estimating groundwater exchange with lakes 1 the stable isotope mass balance method groundwater inflow and outflow contributions to the hydrologic budget of lakes can be determined using a stable isotope 18o 16o mass balance method the stable isotope method provides a way of integrating the spatial and temporal complexities of the flow field around a lake thereby offering an appealing alternative to the traditional time and labor intensive methods using seepage meters and an extensive piezometer network in this paper the method is applied to a lake in northern wisconsin demonstrating that it can be successfully applied to lakes in the upper midwest where thousands of similar lakes exist inflow and outflow rates calculated for the wisconsin lake using the isotope mass balance method are 29 and 54 cm yr respectively which compare well to estimates derived independently using a three dimensional groundwater flow and solute transport model of 20 and 50 cm yr such a favorable comparison lends confidence to the use of the stable isotope method to estimate groundwater exchange with lakes in addition utilization of stable isotopes in studies of groundwater lake systems lends insight into mixing processes occurring in the unsaturated zone and in the aquifer surrounding the lake and verifies assumed flow paths based on head measurements in piezometers

an isotopic study 2h and 18o of water movements in clayey soils under a semiarid climate we applied the natural variations of stable isotopes in water to the study of infiltration in clayey soils and to the study of groundwater recharge in the small drainage basin of barogo in west africa the comparison between the variations in isotopic contents of soil water and rainwater in 1988 and 1989 led us to characterize two infiltration processes 1 an infiltration through the soil matrix of rainwater that mixed with mobile water which was held in the superficial part of the soil and was enriched in heavy isotopes by evaporation and 2 a fast and deeper infiltration by preferential flow along macropores that bypassed the superficial part of the soil the study of the variations in groundwater isotopic content led us again to separate the recharge process into two components 1 a slow infiltration through the soil matrix and the weathered basement distributed recharge and 2 a fast and direct recharge through conducting fissured zones localized recharge a schematic and local representation of groundwater recharge in the barogo basin allowed us to estimate that direct recharge represented around 70 of the total recharge in 1989

isotope c and o composition of auriferous quartz carbonate veins central lode system gadag gold field dharwar craton india implications to source of ore fluids abstract carbon 13 c pdb and oxygen 18 o smow isotopic compositions of auriferous quartz carbonate veins qcvs of gold deposits from sangli kabuliyatkatti nagavi nabapur and mysore mining areas developed on the central lode system of the gadag gold field ggf in the neoarchaean gadag schist belt of the dharwar craton southern india have been examined for the first time to understand the origin of the mineralising fluids in majority of the samples 46 out of 49 13 c pdb of carbonates of the qcvs fall in the range from 2 2 to 9 7 and the 18 o values range from 12 0 to 30 5 smow the calculated fluid 13 c c compositions for these deposits range from 2 1 to 9 6 and 18 o h 2 o from 6 8 to 25 9 respectively carbonate 13 c and fluid 13 c c compositions of the carbonates of the qcvs of the ggf are not only distinct from the carbon isotope range of marine carbonates or meta sedimentary carbonates of the chitradurga schist belt but are consistent with c isotope values of magmatic 5 3 burrows et al 1986 and or mantle 6 2 ohmoto 1986 carbonates as dissolution decarbonation reactions during metamorphism of pre existing carbonate carbonated rocks produce co 2 with 13 c values similar to or more enriched than parent rock the carbonate or fluid 13 c ratios of the qcvs which fall in the compositional range of mantle magmatic derived co 2 or carbonates obtained in this work cannot be the result of metamorphism the present study corroborates our previous reports from ajjanahalli and g r halli gold deposits sarangi et al 2012 occurring in the vicinity of the southern extension of the same crustal scale shear zone on which all the ggf deposits are located the age of gold mineralisation in this area has been reported to be 2522 6 ma by sarma et al 2011 chardon et al 2011 have proposed large scale remobilization of the older gneissic basement as well as emplacement of juvenile granites between 2559 ma and 2507 ma close to the crustal scale shear zone along the eastern margin of the chitradurga schist belt based on these observations and our isotope studies it is proposed that gold mineralising fluids were derived from mantle juvenile magmatic melts and were channelled through crustal scale shear zones to give rise to the gold deposits in the ggf

