simultaneous thin section and phytolith observations of finely stratified deposits from neolithic catalhoyuk turkey implications for paleoeconomy and early holocene paleoenvironment simultaneous thin section and phytolith observations of finely stratified anthropogenic deposits from the neolithic settlement of catalhoyuk turkey dated between 7400 and 6000 bc provide evidence for both the depositional context and phytolith assemblage of these deposits although extracted phytoliths provide a general picture of vegetation that supports existing evidence of a local wet marshland environment comparisons with observations of phytoliths in situ indicate a diverse range of microcontexts as well as depositional and post depositional processes that influence phytolith size this has implications for studies that use conjoined phytolith size as a proxy for water availability and early agricultural practices observations indicate a significant background noise of phytoliths and micro charcoal in the deposits linked to the frequent use of fire which has implications for interpreting assemblages where phytolith counts are low such as from floors of buildings this study confirms the usefulness of phytoliths in providing information on human plant use and environment where the taphonomy of the deposits is clear and provides new evidence for wet farming of at least some of the wheat found at the site it also suggests there needs to be greater consideration of phytolith taphonomy which can be provided to an extent by combining phytolith analysis with thin section micromorphology copyright 2011 john wiley sons ltd

desert agricultural systems at eba jawa jordan integrating archaeological and paleoenvironmental records located in the arid basalt desert of northeastern jordan the settlement of jawa is by far the largest and best preserved archaeological site in the region the early bronze age eba settlement phase of jawa 3500 3000 bce is characterized by a highly sophisticated water storage system made of a series of pools dams and canals in addition recent archaeological and geoarchaeological surveys have uncovered agricultural terrace systems in the nearby vicinity in this study four of these runoff terrace systems were investigated by detailed mapping additionally thirteen sediment profiles from inside and outside the terrace systems were recorded and sampled the examined samples were analyzed for bulk chemistry texture phytoliths diatoms and dung spherulites to supply information on the environmental and depositional conditions the terrace systems were dated using optically stimulated luminescence osl ancient terrace agriculture was practiced on slopes small plateaus and valleys close to jawa through the use of surface canals which collected and diverted floodwater from nearby wadis or runoff from adjacent slopes the terraced fields were usually arranged in cascades and comprised a system of risers canals and spillways the terrace fills investigated yield osl ages of around 3300 bce indicating that the terraces were constructed in the early bronze age the terrace fill sequences are composed of mixed unstratified fine sediments of local origin reflecting low energy fluvial deposition regimes the phytolith record is dominated by pooid grasses that include the most common near eastern cereals such as wheat and barley increased phytolith concentrations in terrace fill sediments as compared to samples from non terrace deposits nearby suggest increased plant growth and water availability within the terraces whether the terrace systems were used for growing food crops only or whether they were additionally used for grazing cannot be ascertained overall quantitative phytolith analyses in arid environments are well suited to investigate temporal and spatial distributions of plant microfossil concentrations and their relation to human activity or paleoenvironmental conditions

δ18o values of coexisting brachiopods and fish temperature differences and estimates of paleo water depths to estimate vertical thermal gradients and paleo water depths to marine platforms we present a new method based on the difference between 18 o values of contemporaneous brachiopod carbonate and fish phosphate present day marine fauna of well known ecology from the surface to the sea floor record isotopic temperatures that agree with measured temperatures we predict distributions of isotopic data that result from sampling strategy basin morphology and fauna ecology and discuss limitations application of the method to the jurassic paris london basin gives vertical thermal variations of up to 14 c associated with depths varying from a few meters to 170 30 m the estimated depths are minimum values and are greater than those estimated from sedimentological criteria for this ancient epicontinental sea

mode of occupation of tabun cave mt carmel israel during the mousterian period a study of the sediments and phytoliths alternative modes of occupation of tabun cave during the deposition of the mousterian levels b and c have been proposed garrod bate 1937 excavations at the wady el mughara volume 1 oxford clarendon press interpreted the archaeological record of both levels as being indicative of domestic occupational activities jelinek et al 1973 palaeorient 1 151 183 proposed that the presence of articulated limb bones of dama mesopotamica in the level b sediments below the cave chimney indicated that the cave was used as a natural game trap they also noted that the white ash layers in level c extended across the whole cave and proposed that this was due to the burning of natural vegetation in the cave this study aims at clarifying the modes of occupation during these periods level b sediments closely resemble the terra rossa soil that is common in this region burning activity is inferred from charcoal fragments seen in thin sections a minor wood ash component is present based on the preponderance of phytoliths with a variable morphology as compared to those with a consistent morphology as well as phytoliths with shapes characteristic of those formed in wood and bark of local trees thus fires were produced in the cave during this period the cave may also have been used as a game trap level c is composed of multiple layers of brown black and white sediments micromorphology mineralogy and phytolith analyses all show that these layers are mixtures of terra rossa soil and ash with the latter being abundant in the white layers the phytoliths in these layers are derived almost entirely from wood and bark and not from grasses these observations are consistent with a domestic occupational mode 1999 academic press

pedology of archaeological soils in tells of the judean foothills israel abstract tells archaeological mounds predominantly consist of poorly consolidated to unconsolidated sediments and soils that are highly anthropogenic this study examines pedogenic processes related to carbonate mobilization in tells in comparison with their peripheral soils reference soil profiles the key objective of this study is to test the hypothesis that tell deposits evolve through concurrent processes of sedimentation and pedogenesis synlithogenic pedogenesis and further explain it case studies are presented from three tells in semi arid and mediterranean climatic zones of the levant the methods applied included field survey analyses of particle size distribution ph caco3 and organic carbon content and soil micromorphology soils of the tells contain miscellaneous cultural materials that derive mainly from degraded mud bricks pottery and burnt wood chemical data show basic ph values high caco3 content and minor amounts of organic carbon field observations and lab analyses both indicate high similarity amongst the tells and their reference soil profiles buried tell soils show same characteristics as near surface soils however the reference soil profiles show incipient horizonation slightly darker colours and more developed structure micromorphology of both the tells and the reference profiles show cohesively welded peds in a vughy microstructure groundmass with an open porphyric c f related distribution and discontinuous carbonate recrystallization relative rates of soil formation in the tells can be estimated when archaeological records are established contrary to the tells the reference soil profiles show lower porosity and only minor remnants related to earth construction materials we classify the soils of the studied tells as archaeological calcareous anthraltic xerorthents the correlative wrb classification would be calcic urbic technosols archaic the anthropogenic materials are as calcareous as the natural soils but due to human action carbonates in the tells are distributed differently based on these observations ancient human actions and the dry climate have led to very little mobilization and accumulation of carbonates the information provided in this study adds to the pedological understanding of archaeological environments specifically it can be useful for the study of site formation processes of tells

an integrated approach to reconstructing primary activities from pit deposits iron smithing and other activities at tel dor under neo assyrian domination abstract secondary pit deposits in historical occupations of near eastern mounds are usually regarded as uninteresting and are seldom analyzed we used an integrated approach to study all the artifacts as well as the sediments in a pit at tel dor on israel s carmel coast dating to the 7th c bce a period when the site served as an assyrian administrative center this pit was unusually large had a peculiar ceramic assemblage and many macroscopic metallurgical wastes a detailed excavation and analysis revealed that the pit served intermittently as a waste disposal site for an iron smithy and for pottery that was presumably involved in maritime trading on two occasions the area was also used for animal penning despite the obvious importance of the iron industry to the neo assyrian empire actual workshops are rare in its archaeological record hence the new information regarding an iron age iron smithy in the southern levant contributes to the study of this industry and also to the history of dor in this period

les crises du devonien superieur par l etude des faunes d ostracodes dans leur cadre paleogeographique abstract ostracod evolution studied at a global scale can contribute to an evaluation of the palaeobilogical crises during the late devonian the mostly pelagic entomozoidae are not affected data on benthic neritic ostracods come from the western canadian platform europe the russian platform north africa and the middle east species extinction rates vary according to provinces and areas extinction occur at the givetian frasnian lower upper frasnian and frasnian famennian boundaries only five families seem to disappear during the late devonian the appearance of new assemblages since the earlisst famennian is worldwide on platforms the thuringian ecotype ostracod assemblages underwent a major change since the early famennian it is characterized by many species with spinous carapaces and is known in the paleotethys during famennian dinantian times it is related to a glacial event in the north of the gondwana which generated cold deep water currents invading the paleotethysian basins the thuringian ecotype allows to propose a paleobathymetric model its species composition shows a double origin by evolution of early devonian roots and with lineages proceeding from circalittoral species causes of these late devonian events can be understood in a particular paleogeographic reconstruction where the paleotethys has no western faunal communication since the givetian frasnian boundary warming water associated with an oxygen deficiency eliminated several species at the givetian frasnian and lower upper frasnian boundaries a first cooling at the frasnian famennian time was sufficient to decimate species strongly adapted to the frasnian conditions the generalized regression at this time probably increased this last phenomenon

