solar cycles and depositional processes in annual be 10 from two varved lake sediment records beryllium 10 concentrations be 10 con were measured at annual resolution from varved sediment cores of lakes tiefer see tsk and czechowskie jc for the period 1983 2009 similar to solar cycles 22 and 23 calibrating the be 10 con time series against complementing proxy records from the same archive as well as local precipitation and neutron monitor data reflecting solar forced changes in atmospheric radionuclide production allowed i identifying the main depositional processes and ii evaluating the potential for solar activity reconstruction be 10 con in tsk and jc sediments are significantly correlated to varying neutron monitor counts tsk r 0 5 p 0 05 n 16 jc r 0 46 p 0 03 n 22 however the further correlations with changes in organic carbon contents in tsk as well as varying organic carbon and detrital matter contents in jc point to catchment specific biases in the 10be con time series in an attempt to correct for these biases multiple regression analysis was applied to extract an atmospheric be 10 production signal be 10 atmosphere to increase the signal to noise ratio a be 10 composite record be 10 composite was calculated from the tsk time series be 10 composite and jc be 10 atmosphere is significantly correlated to variations in the neutron monitor record r 0 49 p 0 01 n 25 and matches the expected amplitude changes in 10be production between solar cycle minima and maxima this calibration study on 10be from two sites indicates the large potential but also partly site specific limitations of be 10 in varved lake sediments for solar activity reconstruction c 2015 elsevier b v all rights reserved less

distribution of beryllium between solution and minerals biotite and albite under atmospheric conditions and variable ph abstract biotite and albite grains having a size range from 20 to 124 m were suspended in be bearing solutions at ph 2 to 9 for periods of 30 min to 20 days the amount of be sorbed onto biotite is up to 40 times higher than onto albite under the same conditions and ph 7 at ph 6 the distribution of be between solution and solids is related to sorption but at ph 6 the solute concentration is strongly controlled by solubility of be oh 2 solid because of this solubility control the calculation of a distribution coefficient k d s c where s is be sorbed at equilibrium per mass or specific surface area of sorbent and c is the be concentration in solution at equilibrium seems to be valid only at ph 6 the k d increases with decreasing suspended particle concentration from 0 2 to 2 0 g l 1 for both minerals for biotite the k d also increases with the fine 20 63 m relative to the coarse 63 124 m size fraction even upon normalization to specific surface area the relatively small amount of be sorbed onto albite at ph 2 and 4 limited extensive evaluation and comparison the rate of be sorption onto biotite follows a logarithmic function and ranges from 0 8 to 1 0 10 11 mol cm 2 s 1 in ph 2 and 6 solutions respectively the time variation of sorbed be onto albite was insignificant with increasing ph the sorption of be onto biotite partly relates to the kinetics of cation release the results of experiments are discussed with respect to some examples of the distribution of be isotopes in continental aquatic systems

partitioning groundwater recharge between rainfall infiltration and irrigation return flow using stable isotopes the crau aquifer abstract this study reports an assessment of the water budget of the crau aquifer southern france which is poorly referenced in the literature anthropogenically controlled by a traditional irrigation practice this alluvial type aquifer requires a robust quantification of the groundwater mass balance in order to establish sustainable water management in the region in view of the high isotopic contrast between exogenous irrigation waters and local precipitations stable isotopes of water can be used as conservative tracers to deduce their contributions to the surface recharge extensive groundwater sampling was performed to obtain 18o and 2h over the whole aquifer based on a new piezometric contour map combined with an updated aquifer geometry the isotopic data were implemented in a geostatistical approach to produce a conceptual equivalent homogeneous reservoir this makes it possible to implement a parsimonious water and isotope mass balance mixing model the isotopic compositions of the two end members were assessed and the quantification of groundwater flows was then used to calculate the two recharge fluxes natural and irrigation nearly at steady state the set of isotopic data treated by geostatistics gave a recharge by irrigation of 4 92 0 89 m3 s 1 i e 1109 202 mm yr 1 and a natural recharge of 2 19 0 85 m3 s 1 i e 128 50 mm yr 1 thus 69 9 of the surface recharge is caused by irrigation return flow this study constitutes a straightforward and independent approach to assess groundwater surface recharges including uncertainties and will help to constrain future transient groundwater models of the crau aquifer

dating of sediments using accelerator mass spectrometry abstract an assessment is given of the current status and future prospects for the dating of recent sediments by the direct counting of radionuclides cosmogenic natural terrestrial and artificial using accelerator based mass spectrometers relevant isotopes and equipment are discussed the latter with particular reference to the 3 mv electrostatic accelerator system of the university of toronto inherent difficulties of the new method are outlined and possible applications are identified the ability to obtain radiocarbon dates from very small samples e g 100 g c illustrates the promise of the method

light stable isotope systematics of large scale hydrologic regimes in california and nevada surface waters shallow groundwaters and precipitation samples were collected along three traverses which begin at the california coast and are oriented in an east west manner roughly parallel to the atmospheric flow path of meteoric water the hydrogen isotope compositions from short term precipitation records varied as much as 40 at one location and were not representative of the average annual isotopic composition of precipitation the hydrogen isotope ratios of surface waters and shallow groundwaters distinguish segments with isotopic variations that correlate with measured vertical fluxes of meteoric water one coastal segment appears to closely approximate an open system in which precipitation dominates over evapotranspiration most segments are described by rather regular variations in d 3 45 per 100 km which represent different degrees of closure of the hydrologic system caused by variable partitioning of precipitation between runoff and evapotranspiration all partially closed systems imply terrestrial recycling of water a simple model estimates this amount to be about 20 across northern and central california three segments representing the great basin show virtually no geographic variation and appear to represent isotopically closed systems

impact of stylolite on carbonate reservoir continuity example from middle east growth of stylolites may adversely affect the continuity of carbonate reservoirs by producing barriers to fluid flow the impact of stylolite development on reservoir performance however may differ from one part of a reservoir to another therefore for effective reservoir management the distribution and the permeability of stylolite bearing beds should be known in an example from the lower cretaceous of the middle east 3 zones of stylolites d1 d2 and d3 are important to reservoir management only the uppermost zone d1 formed largely before oil entrapment local precipitation of calcium carbonate occurred at abundant crystal nucleation sites adjacent to the stylolite zone the other stylolite zones d2 and d3 were formed largely during or after oil entrapment oil inhibited carbonate precipitation by coating crystal nucleation sites calcium carbonate dissolved at pressure solution surfaces was then transported away from stylolite zones prior to precipitation consequently stylolites formed after oil entrapment do not constitute significant barriers to fluid flow