short and long term temporal variations in salinity and the oxygen carbon and hydrogen isotopic compositions of the hooghly estuary water india abstract the hooghly river estuary provides a unique experimental site to understand the effect of monsoonal river discharge on freshwater and seawater mixing water samples collected bi weekly for a duration of 17 months were analyzed for salinity 18o 13cdic as well as d to investigate the differential mixing of freshwater and seawater the differences in salinity and 18o of samples collected during low and high tides on the same day are strongly correlated suggesting a well mixed water column at our sampling site low salinity and depleted 18o during monsoon is consistent with increased river discharge as well as high rainfall we identified different slopes in a 18o versus salinity plot for the estuary water samples collected during monsoon and non monsoon seasons this is driven by composition of the freshwater source which is dominated by rainwater during monsoon and rivers during non monsoon months selected d analyses of samples indicate that groundwater contributes significantly to the hooghly estuary during low rainfall times of the year 13cdic measured in the water recorded low values towards the end of monsoon indicating low productivity i e increased organic respiration while progressively increasing 13cdic values from october till january as well as during some of the pre monsoon months can be explained by increasing productivity very low 13cdic 20 suggests involvement of carbon derived from anaerobic oxidation of organics and or methane with potential contribution from increased anthropogenic water supply an estimate of seawater incursion into the hooghly estuary at different times of the year is obtained by using salinity data in a two component mixing model presence of seawater was found maximum 31 37 during february till july and lowest less than or equal to 6 from september till november we notice a temporal offset between ganges river discharge farther upstream at farakka and salinity variation at the hooghly estuary we believe that this time lag is a result of the physical distance between farakka and kakdweep our sampling location and put constraints on the travel time of river water during early monsoon

environmental isotopes investigation on recharge processes and hydrodynamics of the coastal sedimentary aquifers of tiruvadanai tamilnadu state india summary environmental isotopes 2 h 18 o 3 h 13 c 14 c 34 s in conjunction with hydro geological and hydro chemical data were employed to understand the groundwater recharge processes and hydrodynamics of the tiruvadanai aquifers in the tamilnadu state in southern india hydro chemical characterisation of the groundwater indicated that the tertiary aquifers depth 50 200 m un confined semi confined confined contain no dominant ca mg hco 3 cl to brackish na cl type of waters and the deeper 350 500 m cretaceous aquifer confined contains freshwater the concentration of various chemical species along the general groundwater flow direction northwest to east showed a trend with decrease in mg 2 and ca 2 and an increase in na and k in both tertiary and cretaceous aquifers which is also indicated by decreasing saturation index values for dolomite along the flow path this could be attributed to ion exchange processes a higher ph value of cretaceous aquifer samples 7 4 8 6 could also be responsible for the lowering of mg 2 and ca 2 concentrations by facilitating precipitation of carbonates in them on the 2 h 18 o plot the tertiary aquifers samples fall on an evaporation line their 3 h values near the ephemeral rivers range from 2 to 5 tu while those away from the rivers have 14 c dic model ages range from 1 to 13 ka bp the cretaceous aquifer samples measured 3 h values 14 c dic model ages are 20 ka bp indicating palaeo waters based on 14 c model ages the groundwater velocity was estimated tertiary aquifers 10 2 10 3 m d 1 cretaceous aquifer 10 3 m d 1 dissolution of carbonate bearing minerals in the tertiary aquifer and oxidation of organic matter in the cretaceous aquifers seems to be the dominant processes and thus resulting in the corresponding enrichment and depletion in 13 c dic along the flowpaths the values of 34 s aq so 4 2 showed enrichment in the cretaceous aquifer samples compared to that of the tertiary aquifers samples the 34 s aq so 4 2 enrichment could be due to bacterial reduction of sulphate from the investigation three types of recharge processes to the aquifer system are discerned with the overall modern recharge component being low the cretaceous aquifer contains fossil groundwaters and hence the resources may be finite and their exploitation is mining deeper coastal groundwater isotopic evidence of palaeo climatic excursions between arid and humid phases during the holocene and late pleistocene in the southern india has been obtained for the first time

