rates and possible causes of neotectonic vertical crustal movements of the emerged southeastern united states atlantic coastal plain emerged pliocene and pleistocene shorelines and associated marine deposits were used to determine the magnitude and rate of vertical crustal movement during the past 3 m y in the united states atlantic coastal plain of south and north carolina on the basis of a new regional ostracode assemblage zonation planktic biostratigraphic data and radiometric data emerged marine deposits were determined to be primarily interglacial and can tentatively be correlated with hemispheric warm intervals in evidence from deep sea data the paleontologic evidence indicates a primary glacio eustatic component to the local sea level record and a secondary tectonic component net vertical uplift rates averaging 1 to 3 cm 1 000 yr but perhaps as high as 5 to 10 cm 1 000 yr are in evidence for the emerged coastal plain although details of the timing of regional rheological events remain obscure the trend of net uplift contrasts with general subsidence rates of about 2 to 4 cm 1 000 yr since the cretaceous in submerged parts of the continental margin near subsiding sedimentary troughs hydro isostatic crustal response to multiple deglaciation events may have periodically uplifted the coast but long term lithospheric flexural upwarping in response to sediment loading offshore is a more plausible mechanism to explain the present positions of shorelines above present mean sea level a eustatic sea level model is proposed for interglacial high stands of the past 3 0 m y

short and long term delivery rates of meteoric 10be to terrestrial soils well constrained long term average meteoric 10be deposition rates are important when meteoric 10be is used as a chronometer or tracer of earth surface processes to constrain meteoric 10be delivery to terrestrial soils we estimate time integrated 10be deposition rates from meteoric 10be inventories measured in dated soils and compare these results to a new synthesis of short term measurements of 10be in precipitation comparison of these long term rates to short term measurements suggests that short term measurements likely predict long term meteoric 10be deposition rates within uncertainties of 20 in precipitation measurements it is possible to deconvolve the contribution of atmospherically produced primary meteoric 10be from recycled meteoric 10be delivered by terrestrial dust if a second isotope is measured that quantifies either the recycled or primary components of meteoric 10be deposition we use dust concentration dependent differences between 7be and 10be measurements to make new estimates of the recycled contribution to total meteoric 10be flux delivered to the earth s surface these dust corrected data show a strong linear dependence between precipitation amount and primary meteoric 10be flux concentrations of primary meteoric 10be in mid and low latitude precipitation vary predictably by latitude between 0 63 104 and 2 05 104 atoms cm3 of precipitation providing a first order estimate of primary meteoric 10be deposition for a given latitude and precipitation rate

evidence for a buried fault system in the coastal plain of the carolinas and virginia implications for neotectonics in the southeastern united states geomorphic geologic and geophysical data suggest the presence of an 600 km long north northeast trending buried fault system in the coastal plain of the carolinas and virginia herein named the east coast fault system the east coast fault system is expressed by anomalous changes in fluvial geomorphology that locally coincide with one or more of the following features linear aeromagnetic anomalies buried faults interpreted from seismic reflection data surface faults offsetting pliocene pleistocene surficial units locally brecciated phyllites and argillites gently upwarped sediments topographic highs and seismicity near summerville south carolina river anomalies where the rivers traverse unconsolidated upper pleistocene holocene flood plain sediments are evidence of deformation along the east coast fault system during the past 130 to 10 k y which may be ongoing the fault system traverses the epicentral area of the 1886 charleston south carolina earthquake and lies west of paleoliquefaction sites along the outer south carolina coastal plain thus the fault system could be the source of the charleston earthquake and other large prehistoric earthquakes therefore confirmation and demarcation of the east coast fault system and elucidation of its history will help better assess seismic hazards in the southeastern united states

isostatic uplift driven by karstification and sea level oscillation modeling landscape evolution in north florida isostatic uplift of tectonically stable passive margin lithosphere can preserve a record of paleo shoreline position by elevating coastal geomorphic features above the influence of nearshore wave activity conversely depositional ages and modern elevations of these features can provide valuable information about the uplift history of a region we present a numerical model that combines sea level oscillation subaerial exposure a precipitation karstification function and isostatic uplift to explore the dynamic geomorphic behavior of coastal carbonate landscapes over multiple sea level cycles the model is used to estimate ages of coastal highstand depositional features along the atlantic coast of north florida numerical simulations using current best estimates for pleistocene sea level and precipitation histories suggest ages for trail ridge 1 44 ma the penholoway terrace 408 ka and the talbot terrace 120 ka that are in agreement with fossil evidence in addition model results indicate that the rate of karstification void space creation or equivalent surface lowering rate within the north florida platform is 3 5 times that of previous estimates 1 m 11 2 k y vs 1 m 38 k y and uplift rate is 2 times as high as previously thought 0 047 mm yr vs 0 024 mm yr this process has implications for landscape evolution in other carbonate settings and may play an underappreciated role within the global carbon cycle

riverine dunes on the coastal plain of georgia usa abstract relict eolian dunes on the georgia coastal plain line the north and east sides of many se trending streams and contain important paleoenvironmental information a detailed analysis of four dune fields characterizes dune geomorphology stratigraphy sedimentology and soils georgia s inland dunes range from parabolic to infilled parabolic to irregular in form typically merge to form long chains that parallel source streams and can occur as distinct bands typically the dunes are composed of 95 quartz sand grains with more than half the sand falling in the medium sand fraction dunes overlie flood plain and pointbar sands backswamp and peat deposits fluvial terraces and other dunes in places organic deposits occur on top of dunes cross bedding is observable in dunes more than about 4 m thick and indicates eastward dune migration paleosols found within some dunes indicate holocene reworking conditions favoring dune formation likely included at least seasonal aridity postdepositional modification of the dunes includes a smoothing of the dune surface a clay increase in the c horizon spodic horizon development bioturbation removal of weatherable minerals and fluvial incision

collapse of polar ice sheets during the stage 11 interglacial the magnitude of sea level rise during marine isotope stage 11 about 400 000 years ago is shown to have been probably only 6 to 13 metres in contrast to some earlier estimates of up to 20 metres the ice sheets in greenland and west antarctica are known to be susceptible to climate warming and both are losing mass how the east antarctic ice sheet will respond to warming is less clear recent evidence from shoreline features in bermuda and the bahamas suggested that during marine isotope stage 11 a period of warming that occurred about 400 000 years ago the sea level was 20 metres higher than it is today which pointed to significant melting of the east antarctic ice sheet now an estimate that takes into account post glacial crustal subsidence of the shoreline sites during an anomalously long interglacial period puts the sea level during stage 11 at 6 13 metres higher than today that can be explained by the collapse of the greenland and west antarctic ice sheets with only a small contribution from the east antarctic ice sheet contentious observations of pleistocene shoreline features on the tectonically stable islands of bermuda and the bahamas have suggested that sea level about 400 000 years ago was more than 20 metres higher than it is today1 2 3 4 geochronologic and geomorphic evidence indicates that these features formed during interglacial marine isotope stage mis 11 an unusually long interval of warmth during the ice age1 2 3 4 previous work has advanced two divergent hypotheses for these shoreline features first significant melting of the east antarctic ice sheet in addition to the collapse of the west antarctic ice sheet and the greenland ice sheet1 2 3 or second emplacement by a mega tsunami during mis 11 ref 4 5 here we show that the elevations of these features are corrected downwards by 10 metres when we account for post glacial crustal subsidence of these sites over the course of the anomalously long interglacial on the basis of this correction we estimate that eustatic sea level rose to 6 13 m above the present day value in the second half of mis 11 this suggests that both the greenland ice sheet and the west antarctic ice sheet collapsed during the protracted warm period while changes in the volume of the east antarctic ice sheet were relatively minor thereby resolving the long standing controversy over the stability of the east antarctic ice sheet during mis 11