neodymium and strontium isotopic study of australasian tektites new constraints on the provenance and age of target materials nd and sr isotopic studies of australasian tektites provide information on the age and provenance of the target materials and allow us to characterize the target area and the impact process leading to tektite formation nd values of australites splash form indochinites and muong nong type indochinites are indistinguishable within analytical uncertainty and average 11 5 u depleted mantle nd model ages fall within the narrow range of 1490 1620 ma indicating that the source material was derived dominantly from a proterozoic crustal terrane sr values are variable and are correlated with the geographic location of the tektite samples analyses of four muong nong type or layered indochinites from a single locality in eastern thailand yield an isochron age of 167 12 ma 2 a correlation of rb sr fractionation with sr model ages indicates that the last major rb sr fractionation event experienced by the target materials occurred 175 15 ma ago we interpret this age as the time of deposition of sedimentary target rocks and consider the compositional layering observed in muong nong type tektites to reflect compositional variability inherited from jurassic sediments the nd and sr isotopic data provide evidence that all australasian tektites were derived from a single sedimentary formation with a narrow range of stratigraphic ages close to 170 ma we suggest that all of the australasian tektites were derived from a single impact event and that the australites represent the upper part of a melt sheet ejected at high velocity whereas the indochinites represent melts formed at a lower level in the target material which were distributed closer to the area of impact the impact site is inferred to be within an area of jurassic sedimentary bedrock which spans the geopolitical boundaries between northern cambodia southern laos and southeastern thailand

a cosmic trip 25 years of cosmogenic nuclides in geology terrestrial cosmogenic nuclides produced by secondary cosmic ray interactions in the atmosphere and in situ within minerals in the shallow lithosphere are widely used to date surface exposure of rocks and sediments to estimate erosion and weathering rates and to date sediment deposition or burial their use has transformed geomorphology and quaternary geology for the first time allowing landforms to be dated and denudation rates to be measured over soil forming time scales the application of cosmogenic nuclides to geology began soon after the invention of accelerator mass spectrometry ams in 1977 and increased dramatically with the measurement of in situ produced nuclides in mineral grains near earth s surface in the 1980s the past 25 yr have witnessed the development of cosmogenic nuclides from their initial detection to their prevalence today as a standard geochronological and geochemical tool this review covers the major developments of the past 25 yr by comparing the state of the field in 1988 with that of today and by identifying key advances in that period that moved the field forward we emphasize the most commonly used in situ produced nuclides measured by ams for geological applications but we also discuss other nuclides where their applications overlap our review covers ams instrumentation cosmogenic nuclide production rates the methods of surface exposure dating measurement of erosion and weathering and burial dating and meteoric 10 be in memoriam devendra lal 1929 2012 whose vision inspired the field

10be distribution in soils from merced river terraces california abstract the distribution and residence time of cosmogenic 10 be in clay rich soil horizons is fundamental to understanding and modelling the migration of 10 be on terrestrial sediments and in groundwater solutions we have analyzed seven profiles of clay rich soils developed from terrace sediments of the merced river california the terraces and soils of increasing age are used to compare the 10 be inventory with a simple model of accumulation decay and erosion the data show that the distribution of 10 be varies with soil horizon clay content that the residence time of 10 be in these horizons exceeds 10 5 years and that to a rough approximation the inventory of 10 be in a thoroughly sampled soil profile fits the equation n q em 1 e where q is delivery rate e is erosion rate m is the concentration of 10 be in the eroding surface layer is the decay constant and t is the age of the depositional unit from which the soil has developed the general applicability of this model is uncertain and warrants further testing in well calibrated terrace sequences

the global average production rate of10be precipitation collected in continuously open containers for about a year at seven sites around the united states was analyzed for10be 90sr 210pb and238u based on these data and long term precipitation 90sr and210pb delivery patterns the stratospheric tropospheric and recycled10be components in the collections were estimated and the global10be production rate was assessed single station production rate estimates range from 0 52 106 atoms cm 2 yr 1 to 2 64 106 atoms cm 2 yr 1 the mean value is 1 21 106 atoms cm 2 yr 1 with a standard error of 0 26 106 atoms cm 2 yr 1

geochemistry and deposition of 7be in river estuarine and coastal waters the atmospheric flux of cosmogenic 7be 53 3 day half life and the mode of 7be deposition in river estuarine and coastal environments have been examined the atmospheric flux of 7be commonly supports inventories ranging from 1 0 to 2 0 pci cm2 1 pci 0 037 bq beryllium 7 concentrations in water phase samples collected across salinity gradients in several estuaries along the eastern coastline of the united states range from 0 03 to 0 53 pci l and primarily reflect variations in 7be supply and sorption kinetics the major process controlling the concentration of 7be on estuarine suspended particles appears to be the length of time that these particles remain in the water column field particle to water distribution coefficients for 7be have a median value of about 4 104 but range over an order of magnitude reflecting short term variations in 7be input particle dynamics and particulate iron content rather than equilibrium sorption desorption responses to changes in water salinity or particle type residence times of 7be in the water column range from a few days in estuarine areas of rapid fine particle deposition to several weeks in high energy environments where pronounced sediment resuspension reintroduces deposited 7be back into the water column inventories of 7be in sediments range from nondetectable to 3 3 pci cm2 with the highest inventories in areas where fine particles are accumulating rapidly such sites are also major repositories for other particle reactive substances a 7be budget for the james estuary indicates that less than 5 of the expected 7be input is in the water column and that the short term estuarine trapping efficiency for atmospherically derived 7be is somewhere between 50 and 100

microfacies depositional environment and diagenetic evolution controls on the reservoir quality of the permian upper dalan formation kish gas field zagros basin abstract the upper permian upper dalan formation contains one of the largest gas reservoirs in the world the formation consists of carbonates with some evaporite intercalations that developed on a gently sloping homoclinal carbonate ramp facing the late permian paleo tethys ocean this study focuses on the kish gas field zagros offshore basin situated between iran and qatar and is based on a 222 m thick continuous core based on the integration of core and wireline log data coupled with petrographic analyses of 580 thin sections three major depositional environments facies belts with 11 carbonate microfacies are identified these include 1 sabkha to tidal flat laminated to massive anhydrite dolomudstone with anhydrite nodules dolomudstone and intraclastic dolowackestone 2 lagoon and leeward shoals bioclastic wackestone dolowackestone to packstone and peloid dolopackstone and peloid bioclastic dolopackstone and 3 mobile windward sand shoal ooid peloid dolograinstone ooid dolograinstone ooid intraclast dolograinstone ooid bioclast dolograinstone packstone and coarse bioclast intraclast dolograinstone diagenetic evolution of the upper dalan formation is associated with evaporative marine shallow water normal marine meteoric and burial diagenetic environments common diagenetic effects include dolomite and calcite cementation mechanical and chemical compaction dissolution dolomitization and evaporative anhydrite mineralization reservoir quality is strongly affected by variations in the original rock fabrics and subsequent diagenetic alterations the most common pore types include interparticle moldic and connected vug fracture and cavernous the interparticle porosity permeability relationship for the studied facies suggests that the reservoir quality is not affected by different crystal sizes and most samples plot in the low porosity and low to high permeability field or display lucia class 1 or 2 petrophysical relationships the study shows that the pervasive pore filling anhydrite mineralization lead to a significant decrease in porosity and permeability poikilotopic anhydrite cement reduced matrix porosity but the pore size was less affected