distribution of oxygen and hydrogen isotopes in shallow groundwaters from southern india influence of a dual monsoon system oxygen and hydrogen isotopic investigation of groundwater and river water samples from the southern indian peninsula was undertaken to characterise the isotopic nature of the near surface water sources and provide basic framework for future hydrological studies it is assumed that the shallow groundwater retains the isotopic signature of the local precipitation averaged over a few tens of years except in a few cases where the same gets modified by post precipitation evaporation and or recharge contribution from surface water bodies therefore isotopic character of the groundwater can in principle be used to determine the relative influence of the different vapour sources contributing to the local regional precipitation and to characterise the modifications before groundwater recharge in the present context vapour sources for two rainy seasons namely southwest sw and northeast ne monsoon are respectively the indian ocean arabian sea and the asian continental sources together with the bay of bengal this study shows that i the regions dominated by ne monsoon have distinctly depleted isotopic composition compared to those dominated by sw monsoon ii the 18o d regression line slope of 6 in the east coast region is lower than that expected for local precipitation suggesting secondary evaporation iii the orography of the western ghats hill ranges plays a significant role in controlling the isotopic distribution along the west coast region iv the low d excess values in most part of study area indicate secondary evaporation v the high d excess values over the deccan plateau region in the nw part of the study area suggest admixture of recycled moisture with the inflowing oceanic vapour

groundwater δ18o and δd from central indian peninsula influence of the arabian sea and the bay of bengal branches of the summer monsoon abstract results of oxygen and hydrogen isotopic investigations of shallow groundwater and river water samples from the central indian peninsula are reported the study was undertaken to isotopically characterise the near surface water sources and identify the influence of the two branches of the indian summer monsoon june september in this region the western part of the study area receives vapour flux largely from the arabian sea branch whereas the eastern part receives significant vapour flux from the bay of bengal branch no significant rainfall occurs in the study area during northeast winter monsoon period of october december or the remaining part of the year therefore the isotopic character of shallow groundwater from this region could be used to study the relative influence of the vapour sources from the arabian sea and the bay of bengal the study shows that i the northeast part receiving significant rainfall from the bay of bengal branch has a distinctly depleted isotopic composition 18 o 5 2 compared to areas receiving dominant rain from the arabian sea branch 18 o 1 1 ii in the west coastal belt the average 18 o in groundwater is close to the average 18 o of precipitation at bombay 1 4 1 1 but groundwater samples in the entire deccan plateau region show signatures of evaporative enrichment in the form of a low slope 6 5 of 18 o d regression line b low d excess 0 5 and c slightly enriched 18 o values 1 1 compared to those expected from the limited precipitation data from stations in maner basin approximately in the middle of the study area iii depleted ground waters along the central indian east coast could arise due to continental rainout of the arabian sea vapour source as the moisture laden monsoon winds crossover to the bay of bengal alternatively it is necessary to postulate that the surface waters of the bay of bengal contributing to inland vapour flux are significantly more depleted during the monsoon period than the known depletion of 1 it is also possible that both factors are operative

glacial to interglacial contrasts in the northern indian ocean differences between the 18o 16o ratios of planktonic foraminifera deposited during the last glacial maximum about 18 000 yr ago and those deposited during the holocene show that in the indian ocean the south west monsoon was weaker than today but that the north east monsoon was stronger the upwelling observed in modern conditions along the southern coast of arabia had disappeared because of the low speed of the southwestern winds during glacial summers the reduction in rainfall and runoff over the continent caused a reduction of the salinity gradient in the bay of bengal and along the western coast of india increased precipitation fell on the sea south of 10 n while strong evaporation over the northernmost arabian sea produced an enhanced salinity gradient in that area

