coherence between solar activity and the east asian winter monsoon variability in the past 8000 years from yangtze river derived mud in the east china sea ams 14 c dating and grain size analysis for core pc 6 located in the middle of a mud area on the inner shelf of the east china sea ecs were used to rebuild the holocene history of the east asian winter monsoon eawm the 7 5 m core recorded the history of environmental changes during the postglacial transgression the core s mud section the upper 450 cm has been formed mainly by suspended sediment delivered from the yangtze river mouth by the ecs winter coastal current ecswcc since 7 6 kyr bp using a mathematical method called grain size vs standard deviatiow we can divide the core pc 6 s grain size distribution into two populations at about 28 mu m the fine population 28 mu m is considered to be transported by the ecswcc as suspended loads content of the fine population changes little and represents a stable sedimentary environment in accord with the present situation thus variation of mean grain size from the fine population would reflect the strength of ecswcc which is mainly controlled by the east asian winter monsoon abrupt increasing mean grain size in the mud section is inferred to be transported by sudden strengthened ecswcc which was caused by the strengthened eawm thus the high resolution mean grain size variation might serve as a proxy for reconstruction of the eawm a good correlation between sunspot change and the mean grain size of suspended fine population suggests that one of the primary controls on centennial to decadal scale changes of the eawm in the past 8 ka is the variations of sun irradiance i e the eawm will increase in intensity when the number of sunspots decreases spectral analyses of the mean grain size time series of core pc 6 show statistically significant periodicities centering on 2463 1368 128 106 100 88 91 7678 and 70 72 years the eawm and the east asian summer monsoon easm agree with each other well on these cycles and the east asian monsoon eam and the indian monsoon also share in concurrent cycles in holocene which are in accord with the changes of the sun irradiance c 2005 elsevier b v all rights reserved

geochemical and boron strontium and oxygen isotopic constraints on the origin of the salinity in groundwater from the mediterranean coast of israel in order to identify the origin of the salinity and formation of saline plumes in the central part of the mediterranean coastal aquifer of israel we determined the elemental and boron strontium and oxygen isotopic compositions of fresh and brackish groundwater cl up to 1500 mg l we distinguish between two key anthropogenic sources 1 sewage effluents used for irrigation with high na cl so4 cl and b c1 ratios and low br cl ratios relative to seawater ratios low 11b values 0 10 and high 18o values 4 and 2 imported water from the sea of galilee that is artificially recharged to the aquifer with high br cl 3 10 3 and 18o values 1 and a low 87sr 86sr ratio of 0 70753 the brackish groundwater from the saline plumes have relatively low na cl ratios 0 5 0 8 and high ca mg mg cl and ca so4 hco3 1 ratios relative to seawater ratios marine so4 cl and br cl ratios 11b values of 24 8 49 9 18o of 2 95 to 4 73 and 87sr 86sr ratios of 0 708275 0 708532 the composition of most of the investigated groundwater from the saline plumes differs from those of the anthropogenic sources imported water fresh uncontaminated groundwater 87sr 86sr of 0 70866 11b of 20 30 and saline water from the adjacent eocene aquitard only in areas of artificial recharge does local groundwater have high br cl and 18o values that are typical to the sea of galilee the linear relationships between chloride and most of the ions including b and sr the relatively high 11b 30 and low 18 o 4 values and the chemical signature of the saline plumes e g marine br cl and so4 cl ratios suggest that 1 mixing processes control the chemical composition of the brackish water within the aquifer and 2 the saline postulated end member has a chemical composition that resembles modified seawater with a marine and higher 11b values and a 87sr 86sr ratio of 0 7083 we propose that most of the salinization phenomena and the formation of saline plumes in the inner parts of the coastal aquifer are derived from upconing of underlying natural saline water bodies and enhanced by overexploitation and draw down of the overlying fresh groundwater

boron occurrence in halite and boron isotope geochemistry of halite in the qarhan salt lake western china abstract previous studies have investigated boron b isotope composition of salt lake brines in the qaidam basin western china however the research on b isotope geochemistry of halite from a sediment core in a typical sedimentary basin has been very limited in this study a 102 m long drill core isl1a was recovered from qarhan salt lake in eastern qaidam basin forty three halite samples from upper 44 0 m in isl1a were collected and analyzed for chemical compositions k na ca 2 mg 2 cl so 4 2 sr 2 and b 3 and b isotopes in order to investigate their relationships and b isotope fractionation between halite and brines in the qarhan salt lake the results show that 1 more b 3 and mg 2 values in halite are low concentrations and more concentrated and low b 3 concentrations have a strong correlation with low mg 2 in halite which imply that they might be the same source 2 low mg 2 values in halite from isl1a have a similar trend with m mg 2 molarity of fluid inclusion brines from two sediment cores east to isl1a about 50 km in the study area suggesting that low b 3 and mg 2 concentrations should derive from fluid inclusions in halite based on x ray diffraction results in isl1a that no borate and small amount of magnesium salts were deposited 3 11 b values of halite in isl1a range from 0 35 to 5 84 which are in the range of those of river water and brines 1 0 to 9 6 and almost overlapped with those of brines 2 9 to 7 5 in the qarhan salt lake these results suggest that no or minor b isotope fractionation between halite and brine occurred

a multi isotope b sr o h and c and age dating 3h 3he and 14c study of groundwater from salinas valley california hydrochemistry dynamics and contamination processes 1 the chemical and isotope 11b 10b 87sr 86sr 18o 16o 2h h 13c 12c 14c and 3he 3h compositions of groundwater from the upper aquifer system of the salinas valley in coastal central california were investigated in order to delineate the origin and processes of groundwater contamination in this complex system the salinas valley has a relatively deep confined 400 foot aquifer overlain by a 180 foot aquifer and a shallower perched aquifer all made up of alluvial sand gravel and clay deposits groundwater from the aquifers have different 14c ages fossil 14c 21 3 percent modern carbon pmc for the 400 foot aquifer and modern 14c 72 2 98 2 pmc for the 180 foot aquifer fresh groundwater in all aquifers is recharged naturally and artificially through the salinas river the two modes of recharge can be distinguished chemically we identified several different saline components with distinguishable chemical and isotopic fingerprints 1 saltwater intrusion in the northern basin has c1 concentrations up to 1700 mg l a na cl ratio less than seawater a marine br cl ratio a ca cl ratio greater than seawater 11b between 17 and 38 and 87sr 86sr between 0 7088 and 0 7096 excess dissolved ca relative to the expected concentration for simple dilution of seawater correlates with 87sr 86sr ratios suggesting base exchange reaction with clay materials 2 agriculture return flow is high in no3 and so4 with a 87sr 86sr 0 7082 11b 19 and 13c between 23 and 17 the 3h 3he ages 5 17 years and 14c data suggest vertical infiltration rates of irrigation water of 3 10 m yr 3 nonmarine saline water in the southern part of the valley has high total dissolved solids up to 3800 mg l high so4 na cl ratio 1 11b between 24 and 30 and 87sr 86sr 0 70852 this groundwater may have acquired its geochemical signature from leaching of sedimentary rocks associated with the coast range marine deposits of mesozoic to early cenozoic age the combination of different geochemical and isotopic fingerprints enables us to delineate the impact of salt sources in different areas of the valley and to reconstruct the origin of the so4 enriched no3 depleted saline plume that is located west of the city of salinas we suggest that the latter is derived from a mixture of different natural saline waters rather than from anthropogenic contamination

light element distributions n b li in baltic basin bentonites record organic sources abstract distributions of nitrogen boron and lithium were studied in illite smectite from ordovician silurian k bentonites in the baltic basin these trace elements are linked to thermal maturation of organic matter creating fluid signatures that are distinct from those in regionally buried sediments the fluid chemistry is ideally recorded in authigenic illite within the k bentonite because b substitutes in tetrahedral sites of illite li in octahedral sites and n is fixed in the interlayers as nh 4 three nanometric size fractions of illite 10 among these size fractions relate mainly to changes in fluid composition during illite growth bentonite volcanic ash layers mark stratigraphic timelines while illitization of the bentonite k bentonite varies as a function of burial and tectonic temperature gradients in the central baltic basin bentonites were deposited across a carbonate platform near estonia grading to deep basin shales near denmark and poland compositional variations in illite reflect fluids from different sources high n illite 2000 ppm in the southwest basin transitions to high b 250 ppm and high li 100 ppm illite to the northeast these trends follow a thermal gradient decreasing from southwest 200 c to northeast 90 c isotope ratios of b and li show opposing trends in samples across this thermal gradient the bisotopes decrease from southwest to northeast 18 to 4 while li isotopes increase from 5 to 32 the cambrian alum shale a regional hydrocarbon source rock was studied as a potential source of b and li as more than 50 of its b and li was associated with organic matter with increasing thermal maturity illite 11b decreased from 0 to 13 while 7li increased from 20 to 5 these opposing trends are similar to those observed in the k bentonites this suggests that organic sources of n b and li dominate fluids in bentonites from the southwestern baltic basin whereas basement derived fluids dominate in the northeastern baltic basin these trace elements record paleofluid changes during illite crystal growth and can identify pathways of chemically distinct oil and gas related fluids

late holocene 2 ka east asian monsoon variations inferred from river discharge and climate interrelationships in the pearl river estuary a sediment core from the pearl river estuary pre was analyzed for grain size and organic geochemistry parameters toc and delta c 13 org the results showed that high mean grain size value and increased sand content were correlated with the high toc and negative delta c 13 org these results indicated high river runoff in the pre area peak river discharge occurred during the periods 1900 1750 1500 1600 1400 1200 1000 900 and 750 600 cal yr bp the main changes recorded in grain size distributions toc contents and delta c 13 org variations appear to be directly related to monsoon precipitation in the sediment source area an increased east asian summer monsoon rainfall easm and or an enhanced east asian winter monsoon rainfall could result in the increasing of monsoon rainfall typhoon related rainfalls could act as positive influence on precipitation levels the study of the correlations between the rainfall records and enso activities revealed a close relationship between the monsoon rainfall in the pre and the tropical pacific variations the frequent occurrence of enso might result in the southern migration of the easm rain belt and lead to more typhoon derived rainfall in the prd during the late holocene c 2013 university of washington published by elsevier inc all rights reserved

the pacific decadal oscillation and changes in anchovy populations in the northwest pacific the pacific decadal oscillation pdo has been identified as an important driver for fluctuation of fish populations on the eastern pacific ocean however the relationship between changes in fish population and climate oscillations on a decadal time scale in the northwest pacific is still unclear due to the lack of reliable long term time series data in the present study a time series of engraulis japonicus japanese anchovy populations was reconstructed using the density of sedimentary fish scales in the yellow sea basin e japonicus populations and the pdo index showed similar patterns on a decadal time scale our results confirm that climate is a major driver of ecological changes on a decadal time scale and indicate that suitable sea water temperature might be the main forcing of anchovy migration this work also demonstrates the potential of predicting changes in fish population based on climate records