10be 14c and u th decay series nuclides and δ18o in a box core from the central north atlantic abstract the stratigraphy of several radioisotopes has been determined in an undisturbed core from the central north atlantic 14c 238u 230th 232th 226ra 210pb 10be carbon 14 indicates a sedimentation rate of 1 cm 1000 yrs 1 the core represents about 30 000 years the oxygen isotope signal agrees with this scale the 18 o range is about 1 5 from glacial to holocene the maximum change is near 11 000 years b p mixing effects are minor because of the low fertility of the overlying waters excess lead 210 shows a minimum between 1 and 2 cm depth and a maximum immediately below it does not yield a diffusion coefficient for the goldberg and koide 1962 mixing model the 10be concentration in the holocene sediment on a caco3 free basis is somewhat higher than that deposited during the previous cold period however both clay and 10be deposition rates are lower by a factor of over two during the holocene the source of the excess 10be in the glacial section could be a continental reservoir or increased cosmic ray production the u and th concentrations as well as the excess 230 th 232 th activity ratios of the sediment deposited during the holocene are higher by 30 100 than in glacial sediments again this is in contrast to the deposition rates of u and th which are lower in the holocene by a factor of about two the most reliable signals are the radiocarbon and the oxygen isotope stratigraphy

beryllium geochemistry in soils evaluation of 10be 9be ratios in authigenic minerals as a basis for age models soils contain a diverse and complex set of chemicals and minerals being an open system both in the chemical and nuclear sense soils have defied quantitative nuclear dating however based on the published studies of the cosmogenic atmospheric 10be in soils its relatively long half life 1 5 ma and the fact that 10be gets quickly incorporated in most soil minerals this radionuclide appears to be potentially the most useful for soil dating we therefore studied the natural variations in the specific activities of 10be with respect to the isotope 9be in mineral phases in eight profiles of diverse soils from temperate to tropical climatic regimes and evaluated the implications of the data for determining the time of formation of soil minerals following an earlier suggestion lal et al 1991 development of cosmogenic nuclear methods for the study of soil erosion and formation rates current sci 61 636 639 we find that the 10be 9be ratios in both bulk soils and in the authigenic mineral phases are confined within a narrower range than in 10be concentrations also the highest 10be 9be ratios in authigenic minerals are observed at the soil rock interface as predicted by the model we present model 10be 9be ages of the b horizon and the corresponding soil formation rates for several soil profiles the present study demonstrates that the 10be 9be ratios in the authigenic phases e g clay and fe hydroxides can indeed be used for obtaining useful model ages for soils younger than 10 15 ma however the present work has to be pushed considerably further to take into account more realistic age models in which for instance downward transport 10be and clays and in situ dissolution of clay minerals at depths altering the 10be 9be ratios of the acidic solutions are included we show that in the case of younger soils 1 ma studied here their 10be inventories and 10be 9be ratios have been significantly disturbed possibly by mixing with transported soils

anomalous isotopic concentrations in the sea off southern california measurements are reported of the 10be concentrations in 15 sediments from the sea off southern california the sedimentation patterns are modelled with a two component system one component having the high 10be concentration of pelagic sediment and the other the low concentration of continental runoff the pelagic component brought to the region by the california current with the pacific ocean as reservoir is very likely the source not only of anomalously high 10be deposition but also of similar effects with 2101pb 239 240pu and 241pu

10be and be in the maurice river union lake system of southern new jersey the 10be and be contents of 22 samples taken from seven locations in the maurice river union lake system of southern new jersey are reported bulk 10be contents range from 0 05 to 2 7 dpm kg and be from 0 1 to 2 ppm silicate minerals separated from union lake sediments appear to have a constant surface concentration of 5 105 atom 10be cm2 organic material is greatly enriched in be hand picked samples contain over 10 dpm kg of 10be and 5 ppm of be the deposition rate of l0be in union lake is 1 atom cm2s

early middle pleistocene transitions linking terrestrial and marine realms abstract marked by a progressive increase in the amplitude of climate oscillations an evolving waveform and a shift towards a quasi 100 ky frequency the early middle pleistocene transition empt previously known as the mid pleistocene transition or mid pleistocene revolution 1 4 0 4 ma represents a fundamental transformation in the earth s climate state the empt began with a substantial change in climate dynamics and ended with the mid brunhes event signaling the establishment of a new steady state the reasons for the empt while uncertain appear to involve a non linear response of the earth climate system the physical and biotic responses to this transition amplified by the growth of northern hemisphere ice sheets have been profound two important chronostratigraphic markers characterize the empt the jaramillo subchron 1 070 0 988 ma and the matuyama brunhes chron boundary 773 ka the latter has been chosen as the primary guide for the lower middle pleistocene subseries boundary as it lies at the approximate midpoint of the empt and aids in global recognition both in marine and terrestrial deposits the jaramillo subchron has received less attention but the late early pleistocene is important in europe because it saw the progressive transition from the villafranchian to galerian mammal faunas and expansion of hominins into western and northern europe the jaramillo subchron is represented by marine isotope stages mis 31 to 28 with mis 30 already showing the asymmetrical sawtooth pattern characteristic of the middle pleistocene indeed while variation in the 40 ky band obliquity remains strong throughout the empt low frequency variability begins at around 1250 1200 ky which coincides with a progressive increase in global ice volume against a backdrop of increasingly severe glacial cycles notably during mis 36 34 24 22 the so called 0 9 ma event 16 and 12 pronounced phases of warming are also documented globally including the super interglacial mis 31 the early phase of the empt is characterized by important glaciations beginning with mis 36 and continuing to mis 24 22 a major intensification of the east asian monsoon system intensification of loess deposition in northern europe development of open landscapes in western siberia increased fluvial incision higher amplitude sea level change and spread of large mammals across northern eurasia and a strong reduction in the north atlantic thermohaline circulation in europe the loss of thermophilous plant taxa during the empt and indeed throughout the quaternary is a reminder of the progressive cooling that took place here and elsewhere

glacial water mass geometry and the distribution of δ13c of σco2 in the western atlantic ocean 1 oxygen and carbon isotopic data were produced on the benthic foraminiferal taxa cibicidoides and planulina from 25 new piston cores gravity cores and multicores from the brazil margin the cores span water depths from about 400 to 3000 m and intersect the major water masses in this region these new data fill a critical gap in the south atlantic ocean and provide the motivation for updating the classic glacial western atlantic 13c transect of duplessy et al 1988 the distribution of 13c of co2 requires the presence of three distinct water masses in the glacial atlantic ocean a shallow 1000 m southern source water mass with an end member 13c value of about 0 3 0 5 vpdb a middepth 1500 m northern source water mass with an end member value of about 1 5 and a deep 2000 m southern source water with an end member value of less than 0 2 and perhaps as low as the 0 9 values observed in the south atlantic sector of the southern ocean ninnemann and charles 2002 the origins of the water masses are supported by the meridional gradients in benthic foraminiferal 18o a revised glacial section of deep water 13c documents the positions and gradients among these end member intermediate and deep water masses the large property gradients in the presence of strong vertical mixing can only be maintained by a vigorous overturning circulation

