quartz and quartzite refits at gran dolina sierra de atapuerca burgos connecting lithic artefacts in the middle pleistocene unit of td10 1 abstract this paper expands upon the preliminary refit analysis of the nw area of unit td10 1 at gran dolina sierra de atapuerca burgos spain lopez ortega et al 2011 the refit study described here has been conducted on the quartz and quartzite assemblage recovered from unit td10 1 consisting of a total of 4302 artefacts 709 quartz and 3593 quartzite pieces following the previously established methodological protocol we found additional elements associated with already known connections as well as new refits in quartz and quartzite the association between refits and raw material units rmus has allowed us to distinguish specific concentrations and spatial clusters that could correspond to singular knapping events and to identify the movements of pieces within the same raw material unit outside of their clusters which could point to the use of these artefacts these results together with the presence of artefacts of every phase of the chaine operatoire point to developed knapping activities carried in the settlement and the areas where they took place a new interdisciplinary study will identify the role played by intentionally moved pieces

stable isotope stratigraphy of brachiopods from pennsylvanian shales in texas stable isotope stratigraphies have been generated for brachiopods from five late pennsylvanian sections upper winchell cycle finis shale colony creek shale necessity cycle and wayland shale in north central texas to examine the relationship between isotopic composition paleoenvironment and sea level change nonluminscent calcite from more than 300 specimens of 4 species of brachiopod composita subtilita crurithyris planoconvexa eridmatus texana neospirifer cameratus was analyzed sedimentological and paleontological data are used as evidence for paleoenvironmental change higher 18 o values of brachiopod shells occur in intervals of greatest paleodepth as indicated by fossil content and lithology these higher 18 o values reflect a decrease in bottom temperature with increased water depth normalized for paleodepth the 18 o values of the brachiopods are similar in all of the units except the wayland shale for which they are 0 5 higher this suggests either cooler temperatures or greater continental ice volume during the time of wayland deposition brachiopod 13 c values do not correlate with paleodepth the 13 c values of composita are consistently higher than those of crurithyris and eridmatus composita 13 c values are similar in the upper winchell cycle necessity cycle and wayland shale averaging 4 8 to 4 9 in contrast crurithyris 13 c values range from 2 5 in the necessity cycle to 4 4 in the wayland shale eridmatus values are also lowest in the necessity cycle 3 4 and greatest in the wayland shale 3 9 these differences between species do not correlate with susceptibility to diagenesis and appear to reflect a pore water influence on semi infaunal crurithyris forms the 13 c values of composita shells suggest that the late pennsylvanian ocean off eastern laurussia was enriched in 13 c by about 1 relative to the ocean off western laurussia

late paleozoic glacial episodes in gondwanaland reflected in transgressive regressive depositional sequences in euramerica the late paleozoic glaciation of gondwanaland comprised two short episodes in the famennian i and visean ii confined to brazil and adjacent northwest africa and a long episode that started in the namurian iiia of eastern australia and bolivia argentina expanded to cover much of gondwanaland in the stephanian asselian iiib and collapsed in the early sakmarian iiic dropstones in eastern australia indicate that small ice centers lingered to the kazanian across the belt of low latitudes north of gondwanaland short ranging fossils in widespread shallow marine and paralic deposits indicate synchronous deposition of transgressive regressive sequences in different parts of euramerica these sequences correlate with glacial events in gondwanaland at three levels a four major regressions in euramerica in the famennian 1 visean 2 namurian 3 stephanian 4 and the tastubian transgression that preceded the sterlitamakian regression 5 also recorded in gondwanaland correlate with glacial episodes i ii and iiia iiib and iiic b the time interval of cyclothemic deposition in euramerica brigantian or latest visean to sterlitamakian correlates with that of glacial episode iii and c the dominant period of the euramerican cyclothems as estimated from the middle and late pennsylvanian deposits of the mid continent of north america and of the thickest known gondwanaland glacigenic sediment the earliest permian lyons group of western australia is 0 4 ma equivalent in turn to the long orbital eccentricity period of the quaternary ice age and the dominant period of fluctuation of the late miocene antarctic ice cap the three levels of correlations confirm wanless and shepard9s 1936 hypothesis that the late paleozoic cyclothems are controlled largely by sea level fluctuations related to the gondwanaland glaciation

the tindouf basin a marine refuge during the serpukhovian carboniferous mass extinction in the northwestern gondwana platform abstract several macrofaunas and microfossils of the carboniferous saharan basins have longer stratigraphic ranges than those of other basins in the western palaeotethys realm particularly in the tindouf basin morocco algeria foraminifers are particularly abundant and diverse in the serpukhovian and basal bashkirian compared to coeval basins and some taxa have longer ranges than in the neighbouring reggan and bechar basins although this effect is more marked compared to the western palaeotethyan assemblages in europe several rugose coral species are recorded from the early bashkirian that previously were considered to have disappeared in the serpukhovian the tindouf basin as one of the most western saharan basins in north africa shows the greatest stratigraphic ranges of taxa which diminish eastwards evidence for a mass extinction event during the serpukhovian in the tindouf basin has not been clearly recognized although a possible influence of glaciation is observed in the faunal diversity eustatic sea level changes were experienced in tindouf with the cyclic pattern of sedimentation but warm water ocean currents from the palaeoequator were able to maintain tropical conditions on the platform tectonics in the area led to emerging land masses and barriers and created a partly isolated basin in this sector of the western part of the sahara platform in northern gondwana the combination of those factors controlled the environmental conditions in the area allowing the persistence of the fauna for longer stratigraphic ranges than its equivalent counterparts in the western palaeotethys

namurian uplift in australia and south america triggered the main gondwanan glaciation the permo carboniferous glacigenic sediment at the base of the gondwanan basins reflects the culmination1 2 of the glacial episode that started in australia and southern south america in the namurian after two local episodes in northern south america and adjacent africa in the visean and latest devonian3 fig 1 here we show that the start of each episode was associated with orogenic uplift of the bordering regions northern south america and adjacent africa in the latest devonian and visean and southern south america and eastern and central australia in the namurian all areas except southern south america in the namurian were at mid and not high latitudes thus we show that whereas the first order control of glaciation was the configuration of the continents and oceans during the closing of palaeo tethys orogenesis provided a second order control by the accumulation of ice about bordering uplifts during the three glacial episodes

geomagnetic intensity and 14c abundance in the atmosphere and ocean during the past 50 kyr we have used a new sedimentary record of geomagnetic field intensity combined with published volcanic data to examine the extent to which geomagnetic changes have affected 14c production in the past the production record was then converted into an atmospheric 14c signal using a 4 box model of past oceanic circulation the results indicate that changes in geomagnetic field intensity account for at least 80 of the 14c shift documented by published u th data which are of the order of 500 per mil with respect to a constant production hypothesis model simulations show that changes in past oceanic circulation account for only 100 per mil of 14c variation which is within the uncertainty of the geomagnetic correction in terms of dating these results show that the radiocarbon ages have to be shifted by 2 to 3 5 kyr towards older ages during the 20 40 ka interval

carbon and oxygen isotope stratigraphy of the lower mississippian kinderhookian lower osagean western united states implications for seawater chemistry and glaciation a positive carbon isotope 1 3 c excursion has been recognized in upper kinderhookian and early osagean carbonates in three sections in southeast idaho and nevada the oldest 1 3 c peak 7 is dated to the isostichaconodont zone and a younger peak occurs in the typicus zone the shifts are recorded in a range of carbonate lithofacies representing various water depths along the shelf lithofacies sampled for 1 3 c and 1 8 o at the samaria mountain section in southeast idaho record the shallowest water conditions indicated by cross bedded skeletal and peloidal grainstones the deepest water conditions are present in the pahranagat range section in eastern nevada which consists mainly of bioturbated lime mudstone and skeletal wackestone the 1 3 c values from these widely separated sedimentary basins show a consistent trend that correlates with early mississippian curves generated from brachiopod calcite in western europe and the midcontinent of north america as well as dolomites in utah and wyoming 1 8 o values become more positive up section generally paralleling the positive trend in 1 3 c during the late kinderhookian no subaerial exposure surfaces are recognized in the sections examined in southeast idaho and nevada and at least the 1 3 c trends are interpreted as primary seawater fluctuations sea level changes occurred near the beginning of the late kinderhookian 1 3 c shift early to middle parts of the isosticha zone and within the peak of the 1 3 c excursion kinderhookian osagean boundary although tectonic changes associated with the antler orogeny have likely modified the eustatic signature