boron isotopic geochemistry of the mcmurdo dry valley lakes antarctica abstract the geochemistry of boron was investigated in the ice covered lakes and glacier meltwater streams within taylor and wright valley of the mcmurdo dry valleys mcm antarctica in order to achieve a greater understanding of the source of boron to these aquatic systems and how in lake processes control boron concentration selected lake depths surface and bottom water and streams were analyzed for boron geochemistry boron stable isotope values in these waters span the range of 12 3 to 51 4 which corresponds to the variations from glacier meltwater streams to the hypolimnion of a highly evaporated hypersaline lake the data demonstrate that the major sources of b to the aquatic system are via terrestrial chemical weathering of aluminosilicates within the stream channels and a marine source either currently being introduced by marine derived aerosols or in the form of ancient seawater lakes fryxell hoare and upper waters of lake joyce which experience more terrestrial influence of aluminosilicate chemical weathering via glacial meltwater streams display a mixture of these two major sources while the source of b in the bottom waters of lake joyce appears to be primarily of marine origin lakes bonney and vanda and the blood falls brine have a marine like source whose 11b values have become more positive by mineral precipitation and or adsorption don juan pond displays a terrestrial aluminosilicate influence of a marine like source these hypersaline lake waters from antarctica are similar in 11b to other hypersaline lake waters globally suggesting that similar processes control their b geochemistry

holocene climate changes over the desert loess transition of north central china a 2 m trench section at the desert loess transition of north central china was analyzed at 2 cm intervals for grain size distribution md m and total organic carbon toc ams 14c time series of the md and toc records provides direct information on variations of the east asian monsoon climate during the last 10 000 yr md is considered to represent the wind strength and high md reflects strong winter monsoon winds toc denotes the degree of vegetation cover a function of the intensity of summer monsoon circulations from ca 10 000 to 7000 cal yr bp the climate was dominated by a strong winter monsoon and a very weak summer monsoon as indicated by high md and low toc values subsequently climatic conditions became warmer gradually from ca 7000 to 5500 cal yr bp the period between ca 5500 and 2700 cal yr bp displayed the highest toc and lowest md values over the last 10 000 yr marking a stable state of a warm humid climate i e the holocene climatic optimum of china during the interval of ca 2700 1500 cal yr bp the expansion and intensification of agrarian activities could have led to desertification and acceleration of deposition of coarse grained particles resulting in a decreased organic carbon accumulation rate however the toc during this interval still has values as high as during the episode of ca 7000 5500 cal yr bp reflecting a relatively stronger summer monsoon circulation since ca 1500 cal yr ago high amplitude fluctuations of toc that fluctuate in phase with the clay size fraction imply that the climate experienced three major oscillations with a prominent peak of enhanced summer monsoon circulation at ca 1300 cal yr ago and with two intervals of increased winter monsoon strength occurring around ca 1000 and 300 cal yr ago the md and toc records over the past 5000 yr demonstrate a good correlation with the archaeological phenological and historical records of china climate changes in the east asian monsoon region were not only related to the changing seasonality of solar insolation resulting from progressive changes in the earth s orbital parameters but were also controlled by the pattern and intensity of the atmospheric circulation

high resolution unsaturated alkenones sea surface temperature records in the yellow sea during the period of 3500 1300 cal yr bp abstract high resolution sea surface temperature records based on long chain unsaturated alkenones u 37 k sst in the south yellow sea ys during the period of 3500 1300 cal yr bp were reconstructed in sediment core z8 from the shandong mud wedge the sst records show broad variations between 14 3 and 16 9 c 15 6 c on the average with a high sst phase at 3500 2750 cal yr bp a low and intense fluctuating sst period at 2500 2000 cal yr bp and a sharp cooling period at 1750 1300 cal yr bp superimposed on this trend five cooling periods occurred in 3360 3250 cal yr bp 3150 3050 cal yr bp 2750 2650 cal yr bp 2350 2150 cal yr bp and 1750 1300 cal yr bp variation pattern of the sst records is similar to the fluctuations of the kuroshio current kc indicating a close relationship between the yellow sea warm current yswc and the kc the general u 37 k sst curve fluctuates with the local air temperature variations the intensity of the east asia winter monsoon eawm could be a key factor affected the prevailing relationship between the cold coastal current and the warm yswc and dominated the sst variation in core site z8 during 3500 1300 cal yr bp furthermore our temperature records within age uncertainty coincides with the changes of the solar irradiance changes suggesting a possible link between solar forcing and climate variability

late holocene high frequency east asia winter monsoon variability inferred from the environmentally sensitive grain size component in the distal shelf mud area east china sea the b2 b2g and i4 sediment cores recovered from the centre of the distal mud area of the east china sea ecs were analysed for grain size distribution proxies for environmentally sensitive grai

effects of management policies including artificial recharge on salinization in a sloping aquifer the israeli coastal aquifer case 1 overexploitation of aquifers may impair groundwater quality and cause salinization as occurs in the sloping coastal aquifer in israel the current management policy risks the future of the aquifer as the country s most important water reservoir the paper examines a variety of policies and studies their impact on the salinization of the aquifer two quantitative approaches were applied 1 a balance approach which was used to calculate the mean salinity of the aquifer water and 2 a 2 d numerical solution of the flow and transport equations in a 10 15 km cell representing a portion of the aquifer the policy alternatives include desalination of imported freshwater 180 250 ppm cl desalination of treated wastewater and injection of the desalinated water an increased pumping from the aquifer compensates for the injection of these waters the results show that desalination of imported freshwater or wastewater with no injection would reduce the salinization rate of the aquifer only slightly and that the effect would be noticeable only after a period corresponding to the retention time of the vadose zone the alternatives that involve injection of desalinated water would stop the salinization process the aquifer mean salinity would stabilize around the level that prevailed at the time of implementation of the injection policy the numerical solution confirmed the conclusions of the balance approach while including the complex effect of the high salinity boundary condition on the east and the role of thickness variations in a sloping aquifer this approach addressed the influence of the spatial densities of pumping and of injection and showed that as the density increases the numerical and balance solutions converge it is shown that the numerical simulation should be used for future planning of the injection and pumping layout finally calculations based on our results show that the alternatives involving injection of desalinated freshwater provide the lowest cost of improving the aquifer water salinity

a 2 326 year tree ring record of climate variability on the northeastern qinghai tibetan plateau 1 high resolution climate proxy records covering the last two millennia on the qinghai tibetan plateau are scarce yet essential to evaluation of the patterns synchroneity and spatial extent of past climatic changes including those in the medieval warm period mwp and the little ice age lia here we present a 2326 year tree ring chronology of sabina przewalskii kom for dulan area of northeastern qinghai tibetan plateau we find that the annual growth rings mainly reflect variations in regional spring precipitation the greatest change in spring precipitation during the last two millennia seems to occur in the second half of the 4th century the north atlantic mwp was accompanied by notable wet springs in the study region during a d 929 1031 with the peak occurring around a d 974 three intervals of dry springs occurred in the period of lia our tree ring data will facilitate intercontinental comparisons of large scale synoptic climate variability for the last two millennia

re examining the potential of using sensitive grain size of coastal muddy sediments as proxy of winter monsoon strength sensitive components of grain size in coastal muddy sediments of china have been widely used for reconstruction of the east asian winter monsoon strength however trends of the winter monsoon strength profiles reconstructed for the past 2000 years from different sediment cores tend to be inconsistent and even contradictory in the present study the grain size variation sequence of the sensitive components in a sediment core collected from the middle of the min zhe coastal mud with a time span of 2700 years is determined the striking correspondence between the reconstructed mean grain size of the sensitive component with northern hemisphere temperature in particular the medieval warm period and the little ice age showed that coastal muddy sediments of china can be used to reconstruct a high resolution profile of east asian winter monsoon strength the inconsistencies in the winter monsoon proxy sequences from different studies are most likely caused by low resolution of grain size standard deviation data and direct influence of the river input materials in some studies c 2013 elsevier ltd and inqua all rights reserved

holocene shifts in riverine fine grained sediment supply to the east china sea distal mud in response to climate change holocene changes in fine grained sediment supplies to the east china sea outer shelf were uncovered through the mineralogical and geochemical analysis of core b3 in the east china sea distal mud ecsdm based on the lithology accelerator mass spectrometry ams 14c dating and sea level change core b3 can be divided into two major units transgressive stage unit 1 12 5 6 8 kyr and highstand stage unit 2 6 8 0 kyr significant discrepancy of dolomite calcite ratio in the fine fractions 16 m of changjiang dolomite calcite 3 1 and huanghe dolomite calcite 1 22 sediments was used as a new uniqueness provenance tracer to distinguish these two riverine sources both of the dolomite calcite ratio and rare earth elements fractionation parameters in the fine grained sediment indicated distinct provenance shifts of core b3 during the holocene unit 1 of core 3 12 5 6 8 kyr mainly consists of the reworked and resuspension sediments of the east china sea shelf during the holocene transgression while unit 2 sediments 6 8 0 kyr are most likely sourced from the changjiang and huanghe moreover mixing curves of dolomite calcite ratio reveal that the ecsdm continuously received the changjiang sediment since 6 1 kyr with notable fluctuations whereas the huanghe sediment supply began in 6 8 kyr but abruptly stopped during 4 2 0 8 kyr and then appeared again since 0 8 kyr temporal changes of the changjiang and huanghe fine grained sediment contribution to the ecsdm are closely related to the formation of modern oceanic circulation system since 6 8 kyr shelf sea level change the 4 2 kyr climate event and the followed transition to cold and dry climate condition in the northeastern china global climate change as well as the artificial shift of lower huanghe course in ad 1128 in the war against invasion of the northern nomadic nation human activities

el nino southern oscillation variability recorded in estuarine sediments of the changjiang river china abstract el nino southern oscillation enso has a strong influence on the climate of the changjiang river basin china most notably upon extreme events such as flooding and drought however long term historical records which reveal the impacts of enso variability on climatic and environmental changes in this region are scarce a sediment core g9 was collected from the estuarine delta of the changjiang river and its elemental ratios mineral compositions and grain size distribution were analyzed to investigate the links between sediment parameters in this region and the history of enso variability during the last century observed variations in k 2 o na 2 o al 2 o 3 sio 2 and rb sr ratios are synchronous with changes in mineral compositions and grain size throughout the sediment core lower k 2 o na 2 o al 2 o 3 sio 2 and rb sr ratios generally correspond to lower ratios of clay minerals to rock forming minerals and larger grain sizes which in turn correspond to periods of flooding in the changjiang river basin such trends probably reflect increased physical erosion and the transport of greater amounts of coarse grained suspended matter to the estuary these geochemical proxies are also positively correlated with sea surface temperature anomalies in the nino 3 4 region 120 w 170 w 5 s 5 n using a low pass filter with a cut off of 13 years we therefore conclude that 1 enso related flood events in the changjiang river basin have a strong influence on physical erosion processes in the upper catchment area and thereby influence the grain size distribution elemental ratios and mineral compositions of the estuarine sediments and 2 the geochemical records presented here can serve as a proxy for enso driven regional weathering variations on decadal to centennial time scales because they could potentially be recorded in longer sediment cores recovered from the changjiang river estuary