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

subsidence and thermal history of queen charlotte basin a tectonic model for the formation subsidence and thermal history of queen charlotte basin is developed based upon regional geological and geophysical data subsidence data from offshore wells in hecate strait and queen charlotte sound and thermal criteria derived from present heat flow and vitrinite reflectance information queen charlotte basin is seen to have resulted from two distinct mechanisms 1 during a period of broad regional uplift rifting and crustal extension occurred in queen charlotte sound up to about 17 ma ago and the queen charlotte islands were displaced northwards toward their present position by transcurrent motion along the louscoone inlet sandspit fault system the rifting generated a significant thermal anomaly and a restricted deep basin as a consequence of crustal thinning and subsequent thermal cooling 2 beginning about 6 ma ago oblique underthrusting commenced along the margin resulting in flexural uplift of the western part of the queen charlotte islands and comp

effect of enriched early dropped rainwater on mesoscale isotopic distribution in surface water on the kii peninsula japan 1 mesoscale spatial distributions and temporal variations of oxygen and hydrogen isotope compositions in surface waters were observed on the kii peninsula japan which receives more than 3000 mm of precipitation annually the enriched isotopic values were distributed along the western southern and eastern coasts to explain this we proposed a new parameter early dropped rainwater frequency erf and defined it as the number of times that early dropped rainwater was first observed in a domain erf can be considered a characteristic of rainfall and it is a useful parameter for clarifying mesoscale isotopic distribution a mass balance simulation suggested the early dropped rainwater determined the specific isotopic value of stream water in a watershed

oxygen and hydrogen isotopes for the characteristics of groundwater recharge a case study from the chih pen creek basin taiwan assessing the seasonal variation of groundwater recharge is important for effective management of groundwater resources stable isotopes of oxygen and hydrogen were used to estimate the sources of groundwater and seasonal contributions of precipitation to groundwater recharge in chih pen creek basin of eastern taiwan based on the isotopes of precipitation n 177 two different local meteoric water regression lines lmwl can be obtained for the different seasons d 8 0618o 10 08 for wet season precipitation may through october and d 8 65 18o 17 09 for dry season precipitation november through april the slope and intercept of regression line for wet season precipitation are virtually identical to the global meteoric water line gmwl of craig 1961 in contrast to during dry season precipitation due to evaporation effect the intercept of 17 09 is much higher than of the gmwl of 10 the results show the stable isotopes compositions of precipitation decrease with increasing rainfall amount and air temperature due to the amount effect of precipitation is pronounced the amount effect is clearly but do not show the temperature effect from january to december 2007 using a mass balance equation a comparison of deuterium excess or d values of precipitation and groundwater indicates the groundwater consist of 76 wet season precipitation and 24 dry season precipitation representing a distinct seasonal variation of groundwater recharge in study area about 79 of the groundwater is recharged from the river water of the mountain watershed and 21 is from the rain that falls on the basin

isotopic characteristics of indian precipitation 1 hydrogen 2h 1h and oxygen 18o 16o isotopic ratios were measured in precipitation 900 samples collected from several locations in india during the period 2003 2006 12 locations in 2003 and 18 locations in 2004 2006 the amount of rainfall along with air temperature and humidity were also measured the meteoric water line developed for india using isotopic data of precipitation samples namely 2h 7 93 0 06 18o 9 94 0 51 n 272 r2 0 98 differs slightly from the global meteoric water line regional meteoric water lines were developed for several indian regions i e northern and southern regions of india western himalayas and found to be different from each other southern indian meteoric water line slope is 7 82 intercept or d excess is 10 23 northern indian meteoric water line slope is 8 15 intercept is 9 55 which is attributed to differences in their geographic and meteorological conditions and their associated atmospheric processes i e ambient temperature humidity organ and source of vapor masses the local meteoric water lines developed for a number of locations show wide variations in the slope and intercept these variations are due to different vapor sources such as the northeast ne monsoon that originates in the bay of bengal the southwest monsoon sw that originates in the arabian sea a mixture of ne and sw monsoons retreat of ne and sw monsoons and western disturbances that originate in the mediterranean sea the altitude effect in the isotopic composition of precipitation estimated for western himalayan region also varies from month to month

