian lopingian boundary glb here we report the stratigraphic occurrence patterns of the large keriothecal walled fusulinid foraminifera as well as associated skeletal grains in the abadeh section central iran which contains a relatively complete record through the glb interval the last keriothecal walled fusulinid occurs within the upper wordian at abadeh whereas smaller fusulinids continue to occur below and above the guadalupian lopingian boundary glb a lithologic change from carbonates toward chert and shale within the section suggests that the local disappearance of the keriothecal fusulinids prior to the glb reflects a facies control rather than global extinction long prior to the glb re examination of the last occurrences of keriothecal walled fusulinids in well studied sections of south china japan ne thailand and transcaucasia reveals that facies change to organic rich sediments can explain the local disappearance of these species prior to the glb in both japan and ne thailand apparent diachroneity of extinction in this group appears best interpreted to reflect local facies effects rather than a protracted extinction event global warming induced failure of associations between fusulinids and photosymbionts following emeishan volcanism is the scenario most consistent with available data

guadalupian middle permian ocean redox evolution in south china and its implications for mass extinction abstract the guadalupian mass extinction was a long term biocrisis that started in the early guadalupian epoch permian period many studies of the causes of the extinction have focused on the late guadalupian although the entire guadalupian should be studied to address its origins the selective nature of the species removed during the guadalupian extinction also remains a puzzle here we present pyrite framboid size distributions pyrite sulfur isotopic compositions and c n s profiles for the entire guadalupian from south china to develop a record of ocean redox evolution to help understand the selective extinction our results indicate that euxinia was mostly persistent in the deep water platform basin throughout the guadalupian which triggered long term early and middle guadalupian shallow water dysoxia and frequent episodic late guadalupian euxinia events that resulted in a gradual long term early and middle guadalupian diversity decrease and selective late guadalupian extinction the combined effect of euxinia and global regression led to selective extinction of taxa that had weakly buffered respiratory physiology and high growth efficiency such as brachiopods large fusulinids and giant bivalves

the magnitude of late paleozoic glacioeustatic fluctuations a synthesis a comprehensive literature review shows that the magnitude of eustatic fluctuations varied throughout the carboniferous and permian and that at least eight distinct phases can be recognized facies juxtapositions in carbonate successions and erosional relief in clastic successions indicate that glacioeustatic fluctuations of 20 25 m and occasionally as much as 60 m took place throughout the early mississippian tournaisian a widely recognized glacial period middle mississippian mid chadian through holkerian shallow marine carbonate and clastic successions indicate that eustatic fluctuations were 10 25 m a decrease that matches well with the paucity of coeval glacial deposits late visean asbian through mid brigantian glacioeustatic fluctuations of 10 50 m record the initial phases of ice accumulation in advance of the widespread mid carboniferous glacial event the latest mississippian earliest pennsylvanian mid brigantian through langsettian was a time of widespread glaciation and strata of this age commonly exhibit evidence of glacioeustatic fluctuations of as much as 40 100 m although middle pennsylvanian duckmantian through asturian glacial deposits are present in eastern australia paleovalley depths suggest that coeval glacioeustatic fluctuations were less than 40 m glacioeustatic fluctuations of as much as 100 120 m have been widely reported from late pennsylvanian earliest permian stephanian through mid sakmarian successions in north america an increase that corresponds to the growth of large ice sheets across much of gondwana and the accumulation of ice in the northern hemisphere incision and facies juxtaposition in early middle permian mid sakmarian through kungurian successions in eastern australia indicate that glacioeustatic fluctuations of 30 70 m occurred during the waning stages of major glaciation erosional relief in paleoequatorial carbonates and the presence of coeval glacial deposits in australia suggests that eustatic fluctuations of 10 60 m occurred during the final stages of glaciation in the middle to late permian roadian through capitanian but the modest size of most of these fluctuations makes it difficult to isolate the glacioeustatic signature this review demonstrates that far field cyclic successions record changing glacial conditions in gondwana that the magnitude of glacioeustatic fluctuations was directly related to the volume of glacial ice that carboniferous permian glacioeustasy was more variable than previously recognized and that generalizations from short temporal intervals are probably not representative of the late paleozoic ice age as a whole although any attempt to quantify the magnitude of ancient eustatic changes is based on caveats and assumptions this review incorporates the results of over 100 published papers on the topic in an attempt to minimize the errors inherent in any one study