isotopic and trace element constraints on the origin and evolution of saline groundwaters from central missouri na ca cl groundwaters with salinities of 1 to 30 discharge from natural springs and artesian wells in mississippian carbonates and ordovician sandstones and carbonates in central missouri carbonate saturation and quartz supersaturation are maintained throughout the salinity range major and trace element and isotopic variations in the waters are used to place constraints on models for rock water interaction and regional hydrology the groundwaters have d values that range from 108 to 45 and 18 o values that range from 14 7 to 6 5 smow these data lie approximately along the meteoric water line ranging from values similar to local recharge in missouri to significantly lower values that are similar to 18 o and d for meteoric recharge in high altitude and high latitude regions of north america the more saline samples have the lowest 18 o and d contents a trend that is opposite to that observed in most other studies of saline waters the h o isotopic correlation and the range in salinity and several major and trace element concentrations in central missouri groundwaters are readily explained by a saline dilute water mixing model 87sr 86sr ratios for the groundwaters range from 0 7155 to 0 7161 these values are significantly higher than previously published values for 1 estimates of 87 sr 86 sr in phanerozoic seawater 0 7068 0 7092 and 2 carbonates of the mississippian burlington keokuk fm 0 7075 0 7105 through which some of the waters migrate as they pass to the surface nd 0 values in the groundwaters range from 10 9 to 8 1 and 147 sm 144 nd ratios range from 0 108 to 0 128 these values are similar to or lower than previously published analyses of carbonates and other authigenic phases from the burlington keokuk fm mean nd 0 7 8 0 8 1 mean 147 sm 144 nd 0 141 the h o sr and nd isotopic data and the results of model calculations preclude 1 models involving the modification of ancient seawater for the origin of the saline waters and 2 extensive interaction between the groundwaters and their host carbonates the waters apparently acquired their 18 o and d values as meteoric recharge and their 87sr 86sr and rare earth element signatures from extraformational crustal sources high 87 sr 86 sr low nd 0 low 147sm 144nd and largely preserved these isotopic signatures during subsequent migration through the carbonates chemical exchange via rock water interaction is required for isotopic exchange to occur therefore the present state of chemical equilibrium between the groundwaters and carbonate aquifer minerals may serve to limit rock water interaction and hence preserve the extraformational isotopic signatures in the waters the integration of geochemical isotopic and hydrologic data on a local and regional scale suggests a history for the central missouri groundwaters involving 1 meteoric recharge in the front range of colorado 2 dissolution of permian halite in the subsurface of kansas 3 interaction with predominantly silicate mineral assemblages in paleozoic strata and possibly precambrian basement with aquisition of crustal sr and ree signatures 4 dilution and migration to shallow aquifer levels in central missouri and 5 mixing with local meteoric recharge through mississippian carbonates with no significant change of the isotopic signatures acquired in stage 3

isotopic and geochemical characterization of salinization in the shallow aquifers of a reclaimed subsiding zone the southern venice lagoon coastland summary the coastal plain bordering the southern venice lagoon is a reclaimed lowland characterized by high subsidence rate and ground level and water table depth below sea level in this agricultural region where the surface hydrologic network is entirely artificially controlled by irrigation drainage canals salinization problems have long been encountered in soils and groundwaters here we use isotopic and geochemical tracers to improve our understanding of the origin of salinization and mineralization of the semi confined aquifer 0 40 m and the freshwater inputs to this hydrological system water samples have been collected at different seasons in the coastal adriatic sea lagoon rivers and irrigation canals as well as in the semi confined aquifer at depths between 12 and 35 m 14 boreholes and in the first confined aquifer three boreholes drilled between 40 and 80 m depth stable isotopes 18 o and d and conductivity profiles show that direct saline intrusion from the sea or the lagoon is observed only in a restricted coastal strip while brackish groundwaters are found over the entire topographic and piezometric depression in the centre of the study area fresh groundwaters are found only in the most western zone the sharp isotopic contrast between the western and central regions suggests disconnected hydrological circulations between these two parts of the shallow aquifer the border between these two regions also corresponds to the limits of the most strongly subsiding zone our results can be interpreted in terms of a four end member mixing scheme involving 1 marine water from the lagoon or the open sea 2 alpine and pre alpine regional recharge waters carried either by the main rivers adige bacchiglione and brenta irrigation waters or by the regional groundwater circulation 3 local precipitation and 4 evaporated waters infiltrated from the surface infiltration from the surface is also revealed by the stratification of the electrical conductivity profiles showing that the brackish groundwaters are overlain by a shallow layer of less saline water all over the central depression in the first confined aquifer the groundwaters have isotopic compositions similar to the deep groundwaters of the venetian confined aquifers 40 400 m depth the isotopic data and the br cl ratio show that the origin of the salinization of the phreatic aquifer can be ascribed to seawater intrusion alone with no indication of the involvement of deep brines identified at 450 m depth in the process the chemical composition of the saline and brackish groundwaters is characterized by an excess of sodium and a deficit of calcium compared to conservative mixing between fresh groundwaters and seawater this suggests that the phreatic aquifer is progressively freshening as a consequence of the beneficial influence of the extensive irrigation drainage network including raised canals acting as a hydraulic barrier along the coast this freshening tendency may have been lasting since the reclamation in the mid twentieth century and has probably been accelerated by the ban on groundwater abstraction since the 1970s

strontium isotope evidence on the history of oilfield brines mediterranean coastal plain israel abstract the isotopic composition of sr in oil field brines from the mediterranean coastal plain was determined in 18 drillholes 13 of which are oil producing wells the brines are characterized by salinities ranging from 35 to 93 g l tds sr from 28 to 350 mg l sr ca molar ratios from 0 011 to 0 053 and 87 sr 86 sr ratios from 0 7075 to 0 7090 e a 0 7081 0 0004 2 the brines are classified into two groups 1 a mavqi im group brines with relatively high 87 sr 86 sr ratios 0 7087 and 0 7090 sampled from elastics dolomites and anhydrites of upper miocene age 2 b heletz group brines with relatively low 87 sr 86 sr ratios 0 7075 to 0 7081 sampled from sandstones and dolomites of lower cretaceous age equations were derived to show the relations between 87 sr 86 sr ratio of the brines and the processes through which they evolved dolomitization and dissolution reprecipitation it is suggested that both groups of brines originated from mediterranean evaporated seawater during the messinian desiccation the strontium isotope composition of the seawater is reflected in that of both groups of brines the mavqi im group containing the original 87 sr 86 sr ratio 0 7088 the heletz group evolved later on through exchange reactions of those primary brines with a carbonate sequence of cretaceous age and consequently new 87 sr 86 sr ratios 0 7078 could have been developed the effect of the dissolution reprecipitation reactions on the carbonate rocks is estimated to be very slight only around 1 by weight

reconstruction of winter monsoon strength by elemental ratio of sediments in the east china sea abstract the east asian winter monsoon eawm transports cold air from the high northern latitudes to the mid and low latitudes thus investigations on its variation pattern and mechanism are essential for acquiring further knowledge on the interplay across the high and low latitudes proxies such as grain size and foraminiferal 18o in marine sediments and elemental ratios in the chinese loess have been used for the reconstruction of eawm strength however more high resolution reconstructions for eawm are required for further understanding the mechanism of climate systems and predicting climate change in this study we present a high resolution time series of the late holocene eawm strength reconstructed by element method comparisons of element concentrations elemental ratios and mean grain size mgs of environment sensitive components in a sediment core from the shelf of the east china sea indicate that k ti ratio is an appropriate proxy for the reconstruction of the eawm strength k ti ratio exhibits similar trends with proxies of sea surface temperature and eawm strength in different regions influenced by the eawm warm and cold periods such as the roman warm period medieval warm period and little ice age are identified in the reconstructed results total solar irradiance anomaly tsi and k ti ratios exhibit comparable tendencies in the last two millennia and frequency spectrum analysis exhibits similar periodicities in the time series of tsi and k ti which confirm that solar irradiance has a significant impact on the easm on centennial time scale

coral derived western pacific tropical sea surface temperatures during the last millennium reconstructions of ocean temperatures prior to the industrial era serve to constrain natural climate variability on decadal to centennial timescales yet relatively few such observations are available from the west pacific warm pool here we present multiple coral based sea surface temperature reconstructions from yongle atoll in the south china sea over the last 1 250 years 762 2013 common era ce reconstructed coral sr ca sea surface temperatures indicate that the little ice age 1711 1817 ce period was 0 7 c cooler than the medieval climate anomaly 913 1132 ce and that late 20th century warming of the western pacific is likely unprecedented over the past millennium our findings suggest that the western pacific warm pool may have expanded contracted during the medieval climate anomaly little ice age leading to a strengthening weakening of the asian summer monsoon as recorded in chinese stalagmites

strontium in rainwater from israel sources isotopes and chemistry abstract eighteen rain samples from israel have been analyzed for their chemical composition and87sr 86sr ratios the sr isotopic ratios lie in the range 0 7078 and 0 7092 and the sr concentrations vary from 1 10 4 to 9 10 4 meq sr l soluble salts in rainwater are inherited from three major natural sources seaspray recent marine minerals and mineral dust eroded from rock outcrops and soil a mixing model is formulated to apply the chemical composition of rain cl and sr2 and its isotopic87sr 86sr ratio for the identification and estimation of the sr sources all the samples fall within the mixing space predicted by the model for the three end members mentioned above the data indicate that the most important non seaspray source contributing dissolved salts to the rains in israel comprises a mixture of senonian to eocene chalk and its weathering products and recent marine minerals from local and imported sources most of the samples 67 contain 50 or more non seaspray sr i e sr dissolved from dust or recent marine minerals whereas 56 of the samples display87sr 86sr ratios lower than 0 7090 the rest represent mixtures of seaspray and recent marine minerals

the fault pattern in the northern negev and southern coastal plain of israel and its hydrogeological implications for groundwater flow in the judea group aquifer abstract on the basis of a broadly expanding data base the hydrogeological properties of the judea group sequence in the northern negev and southern coastal plain of israel have been reassessed the updated subsurface model is based on data derived from water and oil wells and on recent large scale geophysical investigations a new regional pattern of the reassessed geological through the subsurface of the study area has been revealed in view of the reassessed geological and hydrological subsurface setting it appears that the judea group aquifer should not be regarded as one continuous and undisturbed hydrological unit owing to the occurrence of regional faults its subaquifers are locally interconnected these subaquifers which contain mainly high quality water are juxtaposed as a result of faulting against kurnub group sandstones containing brackish paleowater the latter group is faulted against late jurassic formations containing highly saline groundwater in the beer sheva area the judea group aquifer is vertically displaced against the senonian and eocene mt scopus and avdat groups which also contain brackish and saline water in the southern coastal plain major faults locally dissect also the pleistocene kurkar group facilitating inflow of mg rich groundwater deriving from judea group dolomites the new geological evidence and its hydrogeological implications provide new solutions for previously unexplained salinization phenomena

sedimentation and diagenesis of chinese loess implications for the preservation of continuous high resolution climate records chinese loess has been extensively utilized to produce continuous and high resolution climate records of the late cenozoic such work assumes uninterrupted loess deposition and limited diagenesis here closely spaced optically stimulated luminescence osl dates are used to characterize the holocene and late pleistocene sedimentation histories of three sites across a nw se transect of the chinese loess plateau the results suggest that sedimentation is episodic at subglacial interglacial time scales with rates rapidly varying within units and between sites unconformities noneolian deposition and mixing of sediments also appear to be common existing understanding of loess deposition therefore requires reexamination while previous reconstructions of rapid climate change not dated using absolute methods should be regarded with caution loess deposits may still yield detailed climate records from specific high sedimentation rate strata and evidence for rapid climate change may yet be obtainable by targeting these units through absolute dating the rapid changes in sedimentation presented here indicate the east asian monsoon has the capacity to vary on millennial scales