loessial soils of priangaria transbaikalia mongolia and northwestern china abstract comparative analysis of loessial soils from priangaria transbaikalia western mongolia and northwestern china investigated the differences in genesis microstructure plasticity and swelling and collapsibility priangarian loess like deposits formed through a combined model where during sedimentation individual primary layers of aeolian origin were deposited in a general background of deluvial deposits successive strata with differing aeolian additions were the media for soil formation microstructure is aggregated skeletal in all areas there is a similarity between the microstructure parameters and the structural model of the loessial soils of priangaria and northwestern china and between soils of transbaikalia and western mongolia the mineral composition particularly smectite and the coefficient of freedom of the fine clay fraction are the factors controlling swelling the loessial soils of transbaikalia western mongolia and northwestern china exhibit collapsibility in priangaria the manifestation of this property is different resulting from the climatic zonation and the differences in genesis

comment on upper paleolithic site tuyana a multi proxy record of sedimentation and environmental history during the late pleistocene and the holocene in the tunka rift valley baikal region quat int 534 2019 138 157 abstract shchetnikov et al recently obtained the first detailed record on the paleo environment in the tunka rift valley in the late pleistocene and the holocene however when dealing with archaeological data shchetnikov et al 2019 have only presented their final conclusions and have not provided us with a comprehensive analysis of the assemblage itself which is the reason provoking these comments

the shuidonggou site complex new excavations and implications for the earliest late paleolithic in north china the initial late paleolithic said to appear between 40 and 30 kya in eastern asia is defined by the appearance of many innovations these archaeological indicators include the appearance of more refined stone tool making techniques e g include the appearance of blade and microblade technology complex hearth construction use of pigments and personal ornamentation as well as worked faunal implements such as bone and antler tools we report here new findings from a multidisciplinary research project conducted at the shuidonggou choei tong keou site complex in northern china a series of localities that date from the initial late paleolithic to the neolithic six new localities sdg7e12 were discovered and five localities sdg2 previously identified and sdg7e9 and 12 were excavated yielding more than 50 000 stone artifacts fauna ostrich eggshell beads and hearths dating results suggest that human occupation of the shuidonggou area occurred during the late pleistocene to middle holocene w32 000e6000 bp some sites are characterized by small irregular flakes casually retouched tools modified or informally retouched tools i e non standardized tools with sporadic retouch which was not well controlled and small numbers of blades or no blades others lithic assemblages are dominated by blades and microblades at two sites higher quality or exotic raw materials were exploited but at the majority of sites locally available river cobbles were used in addition to blades microblades and hearths more than 80 finely perforated and polished ostrich eggshell beads mostly colored with red ochre were recovered from three sites several worked bone needles and an awl were also uncovered from the youngest site sdg12 in deposits dating to c 13 000 cal bp the implications for the initial appearance of the late paleolithic in china and movement of modern human populations into north china are discussed

optically stimulated luminescence dating of sediments over the past 200 000 years optical dating of sediment using optically stimulated luminescence has become important for studying earth surface processes and this technique continues to develop rapidly a group of closely linked luminescence methods can be used to estimate the time since grains of quartz and feldspar were last exposed to daylight by detecting their subsequent response to environmental ionizing radiation exposure the technique is well suited to the dating of deposits as young as one year to several hundred thousand years recent technical developments have established a dating protocol with improved precision a high degree of reliability and an in built means to detect incomplete signal removal during deposition this approach has been extended to age estimation for single grains opening up a wider range of potential environments and new possibilities for understanding postdepositional grain movement ongoing research offers the possibility of significant age range extension and novel applications including low t

a 20 m middle pleistocene sea level highstand bermuda and the bahamas due to partial collapse of antarctic ice marine deposits at 20 3 m on the tectonically stable coastlines of bermuda and the bahamas support the hypothesis of a partial collapse of the antarctic ice sheet during the middle pleistocene beach sediments fill a sea cave at 22 m in bermuda and horizontal fenestrae filled beds crop out on platforms at two sites as high as 21 m in eleuthera bahamas carbonate beach sands are bound by an early generation of isopachous fibrous cement that is characteristic of a phreatic marine environment amino acid racemization and tims thermal ionization mass spectrometry dates constrain the age of the deposits to between 390 and 550 ka while proxy evidence supports a correlation with oxygen isotope stage 11 this direct geologic evidence of a 20 decrease in polar ice during the middle pleistocene has important implications for the stability of ice sheets during warm interglaciations

soil chronosequence studies in temperate to subtropical low latitude low relief terrain with data from the eastern united states the coastal plain of the eastern united states is a low latitude low altitude low relief terrain composed primarily of gently dipping marine and marginal marine sediments that range in age from cretaceous to quaternary population density of the area is moderate and most of the population is concentrated along the coast inland of the coast agriculture including growing trees for pulp is the dominant economy in this region soils have developed along two different pathways one pathway is dominated by the dissolution and movement of oxyhydroxides and the accumulation of organic matter the other by the accumulation of clays and oxyhydroxyides and the adsorption or oxidation of organic matter the first pathway has resulted in the formation of spodosols the second in the development of ultisols no clearly distinguishable age trends have been identified in the spodosols but the properties of ultisols can be measured to quantify surface material alteration through time ultisols are therefore suited to order of magnitude chronostratigraphic interpretations potentially data derived through the study of ultisols can be used to develop models that predict how surface processes will change due to continued weathering and pedogenesis or as the result of climate change

mid pliocene shorelines of the us atlantic coastal plain an improved elevation database with comparison to earth model predictions abstract for nearly a century the atlantic coastal plain acp of the united states has been the focus of studies investigating pliocene and pleistocene shorelines however the mapping of paleoshorelines was primarily done by using elevation contours on topographic maps here we review published geologic maps and compare them to paleoshoreline locations obtained through geomorphometric classification and satellite data we furthermore present the results of an extensive field campaign that measured the mid pliocene 3 3 2 9 ma shorelines of the atlantic coastal plain using high accuracy gps and digital elevation models we compare our new dataset to positions and elevations extracted from published maps and find that the extracted site information from earlier studies is prone to significant error both in the location and more severely in the elevation of the paleoshoreline we also investigate using geophysical modeling the origin of post depositional displacement of the shoreline from georgia to virginia in particular we correct the elevation of our shoreline for glacial isostatic adjustment gia and then compare the corrected elevation to predictions of mantle flow induced dynamic topography dt while a subset of these models does reconcile the general trends in the observed elevation of the mid pliocene shoreline local discrepancies persist these discrepancies suggests that either i the dt and gia models presented here do not capture the full range of uncertainty in the input parameters and or ii other influences such as sediment loading and unloading or local fault driven tectonics may have contributed to post depositional deformation of the mid pliocene shoreline that are not captured in the above models in this context our field measurements represent an important observational dataset with which to compare future generations of geodynamic models improvements in models for dt gia and other relevant processes together with an expanded geographically distributed set of shoreline records will ultimately be the key to obtaining more accurate estimates of eustatic sea level not only in the mid pliocene but also earlier in the cenozoic