a new method for extracting the insoluble occluded carbon in archaeological and modern phytoliths detection of 14c depleted carbon fraction and implications for radiocarbon dating phytolith rich layers in archaeological sites constitute well defined stratigraphic horizons that would be invaluable if absolutely dated previous attempts to radiocarbon date phytoliths produced inconsistent results using plants with known ages in this study a new approach to extract and analyze the silica occluded carbon was tested on well dated archaeological contexts in beth shemesh and tell es safi gath and on modern wheat plants that grew in a controlled environment results show that by dissolving the silica using mild conditions phytolith insoluble fractions can be extracted and their radiocarbon contents analyzed reproducibly after phytolith dissolution the remaining insoluble fractions with 10 30 c have radiocarbon concentrations that are statistically similar to associated charred seeds within 2 and insoluble fractions with 40 c show concentrations that are identical to the seeds these results show that the insoluble fraction of phytoliths is a suitable material for answering chronological questions

ash deposits in hayonim and kebara caves israel macroscopic microscopic and mineralogical observations and their archaeological implications abstract a study of the hearths and ash layers preserved in hayonim and kebara caves israel showed that they are composed of one or several different minerals these include the polymorph of caco3 calcite a variety of phosphate minerals and a suite of siliceous minerals the major component of the latter are siliceous aggregates that are present in wood detailed studies of the mineral associations in these fossil ash layers as well as in fresh wood ash using optical and scanning electron microscopy in the back scattered electron mode together with elemental analyses showed that ash in these caves undergoes a series of diagenetic changes the best preserved ash layers resemble fresh ash and are composed mainly of calcite with minor amounts of siliceous minerals the calcite reacts with phosphate rich solutions to form carbonated apatite and with time the latter dissolves and a variety of other phosphate containing minerals form with each diagenetic change some of the more soluble minerals are lost and ultimately only the ash derived siliceous minerals remain in both caves there are local accumulations of such siliceous minerals that are metres thick in fact ash derived minerals in general are major components of the sediments in both kebara and hayonim caves their diagenesis involves a hugh reduction in volume which in turn may have important effects on the geological structures and stratigraphy of the sediments the changing mineralogy of the sediments due to diagenesis complicates the use of present day estimates of radiation content of the sediments for correcting age estimates by thermoluminescence and electron spin resonance finally the presence of the relatively stable ash derived siliceous minerals in a sedimentary layer in other caves could be a useful means of identifying the presence of ash in other archaeological sites where macroscopic hearth features are absent

comparing oxygen isotope records of silurian calcite and phosphate δ18o compositions of brachiopods and conodonts oxygen isotope compositions of silurian calcitic brachiopod shells from gotland are compared with those of phosphatic inarticulate brachiopod shells and conodonts from identical stratigraphic horizons the 18ophosphate values of inarticulate brachiopod shells vary widely 13 0 to 17 5 v smow and are significantly lower than those of coeval conodont samples 17 5 to 19 5 v smow conodont samples from individual beds have homogenous 18ophosphate values with variations close to the analytical precision 0 2 together with a significant correlation of conodont 18ophosphate and articulate brachiopod shell 18ocarbonate values r 0 85 this observation suggests that primary marine oxygen isotope compositions are better preserved in conodont apatite than in inarticulate brachiopod shell apatite however with decreasing 18ocarbonate values the 18ophosphate values of conodonts are higher than expected for theoretical isotopic equilibrium with brachiopod calcite different habitats of conodonts and brachiopods cannot account for the observed offset in 18o because both organisms were thriving on a broad shallow marine carbonate platform whereas 18ophosphate values of silurian conodonts are close to 18ophosphate values of modern and mesozoic tropical biogenic apatites most silurian calcitic brachiopod shells from gotland are depleted in 18o when compared to modern or mesozoic brachiopods we therefore suggest that silurian conodonts from gotland record paleotemperature and 18o of silurian sea water more faithfully than coeval calcitic brachiopod shells

phytolith rich layers from the late bronze and iron ages at tel dor israel mode of formation and archaeological significance the presence of many phytolith rich layers in late bronze and iron age deposits at tel dor israel are indicative of specific locations where plants were concentrated detailed studies of six of these phytolith rich layers and associated sediments from tel dor show that the phytoliths were derived mainly from wild and domestic grasses the most common domestic grass was the cereal triticum aestivum bread wheat three of these layers have a microlaminated microstructure associated dung spherulites and phosphate nodules characteristics that all point to the phytolith rich layers having formed from dung in animal enclosures in two of the layers the microlaminated structure is absent while dung spherulites and phosphate nodules are present suggesting that these too originate from dung that was not deposited in an enclosure the sixth layer is microlaminated but does not contain spherulites we thus cannot suggest a parsimonious explanation of its observed properties concentrations of burnt phytoliths are present in three locations implying that dung was either burnt in situ or the ashes from burnt dung were redeposited the transformation of dung accumulations into phytolith rich layers involves a loss of organic material and hence a significant reduction in sediment volume which is clearly apparent in the stratigraphy of some of the locations examined the volume reduction can be observed in the macrostratigraphy and has important implications with regard to macrostratigraphic interpretation the presence of abundant phytolith rich layers on the tell has significant implications for the concept of urbanism during these periods 2007 elsevier ltd all rights reserved

beyond redundancy and multiplicity integrating phytolith analysis and micromorphology to the study of brussels dark earth abstract multiplicity when different phytolith morphotypes are produced within a taxon and redundancy when the same phytolith morphotypes are produced by different taxa are persistent challenges in phytolith analysis this article discusses and demonstrates how micromorphological and phytolith analyses of soil thin sections can be integrated to address issues of redundancy and multiplicity as well as depositional history when studying archaeological soils and sediments opal phytoliths are created by the accumulation and precipitation of monosilicic acid si oh 4 within plant tissues usually the process produces a variety of phytolith morphotypes with specific anatomical distribution within the plant tissues when deposited in soil phytoliths from decomposed plant tissue become microfossils of the plants in which they were produced decomposition or decay of plant tissue can take place either before or after it is incorporated into the soil matrix when decay takes place after plant tissue is incorporated into a soil matrix the anatomical distribution of the phytoliths within the tissue is often preserved if the soil has not been affected by post burial disturbances typically analysis of phytoliths in soil begins with removing the phytoliths from the soil using techniques such as heavy liquid floatation thereby destroying much of the distribution pattern of the phytoliths within the matrix and losing potentially important data analysing phytoliths within soil thin sections is becoming a more frequently applied alternative to analysing phytoliths extracted from the soil thin sections preserve the distribution patterns of phytoliths within an archaeological deposit or soil and as such can help researchers answer questions concerning redundancy multiplicity and depositional history in this study we demonstrate how the integration of phytolith analysis with micromorphological analysis of a series of thin sections made from brussels urban archaeological deposits that have complex and multiphase formation histories can be used to differentiate phytoliths with different histories the potential for improved botanical identification of the different groups of phytoliths is also discussed

oxygen isotope variations in phosphate of biogenic apatites ii phosphorite rocks abstract phosphorites from sedimentary sequences ranging in age from archaean to recent were analysed for 18 o in both the po 4 18 o p and co 3 18 o c in the apatite lattice the oxygen isotope record is considerably better preserved in phosphates than in either carbonates or cherts the use of the longinelli and nuti 8 temperature equation yields temperatures for recent phosphorites that are in good agreement with those measured in the field the 18 o p values of ancient phosphorites decrease with increasing age these changes with time are not likely to be due to post depositional exchange changes in 18 o values of seawater and variations of temperature with time can account for the 18 o p time trend but the latter explanation is preferred in ancient phosphorites 18 o c in structurally bound carbonate in apatite is not a reliable geochemical indicator

a 16 ma record of paleodiet using carbon and oxygen isotopes in fossil teeth from pakistan abstract the siwalik sequence of northern pakistan contains a 16 ma record of paleosol carbonate and fossil teeth from which a record of paleovegetation can potentially be reconstructed and compared the carbon isotopic composition of paleosol carbonate and organic matter from siwalik strata reflects a major paleoecological change on the floodplains of major rivers beginning7 3 ma ago by 6 ma c 3 dominated plant communities probably composed of mostly trees and shrubs were displaced by nearly continuous c 4 grassland we find that the carbon isotopic ratios in herbivore tooth enamel reflect this dramatic ecologic shift carbonate in enamel older than 7 ma averages 11 in 13 c pdb consistent with a largely c 3 diet enamel from the plio pieistocene averages 1 9 in 13 c similar to the value displayed by modern c 4 grazers analysis of post burial carbonate cements and the concordance with isotopic evidence from paleosols argues strongly against major isotopic alteration of the enamel while coexisting bone may have been altered early in burial this study confirms that enamel apatite is useful for paleodietary reconstruction much further back in the geologic record than was previously thought