geomorphic tectonic control of sediment discharge to the ocean the importance of small mountainous rivers analysis of data from 280 rivers discharging to the ocean indicates that sediment loads yields are a log linear function of basin area and maximum elevation of the river basin other factors controlling sediment discharge e g climate runoff appear to have secondary importance a notable exception is the influence of human activity climate and geology on the rivers draining southern asia and oceania sediment fluxes from small mountainous rivers many of which discharge directly onto active margins e g western south and north america and most high standing oceanic islands have been greatly underestimated in previous global sediment budgets perhaps by as much as a factor of three in contrast sediment fluxes to the ocean from large rivers nearly all of which discharge onto passive margins or marginal seas have been overestimated as some of the sediment load is subaerially sequestered in subsiding deltas before the proliferation of dam construction in the latter half of this century rivers

aquifer vulnerability and seawater intrusion risk using galdit gqiswi and gis case of a coastal aquifer in tunisia due to increase in population and agricultural activities the sfax coastal aquifer is under tremendous stress and seawater intrusion becomes a serious concern this situation needs an assessment of aquifer vulnerability and seawater intrusion risk a new approach for vulnerability mapping using galdit groundwater quality index for seawater intrusion gqiswi geostatistics the ghyben herzberg model and gis was developed the model is used to determine the trend of groundwater contamination by seawater intrusion in the coastal aquifer in sfax basin tunisia vulnerability assessment method is recognized through assessing weight and ratings of the galdit relevant parameter a second vulnerability map was realized based upon the groundwater quality index for seawater intrusion integrating the water quality parameters for delineating seawater intrusion in the aquifer the validation of gqiswi and galdit vulnerability maps was undertaken through comparison of areas of high jones ratio chloride and tds concentration and their relative vulnerability index the ghyben herzberg model has been used to predict the actual seawater intrusion extend and evaluate the freshwater saltwater dynamics the results reveal that the coastal area is currently undergoing seawater intrusion and its northern part is the most affected one by this contamination

influence of the intertropical convergence zone on the east asian monsoon a palaeoclimate record spanning the past 16 000 years with nearly annual time resolution has been obtained from lake huguang maar in china the magnetic properties and titanium content of the lake sediments are thought to reflect changes in the east asian winter monsoon strength thus providing a complement to palaeoclimate archives that record the strength of the rain bearing summer monsoon the records point to an anti correlation between winter and summer monsoon strength best explained by migration of the intertropical convergence zone itcz a belt of low pressure air at the equator interestingly the decline of china s tang dynasty and the mayan civilization broadly coincide with drought periods recorded in lake huguang maar and cariaco basin sediments respectively did major shifts in the position of the itcz catalyse simultaneous events in civilizations on opposite sides of the pacific ocean the asian australian monsoon is an important component of the earth s climate system that influences the societal and economic activity of roughly half the world s population the past strength of the rain bearing east asian summer monsoon can be reconstructed with archives such as cave deposits1 2 3 but the winter monsoon has no such signature in the hydrological cycle and has thus proved difficult to reconstruct here we present high resolution records of the magnetic properties and the titanium content of the sediments of lake huguang maar in coastal southeast china over the past 16 000 years which we use as proxies for the strength of the winter monsoon winds we find evidence for stronger winter monsoon winds before the bolling allerod warming during the younger dryas episode and during the middle and late holocene when cave stalagmites suggest weaker summer monsoons1 2 3 we conclude that this anticorrelation is best explained by migrations in the intertropical convergence zone similar migrations of the intertropical convergence zone have been observed in central america for the period ad 700 to 900 refs 4 6 suggesting global climatic changes at that time from the coincidence in timing we suggest that these migrations in the tropical rain belt could have contributed to the declines of both the tang dynasty in china and the classic maya in central america

geochemical and isotopic evidence of shallow groundwater salinization in a reclaimed coastal zone the yellow river delta china this paper aims to improve the current knowledge of groundwater salinization processes of a young coastal aquifer in the yellow river delta yrd and to assess the impact of both the transfer of irrigation water from the yellow river and seawater intrusion using a combination of hydrochemical isotopic measurements the major ion cl ratios generally closely follow the mixing line between freshwater end member the yellow river and saline water end members salt groundwater or seawater indicating the importance of mixing under natural and anthropogenic influences the examination of stable isotope in groundwater ranging from 9 0 to 3 5 for 18o and from 73 to 29 for d respectively and chloride concentrations 2 to 629 meq l confirms that the saline end member is associated with saltwater rather than present seawater and most groundwater samples are plotted on mixing lines between the yellow river and saltwater the similar range in stable isotopes 18o and d and cl compositions between saltwater and confined aquifer supports the hypothesis that upward seepage of confined saline water intruded the shallow aquifer moreover the deviations in some cases from mixing line imply water rock interaction is also important in dominant control on groundwater chemistry such as cation exchange so4 2 reduction and nacl solution the brackish water was characterized by slight excess of na and deficit of ca2 compared to non reactive mixing line this indicates that the coastal aquifer is generally freshening with respect to extensive irrigation network as well as the transfer from the yellow river for ecological recharge into wetland

occurrence and mobilization of radium in fresh to saline coastal groundwater inferred from geochemical and isotopic tracers sr s o h ra rn abstract salinization in groundwater systems can induce water rock interaction including the release of naturally occurring trace elements of health significance such as radium ra with possible implications for the usability of water resources in addition to the increase of dissolved solids tds concentrations in general radium mobility is limited by chemical removal mechanisms including adsorption onto clays and or mn and fe oxides exchange processes and coprecipitation with secondary barite in order to examine the effect of aquifer salinity gradients on the distribution of naturally occurring ra in fresh to saline groundwater and the relationship to water rock interaction and ra removal mechanisms two contrasting systems were investigated the shallow unconfined coastal aquifer in agadir southwestern morocco and the confined cretaceous cape fear and pliocene yorktown aquifers of the atlantic coastal plain north carolina usa geochemical and isotopic indicators of salinity sources e g cation ratios 18o 2h br cl 34 s so 4 2 18 o so 4 2 were used to identify the relative contributions of seawater and other saline waters and subsequent geochemical modification by water rock interaction radium activities 224ra 226ra 228ra radon 222 alkaline earth metal mg ca sr ba concentrations and ratios and 87sr 86sr ratios were analyzed to identify water rock interaction processes affecting alkaline earth metals including ra the morocco coastal aquifer is generally oxic exhibits a range of salinity and water types cl 163 2120 mg l median 932 mg l and exhibits ca na ratios above the seawater value typical of monovalent divalent cation exchange base exchange reactions in coastal aquifers in contrast the atlantic coastal plain aquifers are anoxic sulfate reducing cover a wider salinity range cl 5 9890 mg l median 800 mg l representing a transition between na hco 3 and na cl waters and exhibit ca na ratios below that of modern seawater typical of reverse base exchange reactions possible salinity sources in the morocco coastal aquifer include seawater intrusion mesozoic evaporites other natural saline waters and or wastewater whereas the atlantic coastal plain is primarily affected by old seawater present in the aquifer system radium activities are generally low and vary significantly within each aquifer for example 226ra ranges from 1 8 27 7 mbq l in the morocco coastal aquifer median 8 1 mbq l and 1 9 214 mbq l in the atlantic coastal plain median 18 9 mbq l the highest ra activities were observed in the most saline wells sampled in the atlantic coastal plain at total dissolved solids tds concentrations above an apparent threshold of 5000 mg l radium activities increase in a generally linear fashion with salinity in the atlantic coastal plain broadly comparable to previous studies indicating a threshold range of 3000 10 000 mg l at lower tds concentrations water rock interaction processes that vary with local aquifer conditions appear to control ra distribution rather than merely salinity in the morocco coastal aquifer adsorption of ra and coprecipitation with secondary barite are apparently favorable to control ra levels in groundwater radium removal in the anoxic atlantic coastal plain aquifers appears to be associated with adsorption and or exchange processes with the additional possibility of barite precipitation in the cape fear aquifer indicated by barite saturation overall the locally variable factors that can control ra sources and mobility in fresh to brackish groundwater at near neutral ph include variation in solid phase radioactivity redox state affecting adsorption sites availability of competing divalent cations and barite saturation

tropical climate instability the last glacial cycle from a qinghai tibetan ice core an ice core record from the guliya ice cap on the qinghai tibetan plateau provides evidence of regional climatic conditions over the last glacial cycle 36 cl data suggest that the deepest 20 meters of the core may be more than 500 000 years old the 18 o change across termination i is 5 4 per mil similar to that in the huascaran peru and polar ice cores three guliya interstadials stages 3 5a and 5c are marked by increases in 18 o values similar to that of the holocene and eemian 124 000 years ago the similarity of this pattern to that of ch 4 records from polar ice cores indicates that global ch 4 levels and the tropical hydrological cycle are linked the late glacial stage record contains numerous 200 year oscillations in 18 o values and in dust nh 4 and no 3 levels

effect of faults on fluid flow and chloride contamination in a carbonate aquifer system abstract a unified multidiscipline hypothesis is proposed to explain the anomalous pattern by which chloride has been found in water of the upper floridan aquifer in brunswick glynn county georgia analyses of geophysical hydraulic water chemistry and aquifer test data using the equivalent porous medium epm approach are used to support the hypothesis and to improve further the understanding of the fracture flow system in this area using the data presented herein we show that 1 four major northeast southwest trending faults capable of affecting the flow system of the upper floridan aquifer can be inferred from structural analysis of geophysical data and from regional fault patterns 2 the proposed faults account for the anomalous northeastward elongation of the potentiometric surface of the upper floridan aquifer 3 the faults breach the nearly impermeable units that confine the upper floridan aquifer from below allowing substantial quantities of water to leak vertically upward as a result aquifer transmissivity need not be excessively large as previously reported to sustain the heavy long term pumpage at brunswick without developing a steep cone of depression in the potentiometric surface 4 increased fracturing at the intersection of the faults enhances the development of conduits that allow the upward migration of high chloride water in response to pumping from the upper floridan aquifer and 5 the anomalous movement of the chloride plume is almost entirely controlled by the faults

spatial characterization of the seawater upconing process in a coastal mediterranean aquifer plana de castellon spain evolution and controls in this contribution we describe the formation and evolution of the upconing process in a mediterranean coastal aquifer the study area has experienced severe salinization over the last 40 years because of intensive exploitation of groundwater we used historical and current records of piezometric levels and chloride concentrations to trace the development of the salinization of the aquifer we defined the 3d shape of the saline wedge from the spatial distribution of chloride concentrations and vertical well logs of electrical conductivity using monitoring network data upconing first appeared in the early 90s and has continued until the present day in this study we examined the intensity of the upconing process dry periods and the associated increases in pumping caused the advance of seawater intrusion the sharp reduction in groundwater withdrawals over the last 10 years has caused the saline wedge to move backwards although the ongoing pumping and the climate conditions mean that this retreat is quite slow