δ18o values 87sr86sr and sr mg ratios of late devonian abiotic marine calcite implications for the composition of ancient seawater abstract late devonian frasnian abiotic marine calcite has been microsampled and analyzed for 87 sr 86 sr ratios 18o and 13c values and minor element concentrations portions of marine cement crystals from the alberta and canning basins have escaped diagenetic alteration and preserve original marine 18o values 4 8 0 5 pdb 13c values 2 0 to 3 0 pdb 87 sr 86 sr ratios 0 70805 3 and sr mg weight ratios 0 04 to 0 05 marine 87 sr 86 sr ratios are globally consistent and can be correlated within the alberta basin and among the alberta canning and williston basins correlation of isotopic and chemical data strengthen the conclusion that marine cements from the leduc formation preserve original marine 18o values which are 3 to 4 lower than those of modern marine cements these low 18o values are best explained by precipitation from 18o depleted seawater and not by elevated seawater temperature or diagenetic alteration for comparison with devonian data analogous data were collected from holocene mg calcite and aragonite marine cements from enewetak atoll marshall islands mg calcite and aragonite marine cements are in isotopic equilibrium with ambient seawater and mg calcite cements are homogeneous with respect to sr and mg contents empirically derived homogeneous distribution coefficients for mg and sr in modern abiotic mg calcite from enewetak atoll are 0 034 and 0 15 respectively an equation describing the dependence of dsr on mg content was based on a compilation of sr and mg data from holocene abiotic marine calcite dsr 3 52 10 6 ppm mg 6 20 10 3 unlike that derived from experimental data this sr mg relation is consistent over a range of 4 to 20 mol mgco3 and may represent precipitation phenomena which are minimally controlled by kinetic effects comparison of sr and mg contents of analogous devonian and holocene marine cements suggests that the mg ca ratio of late devonian seawater was significantly lower and that the sr ca ratio was significantly higher than that of modern seawater

meteoric 10be in soil profiles a global meta analysis abstract in order to assess current understanding of meteoric 10 be dynamics and distribution in terrestrial soils we assembled a database of all published meteoric 10 be soil depth profiles including 104 profiles from 27 studies in globally diverse locations collectively containing 679 individual measurements this allows for the systematic comparison of meteoric 10 be concentration to other soil characteristics and the comparison of profile depth distributions between geologic settings percent clay 9 be and dithionite citrate extracted al positively correlate to meteoric 10 be in more than half of the soils where they were measured but the lack of significant correlation in other soils suggests that no one soil factor controls meteoric 10 be distribution with depth dithionite citrate extracted fe and cation exchange capacity are only weakly correlated to meteoric 10 be percent organic carbon and ph are not significantly related to meteoric 10 be concentration when all data are complied the compilation shows that meteoric 10 be concentration is seldom uniform with depth in a soil profile in young or rapidly eroding soils maximum meteoric 10 be concentrations are typically found in the uppermost 20 cm in older more slowly eroding soils the highest meteoric 10 be concentrations are found at depth usually between 50 and 200 cm we find that the highest measured meteoric 10 be concentration in a soil profile is an important metric as both the value and the depth of the maximum meteoric 10 be concentration correlate with the total measured meteoric 10 be inventory of the soil profile in order to refine the use of meteoric 10 be as an estimator of soil erosion rate we compare near surface meteoric 10 be concentrations to total meteoric 10 be soil inventories these trends are used to calibrate models of meteoric 10 be loss by soil erosion erosion rates calculated using this method vary based on the assumed depth and timing of erosional events and on the reference data selected

coupling meteoric 10be with pedogenic losses of 9be to improve soil residence time estimates on an ancient north american interfluve we couple meteoric 10 be measurements with mass balance analysis of 9 be to estimate the soil residence time srt of a biogeomorphically stable ultisol in the southern piedmont physiographic region of the southeastern united states we estimate srt after correcting the meteoric 10 be inventory to account for observed 9 be losses which indicate that more than half of the 9 be weathered from primary minerals has been leached from the upper 18 3 m of the ultisol our estimates of minimum srt range between 1 3 1 4 ma and between 2 6 3 1 ma under high and low 2 0 and 1 3 10 6 atoms cm 2 yr 1 respectively estimates of 10 be delivery denudation rates of the physiographic region corroborate our estimates we redefine pedogenic time constraints in the southern piedmont and demonstrate that the assumption of complete meteoric 10 be retention in acidic soil systems cannot always be made the latter has far reaching consequences for soil sediment river and ocean research using meteoric 10 be

luminescence dating of interglacial coastal depositional systems recent developments and future avenues of research abstract luminescence dating offers new opportunities to explore the evolution of quaternary marine coastal facies and landforms this review highlights the main advances in luminescence geochronology of interglacial coastal sediments through the analysis of 547 luminescence ages most of which were published during the last decade the majority of these reported luminescence investigations have been carried out along passive margin coasts since the turn of the century the discovery of a normalization procedure known as single aliquot regeneration sar has drastically reduced data scatter and improved precision with the consequence that quartz sar optically stimulated luminescence osl has become the dating protocol of choice for the last interglacial lig period a more complex technique known as thermally transferred osl tt osl is presumably proposed for dating older interglacials of the mid pleistocene and beyond feldspar luminescence is increasingly being applied to dating pleistocene sea level high stands due to a much higher dose saturation level than quartz osl the use of feldspar irsl infrared stimulated luminescence is limited by the occurrence of variable but ubiquitous anomalous fading af following the advent of af correction methods several middle pleistocene sites have been amenable to dating albeit with significant related uncertainties recently new protocols involving the measurement of post ir irsl at elevated temperatures have yielded relatively coherent ages for interglacial sediments up to ca 300 ka quartz osl tt osl af corrected irsl and post ir irsl ages are generally correlated with periods of sea level high stands a few ages are reported from the early and middle part of the middle pleistocene as mis11 9 and more commonly mis7 high stands are documented in strongly uplifting active margin coasts however by far the most obvious age peak corresponds to the end of the lig the mis5e shoreline is probably the most studied and luminescence dated coastal feature of all as the chronology of the sea level markers is crucial to assess global eustatic sea level variations through the course of the last interglacial nevertheless the observed abundance of young 100 120 ka luminescence ages for presumed mis5e sediments may underline methodological issues and or reflect the higher preservation potential of late regressive sequences on the other hand the occurrence of geographically distant reports of mis5a high stand might reflect a true eustatic origin for this event age analysis supports the impression of general reliability of luminescence for the timing of former sea level high stands there is a clear need to address issues in dose rate variability in the phenomenology of fading in feldspar and in the behaviour of luminescence growth with dose both in laboratory and natural conditions these could be addressed and properly evaluated by dating different minerals as multiple or single grains with consequent variable internal dose rates more robust practices in the application of luminescence dating techniques could eventually constrain the age uncertainties to no better than 2 3 therefore the strength of luminescence as a dating tool is more in terms of its extended age range and the ubiquity of datable material