the natural thermoluminescence of meteorites i twenty three antarctic meteorites of known 26al content the level of thermoluminescence tl naturally present in 23 antarctic chondrites of known 26al content has been measured as a means of exploring their thermal and radiation history antarctic meteorites tend to have lower natural tl than non antarctic meteorites presumably because of their generally longer terrestrial ages seventeen of the meteorites lie on a band of increasing natural tl and 26al activity meteorites with 26al of 45 60 dpm kg have natural tl values normalized to the high temperature tl of 2 4 whereas those with 26al values of 30 45 dpm kg have normalized natural tl values of 1 2 and alha 76008 with an 26al content of 11 dpm kg has a tl value of 0 87 0 01 this suggests that the half life for tl decay is comparable to that of 26al the six meteorites not lying on the tl 26al trend have much lower tl than others of comparable 26al for two of them rkpa 79001 and rkpa 80202 which are tentatively paired the low natural tl probably reflects a recent severe shock while another alha 77294 has previously been measured in this lab and had tl consistent with the tl 26al trend the remaining three alha 78006 alha 77296 and alha 77297 of which the last two are probably paired have suffered a recent reheating such as would be expected from orbits of unusually small perihelia

oceanic and atmospheric anomalies of tropical instability waves tropical instability waves tiws are detected in remotely sensed sea surface height ssh temperature sst and wind records of the eastern equatorial pacific analyses of tiw anomaly relationships reveal strong dynamical influence of tiws within approximately 5 of the equator the first influence is advective heat flux the primary forcing of tiw sst anomalies is advection of the meridional temperature gradient by tiw currents the second influence is modification of the wind stress and ekman pumping fields by tiw surface ocean currents by affecting surface stress and hence roughness tiw currents in this low wind region introduce a significant bias in scatterometer vector wind measurement this bias is evident in both nscat and quikscat winds the difference between wind measurements from tao moorings and scatterometers is phase locked with tiw sst oscillations these results have important implications for scatterometry and for understanding tropical dynamics thermodynamics and biogeochemistry

observations of coupling between surface wind stress and sea surface temperature in the eastern tropical pacific satellite measurements of surface wind stress from the quikscat scatterometer and sea surface temperature sst from the tropical rainfall measuring mission microwave imager are analyzed for the three month period 21 july 20 october 1999 to investigate ocean atmosphere coupling in the eastern tropical pacific oceanic tropical instability waves tiws with periods of 20 40 days and wavelengths of 1000 2000 km perturb the sst fronts that bracket both sides of the equatorial cold tongue which is centered near 1 8s to the east of 1308w these perturbations are characterized by cusp shaped features that propagate systematically westward on both sides of the equator the space time structures of these sst perturbations are reproduced with remarkable detail in the surface wind stress field the wind stress divergence is shown to be linearly related to the downwind component of the sst gradient with a response on the south side of the cold tongue that is about twice that on the north side the wind stress curl is linearly related to the crosswind component of the sst gradient with a response that is approximately half that of the wind stress divergence response to the downwind sst gradient the perturbed sst and wind stress fields propagate synchronously westward with the tiws this close coupling between sst and wind stress supports the wallace et al hypothesis that surface winds vary in response to sst modification of atmospheric boundary layer stability

ocean atmosphere in situ observations at the brazil malvinas confluence region 1 this paper presents a description of marine atmospheric boundary layer mabl and oceanic boundary layer obl interactions at the brazil malvinas confluence although this region is known as one of the most energetic zones of the world ocean very few studies have addressed the mechanisms of oa interaction there based upon novel direct in situ simultaneous oa observations our results show that the obl mabl exchanges are closely correlated with the sea surface temperature sst field the heat fluxes range from 110 w m 2 over warm waters down to 18 w m 2 over cold waters higher heat fluxes and air sea temperature differences are associated with stronger near surface winds this suggests that the mabl is modulated at the synoptic temporal and spatial scale by the strong surface thermal gradients between the warm brazil and the cold malvinas falklands currents