strontium isotopic chemical and sedimentological evidence for the evolution of lake lisan and the dead sea precise strontium isotope ratios combined with chemical analyses and sedimentological information are used to monitor the water sources and the evolution of the dead sea and its late pleistocene precursor lake lisan 70 18 kyr b p the materials analyzed include bulk aragonite water leached soluble salts and residual aragonite and gypsum from the lisan formation in the perazim valley near the sw shore of the dead sea the residual aragonite and the associated soluble salts display systematic fluctuations in 17sr86sr ratios between 0 70803 and 0 70806 and from 0 70805 to 0 70807 respectively in individual soluble salt residual aragonite pairs the soluble salt displays a higher 87sr86sr ratio gypsum samples yield 17sr86sr ratios similar to the soluble salts from adjacent layers in the section this shows that in individual samples the source of sr in aragonite was distinct from that in soluble salts and the gypsum the sterility of the lisan sediments their strictly nonbioturbated fine lamination and their high content of chloride salts indicate that lake lisan was a saline or even hypersaline water body in the absence of alternative sources of hco3 and s042 the abundance of primary aragonite and gypsum in the lisan column reflects an import of very large volumes of freshwater into the otherwise saline lake resulting in a density stratification of this water body the history of the upper water layer and that of the lower brine is reflected in the chemical and strontium isotope composition of the aragonite and in that of the associated soluble salts and in the gypsum samples respectively whereas the bicarbonate and much of the ca2 required for aragonite crystallization were supplied by the freshwater the complementary ca2 and sr 2 were added by the lower brine the upper water layer of lake lisan acted as a so42 capacitor during the lake s rise periods it was removed therefrom as prominent gypsum beds upon climatic induced drier period mixing or even complete overturn of the lake the evolution of lake lisan took place between two distinct modes the first was characterized by an extensive supply of freshwater and resulted in a rise of the lake s level a density layered structure and precipitation of aragonite the second mode was marked by a diminishing freshwater input resulting in mixing or complete overturn of its water and precipitation of gypsum these two modes reflect the climatic evolution of the region in the late pleistocene which fluctuated between drier and wetter periods the transition to the holocene is accompanied by the dry up of lake lisan and its contraction to the present dead sea

provenance discrimination of the clay sediment in the western taiwan strait and its implication for coastal current variability during the late holocene this study aims to quantify the contribution of yangtze clays to the sediment accumulation in the western taiwan strait and reconstruct the strength of chinese coastal current ccc since middle ho

asynchronous holocene optimum of the east asian monsoon abstract the spatial and temporal distribution of summer monsoon precipitation or effective moisture during the holocene has been reconstructed on the basis of geological data including lake levels pollen profiles and loess paleosol records in addition the summer july precipitation increment effective precipitation and monsoon strength index have been obtained from numerical modeling experiments both geological data and numerical modeling indicate that the holocene optimum as defined by peak east asian summer monsoon precipitation was asynchronous in central and eastern china reaching a maximum at different times in different regions e g ca 10 000 8000 yr ago in northeastern china 10 000 7000 yr ago in north central and northern east central china ca 7000 5000 yr ago in the middle and lower reaches of the yangtze river and ca 3000 yr ago in southern china in southwestern china the maximum appeared ca 11 000 yr ago but probably was related to the maximum landward extension of the indian summer monsoon the regional shift in the maximum precipitation belt from northwest to southeast over the past 10 000 yr is interpreted as a response to changing seasonality related to orbital forcing of the climate the southeastward shift of the east asian summer monsoon maximum is consistent with the progressive weakening of the summer monsoon as the summer solar radiation anomaly decreased progressively through the holocene and the east asian monsoon index declined while the early maximum in southwestern china matches the maximum of the indian monsoon index

integrated hydrogeochemical isotopic and geomorphological depiction of the groundwater salinization in the aquifer system of delhi india abstract the problem of salinization in the delhi aquifer that currently exhibits rapid landuse change is conspicuous and severe salinization may be caused either by a single process or a combination of different processes including anthropogenic related activities water logging and evaporative concentration of salts influx of natural saline water upconing of brines from the deeper parts of the aquifer and airborne salts depositions however there is a lack of well proven theory that can explain the salinity of the order of 5000 s cm in the deeper aquifers of delhi this work identifies inconclusiveness in the previous theories of marine ingression evaporation enrichment and subsequent leaching of salt further the study depicts a conceptual understanding of the origin of salinity in groundwater based on the integrated investigations of groundwater quality age and stable isotopic fingerprinting as well as gis based mapping of geomorphic features in order to explain the salinity observed in groundwater of nct delhi a phenomenological scenario is illustrated and supported by additional evidences the highest average ec value was for the shallow aquifer and is strongly symptomatic of anthropogenic influences on groundwater chemistry piper diagram showed heterogeneous water type and sufficient recharge mixing of the groundwater from different aquifers the relationship between cl br ratios vs cl indicated dissolution of salt deposits containing evaporative fraction present in the unsaturated zones or in the sediments of deeper aquifers and leaching of evaporative minerals from dunes of the adjacent thar desert cl so 4 2 ratio suggested the presence of connate seawater halite dissolution and concentration of dissolved salts by evapo transpiration of river water diverted for irrigation the results show that the closed inland marine conditions developed and buried with the active sedimentation in the geological past in this region and further intensive exploitation of groundwater and enhanced evaporation have together resulted in saline playa condition in some part of the region the scenario was further verified by matching the required condition for the formation of salt pan or playa with the existing geo morphological conditions of the area isotopic results indicate that salinity flushing is possible and proceeds in the areas of freshwater recharge

moisture changes in northeast china since the last deglaciation spatiotemporal out of phase patterns and possible forcing mechanisms abstract there is a strong chance that the 21 st century warming will cause differences in precipitation distribution over the globe northeast ne china is a unique area whose atmospheric circulation is still a controversial subject and is likely to be strongly impacted by global warming thus a good understanding of the past variations in effective moisture in ne china will be benefit for the prediction of future hydrological changes in this study we use basal peat ages and published paleoclimate records to evaluate the spatial and temporal patterns and possible forcing mechanisms for the moisture changes in ne china over the past 16 000 years basal peat ages suggest that the moisture conditions in different regions of ne china show as a spatiotemporal out phase pattern in addition the paleoclimate records of 17 sites also indicate that ne china experienced a spatiotemporal out phase pattern of moisture changes along northwest southeast direction since the last deglaciation the moisture in southern ne china experienced increasing trend during the period of 16 8 cal ka bp with the maximum moisture occurring 8 3 cal ka bp and decreasing trend after 3 cal ka bp the moisture pattern in western ne china is similar to that in southern ne china it experienced increasing trend during the period of 16 8 cal ka bp the maximum moisture during the period 8 4 cal ka bp and decreasing trend from 4 cal ka bp to present the moisture in eastern ne china experienced wet conditions from 16 cal ka bp to 4 cal ka bp and decreasing trend after 4 cal ka bp in central ne china two relatively wet periods occurred during the periods of 13 8 cal ka bp and 6 3 cal ka bp respectively in addition two wet periods occurred during the periods of 14 11 cal ka bp and 7 1 cal ka bp in northern ne china respectively the moisture patterns between ne china and other regions of china are also compared in this study we propose that the possible forcing mechanisms for the moisture changes in ne china were different for each 4000 year interval during the period of 16 12 cal ka bp the weak east asian summer monsoon easm and strong northeast monsoon nem were the major water vapor sources of ne china during the period of 12 8 cal ka bp the increasing easm and strong nem were still the major water vapor sources of ne china during the period of 8 4 cal ka bp the strongest easm was the major water vapor sources of the whole ne china furthermore the increasing westerlies slightly penetrated into northern ne china during this period from 4 cal ka bp to present the decreasing easm provided precipitation for the most regions of ne china the westerlies reached the maximum and further penetrated into the whole northern ne china during this period

grain size of quartz as an indicator of winter monsoon strength on the loess plateau of central china during the last 130 000 yr the chinese loess paleosol sequence constitutes an important record of variations in asian monsoon climate over the past 2 4 myr magnetic susceptibility of loess and paleosols has been used as a proxy for summer monsoon intensity while median grain size has been regarded as a measure of the strength of winter monsoon winds that were responsible for most of the dust transport however median grain size is only an approximate index of winter monsoon strength because both paleosols and loess have been modified to various degrees by weathering processes that have produced pedogenic clay the quartz component of loess and paleosols is largely unaffected by weathering processes and therefore constitutes a more reliable proxy index of monsoon wind strength median grain size qmd and maximum grain size qmax values of monomineralic quartz isolated from the loess paleosol section at luochuan in the central loess plateau are characterized by two main intervals during the last ca 130 000 yr when these parameters were significantly greater than 9 and 85 m respectively and three main intervals when they were lower the data imply that the winter monsoon weakened during the intervals with low qmd and qmax values which coincide with marine oxygen isotope stages 5 3 and 1 and was strongest ca 67 000 and 20 000 yr ago during isotope stages 4 and 2 however both quartz grainsize records display second order high frequency high amplitude variations which are lacking in the magnetic susceptibility record that imply rapid and significant changes in atmospheric conditions that affect dust transport and deposition

widespread dispersal and aging of organic carbon in shallow marginal seas the occurrence of pre aged organic carbon oc in continental margin surface sediments is a commonly observed phenomenon yet the nature sources and causes of this aged oc remain largely undetermined for many continental shelf settings here we present the results of an extensive survey of the abundance and radiocarbon content of oc in surface sediments from the northern chinese marginal seas pre aged oc is associated with both coarser 63 m and finer 63 m sedimentary components measurements on specific grain size fractions reveal that it is especially prevalent within the 20 63 m fraction of inner shelf sediments we suggest that organic matter associated with this sortable silt fraction is subject to protracted entrainment in resuspension deposition loops during which it ages is modified and is laterally dispersed most likely via entrainment within benthic nepheloid layers this finding highlights the complex dynamics and predepositional history of organic matter accumulating in continental shelf sediments with implications for our understanding of carbon cycling on continental shelves development of regional carbon budgets and interpretation of sedimentary records

holocene east asian winter monsoon changes reconstructed by sensitive grain size of sediments from chinese coastal seas a review abstract while mean grain size of sensitive component in muddy sediments from chinese coastal seas was widely used as a proxy for reconstruction of the east asian winter monsoon eawm strength many intractable problems still remain concerning the discrepancies in different studies this paper provides a comprehensive overview of recent researches on the reconstruction of holocene eawm strength using sensitive grain size sgs in muddy sediments from the chinese coastal seas in the present study 15 time series of sgs in sediments from six mud areas are included these records are summarized and compared during the last 8000 years 3000 years and 150 years respectively the results show that trends of sgs time series are inconsistent at millennial multi centennial and decadal time scales the inconsistencies could be partly caused by age uncertainties and chosen sgss more important grain size characteristics in sediments from some mud areas could be influenced by factors other than coastal currents driven by eawm such as sedimentary environments riverine runoff and storms thus sgs of muddy sediments should be used with caution when reconstructing winter monsoon strength especially those in the northern yellow sea and near the yangtze river estuary