beryllium 10 in chesapeake bay sediments an indicator of sediment provenance in a plot of 10 be vs fe central chesapeake bay sediments can be segregated into distinct units this plot reveals an unexpected statistically significant difference between sediments on the eastern and western flanks of the main channel implying different origins although the 10 be concentrations in sediments from these two regions span as much as an order of magnitude range the 10 be fe ratios vary by an amount approximating analytical error alone the large concentration ranges are ascribed to hydraulic sorting which can produce variance in composition while not affecting ratios between grain surface components such as fe and be on the basis of 10 be fe signatures sediments on the western flank of the main channel appear to have been derived from the susquehanna or another piedmont appalachian river sediments on the eastern flank may have been transported from the south by landward flowing bottom currents or may be relicts of a pleistocene estuarine system conditions under which 10 be may prove a useful tool in sediment provenance studies elsewhere are discussed

beryllium 10 in continental sediments abstract the concentration of 10 be has been measured in 10 samples taken from a transect of surface sediments beginning in the atchafalaya river and extending across the bay 136 km into the gulf of mexico if corrected for a lower retentivity of sand for be they have a concentration that is constant within 13 this concentration is about an order of magnitude smaller than that of deep ocean sediments for comparison measurements of 10 be in rainwater in a sample of soil and in a deep ocean core were made

modeling rock weathering in small watersheds summary many mountainous watersheds are conceived as aquifer media where multiple groundwater flow systems have developed toth 1963 and as bimodal landscapes where differential weathering of bare and soil mantled rock has occurred wahrhaftig 1965 the results of a weathering algorithm pacheco and van der weijden 2012a 2014 which integrates topographic hydrologic rock structure and chemical data to calculate weathering rates at the watershed scale validated the conceptual models in the river sordo basin a small watershed located in the marao cordillera north of portugal the coupling of weathering groundwater flow and landscape evolution analyses as accomplished in this study is innovative and represents a remarkable achievement towards regionalization of rock weathering at the watershed scale the river sordo basin occupies an area of approximately 51 2 km 2 and was shaped on granite and metassediment terrains between the altitudes 185 1300 m the groundwater flow system is composed of recharge areas located at elevations 700 m identified on the basis of 18 o data discharge cells comprehend terminations of local intermediate and regional flow systems identified on the basis of spring density patterns infiltration depth estimates based on 87 sr 86 sr data and spatial distributions of groundwater ph and natural mineralization intermediate and regional flow systems defined where infiltration depths 125 m develop solely along the contact zone between granites and metassediments because fractures in this region are profound and their density is very large weathering is accelerated where rocks are covered by thick soils being five times faster relative to sectors of the basin where rocks are covered by thin soils differential weathering of bare and soil mantled rock is also revealed by the spatial distribution of calculated aquifer hydraulic diffusivities and groundwater travel times

the geochemical cycle of 9be a reconnaissance an initial survey has been made of the geochemistry of 9be in natural waters with a view to utilizing the isotope with the cosmogenic species 10be t1 2 1 5 m y in geochronological studies of sedimentary accumulation the mobility of9be in continental waters is a strong function of ph with acid streams ph 6 being strongly enriched as compared to alkaline carbonate rivers large scale scavenging of beryllium occurs in the estuaries of rivers containing more than about 200 pm of the element in alkaline systems of lower concentration the element appears to behave conservatively the net flux of beryllium to the ocean is estimated as that equivalent to an average effective river concentration of about 150 pm beryllium is strongly enriched in ridge crest hydrothermal solutions over ambient seawater the flux is approximately 70 of that from the continents the deep water concentrations of 9be vary by only 20 between the north atlantic and north pacific demonstrating that the chemical saltation produced by scavenging from the deep water column and release from the sediments predominates over simple advective concentration along flow lines isotopic homogenization of 10be and 9be is probably achieved in the ocean the situation in continental waters appears much less promising

be isotopes in rivers estuaries and their oceanic budgets 10be and 9be have been determined in several north american rivers and in the estuaries of san francisco bay and the pearl river china the average fluvial concentration of dissolved 10be in the rivers is 3220 1960 1 atoms g almost an order of magnitude higher than the observed estuarine values and slightly higher than the 10be concentration in the ocean 1700 atoms g for dissolved 9be a similar order of magnitude drop in concentration also occurs in going from rivers 750 740 pm to estuaries 80 140 pm however in contrast to the 10be situation there appears another order of magnitude drop from estuaries to the ocean which has 9be concentrations of 5 30 pm in spite of the wide range of concentrations for both isotopes in river and estuarine waters 10be 9be ratios range mostly from 2 to 12 10 9 with a median value of 7 10 9 atom atom and are much lower than the seawater ratio of 10 7 in the rivers studied a given volume of water contains roughly equal amounts of particulate and dissolved 10be the 10be concentration in particulate matter ranges from 2 106 to 1 109 atoms g particulate with a median value of about 5 107 atoms g particulate a two box model calculation shows that coastal regions play an important role in the removal of be isotopes from the ocean and that eolian dusts may be the chief source of oceanic 9be because of the marginal removal effect the overall oceanic residence time of be should be shorter than the residence time of 500 1200 yr estimated for the open ocean

reconstruction of the paleoaccumulation rate of central greenland during the last 75 kyr using the cosmogenic radionuclides 36cl and 10be and geomagnetic field intensity data abstract the accumulation rate is one of the most fundamental climate parameters to be derived from ice cores in addition to its climatic importance the accumulation rate provides a crucial constraint on depth age scales where annual layer counting is not possible so far there is no consistent picture of the accumulation rate for the last ice age in central greenland therefore we have derived the accumulation rate for the time interval of about 3 75 kyr bp by applying a method based on the cosmogenic radionuclides 36cl and 10be in the summit ice cores and on geomagnetic field data the main difference between our approach and the methods applied previously is that the accumulation rate based on 36cl and 10be does not depend on an ice flow model estimating the original thickness of annual layers our new reconstruction agrees well with the accumulation rate published by johnsen et al tellus 47b 1995 624 629 until 60 kyr bp and differs significantly from that of cuffey and clow j geophys res 102 1997 26383 26393