an alternative view on the origin of chemical and isotopic patterns in groundwater from the milk river aquifer canada the milk river artesian aquifer underlies 15 000 km2 of southern alberta canada it consists of thin 30 75 m thick sandstone and is confined above by the pakowki shale typically 120 m thick and below by the colorado shale the aquifer subcrops in southern alberta and northern montana groundwater movement is to the north west and east from the outcrop area dominant recharge area cl and i concentrations increase in the direction of flow from less than 0 05 and 0 001 mmol l respectively near the recharge area to more than 140 and 0 15 mmol l at the northern edge of the aquifer similarly waters become more enriched in oxygen 18 and deuterium from less than 21 0 and 167 near the recharge area to values approaching 8 0 and 70 0 in the north isotope values in the recharge area plot on the global meteoric water line and indicate that the recharge waters are isotopically unaltered meteoric waters downgradient from the recharge area the data deviate from the meteoric water line slope of 6 3 instead of 8 0 three mechanisms have been advanced to explain the origin of the chemical and isotopic patterns the introduction of connate formation water through the colorado shale and subsequent mixing with infiltrating meteoric water a finite source of meteoric recharge mixing with more saline water in the aquifer and chemical and isotopic enrichment due to ion filtration hydraulic conductivity and hydraulic head data cl concentrations of drill cuttings and isotopic values from groundwater from the colorado shale provide arguments for reevaluating these ideas an alternative mechanism based on diffusion between saline isotopically enriched water in the colorado shale and fresher isotopically depleted water in the aquifer is tested using an analytical mass transport model although uncertainty exists in the model parameters results showed that the patterns in cl i 18o and 2h in the aquifer can be explained by aquitard diffusion further aquitard diffusion must be considered when using chlorine 36 dating methods in aquifer aquitard systems such as the milk river aquifer

hydrochemical and isotopic characteristics of groundwater in the ndop plain northwest cameroon resilience to seasonal climatic changes shallow groundwater 30 mbgl is an essential source of drinking water to rural communities in the ndop plain northwest cameroon as a contribution to water management the effect of seasonal variation on the groundwater chemistry hydrochemical controls drinking quality and recharge were investigated during the peaks of the dry january and rainy september seasons field measurements of physical parameters were preceded by sampling 58 groundwater samples during both seasons for major ions and stable isotope analyses the groundwater which was barely acidic mean ph of 6 and less mineralised tds ca2 mg2 k and na mg2 ca2 k in the dry and rainy seasons respectively but that of anions text hco 3 text no 3 cl text so 4 2 f was similar in both seasons this suggests a negligible effect of seasonal variations on groundwater chemistry the groundwater which was camghco3 and nahco3 is chemically evolved rainfall camgso4cl in the area silicate mineral dissolution and cation exchange were the main controls on groundwater chemistry while there was little anthropogenic influence the major ions and tds concentrations classified the water as suitable for human consumption as per who guidelines the narrow cluster of 18o and d of same groundwater from both seasons between the 18o and d values of may june precipitation along the ndop meteoric water line indicates meteoric origin rapid recharge after precipitation and timing of recharge between may and june rainfall diffuse groundwater recharge mainly occurs at low altitudes 1 400 m asl within the plain besides major ions and tds the similar 18o and d of groundwater from both seasons indicate a consistent groundwater recharge and flow pattern throughout the year and resilience to present day short term seasonal climatic variations however controlled groundwater abstraction is recommended given the increasing demand

evolution of the queen charlotte basin further paleomagnetic evidence of tertiary extension and tilting abstract the queen charlotte islands form the northwestern margin of the queen charlotte basin the basin which was formed by extension contains numerous mid tertiary lavas plutons and dykes referred to as the masset igneous complex and eocene to present marine and non marine sedimentary rocks throughout its history the basin has been bounded on the west by a north northwest oriented transform plate boundary the queen charlotte fault initially motion along this fault was transtensional phase 1 then more purely transform phase 2 and finally transpressive phase 3 most of the masset igneous complex appears to have been formed under transtension phase 1 middle eocene through early miocene previous paleomagnetic studies of the complex 129 sites mainly from the southern queen charlotte islands and new results herein 102 sites mainly from the northern islands illustrate magnetizations with inclinations generally steeper than those expected from coeval rocks of continental north america indicating north south extension segmentation and tilting of fault bound slivers along the western margin of the basin we argue that this north south extension occurred in phase 2 during the middle and or late miocene long after the main east west extension of phase 1 results from the northwest corner of the queen charlotte islands although commonly anomalous are not oversteepened and may delineate a structural domain separate from the rest of the archipelago as a by product this study provides two reference paleopoles for north america one for the late eocene early oligocene from ramsay island lavas 78 1 n 119 9 e a 95 7 0 and one of lesser reliability for the early miocene from the lavas of dinan bay 83 3 n 137 8 e a 95 9 8 a second by product is that the magnetic polarities and radiometric ages are consistent with the cande and kent global geomagnetic polarity time scale