significant contribution of authigenic carbonate to marine carbon burial carbon is removed from the earth s surface through the formation and burial of carbon bearing rocks and minerals an analysis of pore water profiles collected from marine sediments around the globe suggests that the precipitation of authigenic calcium carbonate accounts for around 10 of the carbonate that accumulates in marine sediments globally carbon is removed from the earth s surface through the formation and burial of carbon bearing rocks and minerals1 2 the formation of calcium carbonate and its burial in marine sediments accounts for around 80 of the total carbon removed from the earth s surface however the fraction of calcium carbonate that precipitates in the oceans versus that which precipitates authigenically in marine sediments is unclear here we compile measurements of the calcium concentration of pore fluids collected at 672 seafloor sites around the globe to calculate the global flux of calcium within marine sediments we use these data combined with alkalinity measurements of pore fluids to quantify authigenic calcium carbonate precipitation we estimate that the net calcium flux into marine sediments that can be ascribed to authigenic carbonate precipitation amounts to around 1 1012 mol yr 1 as such we estimate that authigenic carbonate precipitation accounts for at least 10 of global carbonate accumulation we show that much of the precipitation occurs along the eastern margins of ocean basins where organic matter delivery to the sea floor is likely to be high we suggest that authigenic calcium carbonate precipitation represents a non negligible component of the global carbon cycle

rates of relative plate motion during the acadian orogeny based on the spatial distribution of black shales devonian mississippian black shales apparently were deposited in foreland basins formed in response to deformational loading in the acadian orogen these black shales were deposited in a succession of partially overlapping basins separated from each other by coarser clastic units which migrated episodically south westward in time parallel to the orogen if foreland basins are results of an isostatic response to deformational loading in the orogen migration of successive basins along the orogen must reflect concomitant shift of orogeny and hence relative plate motion in the same direction these black shale deposits then not only demonstrate the diachronous nature of the acadian orogeny a fact previously indicated by other lines of evidence but also enable approximation of rates of relative plate motion to be made using three different dating schemes the black shale deposits indicate late devonian plate motion along an 800 km segment of the orogen during approximately 11 ma for an average rate of

chronology of inland eolian dunes on the coastal plain of georgia usa most inland eolian dunes associated with rivers on the georgia coastal plain probably date to glacial periods direct dating of the dune sand by optically stimulated luminescence dating combined with limiting ages from radiocarbon dating shows that dunes formed during isotope stage 2 stage 3 the transition between stages 4 and 5 and isotope stage 6 or earlier most of the dates indicate dune activity between 30 000 and 15 000 years ago holocene activity included limited and local reworking of the crests of some thick dunes along streams that flow from the piedmont

sedimentary geochemistry of manganese implications for the environment of formation of manganiferous black shales the sedimentary geochemistry of manganese is dominated by the redox control of its speciation higher oxidation states mn super 3 and super 4 occurring as insoluble oxyhydroxides in well oxygenated environments and the lower oxidation state mn super 2 being much more soluble in oxygen deficient settings its geochemical behavior is therefore quite different in oxic and anoxic environments and where oxic and anoxic conditions are juxtaposed mn is recycled between the two environments in modern marine sediments mn is present above its crustal abundance as an oxyhydroxide in all slowly accumulating pelagic sediments of the deep ocean and in surficial deposits of continental margin environments diagenetic recycling of mn in the latter causes surficial deposits to have larger mn enrichments than in many pelagic sediments bottom sediments of permanently anoxic basins show no enrichments and have mn concentrations that are controlled solely by the aluminosilicate fraction manganese carbonates kutnohorite and calcic rhodochrosite are found only in anoxic sediments accumulating beneath surface oxic horizons and therefore under oxygenated bottom waters in many nearshore environments such enrichments are due to delivery of mn by burial of surface oxyhydroxides into the subsurface anoxic environment where they are dissolved pore water mn levels can reach saturation with respect to a mixed mn ca carbonate phase in such sediments the diagenetic origin for these phases is shown by their carbon isotope compositions which typically indicate a carbon source from decomposing organic matter the presence of mn carbonates therefore signifies that the host sediment must have accumulated under oxygenated bottom waters on the basis of this information it is proposed that in contrast to several current explanations for the formation of mn carbonates kutnohorite and rhodochrosite in ancient organic rich shales limestone and marl sequences and in many mn ore deposits the occurrence of these mineral phases indicates that the sediments originally accumulated beneath oxygenated bottom waters by analogy with the present mn carbonates could not have formed in the bottom waters of anoxic basins these diagenetic phases however did form where mn was supplied at a high rate namely by the burial of oxyhydroxide enriched surface sediments to a subsurface anoxic environment this situation could only have occurred under oxygenated bottom waters the presence of mn carbonates in ancient black shales and in some carbonate rich rocks lends strong support to the notion that these rocks did not necessarily form in anoxic basins but owe their carbon richness to a high supply of organic matter to sediments deposited under oxygenated bottom waters probably in continental margin settings

raw material procurement as a crucial factor determining knapping technology in the katta sai complex of middle palaeolithic sites in the western tian shan piedmonts of uzbekistan abstract this paper presents the results of the study of raw material procurement on two late middle paleolithic sites katta sai 1 and katta sai 2 located in the western tian shan piedmont the previous studies allowed to identify an unknown levallois variant of human cultural adaptation in the regional middle paleolithic predetermined flake technology focused on obtaining the thin triangular flakes or even blades at the same time the river pebbles of effusive rocks brought from the nearby river gorges were used for knapping the paper analyses the sources of the raw material collected and its knapping quality together with the technological features indicating how the manufacturing scheme was adjusted to the quality of used raw material

strontium isotope stratigraphy potential resolution and event correlation abstract a new generation 87sr 86sr isotope curve for the phanerozoic seawater based on a compilation of 3635 stratigraphically well defined and well preserved skeletal components results in a substantially narrower band with some discrepancies if compared to the curve of burke et al 1982 which is based mostly on whole rock samples the results obtained from low mg calcite shells foraminifers belemnites brachiopods and oysters are mostly superior to those from phosphatic skeletal components such as conodonts even if the latter are exceptionally well preserved cai 1 5 at this stage the phanerozoic data set based on fossils is patchy for the cambrian upper ordovician lower devonian and upper carboniferous triassic intervals the major practical constraint that precludes delineation of an unequivocal sr isotope curve for the phanerozoic seawater is the uncertainty in the assignment of absolute ages to the samples as a result the curve is in reality a band this is a reflection of the limitations of biostratigraphy and geochronology that are inherited by any derivative correlation and dating technique including isotope stratigraphy it is therefore unlikely that in the near future the sr isotope stratigraphy will surpass the resolution capability of biostratigraphy as a global correlation tool on the other hand if complemented by lithostratigraphy it is potentially a valuable tool for correlation of sequences on intrabasinal and regional scales taking into account the above limitations careful consideration must be given to assignment of higher order isotope peaks to specific events within a biozone and to the use of such events as a global correlation tool

geologic evidence for recurrent moderate to large earthquakes near charleston south carolina multiple generations of earthquake induced sand blows in quaternary sediments and soils near charleston south carolina are evidence of recurrent moderate to large earthquakes in that area the large 1886 earthquake the only historic earthquake known to have produced sand blows at charleston probably caused the youngest observed blows older late quaternary sand blows in the charleston area indicate at least two prehistoric earthquakes with shaking severities comparable to the 1886 event