geochemistry of modern brachiopods applications and implications for oceanography and paleoceanography abstract modern rhynchonellida terebratulida thecideida and a few inarticulated brachiopods were collected live or soon after death at 30 locations from depths of 2 3940 m from the equator to high latitudes covering the atlantic pacific indian caribbean and mediterranean oceans seas well preserved fibers of the secondary layer combined with sr 450 1928 mg kg mn 1 199 mg kg and fe 1 610 mg kg contents confirm with few exceptions the excellent preservation of the modern brachiopod material evaluation of the stable isotope compositions was conducted on 276 specimens and on 374 published samples for a total database of 650 samples from 80 locations it revealed that oxygen isotope incorporation into shell calcite secondary layer of modern articulated brachiopods in most cases occurs in equilibrium with the ambient water and as such reflects surrounding environmental conditions thecideida as a group shallow water and low latitude incorporate oxygen isotopes 3 04 to 0 35 into shell calcite in equilibrium with their ambient water a large majority of genera and species of the terebratulida shallow water and low mid latitude also incorporate oxygen 2 30 to 3 48 into shell calcite in isotopic equilibrium with their surrounding water in contrast equilibrium incorporation of oxygen isotopes into shell calcite by the rhynchonellida is uncertain but a vital effect probably applies to the craniida the question of equilibrium disequilibrium incorporation of carbon isotopes into shell calcite of modern brachiopods remains unresolved at this time isotope compositions range up to 4 5 5 6 and 1 5 for 13 c and up to 5 5 5 9 and 0 3 for 18 o for shallow water low mid and high latitude brachiopods respectively strontium isotopes of modern brachiopods as expected show no significant variation with location latitude water depth temperature salinity and general water conditions once local habitat and ecological influences of fossil brachiopods from similar latitudes are considered their isotopic elemental values should be valuable diagenetic indicators and important oceanographic chemostratigraphic proxies

discharge of metals from the st lawrence river the concentrations of dissolved and total al fe mn co ni cu zn and cd in st lawrence river water have been measured on a monthly basis over a 2 year period riverine suspended particulate matter was also analyzed for nondetrital mg ca si al fe mn co ni cu zn and cd and detrital mg ca si al fe and mn variability in the concentration of dissolved metals is unrelated to changes in water flow or suspended load particulate al fe mn and zn concentrations are related to water flow the metal aluminum ratios of particulate mn cu zn and cd are elevated with respect to crustal rocks or coastal marine sediments with the enrichment occurring in the nondetrital or weak acid soluble fraction annual dissolved metal discharges and nondetrital and total particulate metal discharges that take into account monthly variations in metal concentrations have been calculated for the st lawrence river these discharges have been used to estimate global annual river discharges of metals to the oce

sediments exposed to high temperatures reconstructing pyrotechnological processes in late bronze and iron age strata at tel dor israel many of the sediments analysed from tel dor israel show structural alterations indicating that they were exposed to high temperatures this observation is consistent with the abundant evidence for use of pyrotechnology from the earliest exposed middle bronze age strata through the roman period such structurally altered sediments may well represent one of the more widespread and durable records of pyrotechnology and as such could be invaluable for reconstructing past human activities the specific aims of this research are therefore to develop the means for identifying local sediments that were altered by different pyrotechnological activities and to elucidate the varying circumstances whereby sediments were exposed to high temperatures in a late bronze and iron age 1 section we first characterize natural sediments sampled on and in the proximity of the tell and monitor their transformations due to exposure to high temperatures in an oven and in open fires focusing in particular on the transformations of the clay mineral components of mud brick materials the analytical techniques used include micromorphology fourier transform infrared spectrometry ftir x ray powder diffractometry xrd and x ray fluorescence xrf spectrometry using the temperature calibrated data we confirm that large volumes of sediments at tel dor were exposed to high temperatures in area g we identify three fundamentally different ways that heat affected sediments were produced and accumulated 1 inthelatebronzeage phases11e12 thesedimentswereheatedtotemperaturesbetween800and900 candwerethendeposited in the area under investigation a plausible scenario is that these sediments were exposed to heat from ovens or kilns 2 during the early iron age phase 10 the heat affected sediments heated above 1000 c formed in close association with casting pits for the working of copper containing bronze objects 3 duringphase9oftheironage heat affectedsedimentswereproducedinsituatthislocationduetoamajorconflagration the temperatures reached around 1000 c this study shows that analysis of high temperature exposed sediments may be an invaluable means of reconstructing fire associated activities even when the actual installations have not been identified during the excavation or were not preserved

carbon isotope geochemistry of the frasnian famennian transition abstract carbon isotope records for inorganic and total organic carbon toc as well as for individual organic biomarkers show two positive excursions in the late frasnian with comparable shape and amplitude in 13c the positive shifts in 13c can be correlated with the deposition of the kellwasser horizons the inorganic carbon isotope excursions are explained by an enhanced organic carbon burial that is expected to lower the concentration of oceanic dissolved co2 toc 13c values do not exhibit a larger shift than that recorded by inorganic carbon 13c values this is unexpected since a decrease in the dissolved co2 concentration should result in lower carbon isotope fractionation during photosynthesis ep 13c values of presumed algal biomarkers low molecular weight n alkanes pristane phytane although offset by 2 5 exhibit essentially identical records as toc and confirm this unexpected result it is proposed that high atmospheric and oceanic co2 concentrations during the devonian resulted in maximum photosynthetic fractionation any change in the co2 concentration would thus not affect ep as such 13c of primary organic carbon and 13ccarb will exhibit parallel excursions the data imply that carbon isotopes and the relationship between ep and co2 will not be effective to study changes in pco2 levels during the devonian since co2 concentrations were too high

palaeoecological significance of palms at olduvai gorge tanzania based on phytolith remains abstract palms are among the most abundant diverse and economically important families of plants in tropical and subtropical regions of the world their number and diversity make them an important part of the ecosystem phytoliths are abundantly produced in palms mainly the spheroid echinate type and although their number decreases notably after their deposition in soils they remain stable for long periods of time palm phytoliths were recovered from sediments at hwkee on the eastern palaeolake margin of the olduvai basin during lowermost bed ii between tuffs if and iia 1 795 1 71 ma their abundance in trench 107 the only freshwater source recognised to date occurs in three stratigraphically consecutive layers the first one located immediately above the incision layer 40 cm above tuff if above these samples there are no palm phytoliths in the fossil record the identification of the type of palms represented will be useful for determining the landscape distribution and nature of hominin activities along the lake margin and alluvial fan of the central olduvai basin here we use morphometric analysis of spheroid echinate phytoliths from fossil and modern palms phoenix reclinata and hyphaene petersiana and their corresponding soils to determine if the differences are significant and can be confidently applied to the fossil samples fossil and modern soil samples were found to be very similar to each other but the spheroid echinates from the fossil soils were bigger than the modern soil samples either the palms from the samples were different or there is a strong bias towards preserving phytoliths from the smaller end of the range if this is the case then the implication would be that the fossil samples are the leaves and inflorescences of phoenix reclinata a wider variety of modern palms needs to be analysed

an integrated study of dark earth from the alluvial valley of the senne river brussels belgium abstract the present article discusses the integration of urban geoarchaeological and archaeobotanical data of a series of dark earth deposits situated in the alluvial valley of the senne river in brussels belgium due to their homogeneous character their interpretation is a huge challenge for archaeologists through a case by case approach a detailed picture of the sequence of different activities and semi natural events leading to the build up of dark earth at each individual site has been obtained among the activities agricultural practices and waste management which are rarely archaeologically recorded in urban contexts have been identified despite being situated in a valley context none of the sites presented an excellent preservation of the organic plant remains however through the integration of geoarchaeological and botanical data the taphonomical history of the botanical remains could better be understood allowing us to document the evolution of the environment surrounding the sites additionally it has been demonstrated that the botanical study of dark earth units can also provide valuable information on vegetal consumption in particular fruits on a broader scale this integrated geoarchaeologial and archaeobotanical study sheds some light on the process of urbanisation of the senne alluvial valley between the 11th 12th and the 16th century ad

human impact around settlement sites a phytolith and mineralogical study for assessing site boundaries phytolith preservation and implications for spatial reconstructions using plant remains abstract defining the extent of human activity around settlement sites is of particular significance in archaeology as it may define peripheral activity areas and thus the site s boundary in near eastern archaeology site boundaries are usually defined by the presence of architectural and other macroscopic archaeological remains here we use the phytolith concentrations and morphotype assemblages as well as changes in the mineralogical composition of the sediments in and around the small iron age site of izbet sartah in central israel to determine the site boundaries the site has a shallow stratigraphy and highly bioturbated sediments coincidental changes in the clay quartz ratio and phytolith concentrations define the boundary between high and low impact anthropogenic activities this boundary is generally some 20 m away from the architectural remains in addition we note that the phytoliths in the site s core show clear evidence of having been affected by chemical dissolution i e diagenesis while those in the vicinity of the site s boundary have undergone severe diagenesis these observations indicate that phytolith diagenesis will affect site boundaries determination as well as phytolith based reconstructions of activity areas we propose that phytolith preservation depends on the initial amount of available silica the depth of burial with respect to the active root area of modern vegetation and the presence of fresh phytoliths in the soil