10be in a deep sea core implications regarding10be production changes over the past 420 ka abstract the influx of 10 be into a globigerinid ooze core ch72 02 from the eastern north atlantic has been studied this core contains a depositional record of the first 11 18 o stages covering the last 423 ka it is shown that the marine deposition of 10 be is strongly influenced by the sedimentation of clays clay particles appear 10 times more efficient than the carbonate component as a carrier in bringing 10 be to the bottom sediments in core ch72 02 the deposition rates of 10 be averaged over each oxygen isotope stage for the past 11 stages show a scatter of 40 about the mean value of 6 6 10 8 atoms cm 2 ka 1 however after correction for changes in lithology the data show that the production rate of 10 be over the same period has varied no more than 25 and the variations are not systematic in that high or low 10 be production appear to be associated with either cold or warm climates on the time scale of this investigation intervals of ca 50 ka over the last 420 ka with resolutions as fine as 10 ka for portions of the record it is unlikely that the shielding effect of the solar wind has deviated by more than 25 or the geomagnetic field intensity has deviated by more than a factor of 1 6 from their long term averages

transport of10be and9be in the ocean beryllium isotopes 10be and9be have been measured in suspended particles of 1 mm size collected by mid water sediment traps deployed in the eastern pacific at manop sites h 6 32 n 92 50 w water depth 3600 m and m 8 50 n 104 00 w 3100 m for comparison surface sediments from box cores taken from the two sites were also studied the concentrations of10be and9be in sediment trap particles are about an order of magnitude smaller than those in the bottom sediments which contain about 8 109 and 6 1016 atoms g 1 of10be and9be respectively the sediment trap samples collected from 50 m off the bottom showed significant 26 63 contributions from resuspended bottom sediments the10be 9be ratio in trap samples varies from 3 to 20 10 8 the variation may partly result from varied proportion of authigenic detrital material the fluxes of both isotopes exhibit a very strong seasonality the fluxes of10be into the traps at about 1500 m are estimated as 9 105 and 4 105 atoms cm 2 a 1 at sites h and m respectively these values are to be compared with the fluxes into the sediments of 4 5 105 atoms cm 2 a 1 at both locations good correlations exist between10be 9be and27al indicating that the primary carrier phase s for the beryllium isotopes in the water column may be aluminosilicates

tektites and climate only four tektite strewn fields have been produced during the past 40 m y even though at least 60 impact craters have been produced during the same period in continental lithologies having tektite like compositions the apparent reason for this discrepancy is that the ejecta from most crater forming impacts was not completely melted laboratory and modeling studies show that projectiles as different as anorthosite and metal densities from 2 8 to 8 g cm 3 produce similar amounts of melt and this conclusion probably holds for comet like densities near 1 5 g cm 3 our interpretation of the limited evidence indicates that the influence of projectile trajectory and velocity on melting efficiency is minor the key factor affecting melt production seems to be the nature of the target particularly its porosity the fraction of projectile kinetic energy converted to heat may be an order of magnitude higher in a highly porous target than in a void free target the grain size and water content of the target are also important the ideal target is a porous fine grained sediment such as loess particularly if it is also dry we suggest that the rate of impact production of fully molten crater ejecta is proportional to the fraction of the continental surface having thick 10 m blankets of dry loess and that tektites are mainly produced during cold dry climate periods when such deposits are an order of magnitude more common than at present this model is best tested at the australasian site since detailed climate records cannot be obtained for the czechoslovakian and north american sites and have not yet been obtained for the ivory coast site the fossil o isotopic records in cores containing the australasian microtektites show that these were deposited during a period of cold climate near glacial stage 20 2 the chemical homogeneity and the high 10be contents of australasian tektites are well explained by melting a loess target

10be accumulation in a soil chronosequence we have measured the concentration of the cosmogenic isotope10be in soil samples from various horizons at six sites including three independently dated rappahannock river terraces and a previously undated piedmont soil to which we have assigned an age all of the incident10be can be accounted for in one of these soils and a second is within a factor of two in three soils whose concentrations vary widely with depth a significant fraction of the incident10be cannot be accounted for incomplete sampling and enhanced be mobility caused by organic components are the probable reasons for the low inventory of be from these three soils overall the data from these six sites indicate that10be accumulation could be used to assign ages to soils if be is not mobilized and lost from the soil profile

10be and 9be in marine sediments and their potential for dating using sequential leaching experiments we have measured the fraction of the cosmogenic isotope 10be half life 1 5 my and its stable isotope 9be co extracted with the following phases in marine sediments exchangeable calcium carbonate fe and mn oxyhydroxides organic opal and detrital the extraction of the authigenic phases typically release 70 of the 10be but only 40 of the 9be in order to test its potential for dating marine sediments we have measured the authigeniccally associated 10be 9be in 17 surface sediment samples from different ocean basins the observed spatial variability which appears to be influenced by proximity to continental input of 9be precludes the general and precise applications of leached 10be 9be for dating however the relatively constant value observed in surface sediments over large areas of the pacific indian and southern atlantic oceans shows considerable promise for approximate dating of open oceans sediments in order to test temporal variability a profile of the authigenically associated 10be 9be ratio has been measured in the independently dated central pacific core rc12 65 the observed variation in 10be 9be over the past nine my is approximately twice that expected on the basis of 10be decay alone several possible explanations for such behavior and their potential consequences for the use of leached 10be 9be for dating are discussed

volcanic and solar activity and atmospheric circulation influences on cosmogenic 10be fallout at vostok and concordia antarctica over the last 60years abstract the cosmogenic nuclide beryllium 10 10be recovered from ice cores is often used to study solar activity on long timescales however the 10be signal is also influenced by factors other than the sun to identify and quantify various contributions to the 10be signal two antarctic snow records from the vostok and concordia sites spanning the last 60 years were studied at a sub annual resolution three factors that contribute to the 10be signal were identified first a significant period of approximately 11 yr that can be associated with the modulation of 10be production by solar activity was detected in both records the solar imprint constitutes 20 35 of the variance within the total signal the 11 yr 10be snow component was attenuated by a factor of 0 5 and was delayed by 1 4 yr compared to the 10be production expected within the polar atmosphere the result could be interpreted as the composite response of a stratospheric 10be reservoir with an 11 yr modulation that was attenuated and delayed with respect to 10be polar production and to a tropospheric 10be reservoir with an 11 yr modulation that was not attenuated or delayed then peaks in 10be concentrations that were 66 and 35 higher than the average concentration were observed during the stratospheric volcanic eruptions of agung in 1963 and pinatubo in 1991 respectively in light of these new results published 10be ice core records could be reinterpreted because spikes in 10be concentration appear at the time of several stratospheric events the data indicate that stratospheric volcanic eruptions can impact 10be transport and deposition as a result of the roles played by the sedimentation of sulfate aerosols and the formation and rapid settling of polar stratospheric clouds psc also an interannual variability of 4 yr was determined in both 10be records corresponding to 26 of the variance within the signal at vostok as with species of marine origin sodium this 4 yr variability is interpreted as a tropospheric modulation the 4 yr variability could be associated with atmospheric circulation associated with the coupled southern ocean ocean atmosphere system the results presented here from sites within the high antarctic plateau open new possibilities for ice core dating over the last few centuries and for the reconstruction of past solar activity in relation to climate