temperature limits for preservation of primary calcite clumped isotope paleotemperatures abstract solid state reordering of c o bonds in the calcite lattice can alter the clumped isotope composition of paleotemperature archives such as fossil brachiopod shells without inducing significant changes in shell microstructure and trace element concentrations metrics commonly used to gauge preservation quality to correctly interpret the paleoenvironmental significance of clumped isotope derived paleotemperatures it is necessary to understand the temperature time domain in which solid state c o bond reordering is important we address this question using a combination of laboratory and natural geological experiments on paleozoic brachiopod shells the laboratory experiments involve heating fossil brachiopod calcite at different temperatures and times to directly observe rates of 13 c 18 o bond reordering the resulting arrhenius parameters are indistinguishable from values previously determined for an optical calcite with similar trace element compositions we develop an alternative kinetic model for reordering that accounts for non first order reaction progress observed during the initial several hundred minutes of laboratory heating experiments and show that the simplified first order approximation model passey and henkes 2012 predicts reaction progress equally well for temperatures and timescales relevant to sedimentary basins we evaluate our laboratory based rate predictions by studying brachiopod calcite from several sedimentary basins with independently constrained burial temperature histories specifically we use the laboratory derived arrhenius parameters to predict the evolution of brachiopod calcite clumped isotope compositions during successive one million year time steps reflecting the burial and exhumation temperature paths of each basin while this exercise is limited by the relatively large uncertainties in the temperature histories of these basins we find general correspondence within error between predicted and observed clumped isotope values we present simplified temperature time diagrams for calcite showing domains where primary clumped isotope compositions will be preserved partially reordered and fully reordered in conclusion calcite samples dwelling at 100 c or lower for 10 6 10 8 year timescales should not be affected by solid state c o bond reordering

use wear analysis of an amudian laminar assemblage from the acheuleo yabrudian of qesem cave israel in this paper the results of use wear analysis of an amudian lithic assemblage recently discovered at qesem cave israel are presented although very old this assemblage maintains well preserved traces of use that indicate that butchering activities and plants collecting were carried out at the site cut marks on faunal remains confirm the observations obtained by use wear analysis

is mid late paleozoic ocean water chemistry coupled with epeiric seawater isotope records isotopes of epeiric sea carbonates are used to construct seawater records for modeling global changes in paleozoic ocean chemistry climate and for intercontinental correlation we present for the first time geochemical results of paleozoic brachiopods biogenic low mg calcite blmc from open ocean permian carboniferous seamounts of japan situated in the tropical mid panthalassic ocean strontium isotope values of blmc from the panthalassic and paleotethys oceans are coupled with those of coeval specimens from epeiric seas of north america europe and russia p 0 393 but not with those of epeiric sea whole rocks matrix aragonite calcite mac p 0 029 and conodonts biogenic apatite ba p 0 031 oxygen isotope values of blmc from the panthalassic and paleotethys exhibit mixed results with studies of counterparts from epeiric seas p 0 596 reflecting overprinting of local environmental conditions on global trends carbon isotope values of blmc and mac from the panthalassic and paleotethys oceans are generally dissimilar to those of coeval material from epeiric seas of north america europe and russia p 0 001 and 0 002 respectively factors such as water mass stratification evaporation dilution depth temperature carbon burial and or oxidation variations and syndepositional diagenesis within the local environment probably influenced the chemistry of the fauna and accumulating sediments this decoupling of carbon and oxygen isotope values from the open ocean with those from epeiric seas makes questionable the use of isotope results from epeiric seas for international correlation constructing global seawater records determining fluxes in the global carbon cycle and for modeling climate changes and subsequently atmospheric carbon dioxide levels

isotopic records of brachiopod shells from the russian platform evidence for the onset of mid carboniferous glaciation we performed isotopic analyses of carboniferous brachiopod shells from the russian platform to examine global and regional environmental change along the western and eastern margins of laurussia during the formation of pangea and specifically to examine the isotopic evidence for the onset of mid carboniferous glaciation shell preservation was evaluated from shell microstructure cathodoluminescence trace element content and isotopic comparison with matrix material most interior nonluminescent nl prismatic shell appears to be chemically well preserved as indicated by low to undetectable si al fe and mn contents with minor exception nl shell 13c and 18o values are higher than those of corresponding cements and matrix the 13c record for the russian platform clearly shows a 3 increase from 2 4 0 7 to 5 5 0 6 in the serpukhovian or early bashkirian this shift was first reported by popp et al popp b n anderson t f sandberg p a 1986 brachiopods as indicators of original isotopic compositions in some paleozoic limestones geol soc am bull 97 1262 1269 but had not been documented for a single region widespread occurrence of high 13c values in the late carboniferous support the interpretation of popp et al with regard to this shift as a record of increased burial of organic carbon north american sections show a mid carboniferous 13c shift of only 1 5 we hypothesize that the reduced 13c shift reflects enhanced upwelling on the epicontinental seas of north america after the closing of the seaway between laurussia and gondwana the 18o record for the russian platform shows a 1 8 increase in the mid carboniferous correlative with increased occurrence of glacial sediments and a drop in sea level as a first approximation ice volume calculations suggest that 0 7 of the mid carboniferous 18o shift is due to changes in seawater 18o and 1 1 is due to 5 c cooling concurrent positive 13c and 18o shifts provide evidence for a relationship between mid carboniferous glaciation and burial of organic carbon presumably through changes in atmospheric co2 levels

pleistocene sedimentary facies of the gran dolina archaeo paleoanthropological site sierra de atapuerca burgos spain abstract gran dolina is a cavity infill of the sierra de atapuerca containing three important early and middle pleistocene archaeo paleontological layers including hominid bones fauna and lithic remains due to the relevance of this site to understand human evolution in europe it is essential to define in detail the sedimentary processes and environments associated with the archaeological remains gran dolina has a 19 m thick sedimentary infill divided into 11 lithostratigraphic units in this work we describe the sedimentary facies of the early and middle pleistocene units and we update its stratigraphy for that purpose we have studied the stratigraphic excavation profiles available where we have combined field observations with laboratory sedimentary analysis sieving laser diffraction and image analysis to characterize the texture and structure of the sediments through these studies 19 sedimentary facies have been distinguished grouped as sediment gravity flow facies fluvial facies and autochthonous facies the facies associations indicate two main trends in the allochthonous sequence during the early pleistocene td4 td7 the cavity acted as a stream sink where channel and floodplain facies migrated along the sequence and were interbedded with lateral gravity sediment flows on the other hand the middle pleistocene sequence between td7 and td10 is dominated almost exclusively by gravity flows at least three main entrances have been inferred from input directions of the sediments which changed over time sediment characteristics have allowed us to preliminarily infer environmental conditions around the cavity

global events of the late paleozoic early devonian to middle permian a review abstract the late paleozoic early devonian to middle permian was an interval of profound changes in earth surface systems reflected in dynamic interplay among the biosphere hydrosphere atmosphere and geosphere major events transpired including the colonization of landmasses by vascular plants the assembly of the supercontinent pangea two first order mass extinctions the frasnian famennian and devonian carboniferous boundary events and the most severe icehouse climate mode of the phanerozoic the late paleozoic ice age lpia the goals of the present review are 1 to summarize major global developments in climate oceanography and paleobiology during the late paleozoic 2 to examine the roles of land plant evolution global tectonics and large igneous province magmatism in driving these developments and 3 to serve as an introduction to the 23 contributions to this special issue of palaeogeography palaeoclimatology palaeoecology indicating how they advance our knowledge of various scientific issues related to these developments