geoarchaeological and palaeobotanical evidence for prehistoric cereal storage in the southern caucasus the neolithic settlement of goytepe mid 8th millennium bp this paper presents direct evidence for cereal storage by neolithic farmers in west asia storage features analyzed this study are circular clay bins that frequently occur at neolithic settlements 8th millennium cal bp in the southern caucasus we examined contexts and uses of clay bin features at the neolithic settlement of goytepe azerbaijan we analyzed biogenic microfossil evidence primarily from phytoliths and dung spherulites and the sediments of the clay bins through micromorphology in combination with their associated charred macrobotanical remains while phytoliths and charred botanical remains indicate direct remnants of stored plants mainly chaffs micromorphology and the analyses of faecal spherulites allow us to examine depositional and diagenetic processes of the archaeological sediments inside and outside these features as a result one of the clay bins was found to retain deposits at its base exhibiting high concentrations of grass phytoliths with relatively high proportions of inflorescences and low percentages of anatomically connected phytoliths in comparison with its upper fill deposits and areas outside of the bin these finds combined with the association of the two complete grinding stones inside the bottom of the bin suggest that the remains of cereal processing activities specifically dehusking may have been placed in the bin this interpretation is corroborated by the recovery of charred rachises and chaffs of wheat and barley as well as micromorphological observations that the bottommost fill of the bin consists almost entirely of grass phytoliths with few very small charcoal fragments and fine amorphous organic matter

the micromorphological identification of faecal spherulites from archaeological and modern materials abstract microscopic calcium carbonate spherulites from animal dung are now regularly found in archaeological micromorphology samples they have a particular set of morphological and optical characteristics including a fixed cross of extinction which is always pseudo uniaxial negative this paper gives details of these characteristics and provides methodologies for using them to distinguish faecal spherulites from similar materials e g coccoliths and related biominerals such as plant derived calcium oxalate druses and avian reptilian uric acid spheres simple predictions are made concerning the effect of thin section versus liquid mount preparations on maximum retardation diameter plots these are confirmed by the pattern of the real data but a discrepancy remains between the measured birefringence of the spherulite material and the expected birefringence from radial calcite using morse donnay s 1932 american journal of science 23 421 461 calculation possible reasons for this discrepancy are discussed

stability of phytoliths in the archaeological record a dissolution study of modern and fossil phytoliths opaline phytoliths are important microfossils used in archaeological and ecological research relatively little is known about the stability of phytoliths after burial under alkaline ph conditions they can dissolve and mechanical disturbances can cause a loss of their more delicate appendages here we present an experimental study of phytolith stability combination of solubility and abrasion modern and fossil phytoliths were extracted from wheat using new methods to minimize dissolution and by burning in an oven these assemblages were placed in a solution buffered to ph 10 and maintained under constant temperature and shaking conditions the silicon concentrations in the solution were monitored once a week for 5 weeks the phytolith morphologies in each assemblage were determined at the outset of the experiment and after 5 weeks the results show that there are differences in stability between various assemblages modern inflorescence wheat phytolith assemblages are more unstable than those from leaves stems burnt assemblages are less stable than unburnt assemblages and a fossil phytolith assemblage about 3000 years old is more stable than the modern wheat assemblages the results also show that individual phytolith morphotypes have different stabilities and as a result of dissolution and abrasion some morphotypes may resemble others this study further shows that archaeological and or paleo environmental interpretation of phytolith assemblages may change with the assemblage s state of preservation

subsistence practices in an arid environment a geoarchaeological investigation in an iron age site the negev highlands israel the negev highlands southern israel is an arid zone characterized by settlement oscillations one settlement peak occurred in the early iron age iia late 10th and early 9th centuries bc the most conspicuous structure in many sites of this period is an oval compound comprised of an internal courtyard surrounded by rooms two hypotheses for the function of these oval compounds are that they served as israelite fortresses which guarded the southern border and routes of the solomonic kingdom or that they represent local agro pastoral groups in order to gather more information regarding the subsistence practices conducted in these oval compounds we carried out a small scale excavation at the site of atar haroa we focused on sediment sampling and used several geoarchaeological as well as isotopic techniques in order to identify macroscopic and microscopic remains related to animal husbandry and crop agriculture the remains identified from the archaeological sediments were compared with modern reference materials collected from abandoned bedouin camps the excavation included two half rooms and several test pits in the courtyard of the oval compound featuring one iron age occupation level composed of gray sediments and relatively small amounts of pottery bones and macro botanical charred remains micromorphological mineralogical dung spherulite and isotopic analyses carried out on the gray occupational sediments from the rooms show that they originate from wood ash and dung both used as fuel similar analyses of the gray sediments in the courtyard show that they originate only from degraded livestock dung phytolith analyses show that the gray anthropogenic sediments have similar concentrations of phytoliths as in control yellowish sediments and in the dung of winter free grazing desert livestock and lichen grazing black dwarf bedouin goats phytoliths indicative of cereal crops are completely absent in the archaeological dung remains indicating that cereal crops were not processed by the site inhabitants based on ethnographic and archaeological parallels and on the presence of grinding stones and absence of sickle blades in the excavated rooms we infer that the inhabitants at the oval compound at atar haroa subsisted on livestock herding and bought or exchanged cereal grains our results support the hypothesis that the inhabitants at the oval compound at atar haroa were desert adapted pastoralists rather than garrisoned soldiers

preservation of anthropogenic materials under different geochemical processes a mineralogical approach minerals that are preserved or formed inside the sediment or soil can be used to determine whether primary anthropogenic constituents bones phytoliths organic matter charcoal etc would have been affected by diagenesis stability diagrams of the minerals that describe the chemical system under investigation can be constructed and then tested in the field in this approach it is assumed that the stability of the archaeological material of interest is known except for bone there are not many studies on the stability of other archaeological materials this approach does not provide information on the former presence of an archaeological material in the sediment or soil but only whether these materials are stable in such an environment some indirect indication may be provided by unique mineral associations but much more has to be done in this direction

oxygen isotope analyses of co existing carbonate and phosphate in biogenic apatite a way to monitor diagenetic alteration of bone phosphate abstract the oxygen isotopic composition of phosphate 18 op and structural carbonate 18 oc of hydroxylapatite was determined in 31 bone and tooth samples of modern mammals from different countries these two variables are highly correlate r 2 0 98 and the calculated best fit of linear regression is very similar to the equation calculated from the phosphate and carbonate palaeotemperature equations 1 2 according to previous measurements 3 6 on fossils of different ages from different areas it seems quite improbable to find isotopically altered skeletal remains showing a good correlation between 18 op and 18 oc as is the case with modern samples it therefore seems possible at least in some cases to use these measurements for monitoring fossil bone and tooth diagenetic alteration when a set of points lie on the equilibrium line or close to it the 18 o values could be considered close to the original values in contrast when the points lie to the left or to the right of this line this probably means that the values are diagenetically modified due to interaction with meteoric water or 18 o enriched water respectively

an experimental micromorphological investigation of bedding construction in the middle stone age of sibudu south africa abstract we conducted experiments to compare the micromorphological signatures of modern burnt sedge and grass bedding to laminated layers of carbonized material and phytoliths in middle stone age deposits at the shelter sibudu the experiments were designed to clarify the formation processes associated with the laminated layers and to investigate whether these previously identified layers of bedding were deliberately burned or not the results indicate that the laminated layers were most likely produced by human activity related to the construction maintenance and burning of bedding furthermore our experiments demonstrate that large volumes of vegetal material could have produced the relatively thin archaeological deposits of burnt bedding

dissolved and particulate metal distributions in the st lawrence estuary dissolved and particulate metal concentrations in the st lawrence estuary were determined during the high spring runoff and at a period of lower runoff in the fall the distributions in the estuary are influenced by seasonally variable freshwater discharges and a turbidity maximum zone tmz dissolved al fe mn co cu ni and zn concentrations generally decrease significantly with increasing salinity but cd shows no significant covarience with salinity most metals show complex distribution patterns and only the distributions of cu and ni can be described by linear regression equations maximum concentrations of dissolved al fe mn and co occur in the turbidity maximum and decrease seaward with increasing salinity during the spring runoff period total particulate mass was almost twice that in the lower fall runoff period chemical partition of the suspended particulate matter spm shows that detrital particulate fe mn and zn concentrations vary directly with spm load and inversely with salin

archaeological soil and pollen analysis of experimental floor deposits with special reference to butser ancient farm hampshire uk archaeological stratigraphies that may contain floors are often encountered for more than a decade soil micromorphologists working on archaeological sequences have benefited from having access to reference thin sections of ethnoarchaeological and experimental floors including those from the floors of iron age houses reconstructed by the late dr peter reynolds at butser ancient farm hampshire uk this paper reports upon experimental studies mainly carried out at butser during 1990 95 and their suggested application to microstratigraphic and microfacies analysis of occupation sites sampling at butser in 1990 was very much a rescue operation nevertheless fundamental differences in soil micromorphology were found between domestic house beaten floor deposits and those formed in a stable these differences were also reflected in the parallel study of pollen from these deposits with microchemical analyses helping to explain anomalous pollen preservation in the unsuitable soil at butser the limited bulk chemical study produced less clear results but when compared with findings from some roman and early medieval sites in london showed that the chemical trends hinted at butser are probably replicated in some ancient floors a preliminary interdisciplinary study of samples from the london guildhall clearly suggested the potential of such microstratigraphical and microfacies analyses and intimates at the potential of attaining rigorous consensus interpretations stable floor deposits are both organic and phosphate rich with homogeneous soil micromorphological and pollen characteristics beaten floors are much more mineralogenic and heterogeneous in terms of their microfabric and pollen that also indicate trampling in of a wide variety of allocthonous materials the last commonly responsible for raised magnetic susceptibility at archaeological sites these findings prove the worth of the ethnoarchaeological simulations carried out at the moel y gar stable and domestic pimperne house this microfacies approach is viewed as complementary to site reconstruction through macrofossil analysis of beetles and plant remains especially where sites are being investigated at the microstratigraphic level the phosphate content of stabling deposits may allow preservation of pollen in what may otherwise be deemed unsuitable material as demonstrated at butser