beryllium 10 in australasian tektites evidence for a sedimentary precursor each of seven australasian tektites contains about 1 x 10 sup 8 atoms of beryllium 10 half life 1 53 x 10 sup 6 years per gram cosmic ray bombardment of the australites cannot have produced the measured amounts of beryllium 10 either at the earth s surface or in space the beryllium 10 contents of these australites are consistent with a sedimentary precursor that adsorbed from precipitation beryllium 10 produced in the atmosphere the sediments must have spent several thousand years at the earth s surface within a few million years of the tektite producing event

regolith production and transport at the susquehanna shale hills critical zone observatory part 2 insights from meteoric 10be 1 regolith mantled hillslopes are ubiquitous features of most temperate landscapes and their morphology reflects the climatically biologically and tectonically mediated interplay between regolith production and downslope transport despite intensive research few studies have quantified both of these mass fluxes in the same field site here we present an analysis of 87 meteoric 10be measurements from regolith and bedrock within the susquehanna shale hills critical zone observatory ssho in central pennsylvania meteoric 10be concentrations in bulk regolith samples n 73 decrease with regolith depth comparison of hillslope meteoric 10be inventories with analyses of rock chip samples n 14 from a 24 m bedrock core confirms that 80 of the total inventory is retained in the regolith the systematic downslope increase of meteoric 10be inventories observed at ssho is consistent with 10be accumulation in slowly creeping regolith 0 2 cm yr 1 regolith flux inferred from meteoric 10be varies linearly with topographic gradient determined from high resolution light detection and ranging based topography along the upper portions of hillslopes at ssho however regolith flux appears to depend on the product of gradient and regolith depth where regolith is thick near the base of hillslopes meteoric 10be inventories at the north and south ridgetops indicate minimum regolith residence times of 10 5 3 7 and 9 1 2 9 ky respectively similar to residence times inferred from u series isotopes in ma et al 2013 the combination of our results with u series derived regolith production rates implies that regolith production and erosion rates are similar to within a factor of two on ssho hillcrests

10be in chinese loess we report a first series of10be measurements on chinese loess covering the last 750 000 years the10be concentration shows a tendency to decrease with increasing grain size leaching experiments with acid solutions show that10be is strongly bound to particles and therefore mobility due to dissolution can be excluded the10be record in loess shows features similar to those observed in 180 records from deep sea sediments which strongly reflect climatic variations this allows one to correlate the10be loess records with 180 deep sea records and to establish a time scale based on this time scale accumulation rates of loess and10be fluxes can be calculated these reveal generally higher values for cold arid and windy periods than for warm humid and calmer intervals

10be spikes in plio pleistocene cyclothems wanganui basin new zealand identification of the local flooding surface lfs marine shelf sediments of the wanganui basin castlecliff section spanning oxygen isotope stages 21 17 ca 920 680 ka contain spikes of enriched 10be concentrations and enhanced 10be 9be ratios up to 10 background values the 10be spikes do not coincide precisely with peaks in carbonate content and grainsize or with changes in bulk rock chemical composition rather they appear in the sequence a little above the base of each cyclothem at the presumed location of the local flooding surface lfs they therefore originated in response to seafloor sediment starvation during transgression and not from ice sheet melting biogenic scavenging or geomagnetic intensity changes as has been suggested previously for 10be spikes in some deep sea or continental margin sequences

10be study of rapid erosion in taiwan cosmogenic 10be was measured using accelerator mass spectrometry in soils and sediments to study the erosion of taiwan which has the highest denudation rate in the world the river sediments in taiwan have very low 10be concentrations around 5 million atoms per gram about 145 the world wide average this is the direct consequence of its high sediment yield of more than 1000 mg cm2 yr 70 times the world average combining these values we found that for taiwan as a whole the 10be output to the sea only slightly exceeds the input from the rain a situation typical of many areas around the world therefore even in this example of extremely rapid erosion 10be seems to remain a useful indicator for erosion status the total 10be inventory found in a soil profile from a geologically stable area is at least 18 of the maximum possible inventory the minimum age thus estimated for the soil is 0 11 ma in reasonable agreement with estimates from other means the maximum erosion rate for this area thus estimated is at most 0 14 mg cm2 yr four orders of magnitude slower than the average value observed for taiwan we also demonstrate that the shelf sediments around taiwan have received the admixing of a 10be rich component from the ocean and would give a poor estimate for material eroded from taiwan

10be contents of mono lake sediments search for enhancement during a geomagnetic excursion summary we report the 10be and be contents of 22 sediment samples of lacustrine silt from the wilson creek section of mono lake california the section spans about 20 35 kyr bp and contains a record of a geomagnetic excursion for which the relative palaeointensity is estimated from the ratio of natural remanent magnetization to anhysteretic remanent magnetization the 10be contents of the excursion samples are somewhat higher than the average of non excursion samples 0 24 0 02 versus 0 15 0 02 dpm kg 1 it is clear however that geomagnetic effects are not the sole cause of the observed variations

porosity depth saturation pds model quantification of porosity preservation with burial in carbonate oil reservoirs and application to infer oil charging time abstract oil saturated carbonate reservoirs typically display anomalously high porosities compared to their water filled counterparts and this has been largely documented in the literature nevertheless no porosity model has been proposed yet to quantify the evolution of porosity preservation by oil under burial this paper presents a porosity depth saturation model pds model for carbonate reservoirs that quantifies for the first time the evolution of porosity with depth and oil saturation for a given charging time the pds model formulation decouples compaction from porosity preservation the mechanical and chemical compaction is defined phenomenologically from the schmoker and halley 1982 compaction trend but applied to the water domain only the computation of the porosity preservation is based on 2 new concepts the porosity preservation potential that is solely a function of time of charge and the porosity preservation factor that is a function of fluid saturation the work focuses on a large and laterally homogeneous carbonate reservoir the relations between porosity oil saturation and depth are extracted from the associated reservoir geomodel and analyzed to define the porosity preservation factor the pds model is tested on a specific reservoir facies and provides the porosity evolution with depth and saturation at any time of charge it indicates that even at a low water saturation such as irreducible water condition of an oil reservoir a reduced amount of water still suffice to reduce somewhat the porosity with burial from the current reservoir condition it is shown that the pds model solely based on porosity depth and residual water saturation can back calculate the time of charge of a reservoir not only the pds model proposes an initial time of charge in line with the findings of an independent study but it can also provide relative and quantified charging time for the various zones within the reservoir offering a level of granularity never achieved before