late cenozoic flexural deformation of the middle u s atlantic passive margin despite the century long recognition of regional epeirogeny along the middle atlantic passive margin relatively few studies have focused on understanding postrift uplift mechanisms here we demonstrate that epeirogenic uplift of the central appalachian piedmont and subsidence of the salisbury embayment represent first order flexural isostatic processes driven by continental denudation and offshore deposition our results show that regional epeirogenic processes present on all atlantic type passive margins are best resolved by specific stratigraphic and geomorphic relationships rather than topography a simple one dimensional geodynamic model constrained by well dated baltimore canyon trough coastal plain and lower susquehanna river piedmont stratigraphy simulates flexural deformation of the u s atlantic margin the model represents the passive margin lithosphere as a uniformly thick elastic plate without horizontal compressive stresses that deforms flexurally under the stress of strike averaged vertically applied line loads model results illustrate a complex interaction among margin stratigraphy and geomorphology the isostatic response to denudational and depositional processes and the modulating influence of exogenic forces such as eustasy the current elevation with respect to modern sea level of fluvial terraces and correlative coastal plain deposits or unconformities is successfully predicted through the synthesis of paleotopography eustatic change and margin flexure results suggest that the middle u s atlantic margin landward of east coast magnetic anomaly is underlain by lithosphere with an average elastic thickness of 40 km flexural rigidity d 4 1023 n m the margin experiences an average long term denudation rate of approximately 10 m m y and the piedmont has been flexurally upwarped between 35 and 130 meters in the last 15 m y long term isostatic continental uplift resulting from denudation and basin subsidence resulting from sediment loading are accommodated primarily by a convex up flexural hinge physiographically represented by the fall zone our results elucidate an inherent danger in using topography alone to constrain late stage passive margin deformation mechanisms only through careful synthesis of field stratigraphic and geomorphic elements such as fluvial terraces coastal plain deposits and offshore stratigraphy can age control be extended from the offshore depositional setting to the erosionally dominated continent this study demonstrates that despite a relatively subdued topography the middle u s atlantic margin experiences progressive flexural isostatic deformation similar to that proposed for high relief margins characterized by great escarpments thus margin topographic diversity remains a function of other factors such as lithospheric composition and or structure supracrustal stratigraphy and structure degree of drainage integration drainage divide migration and climate

10be analysis of a quaternary weathering profile in the virginia piedmont samples from a residual weathering profile in the virginia piedmont have been analyzed for cosmogenic 10be concentrations are highest in clay rich soil and decrease exponentially to a depth of about 15 m despite uncertainties about the processes by which 10be may be intercepted before entering the solum and eroded after incorporation a minimum age may be calculated for the regolith this calculation is based on the delivery rate of 10be and its decay rate and suggests that this residual profile developed during a period no shorter than 8 105 yr the calculated minimum age may be within a factor of 2 of maximum age estimates based on surface lowering by erosion and on the rate of rock weathering to saprolite the vertical distribution of 10be in the profile could result from a steady state balance of deposition weathering radioactive decay and erosion

preparation and characterization of bone and tooth collagen for isotopic analysis abstract criteria are presented for the identification of diagenetic alteration of carbon and nitrogen isotope ratios of bone and tooth collagen prepared by a widely used method measurements of collagen concentrations in tooth and bone atomic c n ratios and carbon and nitrogen concentrations in collagen of 359 historic and prehistoric african humans and modern and prehistoric east african non human mammals are described carbon isotope ratios of collagen lipids from four bones are also presented compared to bone whole teeth have significantly lower collagen concentrations lower carbon and nitrogen concentrations in collagen and similar c n ratios carbon and nitrogen concentrations and c n ratios are relatively constant over a wide range of collagen concentrations however prehistoric specimens with very low collagen concentrations have highly variable c n ratios very low carbon and nitrogen concentrations in collagen and stable carbon and nitrogen isotope ratios unlike collagen at the transition from well preserved to poorly preserved collagen the most reliable indicator of collagen preservation is the concentration of carbon and nitrogen in collagen concentrations of c and n drop abruptly by an order of magnitude at this transition point these attributes provide simple criteria for assessing sample quality since collagen preservation can vary greatly within prehistoric sites these attributes should be reported for each specimen use of purification procedures that remove acid and base soluble contaminants and particulate matter carbonates fulvic acids lipids humic acids sediments and rootlets are recommended wider adoption of these procedures would insure comparability of results between laboratories and permit independent and objective evaluation of sample preservation and more precise dietary climatic and habitat interpretations of collagen isotopic analyses

quartz as a natural luminescence dosimeter abstract luminescence from quartz is commonly used in retrospective dosimetry in particular for the dating of archaeological materials and sediments from the quaternary period the phenomenon of luminescence is related to the interaction of natural radiation with mineral grains by the activation of and subsequent trapping of electrons at defects within the quartz lattice the latent luminescence signal i e the trapped electrons is released when the grains are exposed to stimulation energy in the form of light or heat despite the fact that quartz is most nominally pure sio2 the mineral forms in several different geological settings i e under different pressure and temperature conditions the luminescence emitted from quartz is complex and shows a variety of different components with diverse physical properties this complexity is explained by the variety of defects in quartz that are either intrinsic e g si and o vacancies or related to impurity atoms e g al or ti the concentration of impurity related defects is dependent on the conditions of mineral formation or subsequent alteration experimental data have shown that the luminescence properties of quartz are highly variable with geological source and vary even at a grain to grain level within a sediment as a consequence caution is needed when making any general statements about the luminescence properties of quartz when using luminescence measurements as a dating technique it is necessary to adjust the measurement procedures for each geological provenance furthermore some quartz has luminescence properties that make it problematic or even unsuitable for certain applications these problems can arise from low and changing luminescence sensitivity thermal transfer of trapped electrons thermal instability of the trapped electrons and low saturation dose reviewing the present knowledge reveals that insufficient information is available either to unambiguously link distinctive lattice defects with characteristic luminescence components or even to explain problems observed in application studies by potential dynamics of the defects within the crystal this paper gives some ideas on how future research could utilise innovative analytical tools to identify or map the distribution of lattice defects and how practitioners could relate lattice defects to measured luminescence properties of quartz

amino acid age estimates quaternary atlantic coastal plain comparison with u series dates biostratigraphy and paleomagnetic control amino acid enantiomeric dl ratios in the mollusk mercenaria are compared with recently published biostratigraphic and or u series solitary coral data from 22 quaternary localities on the central and southern atlantic coastal plain in all cases local relative aminostratigraphic sequences are consistent with relative ages inferred from u series or biostratigraphic data although occasionally more depositional events are recognized by aminostratigraphic than biostratigraphic methods however if the u series data are used as age calibrations for the dl values latitudinal trends of isochronous dl values are highly variable and conflict with trends expected from the present temperature gradient which is smooth and nearly linear between 45 and 25 n age estimation can be performed independently of the u series data using a kinetic model that relies on the assumption that pleistocene temperature gradients have also been smooth functions of latitude although significantly steeper than the present temperature gradient within the uncertainties of this assumption kinetic model age estimates for localities in the coastal plain fall into the following groups 70 000 130 000 yr 200 250 000 yr 300 000 400 000 yr 500 000 600 000 yr 700 000 800 000 yr and 1 000 000 yr major conflicts between these model age estimates are observed for localities near charleston south carolina and in central virginia these conflicts could indicate that the basic temperature assumptions of aminostratigraphy are incorrect and that apparent local aminostratigraphic sequences clusters of different dl values could be due to factors other than age difference alternatively some of the u series dates may be only minimum ages for these localities