the surface alteration features of flint artefacts as a record of environmental processes this paper introduces a method to study the degree of change that affected a prehistoric context as the result of environmental processes it is based on the direct examination of a representative sample of stone tool by products and on the identification of all surface alteration features we summarize the theoretical bases for the formation of some wear features and the main results of a number of experiments involving interaction between chert flakes and sediments experimental results include 1 the wear rate of flakes is not constant 2 the wear rate increases as the size of the grains that compose the matrix increases 3 fine grained chert resists wear better then coarse grained chert and 4 the presence of moisture will trigger some chemical reactions that promote wear and the formation of films on chert surfaces we apply these findings to the cave site of grotta di pozzo italy and conclude that strictly within the area sampled there is low degree of disturbance and low intensity of chemical processes that may however confound the reconstruction of human activities in this part of the cave

estimating carboniferous sea level fluctuations from gondwanan ice extent the magnitude of carboniferous sea level fluctuations is not well known but the estimates are important for constraining cyclothem models in this paper we apply area volume relations developed for quaternary ice sheets to estimate the glacio eustatic component of sea level fluctuations in the carboniferous utilizing the best estimate of gondwanan ice area at the time of its greatest extent we arrive at a figure of 60 15 m for the isostasy corrected glacio eustatic component this value is nearer the lower limit of sea level estimates for cyclothem fluctuations from other sources

diagenesis of fossil ostracods implications for stable isotope based palaeoenvironmental reconstruction a protocol for assessing the diagenetic alteration of ostracod carapaces for use in palaeoenvironmental reconstruction is proposed based on comparison between fossil carboniferous and recent specimens recent ostracods have a carapace ultrastructure of fine 0 5 m diameter crystals of primary low magnesium calcite the degree of recrystallisation in fossil ostracods is assessed based on the carapace ultrastructure and geochemistry six diagenetic stages are identified 1 replacement of the original finely crystalline calcite carapace with neomorphic calcite 2 framboidal and euhedral pyrite growth 3 ferroan calcite carapace replacement and cavity void filling cement 4 ferroan dolomite carapace replacement and void fills 5 siderite growth and 6 sphalerite and barite mineralisation stage 1 occurs during early shallow burial stages 2 3 soon after and stages 4 6 during much later burial possibly hydrothermal alteration ostracods and macrofossils exhibiting diagenetic stages 1 5 were analysed for oxygen and carbon isotope ratios the oxygen isotope compositions clearly reflect the diagenetic stages the most negative oxygen isotopes 18o 12 9 represent the precipitation of ferroan dolomite stage 4 and the most positive values of the neomorphic calcite 18o 0 9 represent stage 1 and are within the predicted range of carboniferous seawater 18o 4 to 0 the diagenetic protocol established here is specific to palaeozoic fossil ostracods from carbonate and clastic sediments that were subject to shallow burial diagenesis and later hydrothermal alteration nevertheless the approach could be used to assess the utility of fossil ostracods for palaeoenvironmental interpretation from a wide range of geological settings

micromorphology and differential preservation of upper permian brachiopod low mg calcite abstract calcareous shells of rhynchonelliform brachiopods from the nesen formation late permian of iran were studied by scanning electron microscope cathodoluminescence and trace element chemistry to define their microstructure and state of preservation in the strophomenata shell succession the secondary layer consists of cross bladed laminar calcite and in a few species there is a tertiary layer of prisms in the rhynchonellata shell succession the secondary layer consists of elongated fibers and the tertiary layer of prisms all specimens were classified into six micromorphological types based on the fabric of the layer and the morphology of their microstructural units laminae fibres and prisms shell micromorphology and enclosing whole rock were further analyzed by cathodoluminescence and trace chemistry to assess preservation of brachiopod low mg calcite and specifically of their layers and microstructural units relative color frequencies were determined for each morphological type and degree of luminescence based on the lithology of the host rocks to evaluate the main factors that affect shell preservation results suggest that diagenetic alteration may depend on shell fabric and taxonomy as well as lithology of the host rock but it appears that the first and the second features are the most important factors in determining the degree of brachiopod low mg calcite preservation in general the fibrous secondary layer is likely more often and better preserved than its laminar counterpart irrespective of host rock lithology furthermore tertiary layers tend to be better preserved than secondary ones in rhynchonellata low mg calcite shells whereas no preferential preservation of either layer over the other was observed in the shells of strophomenata this information is important when selecting fossil brachiopod low mg calcite shells as geochemical proxies for paleoclimatic paleoecologic paleoenvironmental and other studies

development of the late paleozoic glaciations of the south american gondwana in western argentina abstract the late paleozoic ice age in the south american segment of gondwana consisted of several glaciations which can be grouped into two main glacial periods the oldest of them occurred in late early to early late carboniferous time and the younger in early permian time paleontological evidence in the western argentine precordillera supports a late visean age for the beginning and a probable early westphalian age for the end of the carboniferous glacial period in this span of time subsidence and deposition of glacial debris took place in the western mobile belt and in patagonia but no sediments of that age were deposited in the eastern portion of the south american gondwana where subsidence started later a carboniferous glacial sequence is remarkably well preserved in the san eduardo group on the western flank of the precordillera where at least three distinct glaciations are recognized this sequence can be taken as a reference section for the carboniferous glacial deposits shorter than the former and probably restricted to the asselian epoch the permian glacial period is better known the evidence for it is well developed in eastern south american gondwana although a relic is also present in the precordillera the recognition of two glacial periods within the late paleozoic ice age is supported by the existence of a long lasting interglacial which seemingly began in the late westphalian and lasted until the end of the carboniferous period this major interglacial period is inferred from the total absence of glacial features in the upper carboniferous sequences in spite of the existence of a mountainous belt parallel to the pacific during the carboniferous period the presence of marine beds and glacial drift well to the east of these ranges suggests that it was not altitude that was the main factor in determining the formation of glaciers but latitude plus a global change in temperature it is argued that the ice sheets extended greatly during the carboniferous glaciations and reached neighboring areas of the paganzo basin in central argentina

late pennsylvanian seasonality reflected in the 18o and elemental composition of a brachiopod shell to evaluate the potential for the study of late pennsylvanian seasonality detailed isotopic and elemental analyses were performed on a single specimen of the brachiopod neospirifer dunbari shell preservation was evaluated by petrographic and cathodoluminescence microscopy carbonate powders from 112 spots were collected from the sectioned shell for isotopic analyses and 369 spots on the complementary thin section were analyzed by electron microprobe for chemical composition in the nonluminescent part of the shell mg ca ratios were between 0 001 and 0 012 and na ca and s ca ratios ranged from 0 003 to 0 012 and 0 003 to 0 021 respectively values of 18 o vary between 2 3 and 1 1 contours of 18 o mg na and s concentrations parallel growth bands and reveal a record of 1 to 2 cycles mg s and na contents varied nversely with 18 o this trend is opposite to the expected diagenetic trend and is consistent with the temperature dependences of mg content and 18 o thus implying preservation of shell chemistry the 1 2 range in 18 o values suggests a seasonal temperature variation of 5 to 6 c assuming no change in the 18 o of the water this high seasonality for the tropical epicontinental sea of kansas supports climate model predictions of enhanced continentality in pangean climate detailed stable isotope and element concentration profiles across growth bands of brachiopod shells can provide quantitative records of paleozoic seasonality