10be and th isotopes in manganese nodules and adjacent sediments nodule growth histories and nuclide behavior abstract the concentration profiles of 9 be 10 be 230 th 232 th 231 pa via 227 th and 238 u have been measured in three manganese nodules one each from the north pacific a47 16 4 the south pacific tf 5 and the indian ocean r v vitiaz in addition the 10 be concentration in deep water from the geosecs reoccupation station 500 of the north pacific and in cores raised from the manganese nodule field in the north pacific have been measured the 10 be concentration in nodule and seawater samples was measured by the accelerator masss spectrometric technique employing the yale tandem van de graaff accelerator the concentrations of 10 be 230 th exc and 231 pa exc and ratios of 10 be 9 be and 230 th exc 232 th all decrease with depth in the nodules this decrease interpreted in terms of nodule growth yields average growth rates of a few millimeters per million years for the nodules the growth rates of the nodules exhibit temporal variations both on short time 50 000 years and long time several million years scales of the three nodules studied only in tf 5 is the short term average growth rate based on 230 th exc in the top 0 0 5 mm the same as the long term average rate based on be isotope data for the 0 5 17 mm interval for the other two nodules the recent average growth rates based on 230 th exc data differ significantly from the long term average growth rates based on be isotopes in a47 16 4 the 10 be based rate is less than the 230 th exc rate and in r v vitiaz the 10 be based rate is greater than the 230 th exc rate this observation coupled with measurable changes in growth rates even during the past few hundred thousand years suggests but does not prove that the discordant growth rates deduced from 230 th exc and 10 be profiles document changes in nodule growth rate with time rather than mixing effects on 230 th exc profiles the 10 be concentration in the geosecs north pacific deep water is 6100 1200 atoms g this value coupled with the average surface 10 be 9 be ratio of north pacific nodules predicts a 9 be concentration within the limits of measured values the inventory of 10 be and 230 th exc in the nodules is only 10 of the total the remaining being in sediments the 10 be concentrations in the upper portions of two adjacent cores studied are nearly the same but the deposition fluxes of both 10 be and 230 th based on 230 th dating vary by a factor of two this difference is attributable to local redistribution of sediment at the time of deposition prior to accumulation

26al 10be and u th isotopes in blake outer ridge sediments implications for past changes in boundary scavenging we have investigated the distributions of 26 al 10 be u th isotopes and stable 27 al and 9 be in core ch88 11p 30 40pn 74 41pw 3337 m from the blake outer ridge bor in the western north atlantic an area that is characterized by high terrigenous input results show authigenic 26 al 27 al of 6 2 8u10 314 atom atom authigenic 10 be 9 be of 0 5 2 6u10 38 atom atom 6 0 2 1 8u10 6 atoms g of 26 al and 5 3 15 1u10 8 atoms g of 10 be in the core over the last glacial interglacial cycle these values as well as total 230 thex 232 th and 10 be 9 be ratios were all at their minima during the last glacial maximum lgm reflecting intensified terrestrial influx to the area aluminosilicate material clays in this influx preferentially scavenged 230 th over the two other particle reactive nuclides 26 al and 10 be such that their boundary scavenging during lgm followed the order 230 ths 10 bes 26 al as opposed to 10 bev 230 ths 26 al in the holocene they appear at variance with the order 10 bes 26 alw 230 th as would be predicted from the relative particle reactivities of the three species these scavenging characteristics point to 10 be 26 al as a potentially more suitable proxy for paleoproductivity than 10 be 230 thex mass balance considerations for 26 al and 10 be show a five fold lgm to holocene increase in deep water circulation in the study area with little change in ocean productivity except during the deglaciation when it increased noticeably fl 2001 elsevier science b v all rights reserved

stratigraphy of the kazusa group boso peninsula an expanded and highly resolved marine sedimentary record from the lower and middle pleistocene of central japan major climatic reorganizations including changes in the nature of glacial interglacial cycles through the pleistocene are a key issue for improving the understanding of earth s climate system highly resolved marine sedimentary records are essential to reconstruct the details of these past climatic changes and investigate the mechanisms responsible for them the kazusa group located in the central part of the japanese island chain is well exposed and contains a remarkably continuous and thick deep and shallow water marine sedimentary succession this group also contains well preserved marine microfossils pollen paleomagnetic reversal events geochemical signatures and a large number of tephra beds these features allow us to establish a robust chronological and stratigraphic framework for the kazusa group and provide a rare opportunity to study oceanic and terrestrial climatic and environmental changes at high resolution especially through the lower and lower middle pleistocene in the boso peninsula chiba prefecture the kazusa group is deeply incised yielding spectacular river cut exposures the matuyama brunhes paleomagnetic reversal is observed immediately above the widespread byakubi e byk e tephra in the chiba composite section within the kokumoto formation kazusa group because the matuyama brunhes boundary customarily serves as the primary guide for the lower middle pleistocene subseries boundary the chiba composite section is considered an excellent candidate for its global boundary stratotype section and point gssp this study reviews the published data for the kazusa group hitherto almost exclusively in japanese in order to place the chiba composite section within its broader depositional and chronostratigraphic context

erosion of the eastern united states observed with 10be the problem of identifying areas of accelerated erosion in a dynamic landscape is complicated the limited history of sediment yield measurements makes this task difficult even if geomorphic evidence is available beryllium 10 a cosmogenic isotope produced by cosmic rays interacting with the earth s atmosphere and surface has chemical and physical properties that make it useful as a tracer for erosion and sediment transport processes the rarity of the stable isotope 9be allows 10be to be detected with accelerator mass spectrometry in natural materials at extremely low levels backgrounds for rocks and sediments below 105 atom per g are now attainable a value to be compared with an average deposition rate of 1 3 106 atom cm 2 yr 1 the affinity of be for the components of soil and sediment is sufficiently high that it is effectively immobilized on contact thereby allowing 10be to function as a tracer of sediment transport to a good approximation all the 10be transport out of a drainage basin is on the sediment leaving it the number of 10be atoms passing the gauging station can be determined by measuring the concentration of the isotope in the sediment if the annual sediment load is known the ratio of the 10be carried from the basin by the sediment to that incident upon it called the erosion index has been determined for 48 drainage basins within the same physiographic province which allows them to be reasonably compared all of which have sediment yield data basins located in the atlantic coastal plain have an average index of 0 3 with the maximum observed being 0 9 basins located between the fall line and the mountains a region called the piedmont have an average value of 2 2 with individual values ranging from 0 6 to 6 7 this marked difference is thought to result from two centuries of farming on land of moderate gradient basins in the highland regions reflect local conditions with low indices for those in grass and timber and high indices associated with destructive land use the data allow an estimate of the erosion index for the pre colonial piedmont which then allows the pre colonial sediment yield to be calculated a number of basins have also been examined world wide with similar conclusions derived an important deviation from the rule is noted for rivers that erode large regions of loess such as the mississippi hwang ho and yangtze large aeolian deposits were laid down during the ice age in these basins deposits that brought inherited 10be with them and that are easily eroded