rethinking the initial upper paleolithic the term initial upper paleolithic iup was originally proposed to describe a specific assemblage from the site of boker tachtit level 4 the use of the term was subsequently extended to cover the earliest upper paleolithic assemblages in the levant characterized by forms of blade production that combines elements of levallois method faceted platforms hard hammer percussion flat faced cores with features more typical of upper paleolithic blade technologies more recently the term iup has been broadened again to include any early upper paleolithic assemblage with levallois like features in methods of blade production irrespective of location artifact assemblages conforming to this broadest definition of the iup have been reported from a vast area stretching from the levant through central and eastern europe to the siberian altai and northwest china whereas it is indisputable that similar lithic technologies can be found in all of these areas it is not self evident that they represent a unified cultural phenomenon an alternative possibility is convergence common responses to adapting mousterian msa levallois technology to the production of blade blanks or some combination of multiple local origins with subsequent dispersal in this paper we suggest that the current definition of iup has become too broad to address such issues and that understanding the origins of this phenomenon requires a more explicit differentiation between analogies and homologies in lithic assemblages

uranium series coral ages from the us atlantic coastal plain the 80 ka problem revisited abstract uranium series coral ages for emergent units from the passive continental margin us atlantic coastal plain acp suggest sea level above present levels at the end of marine oxygen isotope stage mis 5 contradicting age elevation relations based on marine isotopic or coral reef models of ice equivalent sea level we have reexamined this problem by obtaining high precision 230th 238u and 231pa 235u thermal ionization mass spectrometric ages for recently collected and carefully cleaned acp corals many in situ we recognize samples that show no evidence for diagenesis on the basis of uranium isotopic composition and age concordance combining new and earlier data among those ages close to or within the age range of mis 5 over 85 cluster between 65 and 85 ka bp of the corals that we have analyzed those that show the least evidence for diagenesis on the basis of uranium isotopic composition and age concordance have ages between 80 and 85 ka bp consistent with a mis 5a correlation the units from which these samples have been collected are all emergent and have elevations within 3 5 m of those few units where early stage 5 125 000 ka bp coral ages have been obtained the acp appears to record an unusual history of relative sea level throughout mis 5 a history that is also apparent in the dated coral record for bermuda we speculate that this history is related to the regional near to intermediate field effects of ancestral laurentide ice sheets on last interglacial shorelines of the western north atlantic

deformation in response to landscape evolution during glacial cycles on the u s atlantic passive margin abstract elevations of pleistocene highstand formations that lie across the south carolina and northern georgia coastal plain lie well above those of reconstructed past sea levels this discrepancy has been attributed to some combination of tectonics glacial isostatic adjustment and or deviations in estimated ocean volumes derived from the marine 18 o record to reconcile these anomalous elevations we combine a landscape evolution model with models of coupled ice sheet sea level and solid earth deformation along the southern u s atlantic passive margin to estimate erosion deposition and corresponding isostatic response since marine isotope stage mis 11 410 ka we find that along shore changes in modeled paleo shoreline elevations are similar to measured elevations along 100s of kilometers up to 10 m of shoreline uplift since mis 11 may be attributed to isostatic feedback in response to sediment redistribution

uranium series dating of fossil corals from marine sediments of southeastern united states atlantic coastal plain extensive low lying marine deposits border the southeastern united states atlantic coastal plain some units are fossiliferous and contain corals as isolated fragments in sediments of a detrital character these corals are subject to alteration processes such that suites of related samples must be examined to determine the suitability of these coral samples for reliable uranium series dating with the exception of those from one location most samples appear to have remained closed systems with respect to the isotopes of uranium and thorium throughout their geologic history extraneous 230th has been detected in some of the corals due to incorporation of some detrital materials into their skeletons for these samples different methods are applied to correct for the initial 230th contamination continued sampling and analyses have resulted in 55 individual uranium thorium determinations the average 230th ages of samples from the norfolk formation and from later and earlier deposited sediments of the wando formation are 71 000 87 000 and 129 000 yr and they appear to correlate with oxygen isotope substages 5a 5c and 5e respectively the average 230th age of samples from beds of the rappahannock river ponzer and ten mile hill localities is 212 000 yr and they correlate with oxygen isotope stage 7 the sediment of the canepatch formation is 460 000 yr old and it is tentatively correlated with oxygen isotope stage 11 there is general agreement between uranium series and uranium trend dates and between the quantitative trends of the amino acid data and uranium series dates the amino acid values however ure unacceptably high in at least two groups of samples those from localities near charleston south carolina and from central virginia

quaternary climates and sea levels of the u s atlantic coastal plain uranium series dating of corals from marine deposits of the u s atlantic coastal plain coupled with paleoclimatic reconstructions based on ostracode marine and pollen continent data document at least five relatively warm intervals during the last 500 000 years on the basis of multiple paleoenvironmental criteria we determined relative sea level positions during the warm intervals relative to present mean sea level were 7 5 meters at 188 000 years ago 7 5 1 5 meters at 120 000 years ago 6 5 3 5 meters at 94 000 years ago and 7 3 meters at 72 000 years ago the composite sea level chronology for the atlantic coastal plain is inconsistent with independent estimates of eustatic sea level positions during interglacial intervals of the last 200 000 years hydroisostatic adjustment from glacial interglacial sea level fluctuations lithospheric flexure and isostatic uplift from sediment unloading due to erosion provide possible mechanisms to account for the discrepancies alternatively current eustatic sea level estimates for the middle and late quaternary may require revision

high eustatic sea level during the middle pliocene evidence from the southeastern u s atlantic coastal plain the middle pliocene approximately 3 5 2 5 ma was a period of global warmth preceding the growth of major northern hemisphere ice sheets the authors report on eustatic sea level for the middle pliocene based on microspaleontologic study of marine deposits of the duplin formation of south carolina and north carolina the duplin was deposited during a middle pliocene marine transgression that formed the orangeburg scarp a prominent wave cut geomorphic paleoshoreline of the southeastern u s atlantic coastal plain they concluded that 1 the scarp in south carolina was formed mostly during the middle pliocene 3 5 3 0 ma 2 eustatic sea level was about 35 plus minus 18 m higher than modern sea level the scarp has been uplifted about 50 65 m since the middle pliocene and 3 ocean water temperatures along eastern north america were warmer when the scarp was formed that they are at present

origin of the epeirogenic uplift of pliocene pleistocene beach ridges in florida and development of the florida karst marine fossils of pleistocene age are known to occur in beach ridges near the border of northern florida and southern georgia at elevations of between 42 and 49 m above mean sea level no evidence exists for a massive melt off of glacial ice which would be required to raise sea level to these elevations florida therefore must have been uplifted epeirogenically during the pleistocene measurement of dissolved solids in florida9s springs demonstrates that the karst area is losing a minimum of 1 2 10 6 m 3 yr of limestone through spring flow the equivalent of 1 m of surficial limestone every 38 000 yr this loss has led to an isostatic uplift of the north central part of the florida peninsula of at least 36 m during pleistocene and holocene time which agrees with observed elevations of marine terraces