earthen mound formation in the uruguayan lowlands south america micromorphological analyses of the pago lindo archaeological complex the stratigraphic excavation of the pago lindo archaeological complex in central eastern uruguay la plata basin helped to propose an alternative model for mound formation that expresses the intrinsic complexity of prehistoric earthen architecture this model known as the spatial temporal discontinuous model sees mound complexes as multi functional areas with diverse earth works occupied and abandoned intermittently since earthen mound sediments are homogeneous resemble natural soils and show evidences of intense bioturbation soil micromorphology was used to confirm refute and further investigate issues raised during field work related with the prime material used for mound construction detection of major episodes of mound building identification of activity areas and taphonomic processes in this paper we present the results of the micromorphological analyses of two different earth works from the pago lindo archaeological complex a mound and a micro relief analyses proved the recurrent use of surface horizons for mound and micro relief building throughout the entire period of site occupation it also demonstrated the difficulty in identifying discrete depositional episodes and occupation surfaces because of the intense bioturbation two activity areas where recognized a domestic hut built over a platform ca 1600 yrs bp and an area of plant residue accumulation over a platform raised almost 800 hundred year after the domestic hut the practice of cleaning the occupation surfaces was interpreted from the complete absence of bioarchaeological remains bones and micro charcoal the use of micromorphology as a complementary tool in the stratigraphic excavation of pago lindo unraveled evidences that corroborate a newly proposed model for mound growth

identification of pastoral sites using stable nitrogen and carbon isotopes from bulk sediment samples a case study in modern and archaeological pastoral settlements in kenya abstract the identification of pastoral sites in the east african archaeological record is problematic recently a method for the identification of degraded livestock enclosure sediments had been developed that takes into account the geoarchaeological indicators of micromorphology phytolith concentrations and the mineral assemblages this suite of indicators may not always be present in degraded livestock enclosure sediments this study presents an additional indicator by which degraded livestock enclosure sediments may be identified namely the isotopic composition of organic nitrogen measured on bulk sediment samples we studied a highly controlled ethnoarchaeological sequence of abandoned maasai livestock enclosure sediments sampled in rombo area southern kenya the results were compared to archaeological sediments from the elmenteitan pastoral neolithic site of sugenya southwestern kenya radiocarbon dated to ca 2000 bp uncalibrated the sediments from both sites were studied using all four types of analyses i e micromorphology mineralogy phytolith concentrations and stable carbon and nitrogen isotopic compositions on bulk sediment samples the results show that in abandoned livestock enclosure sediments of known ages a significant enrichment in the heavy nitrogen isotope 15 n occurs and that carbon isotopic compositions may be useful for differentiating cattle from caprine enclosures following their dietary preferences i e grazers vs browsers a similar pattern of 15 n enrichment is observed in sediments sampled within the site of sugenya while sediments sampled outside the site s perimeter are generally depleted in 15 n the micromorphological mineralogical and phytolith analyses support the conclusion that the sediments from within the site of sugenya represent degraded livestock enclosure sediments the carbon isotopic composition from the degraded dung deposits strongly suggests that livestock kept at sugenya were cattle overall this study presents new empirical data that can be used for the identification of livestock enclosures and shows that the isotopic signatures and geoarchaeological indicators can preserve for at least two millennia

degradation of mud brick houses in an arid environment a geoarchaeological model a common assumption in near eastern tell archaeology is that the majority of sediments originate from degraded mud bricks little is known about the mechanism of mud brick wall degradation here we present a detailed macro and microscopic ethnoarchaeological study of the degradation of a mud brick house and propose a comprehensive mechanism for tell formation processes in arid environments the study took place in southern israel by trenching a ca 60 year old abandoned mud brick house followed by extensive sediment sampling macroscopic observations showed that mud brick walls degrade by collapse of single bricks and or collapse of intact wall parts either inwards or outwards in addition infill sediments within the house and outside it in close proximity to its walls form alternating sedimentary layers of various colors and textures the degraded mud brick material lost its distinctive macroscopic structure which makes it impossible to accurately identify this material by field observations alone mineralogical and elemental analyses established the sources of the house infill sediments namely mud bricks and wind blown sediments alternating layers mostly originate from mixing between degraded mud brick material and wind blown sediments micromorphological observations revealed microscopic mechanisms of mud brick degradation and include processes of mud slurry gravity flows sediment coatings and infillings wind abrasion of walls small scale puddling and bioturbation this study provides a working scheme for site formation of abandoned mud brick structures in arid environments it provides a set of criteria by which it is possible to differentiate floors from post abandonment sedimentary features and thus improves the reliability of activity area research

deciphering kinetic metabolic and environmental controls on stable isotope fractionations between seawater and the shell of terebratalia transversa brachiopoda this study presents carbon and oxygen stable isotope data obtained from high resolution sampling 500 m of the brachiopod terebratalia transversa from the san juan islands washington state usa the aim of this study is to unravel the respective effects of physiological and environmental controls on the stable isotopic composition of brachiopod shell calcite based on an sem study of the shell a three dimensional sampling was performed in order to investigate carbon and oxygen isotope variations along isochrons and ontogenetic transects the primary as well as the outer part of the secondary shell layer display large and variable isotopic offsets as high as 7 for 13c and 6 for 18o relative to expected equilibrium values the significant positive correlations between 18o and 13c values indicate that the isotopic compositions of these shell domains are mainly controlled by kinetic isotope fractionation effects the ontogenetic 13c and 18o variations can be used to establish a growth curve of the studied specimen whose age is estimated close to 8 years the extent of apparent o 18 disequilibrium observed in this study is about as large as any yet measured in any organism which makes this brachiopod an interesting and important case the carbon and oxygen isotope compositions increase from the outer towards the inner part of the secondary layer where they reach values of 0 0 8 and 0 8 to 0 2 respectively corresponding calculated temperatures are between 12 and 13 8 c and fall in the range of seawater temperatures recorded off the san juan islands 7 13 c these results suggest that the calcite fibres were secreted more and more slowly during the thickening of the shell throughout the animal s life finally approximating isotopic equilibrium this study illustrates that the stable isotopic composition of the modern brachiopod t transversa is predominantly influenced by kinetic fractionation and to a minor degree by metabolic effects except for the innermost part of the shell the measured isotope ratios do not reflect environmental conditions during shell precipitation it remains to be tested by comparable studies whether other modern brachiopod species or even fossil brachiopods reflect comparable fractionation effects these results point out the need for re examination of paleozoic oceanographic conditions

oxygen isotope variations in phosphate of biogenic apatites i fish bone apatite rechecking the rules of the game abstract the major advantage of the oxygen in phosphate isotope paleothermometry is that it is a system which records temperatures with great sensitivity while bone and teeth building organisms are alive and the record is nearly perfectly preserved after death fish from seven water bodies of different temperatures 3 23 c and different 18 o values 16 to 3 of the water were analysed the 18 o values of the analysed po 4 vary from 6 to 25 the system passed the following tests a the temperatures deduced from isotopic analyses of the sequence of fish from lake baikal are in good agreement with the temperatures measured in the thermally stratified lake b the isotopic composition of fish bone phosphate is not influenced by the isotopic composition of the phosphate which is fed to the fish but only by temperature and water composition isotopic analysis of fossil fish in combination with analysis of mammal bones should be a useful tool in deciphering continental paleoclimates

modelling of the oxygen isotope evolution of seawater implications for the climate interpretation of the δ18o of marine sediments it is often argued that the 18o value of oceanic water was maintained close to 0 for hundreds of millions of years as a consequence of oxygen isotope exchange between oceanic crust and seawater however for several decades the interpretation of the biosedimentary oxygen isotope record has conflicted with the igneous record because with increasing age a general trend of decreasing 18o values about 6 is observed in most carbonates cherts and phosphates especially for the paleozoic and early mesozoic we developed a dynamical model of seawater crust interaction that computes the 18o value in these two reservoirs as function of time this model takes into account the continuous production of crust at oceanic ridges its expansion rate the permeability profile with space and time the mineralogical mode of the crust and the kinetics of oxygen isotope exchange between rock forming minerals and seawater the model indicates that the 18o value of seawater may vary by 2 with a time response ranging from 5 to 50 ma for expansion rates of 1 to 10 cm a 1 the variation of 2 is fixed by both integrated water rock ratio and closure time of the seawater crust system by sediments variations in the oxygen isotope ratio of seawater through time have important implications for the interpretation of the systematically low 18o values of pre jurassic marine sediments according to our model marine paleotemperatures could be up to 10 c lower than those expected when applying the classical hypothesis of an ice free ocean with a 18o value of 1