formation of a salt plume in the coastal plain aquifer of israel the be er toviyya region the formation and development of a salt plume salinity up to 800 mg cl 1 1 in the inner part of the coastal plain aquifer of israel is analyzed massive groundwater exploitation during the 1950s caused a large drop in the water level and formation of a hydrologic depression in the be er toviyya kefar warburg area the depression reached a maximal depth during the late 1960s thereafter a reduction in the rate of pumpage led to restoration of water levels and shallowing of the depression until its complete disappearance towards the end of the 1980s a spot of high salinity first appeared in 1956 following a deep drawdown in the water levels this saline plume has been continuously expanding with increasing salinity concentrations 200 800 mg cl 1 1 in its center the average rate of radial expansion was about 50 m year 1 the expansion and salinization did not cease as the depression disappeared rather equalization of water levels in wells situated within the plume area with those of situated along its margins resulted in the salinization of the latter within a period of 1 year mass balances for water and chloride contents were made for the period 1967 1990 taking into consideration the storage change pumpage natural replenishment and artificial recharge the lateral inflow to the depression is estimated as 60 106 m3 upon addition of the chloride balance and taking into consideration the chloride concentrations of the surrounding fresh water and the apparent possible end member of the saline source based on geochemical considerations the saline inflow is estimated as 40 60 106 m3 these estimates indicate that a large amount of saline water penetrated into the aquifer of about half of the natural replenishment of the study area with an estimated salinity of 1900 2700 mg cl 1 1 it is suggested that the salt plume was formed as a result of a drop in water level combined with a flow of underlying saline water bodies from deeper strata the chemical composition of the groundwater points to the existence of two saline water bodies of ca chloride composition and a marine brcl ratio 1 saline water with low nacl 0 6 so4cl and b cl ratio 2 saline water with higher nacl 0 6 so4cl and b cl ratios these chemical compositions resemble ca chloride saline waters found in other locations in the coastal plain aquifer and in underlying formations the saline water bodies may occur in either pockets at the bottom of the aquifer or lumachelle and sandstone layers of high hydraulic conductivity in underlying sediments

reconstruction of holocene monsoon history from the pearl river estuary southern china using diatoms and carbon isotope ratios this study employs a multiproxy approach in the reconstruction of holocene monsoon history from sedimentary sequences obtained from the pearl river estuary southern china a set of modern surface sediment samples were collected within and outside the estuary and a sediment core was obtained from the mouth of the estuary a range of modern environmental variables were recorded including water salinity summer winter and annual average and water depth the diatom results show a good relationship with water salinity with marine diatoms dominating the more distal samples from outside the main estuary and freshwater diatoms dominating the proximal samples influenced by higher freshwater flux this pattern is matched by the bulk organic carbon isotopes the isotope values vary between 21 1 0 3 0 for samples from the fully marine environment between 23 2 0 8 and 23 7 0 8 for samples from the mid to outer estuary brackish water environment and less than 24 7 1 3 for samples from the inner estuary close to the freshwater sources similarly the c n ratios vary from below 7 0 6 in the marine end members to over 14 8 3 0 in the freshwater end members both the diatom and carbon data from the sediment core reveal a significant increase in freshwater flux from 8500 cal yr bp resulting from the enhanced summer monsoon regime in early holocene the strength of freshwater flux reached its highest between 7500 and 6000 cal yr bp in the last 6000 years freshwater flux decreased towards present reflecting a gradual weakening of the summer monsoon

chinese loess record of monsoon climate during the last glacial interglacial cycle the thick loess paleosol succession of central china contains a detailed record of changes in east asian monsoon climate since the late miocene epoch the alternating loess paleosol stratigraphy closely resembles the marine oxygen isotope record implying that episodic dust deposition and pedogenesis are in phase with global ice volume fluctuations and controlled by variations in solar radiation reaching the land surface deposits equivalent to marine isotope stages mis 5 through 1 have been dated by 14c 10be luminescence and magnetic susceptibility and grain size models malan loess mis 4 2 decreases in thickness southeastward from 30 m in the western loess plateau to 5 m east of xi an downwind asian dust is found in japan the north pacific ocean and the greenland ice sheet where it has a chemical signature that points to a primary source in western china during glacial times the mean dust flux in the central loess plateau reached 0 35 mm year whereas in interglacial times it fell to 0 1 mm year times of high dust influx and reduced soil development coincided with strengthened winter monsoon conditions which are inferred from variations in loess grain size times of decreased dust accumulation and strong pedogenesis marked by high values of magnetic susceptibility represent times of strengthened summer monsoon conditions high frequency fluctuations in dust influx during deposition of the malan loess include peaks that likely correlate with north atlantic heinrich events the younger dryas oscillation is recorded in chinese eolian and organic deposits by a shift from cool humid late glacial conditions to cold and dry conditions followed by a return to milder humid climate at the beginning of the holocene warm moist climate associated with a strong summer monsoon characterized the first half of the holocene epoch when a widespread paleosol complex developed on the loess plateau increased dust deposition during the middle to late holocene marked a shift to cooler drier conditions

saline groundwater in israel its bearing on the water crisis in the country abstract one of the major causes for the deterioration of water quality bearing heavily on the water crisis in israel is the ongoing contamination of its water resources by saline water bodies the present paper reviews the geochemical processes forming saline water lists and explains certain chemical and isotopic parameters which enable understanding these processes and describes the saline groundwater bodies and various salinization phenomena occurring in the country s various aquifers deterioration of groundwater in israel is caused by numerous natural processes such as encroachment of sea water migration of connate highly pressurized brines penetrating into fresh groundwater by subsurface dissolution of soluble salts originating in surrounding country rocks and by water rock interaction in addition to sea water two saline water bodies were identified as the main factors causing salinization of fresh groundwater a ca chloride brines encountered in the jordan dead sea rift valley in various parts of the negev and of the coastal plain and b na chloride saline water identified in the subsurface of the negev and in the southern part of the coastal plain intensive exploitation of groundwater in israel has disturbed the natural equilibrium which prevailed between fresh and saline water the newly established groundwater flow regimes have facilitated the migration of saline water bodies their participation in the active hydrological cycle and the progressive contamination of fresh groundwater these processes which were not anticipated by planners and water resources managers emphasize that large scale groundwater exploitation was undertaken without giving sufficient consideration to the occurrence and subsurface migration of saline water and brines

groundwater salinization processes and reversibility of seawater intrusion in coastal carbonate aquifers summary seawater intrusion swi has led to salinization of fresh groundwater reserves in coastal areas worldwide and has forced the closure of water supply wells there is a paucity of well documented studies that report on the reversal of swi after the closure of a well field this study presents data from the coastal carbonate aquifer in northeast china where large scale extraction has ceased since 2001 after salinization of the main well field the physical flow and concomitant hydrogeochemical processes were investigated by analyzing water level and geochemical data including major ion chemistry and stable water isotope data seasonal water table and salinity fluctuations as well as changes of 2 h 18 o values of groundwater between the wet and dry season suggest local meteoric recharge with a pronounced seasonal regime historical monitoring testifies of the reversibility of swi in the carbonate aquifer as evidenced by a decrease of the cl concentrations in groundwater following restrictions on groundwater abstraction this is attributed to the rapid flushing in this system where flow occurs preferentially along karst conduits fractures and fault zones the partially positive correlation between 18 o values and tds concentrations of groundwater as well as high no 3 concentrations 39 mg l suggest that irrigation return flow is a significant recharge component therefore the present day elevated salinities are more likely due to agricultural activities rather than swi nevertheless seawater mixing with fresh groundwater cannot be ruled out in particular where formerly intruded seawater may still reside in immobile zones of the carbonate aquifer the massive expansion of fish farming in seawater ponds in the coastal zone poses a new risk of salinization cation exchange carbonate dissolution and fertilizer application are the dominant processes further modifying the groundwater composition which is investigated quantitatively using hydrogeochemical models

the sedimentary cycle of the boron isotopes abstract marine sediments contain two isotopically distinct components a non desorbable fraction with 11b between 4 3 and 2 8 per mil n 10 and a desorbable component with 11b between 13 9 and 15 8 per mil n 6 the adsorption coefficient k for the uptake of b from seawater by fluvial suspended material mississippi has an experimentally determined value of 1 54 0 05 the associated isotope fractionation factor is 0 974 0 003 empirical values for k determined from the analysis of marine sediments n 6 were between 3 and 4 the amount of b adsorbed onto fluvial suspended material during estuarine mixing is about 9 109 moles yr based on pore water data adsorption experiments and comparative size fraction analyses suspended sediments from the mississippi river vs bottom deposits from the delta there is no evidence for the incorporation of b into detrital sediments at low temperature however the high b content of bauer deep metalliferous sediments must be due to incorporation of seawater b during formation of authigenic silicates the 11b of these minerals is 2 3 per mil hydrothermally altered sediments from dsdp hole 477 guaymas basin gulf of california have variable b contents from 33 ppm similar to the unaltered detritus to 1 2 ppm in the recrystallized material the latter has 11b as low as 9 0 per mil substantially lower than the unaltered material hydrothermal solutions collected from vents adjacent to the hole have boron contents elevated by about a factor of 4 relative to seawater and 11b between 16 5 and 23 2 per mil the b mobilized from the sediments is isotopically fractionated with the fluids being preferentially enriched in the heavy isotope analysis of an oxisol profile developed over granite in the guyana shield showed that boron is partially mobilized during weathering with an isotopic offset of 2 5 per mil between bedrock and soil the observed enrichment of b in shales relative to igneous rocks does not occur during weathering or during exposure to seawater at low temperature incorporation occurs only during burial diagenesis at temperatures greater than about 60 c however the enrichments cannot be attained during a single cycle of primary weathering and burial but must be cumulative over many cycles

boron isotope geochemistry of salt sediments from the dongtai salt lake in qaidam basin boron budget and sources abstract dongtai salt lake in qaidam basin contains abundant boron and lithium resources and has the highest reserve of lithium found in the world but the origin of these resources is highly controversial in this study we carried out a detailed study on chemical compositions and boron isotope characteristics of salt sediments collected from a drill core in the dongtai salt lake the evaporite carbonate and silicate phases of the sediments show 11 b values of 6 4 to 2 2 17 3 to 0 5 and 14 6 to 2 8 respectively which suggest a non marine origin for the salt lake the variation of 11 b vs k identified the evolution process of the salt lake the geochemical hydrochemical signatures and the reserve estimation of boron resources approved the dominant sources of saline resources containing abundant b k and li from the inflowing nalenggele river the boron isotopic fractionation factors between evaporite and brine i e evaporite brine vary from 0 9869 to 0 9955 and the linear variation of evaporite brine vs li mg molar ratios reflects the boron isotopic fractionation during crystallization of the salts the positive correlation between 11 b and b in the carbonate phase reflects the ph control on the incorporation of boron into the carbonates and the equilibrium isotope fractionation follows the rayleigh isotope fractionation rule in a closed system the variation of 11 b values in the silicate phase behaved as an oscillating pattern and the more negative shift of 11 b values corresponds to the mudstone strata deposited under warm humid climate conditions indicating the influence of intensive weathering

factors controlling mechanisms of groundwater salinization and hydrogeochemical processes in the quaternary aquifer of the eastern nile delta egypt in this study combining interpretations of conservative dissolved ions and environmental isotopes in water were used to investigate the main factors and mechanisms controlling groundwater salinization and hydrogeochemical processes in the eastern nile delta egypt hydrogeochemical and isotopic study has been carried out for 61 water samples from the study area total dissolved solid tds contents of groundwater are highly variable rising along flowpath from the south 410 mg l to the north 14 784 mg l implying significant deterioration and salinization of groundwater based on tds and ionic ratios groundwater samples were classified into three groups in low saline groups water chemistry is greatly influenced by cation exchange mineral dissolution precipitation anthropogenic pollutants and mixing with surface water whilst in high saline groups water chemistry is affected by salt water intrusion reverse cation exchange and evaporation the chemical constituents originating from saline water sources reverse ion exchange and mineral dissolution are successfully differentiated using ionic delta and saturation index approaches the 18o 2h relationship plots on a typical evaporation line suggesting potential evaporation of the recharging water prior to infiltration isotope evidence concludes that the groundwater have been considerably formed by mixing between depleted meteoric water recharged under different climatic conditions and recently infiltrating enriched surface water and excess of irrigation water the 18o data in conjunction with chloride concentrations provide firm evidence for impact of dissolution of marine origin evaporite deposits during past geologic periods on groundwater salinity in the northern region moreover the relation between 14c activities and cl concentration confirms this hypothesis