cretaceous black shales as active bioreactors a biogeochemical model for the deep biosphere encountered during odp leg 207 demerara rise abstract a transport reaction model was designed to identify the combination and importance of biogeochemical processes operating in four sites drilled during odp leg 207 demerara rise equatorial atlantic almost 100 ma after their deposition deeply buried cretaceous black shales still act as active bioreactors in great sediment depths and control the biogeochemical reaction network of the whole sediment column according to a model calibrated at the four drill sites through inverse modeling techniques methanogenesis could be identified as a key process that dominates not only organic matter degradation but also sulfate availability through the anaerobic oxidation of methane above the black shales a complete depletion of sulfate within the black shale sequences promotes the remobilization of biogenic barium that reprecipitates as authigenic barite at the top of the sulfate depletion zone temporal dynamics of degradation processes caused continuous shifts of the barite precipitation zone during burial thus inhibiting the formation of an authigenic barite front or causing the dissolution of earlier formed fronts major deviations of pore water sulfate profiles from a linear gradient coincide with depths of decelerated or accelerated transport caused by local porosity minima or maxima model determined reaction rates are by far lower than those found in shallower sediments due to the low metabolic activities that are characteristic for the deep biosphere but even after almost 100 ma changing organic matter quality still influences the degradation within the black shale sequences as it is indicated by model results

late quaternary stratigraphy and luminescence geochronology of the northeastern mojave desert abstract the chronology of the holocene and late pleistocene deposits of the northeastern mojave desert have been largely obtained using radiocarbon ages our study refines and extends this framework using optically stimulated luminescence osl to date deposits from valjean valley silurian lake playa red pass and california valley of particular interest are eolian fine silts incorporated in ground water discharge gwd deposits bracketed at 185 140 and 20 50 ka alluvial fan deposits proved amenable for osl by dating both eolian sand lenses and reworked eolian sand in a matrix of gravel that occurs within the fan stratigraphy lacustrine sand in spits and bars also yielded acceptable osl ages these osl ages fill gaps in the geochronology of desert deposits which can provide data relevant to understanding the responses of several depositional systems to regional changes in climate this study identifies the most promising deposits for future luminescence dating and suggests that for several regions of the mojave desert sediments from previously undated landforms can be more accurately placed within correct geologic map units

comparison between holocene and marine isotope stage 11 sea level histories the exceptionally long interglacial warm period known as marine isotope stage 11 mis 11 428 397 ky ago vs ky vs kyr is often considered as a potential analogue for future climate development in the absence of human influence we use a new high resolution sea level record a globally integrated ice volume signal to compare mis 11 and the current interglacial holocene it is found that sea level rise into both interglacials started over similar timescales relative to the respective insolation increases and progressed up to 50 m at similar rates of 1 0 1 2 m per century subsequent weak insolation changes anomalously prolonged the mis11 deglaciation over more than 20 ky the main sea level highstand was achieved at the second mis 11 insolation maximum with a timing closely equivalent to that of the holocene highstand compared to its single insolation maximum consequently while mis 11 was an exceptionally long period of interglacial warmth its ice volume minimum sea level highstand lasted less than 10 ky which is similar to the duration of other major interglacials comparison of the ends of mis 11 and the holocene based on timings relative to their respective maxima in mean 21 june insolation at 65 n suggests that the end of holocene conditions might have been expected 2 0 2 5 ky ago instead interglacial conditions have continued with co2 temperature and sea level remaining high or increasing this apparent discrepancy highlights the need to consider that a comparisons may need to focus on other orbital control indices in which case the discrepancy can vanish and or b the feedback mechanisms that dominate the planetary energy balance may have become decoupled from insolation during the past 2millennia

new evidence for paleolithic human behavior in mongolia the kharganyn gol 5 site abstract situated between the altai mountains and the chinese loess plateau the current territory of mongolia played a pivotal role in pleistocene human population dynamics in northeast asia with archaeological evidence suggesting the existence of cultural links with southern siberia beginning in the late pleistocene here we present preliminary results from the newly discovered site of kharganyn gol 5 in northern mongolia the results obtained from the kharganyn gol 5 site allow new reconstructions of chrono cultural sequences and human behavior in eastern central asia the site has yielded evidence of human occupation corresponding to several phases of the regional upper paleolithic in addition we present the first evidence of human occupation of the region prior to greenland interstadial 12 gi12 40 000 43 000 bp and discuss the implications of such data the kharganyn gol river basin contains sedimentary rock formations including numerous raw material outcrops containing various types of chert prehistoric people used all these chert varieties for tool production but the modes of raw material exploitation changed through time this paper reports the presence unique in central and north asia of a non utilitarian object made of muscovite mica in an initial upper paleolithic assemblage in archaeological horizon 5 of the kharganyn gol 5 site

comparison of amino acid racemization geochronometry with lithostratigraphy biostratigraphy uranium series coral dating and magnetostratigraphy in the atlantic coastal plain of the southeastern united states the results of an integrated study comprising litho and biostratigraphic investigations uranium series coral dating amino acid racemization in molluscs and paleomagnetic measurements are compared to ascertain relative and absolute ages of pleistocene deposits of the atlantic coastal plain in north and south carolina four depositional events are inferred for south carolina and two for north carolina by all methods the data suggest that there are four pleistocene units containing corals that have been dated at about 100 000 yr 200 000 yr 450 000 yr and over 1 000 000 yr some conflicts exist between the different methods regarding the correlation of the younger of these depositional events between charleston and myrtle beach lack of good uranium series dates for the younger material at myrtle beach makes the correlation with the deposits at charleston more difficult

geochronologic evidence for a possible mis 11 emergent barrier beach ridge in southeastern georgia usa abstract predominantly clastic off lapping transgressive near shore marine sediment packages that are morphologically expressed as subparallel ne trending barriers beach ridges and associated back barrier areas characterize the near surface stratigraphic section between the savannah and the ogeechee rivers in effingham county southeastern georgia each barrier back barrier shoreline complex is lower than and cut into a higher older complex each barrier or shoreline complex overlies miocene strata no direct age data are available for these deposits previous researchers have disagreed on their age and provenance using luminescence and meteoric beryllium 10 10 be inventory analyses we estimated a minimum age for the largest westernmost morphologically identifiable and topographically highest barrier beach ridge the wicomico shoreline barrier and constrained the age of a suite of younger barrier beach ridges that lie adjacent and seaward of the wicomico shoreline barrier at the study site the near shore marine estuarine deposits underlying the wicomico shoreline barrier are overlain by eolian sand and an intervening zone of mixing optically stimulated luminescence osl data indicate ages of 43 ka for the eolian sand and 116 ka for the zone of mixing meteoric 10 be and pedostratigraphic data indicate minimum residence times of 33 4 ka for the eolian sand 80 6 ka for the zone of mixing and 247 ka for the paleosol the combined osl and 10 be age data indicate that at this locality the barrier beach ridge has a minimum age of about 360 ka this age for the wicomico shoreline barrier deposit is the first for any pleistocene near shore marine estuarine deposit in southeast georgia that is conclusively older than 80 ka the 360 ka minimum age is in agreement with other geochronologic data for near coastline deposits in georgia and south carolina the geomorphic position of this barrier beach ridge is similar to deposits in south carolina considered to be 450 ka to 1 ma the age and geomorphic data for georgia and south carolina possibly suggest the presence of mis 11 420 360 ka shoreline deposits between 15 m and 28 m above present sea level in the southeastern atlantic coastal plain