pore fluid constraints on the temperature and oxygen isotopic composition of the glacial ocean pore fluids from the upper 60 meters of sediment 3000 meters below the surface of the tropical atlantic indicate that the oxygen isotopic composition 18 o of seawater at this site during the last glacial maximum was 0 8 0 1 per mil higher than it is today combined with the 18 o change in benthic foraminifera from this region the elevated ratio indicates that the temperature of deep water in the tropical atlantic ocean was 4 c colder during the last glacial maximum extrapolation from this site to a global average suggests that the ice volume contribution to the change in 18 o of foraminifera is 1 0 per mil which partially reconciles the foraminiferal oxygen isotope record of tropical sea surface temperatures with estimates from barbados corals and terrestrial climate proxies

the early acheulean technology of barranc de la boella catalonia spain abstract since 2007 excavations at barranc de la boella tarragona catalonia spain have revealed three localities with rich archaeo paleontological assemblages la mina el forn and pit 1 palaeontology palaeomagnetism and cosmogenic analyses have dated these localities to close to 1 ma the presence of mammuthus meridionalis hippopotamus antiquus stephanorhinus cf hundsheimensis mimomys savini and victoriamys chalinei stand out in the sample of macro and micro mammals the lithic assemblages from the three sites are made up of percussion cobbles choppers chopper cores cores simple flakes and some retouched flakes mainly denticulates and notches in the case of the el forn and pit 1 localities two large cutting tools have been recovered a cleaver like tool and a pick made of hard wearing schist the lithic assemblage of pit 1 which includes several refitting lithic sets is closely associated with the remains of a young adult mammuthus meridionalis in a clear butchering site context this evidence suggests that barranc de la boella is the oldest european early acheulean site and one of the oldest butchering site on the subcontinent during the late early pleistocene the study of the variability among these three localities in similar environmental conditions together with information from other sites are discussed in order to gain further knowledge about the appearance of the acheulean in europe and its continuity or discontinuity in relation to pre existing technologies

problems of a late palaeozoic glaciation in australia and subsequent climate in the permian the most recent information suggests two periods of glaciation separated by a considerable time interval the first is found in the namurian early carboniferous and may extend into the beginning of the late carboniferous evidence for the carboniferous glaciation is largely or entirely redeposited striated clasts known only from the new england area of northeastern new south wales these are considered to represent montane type glaciation associated with a developing alpine chain after a long interval glacial deposits are then found in many parts of australia in the asselian the lowest stage of the permian and the glaciation may extend into the beginning of the sakmarian the following stage in western australia a number of major fluctuations are recorded in the asselian the end of the glaciation seems to be associated with a worldwide eustatic rise in sea level in the tastubian the lower stage of the sakmarian after the tastubian no direct verifiable evidence indicates glaciation in the permian in australia or any other part of the world in australia there is no clear evidence on the climate in the interval between the two glacial periods but in south america and other parts of the world a warm interval is reported at this time most of the glacial debris is now found in sedimentary basins which were developing contemporaneously with the glaciation and is of a wet based type glaciers were active on steep hinterland carrying debris in adjacent water covered basins but how far the ice may have spread over lower lying land areas in not clear there is no real evidence of a thick dry based ice sheet like that of present antarctica after the tastubian there are a number of major fluctuations in climate during the rest of the permian at times seasonal ice and or perhaps icebergs may have been active but fluctuations which were cool or warm temperate or in some places in australia even subtropical or tropical are found in the sterlitamakian upper sakmarian beginning and end of the baighenzhinian upper artinskian kungurian kazanian and dzhulfian all separated probably by colder and in some cases considerably colder periods comparison of the marine faunas of the carboniferous and permian suggests that the levipustula fauna may not represent as cold sea water as the eurydesma fauna

a high resolution middle to late permian paleotemperature curve reconstructed using oxygen isotopes of well preserved brachiopod shells abstract climatic warming has been widely cited as a driver for many mass extinction events in earth history including the middle late permian guadalupian lopingian boundary glb mass extinction and end permian mass extinction epme investigated in this study however the role of warming in driving the epme event is under debate because current paleotemperature studies indicate the rapid increase in sea surface temperature postdate the onset of the epme event and a reliable paleotemperature record across the glb event is lacking here we present a high resolution and successive 18 o record using low mg calcite shells of brachiopods blmcs from a single stratigraphic section in central china to reconstruct paleotemperature changes from the middle to the latest permian after a rigorous screening for diagenesis our data show a 1 0 decrease in 18 ocalcite and thus climatic warming during the middle capitanian followed by a gradual 2 0 increase climatic cooling during the late wuchiapingian from the latest wuchiapingian to the early changhsingian 18 o decreased gradually and reached the lowest values of 4 0 and thus rapid climatic warming immediately before the permian triassic boundary the two warming events are coeval with the onset of the emeishan large igneous province and the siberian traps large igneous province respectively suggesting the two volcanic events are the plausible drivers of these climatic warming events a close comparison of paleontological and geochemical records indicates that the warming events occurred predate the glb and epme events this is in contrast with conodont 18 oapatite data which document the rapid climatic warming lagged the onset of the extinction event the comparison between 18 o of blmcs and 18 o of conodonts from the same section shows that the long term trends are similar but at higher temporal resolution discrepancies are present entailing further investigation in the near future our study confirms that 18 o of the brachiopod shells underwent important changes during the end of paleozoic highlighting that sea surface temperature is a key factor to understand the biosphere history since it changes simultaneously with the biological crises and that blmcs are invaluable archive for tracking physical and chemical conditions of past oceans

microwear features on vein quartz rock crystal and quartzite a study combining optical light and scanning electron microscopy abstract in general quartz and most of non flint rocks have not been extensively studied from a functional point of view very frequently the definitions of micro features connected with flint surfaces have been used to describe those encountered on non flint tools this circumstance has repeatedly posed serious methodological problems for evaluating the accuracy of functional results when analysing use wear on quartz and quartzite implements this is due to the intrinsic divergences in morphology and distribution of use wear with regard to the different lithic raw materials even though important efforts to systematise use wear features on quartz have been done almost since the beginning of the discipline there continues to be confusion and lack of standardisation regarding terminology in this aspect in this paper we try to contribute to new insights in this research by means of selecting examples from an extensive experimental programme involving different raw materials from rock crystal the purest form of quartz found in nature to vein quartz and quartzite with the latter two materials extensively used for knapping throughout prehistory and still poorly understood in terms of microwear for data recording we preferentially used sequential experiments and resorted to both optical light and scanning electron microscopy we focused our interest on describing the main groups of wear features the results obtained allowed us to assess the different mechanical behaviours under the stressors induced by tool use from a group of raw materials with the same chemical composition but very different in structure furthermore we propose the revision of some terms commonly employed when documenting micro wear on quartz and similar rocks as well as recurring concepts coming from materials and geological sciences e g tribology quartz exoscopy

isotope stratigraphy of the european carboniferous proxy signals for ocean chemistry climate and tectonics abstract carboniferous brachiopods from western europe and the former ussr have been utilized as carriers of isotopic proxy signals for paleoceanography and paleoclimatology during the assemblage of pangea this is of particular interest because this time interval coincides with the transition from greenhouse to icehouse conditions the 18 o values 3 ma running means show an overall 18 o increase from about 7 1 to 3 1 during the carboniferous the rise in the 18 o is stepwise with major shifts in the mid tournaisian and at the visean serpukhovian transition the comparable 13 c record shows a tournaisian peak at 5 a visean oscillation at about 2 5 1 a serpukhovian rise of more than 3 a plateau around 5 during the bashkirian and moscovian a 4 drop during the kasimovian and another rise of about 3 during the gzhelian the 87 sr 86 sr record shows an early carboniferous decline from 0 7083 to a mid visean minimum of 0 7077 followed by a rapid serpukhovian rise to a bashkirian and moscovian plateau at 0 7087 and a slight decline during the kasimovian and gzhelian the covariance of isotopic trends and the coincidence with geological phenomena indicates that the long term variations in ocean chemistry and climate may be coupled to the tectonic evolution of the earth system the namurian witnesses the onset of hercynian orogeny initiation of the main phase of carboniferous glaciation formation of the extensive coal deposits and the rise in 87 sr 86 sr 13 c and 18 o all this suggests that a tectonically controlled climate change resulting in cooling and increased carbon storage in the organic reservoir was the major triggering factor for all the above phenomena the late carboniferous glacial episode was interrupted by a warm interval in the stephanian the carbon and oxygen isotope data indicate that this episode may have been restricted to the early kasimovian a proposition at odds with the poorly dated record of glacial deposits that are interpreted as indicating a warm climate for the entire stephanian in addition the pattern of short lived peaks in 13 c and 18 o in the tournaisian and possibly visean may be interpreted as a reflection of short lived glacial episodes a proposition consistent with geologic records