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

revised tuning of ocean drilling program site 964 and kc01b mediterranean and implications for the δ18o tephra calcareous nannofossil and geomagnetic reversal chronologies of the past 1 1 myr 1 high resolution color reflectance records of kc01 and kc01b calabrian ridge ionian sea are presented and compared with a modified spliced high resolution color reflectance record of ocean drilling program odp site 964 this comparison revealed that kc01b is characterized by intensive deformation between 27 and 28 5 m piston depth and that some sapropels are tectonically reduced in thickness moreover the piston coring has caused considerable stretching in the top of kc01 and kc01b using a new splice of odp site 964 as guide previous astronomical tuned timescales of kc01b and odp site 964 were evaluated this evaluation resulted in a new sapropel based astronomical timescale for the last 1 1 myr the new timescale implies a much more uniform change in sedimentation rate for the ionian sea cores two prominent excursions to lighter values in the 18o record of the planktonic foraminiferal species globigerinoides ruber occur during marine isotopic stages 12 and 16 applying the new timescale these shifts correspond with maxima in obliquity and are punctuated by minima in the precession cycle they are absent in global ice volume records and are interpreted as reflecting a summer low salinity surface water lens that floats on top of extremely saline intermediate and deep waters at times of the very low sea levels during these glacial periods all biostratigraphic and magnetostratigraphic events found in kc01b and odp site 964 were re dated according to the new timescale and the ages of 33 tephra layers were reviewed the new ages for the calabrian ridge 2 and 3 magnetic events in the brunhes are concordant with minima in the global sint800 composite record derived from worldwide deep sea records of relative paleointensity and have been attributed to the big lost and la palma excursions respectively

a mediterranean perspective on 10be sedimentation and climate around the matuyama brunhes boundary les liaisons dangereuses abstract the 10be 9be ratio is commonly employed as a tool for establishing the stratigraphic position of paleomagnetic excursions and reversals whenever the traditional paleomagnetic approach fails to provide conclusive results in particular it is held that 10be production rates in the atmosphere depend on the strength of the earth s magnetic field and the fallout and deposition of cosmogenic beryllium at the surface happen on a very short time scale however investigations performed on terrestrial and marine successions demonstrate that the 10be record and the paleomagnetic signal are often asynchronous mechanisms that control the conveyance and deposition of cosmogenic 10be to the seafloor are still ambiguous and poorly documented here we discuss the dynamics of 10be in a central mediterranean marginal marine depositional scenario characterized by a pervasive terrigenous influx our data show that a very close correlation exists between 10be concentrations and the local proxy of rainfall rates and regimes pollen indicating that a considerable 10be transport from the mainland may occur in response to the remobilization of terrestrial reservoirs during periods of increased runoff superimposed is a dynamic oceanographic setting that further controls the preservation potential of 10be at the bottom in terms of changing water chemistry and or composition of the sedimentary flux to the seafloor results of our investigation suggest that in particular environmental and depositional settings the interplay between climate terrigenous yield and oceanography may jeopardize the sedimentary depiction of the meteoric 10be contribution thus challenging the use of 10be for tracking the stratigraphic position of geomagnetic reversals

stable isotope tracers natural and anthropogenic recharge orange county california abstract stable isotopic techniques have been utilized to locate occurrences and trace movements of a variety of naturally and anthropogenically recharged waters in aquifers of orange county california this basin is of particular interest not only because it provides the dominant water supply for the two million residents of this well populated county but also because it is representative of a common arid environment where natural recharge is dominated by distant high elevation precipitation transported by a major river such arid basins are particularly sensitive to climatic and anthropogenic disturbance of their recharge and their subsurface hydrology in order to identify distinctive waters oxygen and hydrogen stable isotope ratios from orange county wells have been compared with a regional database including an array of surface water samples representative of watershed runoff four distinctive subsurface water types can be resolved waters of local rainfall and imported colorado river aqueduct origins are easily distinguished from dominant native santa ana river compositions by use of hydrogen and oxygen stable isotope analysis recent human interference with santa ana river flow and recharge is also marginally resolvable by isotopic techniques distinguishable isotopic signatures of recent santa ana recharge appear to be due to evaporative loss perhaps during storage in the prado reservoir or in percolation ponds prior to recharge into orange county aquifers characterization of traceable isotopic signatures of distinct natural and anthropogenic recharge components provides a major advance towards use of such techniques for developing a well constrained three dimensional hydrologic model for this complex basin

last glacial to post glacial 10be fluctuations in a sediment core from the academician ridge lake baikal 10be concentrations sediment composition and sediment accumulation rates were determined in a sediment core from the academician ridge of lake baikal the 10be concentrations vary from 5 07 108 atoms g in the last glacial section to 11 25 108 atoms g in the section representing the post glacial climate stage 10be fluxes on the other hand increase toward the last glacial stage coinciding with an increase of the sediment accumulation rate these facts imply that climate related sedimentation is related to both flux and concentration of the nuclide in the sediment core during the last glacial stage arid conditions in the lake s watershed caused a marked increase in flux of clay particles with low 10be content to the lake resulting in an increased flux but lowered concentration of 10be in the sediments it is suggested that the 10be record of the bottom sediments of lake baikal can be used as a proxy indicator of climate change in central asia

characteristics of soil water movement in a grass slope in a karst peak cluster region china soil water is very important in hilly areas with thin soil layers and deep groundwater tables such as the karst peak cluster region of southwest china an investigation into soil water movement can provide insights into management of shallow water resources and soil nutrients as well as prevention of groundwater pollution in this study o 18 and h 2 tracers were used to trace soil water movement in planar soil mass type microhabitats in the middle part of a steep hillslope covered by grasses in a karst peak cluster region of china from may 2008 to july 2009 samples of precipitation and two types of soil water which had different integrated degrees of mobility and were of different depth intervals or depths were collected the hydrogeochemical characteristics were compared between precipitation and soil water and these data were applied in convolution based lumped parameter models our results indicated that vertical piston flow rather than lateral flow along the soil bedrock interface played an important role in soil water percolation at least in the upper soil layer approximately 7cm over the permeable bedrock the mixing effect and preferential flow might also play a role in soil water percolation in general the evaporation effect on soil water was weak except for the uppermost 10cm soil matrix water during winter the lower limits of mean transit time of soil matrix flow passing through 5 15 25 35 and 41 5cm depths were 4 81 7 70 16 19 21 85 and 27 44days respectively our study demonstrated the crucial functions of the soil reservoir in regulating the water cycle and could provide guidance on conservation of soil water and hydrological studies the applied method was proved to be a suitable approach for investigating soil water movement on a monthly scale

mobilization of beryllium in the sedimentary column at convergent margins studies of be distributions in subduction zone sediments will help to understand questions regarding the enrichments of cosmogenic be 10 in arc volcanic rocks analyses of be 10 and be 9 in sediments of ocean drilling program site 808 nankai trough and be 9 in porewaters of site 808 and sites 671 and 672 barbados ridge complex show significant decreases in solid phase be 10 and large increases of porewater be 9 at the location of the decollement zone and below or at potential flow conduits these data imply the potential mobilization of be during pore fluid expulsion upon sediment burial experiments involving reaction between a decollement sediment and a synthetic nacl cacl2 solution at elevated pressure and temperatures were conducted in an attempt to mimic early subduction zone processes the results demonstrate that be is mobilized under elevated pressure and temperature with a strong ph dependence the be mobilization provides an explanation of be 10 enrichment in arc volcanic rocks and supports the argument of the importance of the fluid processes in subduction zones at convergent margins