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

phytoliths and microcharcoal at jinluojia archeological site in middle reaches of yangtze river indicative of paleoclimate and human activity during the last 3000 years a variety of phytoliths together with prolific microcharcoal particles sponge spicules and diatoms were extracted and identified in four cultural layers from an archeological site at jinluojia macheng hubei province central china the warmth iw and aridity iph indices calculated from grass phytoliths reveal warm and wet periods during the west zhou early east zhou tang and song dynasties whilst cool and dry periods occurred during the late east zhou ming and qing dynasties the paleoclimate conditions reconstructed on the basis of grass phytoliths extracted from archeological sediments are in agreement with those from natural sediments in the middle yangtze region in contrast the woody phytoliths show a positive correlation with microcharcoal particles suggesting an anthropogenic contribution to the woody phytoliths from the use of woody plants for fuel during cooking and heating two episodes of the enhanced abundance of woody phytoliths and microcharcoal particles were found to occur at east zhou dynasty and from ming and qing dynasties to the present proposed to be a consequence of the population expansion and or the frequent wars

the 9th century bce destruction layer at tell es safi gath israel integrating macro and microarchaeology abstract destruction events in multi period sites are valuable marker horizons that represent time synchronous events across the site and sometimes between sites destruction layers often preserve rich finds that provide insights into site use here we use both macro and microarchaeological methods to study a destruction event from the late 9th century at tell es safi gath in israel a major conflagration at this specific location resulted in the consolidation of parts of the roof construction materials thus enabling us to differentiate between roof walls and floor materials we could reconstruct the events which lead to the formation of an approximately 80 cm thick layer the base of this layer that overlies the floor surface is a thin charred organic material rich ash layer as the clays in this layer were not altered by heat and the ceramics still have preserved residues we conclude that the ash was produced elsewhere and was redistributed to this location ceramics that are associated with burnt roof sediments do not have preserved residues we also estimate the time that each of the accumulation events might have taken and conclude that this accumulation occurred over decades the architecture and artifacts found within and beneath the destruction do not allow us to unequivocally identify the function of this area prior to destruction we do however identify an unusual bin and associated stone pavement and a corner rich in artifacts phytoliths and charred organic material we also show that a wall was built of fired mud bricks a most unusual occurrence for this time period in the levant this study demonstrates well the usefulness of an integrated macro and microarchaeological approach to understanding the archaeological record as well as the benefits of using an on site laboratory

geoarchaeology in an urban context the uses of space in a phoenician monumental building at tel dor israel abstract interpretation of past urban societies in the near east whose settlements are known mostly as tell sites is largely based on macro stratigraphy and on the association of architecture with macroscopic artifacts analyses of sediments common in prehistoric sites are rare in tell sites here we show the results of a detailed geoarchaeological study of the micro stratigraphy of a sedimentary sequence associated with early iron age phoenician monumental architecture the study involves mineralogical micromorphological and phytolith analyses and provides new insights into the stratigraphic sequence and the use of architectural spaces the sedimentary sequence examined comprises alternating layers of gray fill deposits and white floors we show that floors made from local calcareous sandstone in the lower part of the sedimentary sequence were heated and are thus in effect plaster floors a concentration of micro laminated trampled fish remains above the most elaborate of these plaster floors indicates activities related to fish processing fine white layers in the upper part of the sedimentary sequence that were considered as plaster based on macroscopic examination are in fact composed almost entirely of opaline grass phytoliths the phytoliths appear in an undulating micro laminated structure and are associated with dung spherulites and phosphate nodules thus probably reflecting livestock penning the formation of phytolith floors involves extensive volume reduction due to the degradation of the organic material and this may result in floor subsidence a phenomenon that is often observed in archaeological sites most fill deposits include macroscopic and microscopic remains of wood ash bones phytoliths charcoal ceramics plaster and mollusk shells reflecting the debris produced from household activities this study shows how a combination of macro stratigraphy with microscopic and mineralogical analyses of the sediments within architectural spaces can provide information on the varying ways in which the space was used through time and also contributes to solving macro stratigraphic problems

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

chronology stratigraphy and hydrological modelling of extensive wetlands and paleolakes in the hyperarid core of the atacama desert during the late quaternary abstract the halite encrusted salt pans salars present at low elevations in the hyperarid core of the atacama desert in northern chile are unique features of one of the driest and possibly oldest deserts on earth here we show that these landscapes were shallow freshwater lakes and wetlands during the last glacial period and formed periodically between 46 9 ka and 7 7 ka the moisture appears to have been sourced from increased andean runoff and most of our chronologies for these deposits were coeval with the central andean pluvial event 17 5 14 2 ka and 13 8 9 7 ka but we also find evidence for older as well as slightly younger wet phases these environments supported a diverse hygrophytic halophytic vegetation as well as an array of diatoms and gastropods using a regional hydrological model we estimate that recharge rates from 1 5 to 4 times present were required to activate and maintain these wetlands in the past activation in the late pleistocene was part of a regional enhancement of water resources extending from the andes downstream and through riparian corridors to the lowest and most arid portions of the desert itself this fundamentally unique environment was encountered by the earliest human explorers in the region and most likely facilitated migration and encampments on a landscape that at present lacks macroscopic life on its surface

plio pleistocene macroplant fossil remains and phytoliths from lowermost bed ii in the eastern palaeolake margin of olduvai gorge tanzania abstract fossil macroplants and phytoliths occur in the sediments of the palaeoanthropological site of olduvai gorge northern tanzania current research on hominin land use in the basin during the plio pleistocene has a strong palaeoenvironmental emphasis on the palaeovegetation in particular the occurrence of macroplants and phytoliths at olduvai and their usefulness and reliability for palaeovegetation interpretation are assessed here for the first time modern reference collections from analogous environments have been established and used to identify the fossil taxa from the eastern palaeolake margin of lowermost bed ii as the test case for very detailed spatially and temporally constrained vegetation reconstruction fourier transform infrared spectrometry ftir analysis was used to identify the minerals of the fossil sediments modern plants produce more phytoliths than are preserved in the fossil soils but there were sufficient numbers to show diverse and changing vegetation over short time periods silicified macroplant fragments of sedge culms and dicot stems occur with phytoliths but do not always represent the same plant taxa a more complex flora was shown when using both forms of fossil plants during lowermost bed ii times at the locality of flkn monocots and dicots occurred indicating the presence of marshland and grassland after the deposition of tuff if at vek the phytoliths indicate a shift in dominance from dicots to monocots to a mixture of the two and including palms at hwkee initially palms dominated then there was a mixture of palms grasses and dicots the vegetation at mck comprised dicots monocots sedges and grasses this detailed vegetation data complements the more broad scale vegetation interpretations that have been deduced from the pollen isotopes and faunal data sets

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 geochemistry of trace metals in the brazos river estuary abstract a seasonal study of trace metal behavior and transport in the brazos river estuary was conducted in the winter spring and fall of 1981 surface water was analyzed for total dissolved pb cu mn and fe and particulate cd pb cu mn and fe ancillary data included river discharge total suspended matter ph major ions nutrients dissolved and particulate organic carbon and humic acid the major ions were generally conservative across the river water seawater mixing zone however a significant input of alkalinity and ca was measured in the spring attributable to cation exchange on clays and sediment diagenetic processes distinct concentration maxima were found in the 3 10 chlorinity range for dissolved pb 0 06 0 9 n m cu 6 42 n m mn 2 290 n m and fe 5 80 n m particulate metal concentrations showed significant seasonal and spatial variations cd 0 09 0 57 ppm pb 15 43 ppm cu 12 32 ppm mn 250 1990 ppm and fe 0 5 5 4 reducing conditions leading to diagenetic remobilization in estuarine sediments are proposed to be an important source of dissolved metals for estuarine water calculations of dissolved riverine metal transport to the ocean that include estuarine metal input are as much as 40 times greater than when estuarine processes are ignored

settlement and environmental history of a multilayered settlement mound in niederroblingen central germany a multi proxy approach a multi disciplinary palaeoecological approach on a sequence of dated archaeosediments was accomplished the sediments derive from a multilayered prehistoric settlement mound in central germany representing the remnants of a prehistoric village based on the analysis of biological remains and geochemical physical analysis of the settlement layers its environment was reconstructed there is a trend to increasing anthropogenic activities and impact on the environment represented through a rise of indicators for productive surplus from the early neolithic 5300 4900 bc until the roman times 400 ad during the early neolithic shifting flat settlements were situated in a locally opened landscape the immediate surrounding of the floodplain was used by the settlers for their economic requirements e g wood from the riparian forest after a hiatus of ca 1900 years a multilayered settlement mount rose from late neolithic times 3000 bc to roman times since the middle bronze age approximately 1500 bc the riparian forest was obviously replaced by agricultural fields and meadows and henceforward the hinterland used by the settlers probably grew in size the continuing demand of wood was maintained by the acquisition of more distant sources the onset of house constructions substituting wood by loam wattle and daub might be a possible societal response to this shortfall this is reflected in the growing thickness and composition of the settlement layers as well as in the archaeological record e g tumbled wattle and daub house walls the rising of the groundwater table and the start of severe floods of the adjacent river helme during pre roman iron age approx 800 100 bc might reflect a geomorphological response to the increased land use intensity at a regional scale