finding resolution for the howiesons poort through the microscope micro residue analysis of segments from sibudu cave south africa in this paper i present the results of a micro residue analysis of stone segments the type fossils of the howiesons poort technocomplex in south africa with an age of more than 60 ka at sibudu cave kwazulu natal fifty three segments were systematically analysed and 1826 organic micro residue occurrences were documented on the sample the distribution patterns of micro residues and other use traces are interpreted in terms of hafting and function it is shown that most of the tools were indeed hafted and most were probably used as inserts for hunting weapons there is evidence for differences and changes over time in haft materials and hafting configurations of the segments the study demonstrates how functional studies could improve our understanding of change and variability in human behaviour during the middle stone age a period that used to be portrayed as static or slow changing

oxygen isotopes in meteoric calcite cements as indicators of continental paleoclimate because meteoric water 18 o values decrease with decreasing ambient temperature and increasing latitude 18 o values of meteoric calcite cement should exhibit a similar relation with paleolatitude and be an indicator of continental paleotemperatures to test this we compiled isotopic and paleolatitude data for 20 meteoric cements and nine speleothems ranging in age from devonian to modern and in paleolatitude from 3 5 to 83 mean 18 o values for meteoric cements and speleothems both show the same negative correlation with paleolatitude the 18 o vs latitude trend for these carbonates is almost identical to that predicted for modern inland environments but differs from the trend for coastal environments this suggests that the ground water controlling the ultimate composition of meteoric cement is derived predominantly from inland recharge if it is assumed that the modern meteoric water 18 o vs temperature relation is valid for the past and that insignificant evaporation occurred prior to carbonate precipitation then coastal and inland paleotemperatures can be calculated from the 18 o values of meteoric calcite 18 o mcl and seawater 18 o sw by using the equations t coastal 13 3 32 6 0 231 0 0613 18 o mcl 18 o sw and t inland 17 8 16 2 0 572 0 1233 18 o mcl 18 o sw where t is temperature in c calcite precipitated from coastal meteoric water at temperatures between 0 and 25 c will exhibit a narrow range in 18 o 6 to 4 where 18 o sw 0 the 18 o of calcite precipitated from inland meteoric water will be sensitive to paleotemperature ranging from 14 to 5 where 18 o sw 0 for temperatures of 0 to 25 c

the function of recycled lithic items at late lower paleolithic qesem cave israel an overview of the use wear data abstract the study of lithic recycling in paleolithic cultures throughout the old world is increasingly becoming a topic of interest for many scholars technological analyses refitting and spatial analyses are disclosing the recycling behavior of many contexts especially those of lower and middle paleolithic sites still lacking however is a functional approach to the subject which would certainly add new pieces to this intriguing jigsaw puzzle use wear analysis one of the most powerful methods to reach functional interpretations in lithic finds can greatly improve our understanding of paleolithic recycling behavior even in those cases where post depositional alterations affected lithic items use wear analyses may produce important data despite the decrease in detail or less than optimal conditions of preservation at the late lower paleolithic site of qesem cave the high degree of conservation and preservation of the lithic tools maximizes the inference potential of this method in this article functional data are summarized following a study of a large sample of amudian parent flakes flakes from which were produced cores on flakes termed cof ffs as well as recycled products blanks produced from cof ffs confirming the inference potential of use wear analyses this data allows for the delineation of functional peculiarities of the studied items which despite first impression are anything but expedient moreover the current use wear analysis expands the scenario outlined by the technological study of the lithic recycling phenomenon at qesem cave confirming its own role in the complex techno functional system practiced by the hominins of qesem cave

carbonate platform drowning in a foreland setting the mid carboniferous platform in western urals russia abstract the stratigraphic evolution through time of the mid carboniferous russian platform deposited on the distal margin of the west uralian prograding foredeep basin can be observed in the approximately 3000 m thick sedimentary cover that constitutes the upper paleozoic foreland mid carboniferous permian of the uralian fold belt it is composed of wave dominated low angle carbonate ramps of late visean to early moscovian age and carbonate platforms bordered by slope reef mounds from the kasimovian to the late artinskian early kungurian eastward in the foredeep the carbonate platforms pass into terrigenous deposits a complete transgressive progradational section at the transition between carbonate ramp and terrigenous deposits exhibits from base to top 1 deepening upward carbonate ramp deposits 2 a shaly condensed section with volcaniclastics glauconite and phosphorites of late moscovian to early asselian age the transgressive part and 3 a shallowing upward section of turbidites ending in coarse grained fan deltas evaporites and meandering river redbeds by the earliest triassic the progradational section this paper focuses on the uppermost part of the carbonate ramp deposits serpukhovian to early moscovian these ramp facies comprise peritidal channels and mud flats wave to storm dominated shoals and patch reefs that are overlain by channel attached sand lobes of turbidites black shales and radiolarites of the condensed section this large scale deepening upward trend from inner ramp to outer ramp environments reflects a change in the depositional profile from a tide and wave dominated flat ramp to a wave and storm dominated steepened ramp margin and then to foreslope turbidites correlation of sections dated by fusulinid faunas in southern urals shows that the ramp evolved from emergent in the north perm solikamsk area as evidenced by karstification and deepened to the south belaya area with emplacement of carbonaceous foreslope debris flows and turbidites capped by deep marine black shales and radiolarites the time gap increases northward and reaches a span including the siuransky pro parte the akavassky the askynbashky and the asatausky pro parte biohorizons the mapping of these facies belts across all the urals shows that carbonate ramps wedge out in the middle urals and give rise to widely distributed diversified and deeper marine facies belts not only to the south towards the precaspian depression but also to the north towards the polar urals the drowning of these carbonate ramps and the cutoff in carbonate production on the russian platform during the mid carboniferous is explained by a succession of low frequency flexure relaxation cycles in the foreland associated with dilution by siliciclastics outpouring of volcaniclastics and changes in the nature and direction of the sediment input and high frequency cycles mainly controlled by eustasy

brachiopods as indicators of original isotopic compositions in some paleozoic limestones the original stable isotopic composition of paleozoic marine carbonate rocks is important to establish a baseline for evaluating diagenetic alteration and providing a reliable data base for modeling exogenic geochemical cycles of the elements we have compared the 18 o and 13 c values in the nonluminescent portions of brachiopods with similar published data of whole brachiopods other whole fossils and estimates of original isotopic composition of marine cements the oxygen and carbon isotopic records for each of these paleozoic components show generally good internal consistency significant discrepancies however were noted between results on the different components isotopic and trace element data presented in this study suggest that permo carboniferous whole brachiopods are little altered chemically nonetheless a more reliable but not fool proof approach for obtaining pristine isotopic values is microsampling of least altered regions based on cathodoluminescence in conjunction with staining techniques and elemental analyses the carbon and oxygen isotopic compositions of all components decrease in 18 o and 13 c in geologically older material neither temporal trend is monotonic however oxygen isotopic results suggest an important positive shift in 18 o of about 2 during the early carboniferous whereas the carbon isotope trend shows a major positive shift 2 3 during the mid carboniferous