millennial scale climatic oscillations during the last interglaciation in central china repeated southward excursions of north atlantic polar water during the last interglaciation 18 o stage 5 130 74 ka are recorded by planktonic foraminifera and ice rafted detritus in north atlantic sediment cores and greenland ice sheet cores display quasi synchronous fluctuations comparable high frequency variations in the east asian winter monsoon climate are discernible in three loess paleosol profiles in central china that span the last interglaciation peak values of the 40 m quartz fraction and bulk sediment samples from the s1 last interglacial accretionary paleosol complex reflect major dust flux events when winter monsoon winds strengthened frequent oscillations of the dust flux and nine significant dust events are recorded six events falling between ca 110 and 70 ka are correlated with cold peaks c19 24 identified in north atlantic cores two comparable dust peaks occur within paleosol s1ss3 substage 5e the older of these dating to ca 121 ka may correlate with a brief cold event recently recognized in high resolution marine and terrestrial climate proxy records

records of east asian monsoon activities in northeastern china since 15 6 ka based on grain size analysis of peaty sediments in the changbai mountains peatlands provide a widespread terrestrial archive for holocene study however little is known about the grain size characteristics of peaty sediments and their environmental significance in order to study these phenomena in detail two sections from the hani and gushantun peatlands in the changbai mountain area were cored and sub sampled based on reliable calibrated ams 14c ages we established grain size variations in the peat cores since 15 6 ka cal bp our results showed that the peaty sediments in the changbai mountains are mainly composed of silt moreover the grain size component which is related to paleoclimate variables can be classified into three groups based on the grain size class vs standard deviation method these sensitive grain size components are 37 0 mm component 1 or c1 37 0e497 8 mm component 2 or c2 and 497 8 mm component 3 or c3 c1 comprises the finest silt in the peaty sediment and is mainly conveyed by the east asian winter monsoon eawm whereas c2 is transported into the peatland by surface runoff related to the enhancement of the east asian summer monsoon easm c3 is conveyed in saltation and bed load mode by strong surface runoff linked to highenergy flow caused by a strong easm and perhaps is an indicator of extreme rainfall events in the changbai mountains our results suggest that the study region was dominated by a cold dry environment during the late glacial period under a strong eawm however there was a marked climatic shift from an eawm dominated cold dry climate to an easm dominated more mesic environment during the early holocene increased percentage of c2 in peat cores during the holocene optimum 9 0e4 5 ka indicates abundant rainfall in the study region even with extreme rainfall events as a result of a significant enhancement of the easm weak monsoon events occurred at 10 5 ka 9 2 ka 8 2 ka 7 2 ka 6 2ka 5 5 ka and 4 2 ka shown by sharp decreases in c2 agreeing with the stalagmite d18o records in china the results obtained from environmentally sensitive grain size component records are largely consistent with other palaeoenvironmental records in the east asian monsoon area substantiating the regional climate patterns and monsoon evolution since late glacial time because intensity of the east asian monsoon is likely responsible for the grain size change in the peat samples the grain size components in peat samples may be used for reconstructions of past environmental conditions and of variability in the east asian monsoon

a hydrogeochemical approach to evaluate the occurrence and source of salinization in the shallow aquifers of the southeastern imphal valley in the indo myanmar range of northeast india the imphal valley is an intramontane basin confined within an anticlinorium of several anticlines and synclines in the disang group of rocks of tertiary age this valley of more than 2 million people is occupied by fluvio lacustrine deposits of quaternary age and is located in the central part of the indo myanmar range of northeast india the hydrogeochemical parameters of temperature ph orp tds na cl br ba b sr li 18o hco3 k mg ca no3 po4 so4 in 173 samples using ion chromatograph icp aes icp oes icp ms and 37 dugwells were studied to understand the occurrence and origin of salinization process for the first time the order of abundance of ions is identified as hco3 na cl ca mg k no3 po4 sr br b ba li so4 five hydrochemical facies na cl ca mg hco3 na hco3 ca mg hco3 cl and ca mg cl represent the types of waters the saline dominated water types na cl and na hco3 represent piedmont and the rest of the facies represent alluvial plain and flood plain groundwaters durov s diagram reveales initial and intermediate stages of groundwater evolution isotope 18o gibbs diagram and ions scatter plots suggest evaporation and crystallization processes leading to halite encrustation in the disang shales negative eh low no3 and the absence of so4 indicates reduced condition coupled with rich dissolve organic matters leading to elevation of salts in soils around piedmont where the rock type is exclusively of the disang shales trilinear plot correlation matrix and water table flow analysis suggest salinization of groundwater originates in piedmont groundwater and disseminates towards alluvial plain and flood plain along the flow path

the evaporation path of seawater and the coprecipitation of br and k with halite brines and salt were sampled at the morton bahamas solar salt production facility on great inagua island in the bahamas the brines were analyzed by ion chromatography to define more precisely than heretofore the evaporation path of seawater to the end of the halite facies at inagua calcium carbonate begins to precipitate at a brine concentration factor of 1 8 times that of seawater gypsum begins to precipitate at a brine concentration of 3 8 times seawater and halite at a concentration factor of 10 6 three of the most concentrated brines from inagua 40 times seawater were evaporated further in the laboratory magnesium sulfate first precipitated at brine concentrations about 70 times those of seawater and potassium bearing phases began to precipitate for these brines at concentrations greater than 90 times those of seawater the distribution of coefficients of br and k between brines and halite were determined by combining analytical data for the inagua brines with measurements of the br and k content of halites from inagua and of halite which had precipitated from inagua brines during storage the observed average value of dbr is 0 032 in good agreement with some of the previous measurements the measured values of dk are highly variable 0 001 to 0 021 dk for halite precipitated early in the halite facies is in the vicinity of 0 015

holocene late pleistocene climatic ice core records from qinghai tibetan plateau three ice cores to bedrock from the dunde ice cap on the north central qinghai tibetan plateau of china provide a detailed record of holocene and wisconsin wurm late glacial stage lgs climate changes in the subtropics the records reveal that lgs conditions were apparently colder wetter and dustier than holocene conditions the lgs part of the cores is characterized by more negative 18 o ratios increased dust content decreased soluble aerosol concentrations and reduced ice crystal sizes than the holocene part these changes occurred rapidly 10 000 years ago in addition the last 60 years were apparently one of the warmest periods in the entire record equalling levels of the holocene maximum between 6000 and 8000 years ago

eolian quartz flux variations in cheju island korea during the last 6500 yr and a possible sun monsoon linkage we have obtained a high resolution sedimentary record covering the last 6500 yr from a maar in cheju island korea in order to reconstruct the history of variations in the eolian quartz flux eqf and hence asian dust the long term variation of eqf reveals three intervals a period of high eqf 4000 2000 cal yr b p and two periods of low eqf 6500 4000 cal yr b p and 2000 cal yr b p to present which have been affected by the east asian monsoon due to insolation change and the cold air activity in high latitudes correlated with polar high pressure systems this long term variation is superimposed by millennial and centennial scale fluctuations with periodicities of 1137 739 214 162 137 127 and 111 yr implying drier conditions in the source areas in china the detrended eqf record correlates visually and statistically cross spectral analysis with the atmospheric d 14 c record solar proxy the centennial scale variability in eqf may be affected

storm generated surface waves and sediment resuspension in the east china and yellow seas abstract surface winds derived from atmospheric pressure fields are used as input to a finite depth wind wave model to predict the sea state during a cold air frontal passage over the yellow and east china seas which occurred 15 18 november 1983 the predicted maximum wave stress field near the bottom is used to examine the concept of turbulent wave intensities causing sediment resuspension the temporal variability of the wave field at three sites is used to illustrate the dependence of the bottom response on depth within the yellow sea maps of the temporal and spatial distribution of index for initiation of sediment movement are computed for different noncohesive sediment materials during this storm period and compared to sedimentological results for this region this study demonstrates that wave action is a mechanism which can significantly influence the sediment transport pattern induced by the regional circulation existing in this marginal sea the results also identify regions where winter storm g

a high resolution absolute dated holocene and deglacial asian monsoon record from dongge cave china abstract we present a continuous record of the asian monsoon over the last 16 ka from 18o measurements of stalagmite calcite over 900 oxygen isotopic measurements providing information on shifts in monsoon precipitation are combined with a chronology from 45 precise 230th dates 18o and therefore asian monsoon intensity generally follows changes in insolation although changes in 18o are generally accommodated in abrupt shifts in contrast to smoothly varying insolation indicating that threshold effects may be important 18o decreased dramatically 3 at the start of the holocene 11 5 ka and remained low for 6 ka four positive 18o events centered at 11225 97 yr bp 1 05 10880 117 yr bp 1 15 9165 75 yr bp 1 4 and a double event centered at 8260 64 yr bp 1 1 and 8080 74 yr bp 1 0 punctuated this period of high monsoon intensity all four events correlate within error with climate changes in greenland ice cores thus the relationship between the asian monsoon and the north atlantic observed during the glacial period appears to continue into the early holocene in addition three of the four events correlate within error with outburst events from lake agassiz the decline of monsoon intensity in the mid late holocene is characterized by an abrupt positive shift in 18o which occurs at 3550 59 yr bp 1 1 in 100 yr in addition the holocene is punctuated by numerous centennial and multi decadal scale events amplitudes 0 5 to 1 up to half the amplitude of the glacial interstadial events seen in the last glacial period thus holocene centennial and multi decadal scale monsoon variability is significant although not as large as glacial millennial scale variability the monsoon shows a strong connection with northern south american hydrological changes related by changes in itcz position spectral analysis of the 18o record shows significant peaks at solar periodicities of 208 yr and 86 yr suggesting variation is influenced by solar forcing however there are numerous other significant peaks including peaks at el nino frequencies observed for high resolution portions of the record between 8110 and 8250 yr which suggest that changes in oceanic and atmospheric circulation patterns in addition to those forced by solar changes are important in controlling holocene monsoon climate in addition for this high resolution portion we observe a distinctive biennial oscillation of the asian monsoon which has been associated with the tropospheric biennial oscillation tbo

asian monsoon oscillations in the northeastern qinghai tibet plateau since the late glacial as interpreted from visible reflectance of qinghai lake sediments abstract qinghai lake is a large saline lake on the qinghai tibetan plateau of central asia that is effected by both the indian and asian monsoons we used reflectance spectroscopy to characterize the sediments in a 795 cm long core taken from the southeastern part of the lake sediment redness which is related to iron oxide content seems to monitor paleoclimatic changes in the core iron oxides appear to be eroded from nearby red beds or loess deposits and are transported by fluvial means into the lake thus redness increases at times of increased precipitation that is as monsoon strength increases our redness monsoon proxy shows climate changes on several times scales on a millennial scale it records humid conditions during the early and mid holocene from about 4200 to 2300 yr bp low redness values suggest a two millennial long dry period which in the late holocene is followed by a more humid period on a centennial scale the redness proxy records not only the little ice age but also the medieval warm period the dark ages cool period and the roman warm period time series analysis of the redness record indicates a 200 yr frequency which corresponds to the de vries solar cycle suggesting that in addition to insolation changes resulting from orbital variations solar forcing also results from cyclic changes in the sun s luminosity