uranium diagenesis in sediments underlying bottom waters with high oxygen content we measured u in sediments both pore waters and solid phase from three locations on the middle atlantic bight mab from the eastern margin of the united states a northern location on the continental shelf off massachusetts oc426 75 m water depth and two southern locations off north carolina en433 1 647 m water depth and en433 2 2648 m water depth these sediments underlie high oxygen bottom waters 250 270 m but become reducing below the sediment water interface due to the relatively high organic carbon oxidation rates in sediments en433 1 212 mol c cm2 y oc426 120 10 mol c cm2 y en433 2 33 mol c cm2 y pore water oxygen goes to zero by 1 4 1 5 cm at en433 1 and oc426 and slightly deeper oxygen penetration depths were measured at en433 2 4 cm all of the pore water profiles show removal of u from pore waters calculated pore water fluxes are greatest at en433 1 0 66 0 08 nmol cm2 y and less at en433 2 and oc426 0 24 0 05 and 0 13 0 05 nmol cm2 y respectively solid phase profiles show authigenic u enrichment in sediments from all three locations the average authigenic u concentrations are greater at en433 1 and oc426 5 8 0 7 nmol g and 5 4 0 2 nmol g respectively relative to en433 2 4 1 0 8 nmol g this progression is consistent with their relative ordering of reduction intensity with greatest reducing conditions in sediments from en433 1 less at oc426 and least at en433 2 the authigenic u accumulation rate is largest at en433 1 0 47 0 05 nmol cm2 y but the average among the three sites on the mab is 0 2 nmol cm2 y pore water profiles suggest diffusive fluxes across the sediment water interface that are 1 4 1 7 times greater than authigenic accumulation rates at en433 1 and en433 2 these differences are consistent with oxidation and loss of u from the solid phase via irrigation and or bioturbation which may compromise the sequestration of u in continental margin sediments that underlie bottom waters with high oxygen concentrations previous literature compilations that include data exclusively from locations where o2 bw 150 m suggest compelling correlations between authigenic u accumulation and organic carbon flux to sediments or organic carbon burial rate sediments that underlie waters with high o2 bw have lower authigenic u accumulation rates than would be predicted from relationships developed from results that include locations where o2 bw 150 m

the diagenetic origin and depositional history of the cherry valley member middle devonian marcellus formation abstract we report 13c 18o 34s records coupled with elemental pyrite morphology and fluid inclusion data spanning the cherry valley member in the middle devonian marcellus shale from two cores located across a depth gradient in the appalachian basin the goal of the study was to evaluate the diagenetic and redox history of this carbonate interbedded layer within a prominent shale gas system three lithological units were identified in the cherry valley member a nodular clay rich marlstone lower unit a fossiliferous limestone middle unit and a calcareous mudstone upper unit low 13c and 18o values of the carbonate matrix display a mixing trend among marine carbonate authigenic carbonate and late stage diagenetic cementation the petrology of barite nodules and associated 34sbarite values suggest that a shoaling sulfate methane transition zone created by methane advection contributed to the nodule growth and pyritization along with other early and late diagenetic processes this mechanism provided the main carbonate source for the lower unit due to elevated rates of aerobic methane oxidation the 34spyrite values u and mo contents and pyrite framboid size distributions together constrain the redox history of the cherry valley member an anoxic euxinic marine environment rather than a fully oxygenated environment continued through the lower unit in areas with deeper paleo bathymetry until it was interrupted by an episode of dysoxia during the deposition of the middle unit basin scale anoxia was then renewed during a subsequent 3rd order sea level rise in the upper unit the entire cherry valley member was ultimately altered by warm burial fluid interaction through vertically distributed veins the combined body of evidence indicates that the duration and spatial distribution of oxygenated marine conditions during the deposition of cherry valley member within the marcellus formation may have been overestimated

meteoric cosmogenic beryllium 10 adsorbed to river sediment and soil applications for earth surface dynamics abstract rainfall scavenges meteoric cosmogenic 10be from the atmosphere 10be falls to the earth s surface where it binds tightly to sediment particles in non acidic soils over the life span of those soils as such meteoric 10be has the potential to be an excellent geochemical tracer of erosion and stability of surfaces in a diverse range of natural settings meteoric 10be has great potential as a recorder of first order erosion rates and soil residence times even though this tracer was first developed in the late 1980s and showed great promise as a geomorphic tool it was sidelined in the past two decades with the rise of the sister nuclide in situ 10be which is produced at a known rate inside quartz minerals since these early days substantial progress has been made in several areas that now shed new light on the applicability of the meteoric variety of this cosmogenic nuclide here we revisit the potential of this tracer and we summarize the progress 1 the atmospheric production and fallout is now described by numeric models and agrees with present day measurements and paleo archives such as from rain and ice cores 2 short term fluctuations in solar modulation of cosmic rays or in the delivery of 10be are averaged out over the time scale soils accumulate 3 in many cases the delivery of 10be is not dependent on the amount of precipitation 4 we explore where 10be is retained in soils and sediment 5 we suggest a law to account for the strong grain size dependence that controls adsorption and the measured nuclide concentrations and 6 we present a set of algebraic expressions that allows calculation of both soil or sediment ages and erosion rates from the inventory of meteoric 10be distributed through a vertical soil column the mathematical description is greatly simplified if the accumulation of 10be is at a steady state with its export through erosion in this case a surface sample allows for the calculation of an erosion rate explored further this approach allows calculation of catchment wide erosion rates from river sediment similar to the approach using 10be produced in situ in contrast to the in situ 10be approach however these analyses can be performed on any sample of fine grained material even where no quartz minerals are present therefore this technique may serve as a tool to date sediment where no other chronometer is available to track particle sources and to measure earth surface process rates in soil suspended river sediment and fine grained sedimentary deposits

sea level and deep water temperature changes derived from benthic foraminifera isotopic records we show that robust regressions can be established between relative sea level rsl data and benthic foraminifera oxygen isotopic ratios from the north atlantic and equatorial pacific ocean over the last climatic cycle we then apply these regressions to long benthic isotopic records retrieved at one north atlantic and one equatorial pacific site to build a composite rsl curve as well as the associated confidence interval over the last four climatic cycles our proposed reconstruction of rsl is in good agreement with the sparse rsl data available prior to the last climatic cycle we compute bottom water temperature changes at the two sites and at one southern indian ocean site taking into account potential variations in north atlantic local deep water 18o our results indicate that a last glacial maximum lgm enrichment of the ocean mean oxygen isotopic ratio of 0 95 is the lowest value compatible with unfrozen deep waters in the southern indian ocean if local deep water 18o did not increase during glacials with respect to present such a value of the lgm mean ocean isotopic enrichment would impose a maximum decrease in local bottom water 18o at the north atlantic site of 0 30 during glacials

late cenozoic marine deposition in the united states atlantic coastal plain related to tectonism and global climate abstract major hiatuses in upper cenozoic marine deposits in the united states atlantic coastal plain are recognized on the basis of molluscan faunal changes at erosional unconformities these hiatuses generally coincided with periods of global cooling and ice sheet formation such hiatuses provide information to supplement global climatic data major hiatuses are recognized within the early miocene 23 20 m y ago at the end of the middle miocene 11 10 m y ago at the end of the late miocene 6 5 5 m y ago at the end of the early pliocene 4 0 2 5 m y ago at the end of the late pliocene 1 9 or 1 8 m y ago within the pleistocene 1 1 0 5 m y ago and several times within the last 0 4 m y estimates of the amount of water contained in ice sheets at different times in the pliocene and pleistocene facilitate calculation of probable minimum sea levels on the coastal plain during different high stands of the sea the altitudes of dated shoreline deposits in the atlantic coastal plain show that the amount of uplift in the cape fear area has averaged at least 1 3 cm per 1000 years since the beginning of pliocene time the coastal plain of georgia has apparently experienced relatively little vertical deformation during this same time