chemical variation in pennsylvanian brachiopod shells diagenetic taxonomic microstructural and seasonal effects abstract to improve our ability to use minor and trace element mte variation in biotic carbonates as diagenetic and paleoenvironmental indicators we performed electron probe microanalysis on more than 100 late pennsylvanian brachiopod shells from texas kansas missouri and new mexico texturally preserved specimens of the genera crurithyris composita and neospirifer from all three regions were analyzed as were eridmatus specimens from texas twenty measurements were made in two transects across each shell shell microstructure and cathodoluminescence were described for each spot analyzed three modern shells were analyzed for comparison diagenesis as indicated by cathodoluminescence and or absence of microstructure tends to enrich shells in fe and mn x ca 0 7 mmol mol and deplete shells in na and s mg content shows no consistent trend with diagenesis in fabric retentive nonluminescent shell areas mg na and s contents vary twofold to sevenfold depending on taxonomy microstructure and season overall taxonomy is the dominant factor controlling mte composition na and s concentrations are consistently highest in crurithyris and eridmatus intermediate in neospirifer and lowest in composita in taxa with mixed microstructure composita neospirifer secondary fibrous layer calcite contains 1 5 to 2 times more na than does interlayer prismatic calcite thus whole shell na contents of these taxa depend on the proportion of fibrous and prismatic shell seasonal cycles are revealed in mte transects across growth lines mg na and s contents commonly vary by more than a factor of two between maxima presumably summer and minima winter within the same shell retention of taxonomic microstructural and seasonal effects in shell chemistry argues for preservation of original chemistry in fabric retentive nonluminescent paleozoic brachiopod shells

deposition of a saline giant in the mississippian windsor group nova scotia and the nascent late paleozoic ice age abstract saline giants are vast marine evaporite deposits that currently have no modern analogues and remain one of the most enigmatic of chemical sedimentary rocks the mississippian windsor group ca 345 ma maritimes basin atlantic canada is a saline giant that consists of two evaporite rich sedimentary sequences that are subdivided into five subzones sequence 1 is composed almost entirely of thick halite belonging to subzone a osagean sequence 2 is in unconformable contact and comprised of stacked carbonate evaporite peritidal cycles of subzones b through e meramecian subzone b the focus of research herein documents the transition from wholly evaporitic to open marine conditions and thus preserves an exceptional window into the processes forming saline giants lithofacies stacking patterns in subzone b reveal that higher order fluctuations in relative sea level produced nine stacked parasequences interpreted to reflect high frequency glacioeustatic oscillations during the onset of the late paleozoic ice age each parasequence reflects progradation of intertidal and sabkha sediments over subtidal carbonate and evaporite deposits dissimilarities in cycle composition between sub basins imply the development of contrasting brine chemistries from differing recharge rates with the open ocean what the windsor group shows is that evaporite type is ostensibly linked to the amplitude and frequency of sea level rise and fall during deposition true saline giants like the basinwide evaporites of sequence 1 apparently require low amplitude long frequency changes in sea level to promote the development of stable brine pools that are only periodically recharged with seawater by contrast the high amplitude short frequency glacioeustatic variability in sea level that controlled the accumulation of peritidal evaporites in subzone b produce smaller subeconomic deposits with more complex facies relationships

geochemistry of brachiopods oxygen and carbon isotopic records of paleozoic oceans abstract combined trace element and isotope studies of 319 brachiopods covering the ordovician to permian time span show that 13c and 18o in well preserved specimens varied during the paleozoic the overall 13c secular trend is in accord with the previously published observations but its details are obscured by vital isotopic fractionation effects at generic level nonetheless the results suggest that the negative correlation between marine 13ccarbonate and 34ssulphate deteriorates at time scales of 106 years due to the long residence time and thus slow response of so42 in the ocean for oxygen isotopes all devonian and older specimens have 18o of 4 while the well preserved permian samples have near present day 18o of about 1 pdb this isotopic dichotomy is probably not due to post depositional phenomena salinity or biogenic fractionation effects this leaves open the perennial arguments for a change in 18 o 16 o of sea water versus warmer ancient oceans the present data are difficult to explain solely by the temperature alternative the coincidence of the proposed shift in 18o with the large late paleozoic changes in marine 87 sr 86 sr 13 c 12 c 34 s 32 s and sea level stands argues for a tectonic cause and for a change in 18 o 16 o of sea water although such explanation is difficult to reconcile with global balance considerations and with isotopic patterns observed in alteration products of ancient basalts and ophiolites whatever the precise cause or combination of causes the implications for tectonism and or paleoclimatology are of first order significance

the δ18o record of phanerozoic abiotic marine calcite cements monomineralic abiotic marine cements formed in low latitude phanerozoic reefs provide the direction and amplitude of secular variation of delta sup 13 c and delta sup 18 o in marine calcite and defines two end member compositions 580 to 360 my minus 7 to minus 5 per thousand delta sup 18 o sub pdb and 360 to present minus 3 to 0 per thousand delta sup 18 o sub pdb sampling of the devono carboniferous transition 375 320 my at several global sites reveals a rapid change in carbonate isotopic compositions bracketed within fammenian to early visean aged strata a 7 to 15 my time interval this shift corresponds to a 2 offset in mean delta sup 13 c and 3 4 offset in delta sup 18 o the abruptness of such change and its overall correlation with variations in sup 87 sr sup 86 sr delta sup 34 s delta sup 13 c and li al ratios in marine sediments suggests a primary offset in marine water composition

use wear analysis of the late middle pleistocene quartzite assemblage from the gran dolina site td10 1 subunit sierra de atapuerca spain abstract quartzite has been poorly studied from a functional point of view since the foundation of use wear analysis as the method was largely built upon the observation of wear on fine grained raw materials e g chert in the case of the middle pleistocene gran dolina td10 1 site in spain ca 300 kya the sole raw material that can provide functional information for the artifacts used by the human occupants of the site is quartzite a sample of 51 quartzite artifacts was mainly analyzed with scanning electron microscopy and functional interpretation was possible for 36 of them the activities identified were mostly connected to the butchering of animals but bone and hide scraping as well as woodworking were also present the performance of activities other than butchering supports the idea that the site was used as a residential camp during the deposition of the basal part of the td10 1 subunit lower td10 1 this study demonstrates the possibility of obtaining functional data from relatively ancient artifacts made of a coarse grained lithology considering that metamorphic quartzose materials often dominate early and middle pleistocene lithic assemblages all over the world the standardization of the functional reading of quartzite will allow acquiring countless functional data with which to reconstruct ancient human behavior

microscopic analysis of technical and functional traces as a method for the use wear analysis of rock crystal tools abstract rock crystal is a high quality quartz variety with an excellent aptitude for knapping although it is relatively uncommon in certain geological contexts such as that of our case study rock crystal can serve as the raw material for a substantial number of tools nevertheless very little research has been devoted to the study of this material this lack of interest may stem from a variety of sources from the difficulty of analysing a translucent material to its direct attachment to the symbolic world here we propose a methodology for the microscopic analysis of rock crystal artefacts in order to establish a better approach for understanding the functionality of this raw material we comprehensively analysed a series of experimental tools before use by means of different microscopic equipment olm with a nomarski prism and sem after the initial documentation the tools were used in a sequential experimental programme in order to monitor and document the development of use wear traces fourteen experiments were conducted on different materials and with different actions in which the different use traces as well as their respective orientations and sizes were recorded over a series of established times the set of experiments resulted in different associations of use wear traces striations chipping rounding and polish characteristic of the various worked materials and actions employed we also documented how a technical mark such as the lancet can provide functional information this is due to the formation process of the mark by percussion or pressure while lancets formed from the impact point on the ventral side are distributed radially those created by flake removal follow the kinematics of the tool finally we demonstrated that rock crystal is a material that offers great possibilities for use wear analyses once a set of technical and functional associations of mark analyses have been determined furthermore although olm with a nomarski prism proved to be highly suitable in the analysis of rock crystal its combination with other techniques such as sem can provide additional information