comment on oxygen and carbon isotopic composition of ordovician brachiopods implications for coeval seawater by h qing and j veizer

domestic activities and spatial distribution in ain abū nukhayla wadi rum southern jordan the use of phytoliths and spherulites studies abstract the pre pottery neolithic b site of ayn ab nukhayla wadi rum jordan contains structural installations loci composed of inter connected oval rock walled pithouses questions that arose from their study centered on how to identify possible herding and agricultural activities and to assess any differences in how the loci were used the combined study of phytoliths and spherulites identified from different loci are presented here the results of quantitative morphologic and morphometric analyses of phytoliths and spherulites identified in the different loci are discussed cereal processing is evident in some loci by the concentration of the inflorescent parts of festucoid grass phytoliths associated with the presence of handstones and querns these loci appear to have encompassed specific areas in which domestic activities including the grinding of cereals and the preparation of other plant resources were undertaken in contrast other loci such as locus 20 seem to have been used as pens for herd animals sheep goats as indicated by very high densities of spherulites the results of this study provide new insights on plant uses herding practices and the economic diversity of early neolithic communities in the levant

carbon and oxygen isotopic composition of silurian brachiopods gotland sweden palaeoceanographic implications abstract one hundred and seventy two non luminescent brachiopod shells from the silurian sequence of gotland were investigated for their carbon and oxygen isotopic composition diagenetic alteration of the shell calcite was excluded by means of petrographic trace element and cathodoluminescence analysis oxygen and carbon isotopic signals vary considerably within the uppermost llandovery to the ludlow average 18o and 13c values of well defined stratigraphic units range from 2 4 to 5 9 and 1 to 8 respectively we observed parallel trends in the carbon and oxygen isotope curves with the most prominent shifts occurring in the lower wenlock upper wenlock and middle ludlow average 18o values 2 4 to 2 9 recorded in the middle ludlow are among the highest 18o values reported for the early palaeozoic the recorded 18o variations cannot solely be explained by changes in sea surface temperature and salinity the variations in the isotopic signals correlate negatively with changes in sea level heavy carbon and oxygen signals coincide with sea level lowstands whereas light signals are recorded during sea level highstands sea level highstands were probably characterized by the formation of warm saline waters on subtropical epicontinental shelves inducing oxygen deficiency in the basins alumshale facies the low 18o values are attributed to 18o depletion in surface waters owing to the storage of 18o enriched saline waters in the basins low 13c values are explained by a low surface water productivity since nutrients were not supplied to the photic zone but rather stored in the deeper ocean during sea level lowstands colder waters that formed in higher latitudes may have represented the main intermediate water source a better ventilation of the basins is documented by the deposition of well aerated sediments whereas the high 18o values are explained by the change in oceanic circulation the high 13c values are attributed to an enhanced primary productivity and possibly to an enhanced burial of corg the model discussed here may provide an attractive scenario for accounting for the recorded short term variations in the isotopic signals without the necessity of introducing an isotopic correction factor for silurian sea water

oxygen isotope variations in phosphate of biogenic apatites iii conodonts abstract the method for measurement of the isotopic composition of oxygen in phosphates has been improved and adapted for analysis of small quantities of apatite down to 10 mg this extension enables one to analyze hand picked conodont samples with an analytical reproducibility better than 0 5 1 46 samples of conodonts ranging from the ordovician to the pennsylvanian of north america were analysed some insoluble phosphatic residues ichthyoliths and inarticulate brachiopods of the same time range were also measured the range of the 18o values of the analysed conodonts is between 15 and 19 it shows a general trend of decreasing d18o with increasing age from an average value of about 19 in the pennsylvanian to 17 in the ordovician this trend parallels that previously detected in marine phosphorites for the time range between the devonian and pennsylvanian our data are in agreement with independent paleoclimatic information specifically we detect maximum18o enrichment at the end of the pennsylvanian and minimum enrichment at the end of the devonian the difference between these two extremes is equivalent to about 10 c from about 40 to 30 c assuming constant isotopic composition of ocean water the success of oxygen isotopic analysis of conodonts raises the possibility of their use in paleozoic paleo oceanography in a similar way to foraminifera in the mesozoic cenozoic

determination of oxygen isotope fractionation between water and phosphate from living lingulids potential application to palaeoenvironmental studies abstract lingulids are inarticulate brachiopods with phosphatic shells which live exclusively in marine waters their distribution is generally restricted to the continental shelf within the 40 belt from temperate to equatorial areas they show a range of morphological physiological and behavioral features that have remained remarkably constant since the cambrian the oxygen isotope fractionation between water and phosphate from living lingulids was determined as a tool to investigate the temperature and or salinity of past coastal seawater oxygen isotope measurements were performed according to the silver phosphate method on a collection of lingulids coming from well known and varied marine environments a global 18o variation of 3 5 was found for these lingulids which proves their good sensitivity to environmental factors namely the oxygen isotope composition and the temperature of seawater oceanographic data provided average temperature and salinity values in the living sites of the studied specimens least squares treatment of the data gave the following fractionation equation t c 112 2 15 3 4 20 0 71 18o po4 18o h2o which is similar to the equations determined by longinelli and nuti 1973a and kolodny et al 1983 for other phosphate bearing invertebrates and fishes all these results suggest that a unique equation describes the phosphate water fractionation of many marine organisms except for mammals

detection of burning of plant materials in the archaeological record by changes in the refractive indices of siliceous phytoliths abstract the most resilient remains of plants in most archaeological sites are the siliceous phytoliths special cells that are partially or completely silicified during the plant s life these cells have characteristic morphologies and thus the phytoliths can often be used to identify the taxonomic affinities of plants brought to an archaeological site in order to determine what they were used for other means of analysis are needed we present here a method to distinguish burnt from unburnt phytolith assemblages the method is based on measuring the refractive index ri of individual phytoliths the phytoliths even from a single plant have a range of ri values burning a phytolith sample causes a shift to higher ri comparing burnt and unburnt samples we demonstrate that it is possible to differentiate between them based on the fraction of phytoliths with ri higher than 1 440 this serves as a basis for a simplified mode of measurement that requires only the use of a petrographic light microscope and a mineral oil of ri 1 440 we apply the simplified method to two natufian samples from hayonim cave western galilee israel

the temperatures and oxygen isotope composition of early devonian oceans the oxygen isotope composition of pre carboniferous 360 myr old marine carbonates cherts and phosphates has been reported1 8 to be lower than that of later post devonian samples according to one explanation1 3 this is a reflection of warmer generally 40 c pre carboniferous oceans relative to modern oceans alternatively it has been proposed5 7 that the pre carboniferous oceans were depleted in 18o by 2 smow relative to modern oceans here i report high 18o values 1 9 to 2 9 pdb in normal shallow marine limestones and three brachiopod shells from the lower devonian haragan and bois d arc formations in south central oklahoma i interpret these values as near primary and therefore constraining the temperature and oxygen isotope composition of early devonian sea water to 25 7 c and 0 1 smow respectively in conjunction with similarly high 18o values obtained from older ordovician and silurian samples8 these results imply that the temperature and oxygen isotope composition of pre carboniferous oceans may at least during some time intervals have been similar to those of modern oceans

no vital effect on δ18o and δ13c values of fossil brachiopod shells middle devonian of china biogenic fractionation vital effect of carbon and oxygen isotopes during metabolism is ubiquitous among marine organisms whether there is vital effect on the isotopic compositions of fossil brachiopods represents one of the most controversial issues in the carbonate stable isotope geochemistry furthermore the problem involves not only the feasibility of the utilization of fossil brachiopod shells as analysis samples for obtaining the original carbon and oxygen isotopic compositions of carbonates but also the credibility of the data and conclusions already achieved in the study field with fossil brachiopods from middle devonian of china this study investigates the vital effect by comparisons of 18o and 13c between the fossils of the same original living environment and the shell s preservation at levels of species genus and family no systematic differences of 18o and 13c between fossils were found which led to the conclusion that no detectable vital effect occurred in the fossil brachiopod shells the argument that the fossil brachiopod possibly has biogenic fractionation with the stable isotopes of carbon and oxygen resulted likely from studies of fossils that are different in the original living environment or the state of preservation