precipitation in the yellow river drainage basin and east asian monsoon strength on a decadal time scale abstract paleomonsoon strength is difficult to reconstruct the strength of the east asian monsoon and precipitation over large areas correlate well on a decadal time scale thus monsoon strength can be reconstructed through proxies of sediments originating from large areas in the present study we investigated the characteristics of a sediment core from the northern yellow sea mud the results showed that sedimentary characteristics are mainly controlled by discharge changes of the yellow river the relationships between median grain size mz magnetic susceptibility ms and the sio2 al2o3 ratio of sediments and spatially averaged precipitation around the yellow river drainage basin reveal that changes in mz and ms are correlated with variation in precipitation the agreement of temporal trends in mz ms and the monsoon strength index confirm that spatially averaged precipitation changes in the yellow river drainage basin on decadal time scale are driven by the monsoon strength these characteristics of marine sediments from the northern yellow sea mud can thus be used as proxies for monsoon strength

holocene paleoenvironmental changes in mud area southwest off cheju island east china sea evidence from benthic foraminiferal assemblages and stable isotope records abstract a sediment core retrieved from the mud area southwest off cheju island masci was analysed for benthic foraminifera grain size and stable isotopes and constrained by ams14c dating holocene paleoenvironmental changes in this broad shallow shelf were investigated with special focus on the evolution of the masci and its related ocean eddy system the results indicate that the east china sea shelf has undergone four major environmental evolution stages during the holocene prior to 9 8 cal kyr bp the benthic foraminiferal assemblages were dominated by low salinity shallow water species ammonia beccarii linnaeus elphidium advenum cushman and cribrononion subincertum asano reflecting a near coast deposit environment a noticeable transition of the benthic foraminifera from an a beccarii dominated to ammonia compressiuscula brady dominated assemblage taking place at approximately 9 8 cal kyr bp together with a contemporaneous increase in 18o and 13c provides evidence that a rapid rise in sea level occurred at this time in the east china shelf a gradual increase in 18o between 9 8 and 6 cal kyr bp indicates a steady strengthening influence of open ocean water on the area under study a sudden increase in the abundance of benthic foraminifera along with a decrease in the coarse fraction imply that an early eddy circulation system was established since almost 6 cal kyr bp in the masci this eddy circulation system was quite weak but gradually strengthened between 6 and 3 cal kyr bp possibly due to the intrusion of the yellow sea warm current yswc a more stable mud deposition period characterised by a high sedimentation rate of fine grained sediment and lighter value of 13c starting at approximately 3 cal kyr bp indicates that the masci was formed mainly during the late holocene we believe that the strengthened yswc since 3 cal kyr bp might increase the trap efficiency of the eddy system thereby accounting for the high sedimentation rate of mud deposits during this period

sediment accumulation and budget in the bohai sea yellow sea and east china sea abstract sediment accumulation and budget in the continental margins provides abundant information of source sink processes from the land to the sea including weathering human activities and sedimentary environment here we show the distribution of mud areas modern sedimentation rates and sediment budget in the bohai sea yellow sea and east china sea using grain size data of 18 000 surface sediment samples and 210 pb data from 413 sites we identify five areas with sediments mainly composed of fine grained fractions mean grain size 6 and find a relatively high sedimentation rates of 1 5 mm yr in the mud areas near the yellow and yangtze river deltas sedimentation reaches 95 0 mm yr approximately 1185 4 10 6 tons of fine grained sediment accumulate annually in the mud areas of the east china seas atmospheric deposition contributes 6 tons yr while the riverine sediment inputs account for 75 917 10 6 tons yr the remainder comes from all other sources including coastal erosion and resuspension of bottom sediments in addition 45 of the fluvial sediment supply deposits on the subaerial delta 40 50 is trapped on the subaqueous delta and shelf and the remainder

origin of salinity in a multilayered aquifer with high salinization vulnerability the kaluvelly watershed is a coastal area tamil nadu india where water abstraction has resulted in a dramatic fall in the level of the water table and a piezometric depression in the most exploited aquifer the vanur aquifer in addition intensification mechanization of agriculture may have affected the quality of recharge water an initial hydrodynamic study showed that the vanur aquifer is highly vulnerable to salinization due to potential seawater intrusion and our aim was to determine the source of salinity recorded in the groundwater of this multilayered aquifer our approach involved the use of existing boreholes and of a moderate number of samples with the aim of developing appropriate water resource management techniques major elements 18o 16o 2h 1h and 87sr 86sr ratios were measured in rainwater surface water and groundwater collected during five sampling campaigns over a two year period geochemical data indicate that the vanur aquifer is recharged and that small mixings between aquifers fluctuate according to monsoon intensity there was no evidence of seawater intrusion the range of recorded salinity originated mainly from water rock interaction but a disconnection of some deeper parts of the aquifer was apparent strontium isotopic ratios in the recharge area suggest an anthropogenic influence possibly related to fertilizer use a high so4 cl ratio was observed in the aquifer in the deeper parts the influence of a formation containing lignite is hypothesized whereas near the surface sulphate may partly originate from fertilizer use and fossil fuel combustion water isotopic data suggest that the origin of precipitation in this region has been unchanged for several hundreds or thousands of years

onset of asian desertification by 22 myr ago inferred from loess deposits in china the initial desertification in the asian interior is thought to be one of the most prominent climate changes in the northern hemisphere during the cenozoic era1 2 3 4 but the dating of this transition is uncertain partly because desert sediments are usually scattered discontinuous and difficult to date here we report nearly continuous aeolian deposits covering the interval from 22 to 6 2 million years ago on the basis of palaeomagnetic measurements and fossil evidence a total of 231 visually definable aeolian layers occur as brownish loesses interbedded with reddish soils this new evidence indicates that large source areas of aeolian dust and energetic winter monsoon winds to transport the material must have existed in the interior of asia by the early miocene epoch at least 14 million years earlier than previously thought3 5 regional tectonic changes and ongoing global cooling are probable causes of these changes in aridity and circulation in asia

strontium isotopic evolution of oil field waters from carbonate reservoir rocks in bindley field central kansas u s a abstract oil field waters produced from mississippian carbonate reservoir rocks in bindley field kansas had an average salinity of about 42 8 mg l they were enriched in ca sr na k rb and li and depleted in mg relative to sea water at the same level of either cl or br concentration the average abundances of different elements are as follows na 13 460 mg l k 325 mg 1 rb 0 9 mg l li 12 mg l ca 1 515 mg l sr 42 mg l mg 430 mg l cl 23 000 mg l so4 2 630 mg l br 32 mg l the 87 sr 86 sr values of the waters ranged between 0 7221 and 0 7230 whereas the values of the host carbonate rocks were between 0 7090 and 0 7093 the very high 87 sr 86 sr values of the waters probably occurred as a result of their reaction with alkali feldspar minerals in buried precambrian crystalline rocks to the east of the bindley field the study demonstrates that despite their residence in carbonate reservoir rocks oil field waters can retain sufficiently distinct isotopic memory that may provide important dues about mineral water interactions in the chemical evolutionary history of the waters the study further indicates that very late diagenetic reactions in many carbonate rocks are of minor extent difference in the sr isotopic data among the oil field waters suggests that the sr isotopic data can be used as a reliable guide in recognising existence of separate pools in an oil field

records of late holocene east asian winter monsoon in the east china sea key grain size component of quartz versus bulk sediments abstract quartz isolated from bulk sediments taken from a core obtained from the distal mud area in the outer shelf of the east china sea was used as a proxy in order to determine the strength of the east asian winter monsoon eawm this data was compared with the grain size of bulk sediment from the same core it was found that the content of the key quartz based indicator fraction 15 2 65 6 m correlated well with the eawm strength with reference to current conditions high content of quartz in the selected fraction reflected strong eawm and vice versa the core record spanned 2100 years and three periods of change in eawm strength were identified a period of increased eawm strength prior to 1520 cal bp was followed by a period of weakened eawm strength from 1520 to 720 cal bp which is consistent with the sui tang warm period and the medieval warm period this is followed by a period of slightly increased eawm between 720 and 220 cal bp which corresponds to what is called the little ice age the history of eawm revealed by the quartz based proxy is in striking agreement with results from a previous study on bulk sediment based proxy however the quartz based proxy showed much higher sensitivity and resolution to the eawm strength and displayed much more distinct and sharper boundaries of transition across the three intervals of eawm change compared to the bulk sediment records eleven short eawm strengthening periods were found compared with four by the bulk sediment based proxy therefore this suggests that the quartz grain size proxy is a superior indicator of the winter monsoon strength in the study area

sedimentary laminae in muddy inner continental shelf sediments of the east china sea formation and implications for geochronology abstract the sedimentary rhythm is well developed in the environment which is controlled by strong seasonal climate changing condition this rhythm is important for sediment core dating purpose in this study we examine muddy sediments on the inner continental shelf of the east china sea that are influenced under seasonal change of the east asian monsoon we use ensemble empirical mode decomposition eemd method to process sediment grain size and x radiograph negatives grayscale value data in three sediment cores from this area and use the results to analyze the patterns of sedimentary variability and the causes of cyclic variability of the sedimentary process the variability in the grain size and grayscale values of the core sediments has three components the high frequency variability low frequency variability and a secular trend among these components the high frequency component reflects variability on annual time scale can be well recognized we suggest that the annual variability is derived from seasonal variation in the sediment flux from the yangtze river to the sea as well as the east asian monsoon s impact on the sedimentary dynamics of the east china sea s inner continental shelf however the other variability is hard to identify which cycles there are this variability may reflect decadal winter monsoon oscillation and human activity of dam construction in the yangtze river each annual variability presents a varve in the sediment sequence which can be used to determine the sediment deposition rate and accurately date the core sediment we found that the average deposition rates of the three cores from north to south on the inner shelf were 3 1 cm yr 1 0 cm yr 0 9 cm yr indicating that the yangtze derived sediment decreased with the increasing distance from the yangtze estuary to the shelf the deposition rate of each core varies over time and the maximum deposition rate can be 3 5 times greater than the minimum rate the sediment ages obtained from varve chronology and radiometric dating are fairly consistent on a centennial scale differing only by 2 5 years thus varve counting is a useful supplementary approach to radiometric age dating for constructing chronologies for core sediment in shelf seas influenced by monsoons

correlation between climate events in the north atlantic and china during the last glaciation episodes of massive iceberg release heinrich events 1 3 into the north atlantic ocean during the last glaciation were associated with recurring episodes of unusually cold north atlantic surface water bond cycles 4 and cold air temperatures over greenland dansgaard oeschger events 5 6 four of the youngest of these cold events have also been reported in climate records from sites outside the north atlantic region7 but until now the entire suite has been identified only in north atlantic marine sediments greenland ice core records and tentatively in french lake sediments8 here we examine grain size data from chinese loess and intercalated accretionary palaeosols of last glacial age for evidence of similar climate signals remote from the north atlantic region we see grain size maxima with ages that match those of the last six heinrich events which we interpret as an indication of the changing strength of the east asian winter monsoon which largely controls the transport and deposition of central asian aeolian dust thus it seems that these heinrich events have left their signature in the chinese loess record this is consistent with simulations of the glacial climate9 which imply that the climates of the north atlantic and china were linked by the effect of westerly winds