isotopic paleoceanography of the caribbean and east pacific role of panama uplift in late neogene time comparisons of carbon isotopic data on benthic foraminifera from deep sea drilling project sites 502 western caribbean and 503 eastern pacific indicate that the difference between the atlantic and the pacific in the per mil enrichment in carbon 13 of total dissolved carbon dioxide increased about 6 million years ago and again 3 million years ago when the difference reached the modern level 1 per mil comparisons of planktonic foraminiferal oxygen isotopic data for the caribbean and the pacific suggest that the salinity of caribbean surface waters began increasing 4 million years ago possibly in response to shoaling of the panama isthmus these results suggest that modern circulation patterns in the caribbean and eastern pacific developed by 3 million years ago in concert with changing tectonic climatic and biogeographic patterns

stable isotopes in late pennsylvanian brachiopods from the united states implications for carboniferous paleoceanography stable isotopic analyses have been performed on nearly 500 nonluminescent brachiopod shells from kansas new mexico and texas to evaluate temporal and geographic variability in the carbon and oxygen isotopic record for late pennsylvanian time brachiopod specimens were collected from missourian and virgilian shales and examined in thin section for preservation of microstructure and absence of cathodoluminescence as a primary test for shell preservation regional variations are observed in the 18o and 13c values of nonluminescent brachiopod shells of the same genera average 18o values for the three genera analyzed crurithyris composita and neospirifer are highest in kansas 1 9 intermediate in texas 2 3 and lowest in new mexico 3 6 vital effect on the 18o of these genera appears minimal 18o data and other evidence suggest warmer temperatures for the shallow new mexico localities and slightly higher salinity for the kansas sea relative to the texas sea the 13c values of composita average about 1 higher than those of co occurring crurithyris and neospirifer suggesting microhabitat differences or vital effects preservation of this species effect argues for preservation of original 13c values average 13c values are highest in texas intermediate in kansas and lowest in new mexico although these values range from 2 6 to 4 9 for individual genera the regional variation in 13c averages less than 1 data for nonluminescent brachiopods and marine cements reveal a mid carboniferous 13c increase of 2 in paleotethyan sea water this increase is not seen in samples from the north american epicontinental seas which opened to the panthalassa ocean this regional difference in 13c appears to be due to changes in ocean circulation associated with the closing of the equatorial seaway and formation of pangea

early carboniferous onset of gondwanian glaciation and neo tethyan rifting in south tibet at least four diamictite bearing intervals of early carboniferous age containing faceted pebbles trapezoidal cobbles and boulders up to 1000 m3 in volume have been recognized and traced for over 200 km along the tethys himalayan zone of south tibet from east of everest to west of shishapangma these largely glacio marine sediments intercalated within the rakyang formation which overlies lower tournaisian limestones and underlies lower bashkirian black shales were deposited during the visean to serpukhovian shore ice thus began to form in this region of northern gondwana several tens of million years earlier than previously thought this glacial event occurred at middle southern latitudes and was triggered by basin inversion and tectonic uplift in the first stages of neo tethyan rifting as documented by the close association of diamictites with olistoliths and olistostromes in lower carboniferous units after a transgressive interglacial episode in the bashkirian a much more widespread glaciation occurred in the latest carboniferous and was shortly followed by continental break up and opening of neo tethys in the late early permian

structural study of two quartzite varieties from the utrillas facies formation olmos de atapuerca burgos spain from a petrographic characterisation to a functional analysis design abstract this overall research initiative was undertaken to evaluate the role of lithic raw material variability in use wear formation processes focusing specifically on two lithological varieties of quartzite present in the lower and middle pleistocene lithic assemblages of the gran dolina galeria and sima del elefante sites sierra de atapuerca burgos two arenas de utrillas facies varieties from a sand quarry located in olmos de atapuerca were studied using petrographic and sem analyses they were both identified as metaquartzites revealing differences in their granular structure and metamorphic grade sequential experiments employing the same quartzite varieties were then conducted involving different activities and several worked materials which made it possible to determine use wear formation on these two quartzite varieties the results helped to clarify the role of intra raw material variability in the process of use wear formation on quartzite and contributed to ongoing studies of the lithic materials from these archaeological sites

oxygen isotope and mg ca composition of late visean mississippian brachiopod shells from sw iberia palaeoclimatic and palaeogeographic implications in northern gondwana abstract latest visean brachiopod shells gigantoproductus sp from the pedroches basin of sw spain were sampled in order to obtain chemical and isotopic evidence that may help first to assess if primary geochemical and isotopical signals are preserved in these shells and second to reconstruct temporal variations in palaeoceanographic and palaeoclimatic conditions in northern gondwana during this time span microtexture cathodoluminescence cl and ultrastructure under sem of the brachiopods were examined to avoid sampling of shell portions altered after deposition shell portions classified as non luminescent nl and non luminescent to slightly luminescent nl sl present geochemical signatures within the ranges considered normal for recent brachiopods that have not undergone significant diagenetic modification these include low to undetectable fe and mn contents high sr values and 18o values similar to those of carbonates in equilibrium with seawater on the other hand valve areas that are luminescent l or moderately luminescent with luminescent portions ml l present higher fe and mn contents lower sr concentrations and lower 18o values than those corresponding to nl and nl sl shells this suggests a greater diagenetic alteration of these portions and that they acted as microzones of reaction with the diagenetic fluids temporal trends through the studied interval show a spread in 13c values much lower than that observed for contemporaneous samples up to 1 6 thus obscuring the 13c global signal at the time scale resolution of this study in contrast the 18o record of brachiopod calcite 18oc shows an overall increase of 1 relative to v pdb from the oldest to the youngest samples this is accompanied by a 30 decrease in mg ca ratios of the brachiopod calcites confirming that at least part of this shift in 18oc was related to cooling combination of mg ca and 18oc proxies established in this paper although not full proof for brachiopods yet allowed for the calculation of a temperature drop of 3 3 c and a change in seawater 18ow that becomes 0 4 more positive during this interval the data are consistent with regional seawater cooling that accompanied an increase in continental ice volume over a relatively short time period of

one million years of cultural evolution in a stable environment at atapuerca burgos spain abstract the present paper analyses the evidence provided by three sites sima del elefante gran dolina and galeria located in the trinchera del ferrocarril of the sierra de atapuerca these three sites are cave infillings that contain sediments deposited from approximately 1 2 ma to 200 kyr pollen herpetofauna and small and large mammal remains are used as proxies to obtain a general picture of the environmental changes that occurred at the sierra de atapuerca throughout the one million year period represented at these sites similarly cultural changes are tracked analyzing the evidence of human behavior obtained from the study of several bone and lithic assemblages from these three sites at least three periods with different cultural features involving technology subsistence and behavior are determined from the available evidence the first two periods correspond to the mode 1 technology and homo antecessor the first is dated around 1 2 to 1 0 ma and reflects opportunistic behavior both in technology and subsistence the second period is around 800 kyr bp mode 1 technology is still maintained but subsistence strategies include systematic hunting and the use of base camps the third period is dated between 500 ka and 200 ka and corresponds to the mode 2 technology and the acquisition of directional hunting and other organizational strategies by homo heidelbergensis a transition from mode 2 to mode 3 seems to appear at the end of this time range and may reflect the early phases of a fourth cultural change with regard to the environment our main conclusion is that there was an absence of extremely harsh conditions at atapuerca throughout this time period the presence of mediterranean taxa was constant and the dominant landscape was a savannah like open environment probably with small forest patches an alternation of mediterranean and mesic species as the dominant component of the tree storey was induced by the climatic cycles and steppes spread across the landscape during the drier periods in any case it is not possible to establish clear cut off points separating entirely different environmental episodes our results show no evidence of any relationship between environmental change and cultural change at the sierra de atapuerca