oxygen isotope evolution of biogenic calcite and apatite during the middle and late devonian oxygen isotope ratios of well preserved brachiopod calcite and conodont apatite were used to reconstruct the palaeotemperature history of the middle and late devonian by assuming an oxygen isotopic composition of 1 v smow for devonian seawater the oxygen isotope values of eifelian and early givetian brachiopods and conodonts give average palaeotemperatures ranging from 22 to 25 c late givetian and frasnian palaeotemperatures calculated from 18o values of conodont apatite are close to 25 c in the early frasnian and increase to 32 c in the latest frasnian and early famennian oxygen isotope ratios of late givetian and frasnian brachiopods are significantly lower than equilibrium values calculated from conodont apatite 18o values and give unrealistically warm temperatures ranging from 30 to 40 c diagenetic recrystallization of shell calcite different habitats of conodonts and brachiopods as well as non equilibrium fractionation processes during the precipitation of brachiopod calcite cannot explain the 18o depletion of brachiopod calcite moreover the 18o depletion of brachiopod calcite with respect to equilibrium 18o values calculated from conodont apatite is too large to be explained by a change in seawater ph that might have influenced the oxygen isotopic composition of brachiopod calcite the realistic palaeotemperatures derived from 18o apatite may suggest that biogenic apatite records the oxygen isotopic composition and palaeotemperature of palaeozoic oceans more faithfully than brachiopod calcite and do not support the hypothesis that the 18o 16o ratio of devonian seawater was significantly different from that of the modern ocean

thermal excursions in the ocean at the cretaceous tertiary boundary northern morocco δ18o record of phosphatic fish debris c lecuyer p grandjean j r o neil h cappetta and f martineau 1993 thermal excursions in the ocean at the cretaceous tertiary boundary northern morocco c lso record of phosphatic fish debris palaeogeogr palaeoclimatol palaeoecol 105 235 243 high precision oxygen isotope analyses were made of phosphate extracted from 17 samples of nektonic and benthic fish debris sampled across the stratigraphic cretaceous tertiary boundary in northern morocco a refinement of the silver phosphate method was used to isolate phosphate from biogenic materials measured 180 values of 18 6 20 5 o are interpreted as reflecting high resolution thermal variations that affected the ocean water column of the western tethys the warm 27 c water masses that characterized maastrichtian times underwent rapid cooling and stabilized at an average temperature of 19 c during the dano montian and thanetian this period of constant and cool temperature was followed by a relatively rapid but more gradual warming to about 25 c achieved in the middle ypresian significant small shifts in 6180 values between nektonic and benthic fauna recorded only during the stages of rapid warming or cooling may correspond to averaged thermal differences within the water column that developed in response to global climatic changes the indicated temperature distribution could have been caused by thermal changes in the atmosphere rather than some signal carried by deep ocean currents the oxygen isotope data coupled with previous measurements of ree and end ti on the same samples support the suggestion that paleo pacific westward currents progressed as far as the northwestern part of the african platform at the end of the cretaceous period

management of residues and natural resources at san cristobal rock shelter contribution to the characterisation of chalcolithic agropastoral groups in the iberian peninsula abstract use of the space and settlement patterns at the deposit of san cristobal are characterised anthropogenic activities at the site are revealed through an interdisciplinar approach based on microstratigraphic and palaeobotanical studies correlation of micromorphological silica phytolith charcoal pollen and non pollen palynomorph analyses and calcitic pseudomorph and faecal spherulite quantification are coupled with excavation data and macroscopic observations results provide insights into livestock keeping practices at the rock shelter animal feeding strategies management of residues and occupation mode of the site they also contribute to reconstruct the formation processes of the deposits and to outline the ecological frame of the site during its use as herding facility over the chalcolithic the immediate chrono cultural context of the investigated sequence is outlined allowing discussion on the possible role of the activities at the rock shelter in the territorial organisation of local early agropastoral groups at the time of megalithism development from a methodological point of view this work shows that high resolution sedimentary contextualisation of archaeological remains is essential to build up more accurate and reliable interpretations on livestock management and the use of natural resources in prehistoric deposits it also highlights the contribution of excavation strategies adapted to the particularities of pen deposits to better understand the archaeological evidence of early pastoral practices in cave and rock shelters during fieldwork

an explanation of the effect of seawater carbonate concentration on foraminiferal oxygen isotopes abstract stable oxygen isotope ratios of foraminiferal calcite are widely used in paleoceanography to provide a chronology of temperature changes during ocean history it was recently demonstrated that the stable oxygen isotope ratios in planktonic foraminifera are affected by changes of the seawater chemistry carbonate system the 18 o of the foraminiferal calcite decreases with increasing co 3 2 concentration or p h this paper provides a simple explanation for seawater chemistry dependent stable oxygen isotope variations in the planktonic foraminifera orbulina universa which is derived from oxygen isotope partitioning during inorganic precipitation the oxygen isotope fractionation between water and the dissolved carbonate species s h 2 co 3 hco 3 co 3 2 decreases with increasing p h provided that calcium carbonate is formed from a mixture of the carbonate species in proportion to their relative contribution to s the oxygen isotopic composition of caco 3 also decreases with increasing p h the slope of shell 18 o vs co 3 2 of orbulina universa observed in culture experiments is 0 0022 mol kg 1 1 spero et al 1997 whereas the slope derived from inorganic precipitation is 0 0024 mol kg 1 the theory also provides an explanation of the nonequilibrium fractionation effects in synthetic carbonates described by kim and o neil 1997 which can be understood in terms of equilibrium fractionation at different p h the results presented here emphasize that the oxygen isotope fractionation between calcium carbonate and water does not only depend on the temperature but also on the p h of the solution from which it is formed

δ18o and δ13c values of modern brachiopod shells abstract researchers have not rigorously tested the hypothesis that calcite from modern brachiopod shells is precipitated in oxygen isotope equilibrium with ambient seawater isotopic variability at the intraspecimen and intertaxon levels has not been examined without such data for modern brachiopods similar data from ancient brachiopods cannot be accurately interpreted in this study a survey is made of 18 o and 13 c values of terebratulid rhynchonellid thecideidine and craniacean brachiopods from antarctica the bay of fundy curacao japan new zealand norway puget sound palau sicily and south africa this suite of samples provides a wide range of taxonomic levels temperatures salinities and depositional environments for evaluating the degree of isotopic equilibrium attained during precipitation of brachiopod calcite new data indicate that modem brachiopod calcite is not always precipitated in oxygen and carbon isotope equilibrium with ambient seawater calcite from the primary layer and specialized shell structures hinge brachidium foramen interarea muscle scars are depleted in both 18 o and 13 c a characteristic of biological fractionation or vital effects often found in other calcerous marine organisms our findings suggest that these portions of the brachiopod shell should be avoided during sampling of ancient brachiopods secondary layer calcite the material most often analyzed in ancient brachiopods has higher 18 o and 13 c values which approach and sometimes correspond with predicted equilibrium values therefore secondary layer calcite is the most suitable portion of the brachiopod shell for use as an ancient seawater proxy although near equilibrium precipitation in secondary layer calcite is encouraging to those studying the isotopic composition of ancient oceans these data come with caveats large intraspecimen variability in the 18 o values of secondary layer calcite 1 in some samples limits the use of brachiopods as precise indicators of the 18 o value or temperature of ancient seawater the 18 o and 13 c values of secondary layer calcite deviate from predicted equilibrium values toward the lower values of the primary layer and specialized shell structures indicating a measurable vital effect in most cases measured 18 o values are lower than the calculated equilibrium values dictated by seasonal variations in the 18 o value and temperature of seawater ontogenetic variations in the 13 c values of secondary layer calcite have also been measured and must be assessed when interpreting ancient data modern brachiopods occur in a wide range of seawater salinities and temperatures therefore the relation between salinity and the 18 o value of seawater must be known to correctly calculate the temperature of calcite precipitation from secondary layer 18 o values errors of up to 15 c are found if ambient seawater is assumed to have a constant 18 o value e g 0 smow and the 18 o values of secondary layer calcite are used to calculate temperature coupled with vital effects and intraspecimen variability these errors can obscure the resolution of secular variations in the rock record

environmental and physiological influences on isotopic and elemental compositions of brachiopod shell calcite implications for the isotopic evolution of paleozoic oceans abstract brachiopods from the demissa bed middle devonian hamilton group biologically regulated the incorporation of mg sr and na into their shell calcite significant taxonomic differences in the elemental contents of three species athyris spiriferoides mediospirifer audacula and mucrospirifer mucronatus may be related to differences in calcification processes in contrast no significant difference or vital effects were observed between the isotopic values of mediospirifer audacula and athyris spiriferoides from erie 18o 0 03 p 0 949 13c 0 76 p 0 083 and genessee counties 18o 0 39 p 0 471 13c 0 06 p 0 854 this suggests that these brachiopods did not exert a biological control over their isotopic compositions and that their shell calcites reflect ambient physicochemical conditions isotopic compositions in unaltered shell calcites of brachiopods from genessee county which was close to the basin depocentre are heavy for carbon 13c x 5 01 pdb and oxygen 18o x 2 85 pdb compared to the species sampled at the basin s edge erie county 13c x 2 79 pdb 18o x 3 83 pdb there is a significant separation in isotopic values between the deeper and shallower water brachiopods of the basin 18o 0 98 p 0 0005 13c 2 22 p 0 0005 the 18o variation suggests a temperature salinity change with water depth whereas the change in 13c composition probably records an enrichment depletion of organic matter with water depth this observation has significant implications for paleozoic ocean isotopic evolution studies because many global changes in marine 18o and 13c are based on isotopic shifts of similar magnitude