correlation of the askyn river section southern urals russia with the mid carboniferous boundary gssp bird spring formation arrow canyon nevada usa implications for global paleoceanography abstract isotopic data of unaltered low mg calcite brachiopods from type bashkirian strata of the askyn river section southern urals russia are correlated with those from the mid carboniferous boundary global stratotype section and point gssp at arrow canyon southern nevada usa strontium isotope and conodont data of precisely located samples from the sub to tropical locations spanning the mid carboniferous boundary facilitate the correlation of the two sequences and support the discontinuous nature of the sequence at askyn carbon isotopic trends of the two sites are generally divergent and demonstrate the influence overprinting of local oceanographic conditions on global parameters oxygen isotopes show a similar divergence for the latest mississippian time period with concurrence of values for the earliest pennsylvanian at the two sites in both instances differences variations in water temperature currents salinity and burial rate amount of organic matter or combinations of these factors may have played roles of influencing water chemistry at the local level it is possible to achieve global correlations at a finer scale than biozones with precisely located material from stratotype and ancillary sections especially if a global stratotype point has been identified and selected according to universally accepted biostratigraphic criteria consequently it is possible to resolve oceanographic influences at the local level and reconcile them with truly global oceanographic conditions and ultimately define global causes effects such as cryospheric and tectonic events seawater chemistry at arrow canyon probably represents panthalassan global mid carboniferous oceanic conditions supported by its similarity with data from other locations and modern global oceanographic parameters askyn represents paleotethys and global oceanographic conditions but in part overprinted by local influences the mid carboniferous seems to be a time of expansion of the cryosphere as documented by a positive shift in seawater oxygen isotope composition of about 0 5 smow from the latest mississippian 1 2 to earliest pennsylvanian 0 7

geocarbsulf a combined model for phanerozoic atmospheric o2 and co2 abstract a model for the combined long term cycles of carbon and sulfur has been constructed which combines all the factors modifying weathering and degassing of the geocarb iii model berner r a kothavala z 2001 geocarb iii a revised model of atmospheric co2 over phanerozoic time am j sci 301 182 204 for co2 with rapid recycling and oxygen dependent carbon and sulfur isotope fractionation of an isotope mass balance model for o2 berner r a 2001 modeling atmospheric o2 over phanerozoic time geochim cosmochim acta 65 685 694 new isotopic data for both carbon and sulfur are used and new feedbacks are created by combining the models sensitivity analysis is done by determining 1 the effect on weathering rates of using rapid recycling rapid recycling treats carbon and sulfur weathering in terms of young rapidly weathering rocks and older more slowly weathering rocks 2 the effect on o2 of using different initial starting conditions 3 the effect on o2 of using different data for carbon isotope fractionation during photosynthesis and alternative values of oceanic 13c for the past 200 million years 4 the effect on sulfur isotope fractionation and on o2 of varying the size of o2 feedback during sedimentary pyrite formation 5 the effect on o2 of varying the dependence of organic matter and pyrite weathering on tectonic uplift plus erosion and the degree of exposure of coastal lands by sea level change 6 the effect on co2 of adding the variability of volcanic rock weathering over time berner r a 2006 inclusion of the weathering of volcanic rocks in the geocarbsulf model am j sci 306 in press results show a similar trend of atmospheric co2 over the phanerozoic to the results of geocarb iii but with some differences during the early paleozoic and for variable volcanic rock weathering lower co2 values during the mesozoic atmospheric oxygen shows a major broad late paleozoic peak with a maximum value of about 30 o2 in the permian a secondary less broad peak centered near the silurian devonian boundary variation between 15 and 20 o2 during the cambrian and ordovician a very sharp drop from 30 to 15 o2 at the permo triassic boundary and a more or less continuous rise in o2 from the late triassic to the present

microwear polishes on early stone tools from koobi fora kenya the functions of the stone artefacts made and used by early hominids has been a matter for speculation however recent experimental work has demonstrated that microscopically distinct wear polishes form on tools of cryptocrystalline silica when used on different materials and that these microwear polishes survive on ancient implements1 3 we have now examined 54 artefacts from five early pleistocene archaeological sites dated to 1 5 myr ago in the koobi fora region of kenya for microwear polishes and other traces of use wear traces were found on nine artefacts variously resembling traces induced experimentally by cutting soft animal tissue and soft plant material and by scraping and sawing wood these results greatly extend the time range for which microwear polish analysis is applicable and increase the evidence of early hominid adaptation

gradients in seasonality and seawater oxygen isotopic composition along the early permian gondwanan coast se australia abstract oxygen isotope compositions of marine carbonates are commonly employed for understanding ancient temperatures but this approach is complicated in the very distant past due to uncertainties about the effects of diagenesis and the isotopic composition of seawater both locally and globally microsampled accretionary calcite from two species of the fossil bivalve eurydesma sowerby and morris 1845 collected from sediments of cisuralian age in high latitude marine sediments along the se coast of australia records cyclic seasonal fluctuations in shell 18 o values during growth demonstrating the primary nature of the isotope signal and thus allowing investigation of early permian seawater isotopic composition and water temperature in the high southern latitudes the mean and seasonal range of 18 o carb decreases poleward across about 10 of paleolatitude 67 s 77 s the presence of co occurring dropstones and stratigraphically associated glendonites constrains winter temperatures across the region to near freezing thus permitting calculation of realistic estimates of water composition and summer temperatures summer 18 o carb values indicate water temperatures between 5 c and 12 c with warmer values at lower latitudes the decrease in both mean sea surface temperature and seasonal amplitude with increasing latitude on the gondwanan coast is much like that observed along high latitude coastlines today calculated 18 o water decreases toward the pole likely associated with an increasing contribution of isotopically light fresh water derived from summer snow melt the gradient in 18 o water is similar to that documented over a similar span of latitude on the modern se greenland coast we infer the presence of a north flowing coastal current of cold o 18 depleted water that entrains progressively greater amounts of more typical seawater as it moves away from the pole 18 o values in se australia however are about 3 lower than those off greenland suggesting comparatively lower salinity water or more o 18 depleted glacial ice runoff in the permian gondwanan high latitudes perhaps augmented by more depleted negative global average seawater conditions in southeastern australia during the largest of the permian deglaciations were warmer than present day antarctica at similar latitudes but may approximate those of early mid miocene antarctica with frozen winters but summers closer to 10 c

tropical marine climate during the late paleozoic ice age using trace element analyses of brachiopods abstract the late paleozoic ice age can be considered an important analogue to the modern ice age but comparisons between the two time intervals have been hampered by the difficulty of resolving climatic changes that occur over short e g seasonal time scales in the paleozoic record as a first step toward overcoming these limitations this study employed mg ca trace element ratios sampled across the growth bands of six specimens of the brachiopod composita to assess differences in tropical marine mean temperature and seasonality in visean and moscovian time these time intervals bracket the onset of the late paleozoic ice age which occurred in mid serpukhovian time and thus provide a snapshot of climate changes from a greenhouse to an icehouse world shells were screened for diagenetic alteration by cathode luminescence and by comparing the values of mn sr na and b to those reported for modern brachiopods in addition a 87sr 86sr value measured for one specimen agreed with a published strontium isotope curve for the late paleozoic era both the mean and range of mg ca values were larger in visean than moscovian time suggesting colder and less seasonal temperatures during the late paleozoic ice age the decline in seasonality was due to a greater proportional reduction of maximum values which presumably represent summer temperatures than minimum values these relative differences between the pre ice age and ice age tropical climate provide a first step toward understanding the broad patterns of seasonal scale changes in temperature during a critical time in earth s history