identification of groundwater recharge sources and processes in a heterogeneous alluvial aquifer results from multi level monitoring of hydrochemistry and environmental isotopes in a riverside agricultural area in korea we evaluated sources and pathways of groundwater recharge for a heterogeneous alluvial aquifer beneath an agricultural field based on multi level monitoring of hydrochemistry and environmental isotopes of a riverside groundwater system at buyeo korea two distinct groundwater zones were identified with depth 1 a shallow oxic groundwater zone characterized by elevated concentrations of no3 and 2 a deeper 10 14 m from the ground surface sub oxic groundwater zone with high concentrations of dissolved fe silica and hco3 but little nitrate the change of redox zones occurred at a depth where the aquifer sediments change from an upper sandy stratum to a silty stratum with mud caps the 18o and 2h values of groundwater were also different between the two zones hydrochemical and 18o 2h data of oxic groundwater are similar to those of soil water this illustrates that recharge of oxic groundwater mainly occurs through direct infiltration of rain and irrigation water in the sandy soil area where vegetable cropping with abundant fertilizer use is predominant oxic groundwater is therefore severely contaminated by agrochemical pollutants such as nitrate in contrast deeper sub oxic groundwater contains only small amounts of dissolved oxygen do and no3 the 3h contents and elevated silica concentrations in sub oxic groundwater indicate a somewhat longer mean residence time of groundwater within this part of the aquifer sub oxic groundwater was also characterized by higher 18o and 2h values and lower d excess values indicating significant evaporation during recharge we suggest that recharge of sub oxic groundwater occurs in the areas of paddy rice fields where standing irrigation and rain water are affected by strong evaporation and that reducing conditions develop during subsequent sub surface infiltration this study illustrates the existence of two groundwater bodies with different recharge processes within an alluvial aquifer copyright 2009 john wiley sons ltd

stable isotope evidence of dual arabian sea and bay of bengal vapour sources in monsoonal precipitation over north india abstract high resolution time series data of hydrogen d and oxygen 18o isotope values of precipitation have been generated for the first time at kolkata eastern india where the summer monsoon clouds from bay of bengal bob commence their journey over india use of a rayleigh cum two component mixing model and comparison of kolkata data with the international atomic energy agency iaea global network of isotopes in precipitation gnip data base of new delhi suggest that the precipitation at new delhi cannot be explained by simple continental effect of a bob vapour source alone traveling and raining successively along kolkata new delhi route it is necessary to invoke an admixture of 20 vapour originating from the arabian sea with the vapour coming from bob and finally causing summer monsoon rains at new delhi the findings have major implications to the regional water vapour budget over india

comparison of resinite related aromatic biomarker distributions in cretaceous tertiary coals from canada and germany a set of 13 cretaceous tertiary coals from western canadian coal deposits and two cretaneous coals from the southern part of the lower saxony basin of germany have been investigated using microscopial and organic geochemical methods the coals are in the ranl range of lignite to medium volatile bituminous 0 37 1 13 rr petrographically the coals are characterized by varying proportions in vitrinite inertinite and liptinite groups in most of the coals resinite constitutes the major liptinite component both of the german wealden coals are composed exclusively of conifer needles gc ms analyses indicate differences in the composition of resin related molecular biomarkers comparing samples from both deposits in the canadian coals of moderate rank 0 4 0 8 rr resin related napthalene derivatives are associated with tricyclic aromatic hydrocarbons such as retene abieta 6 8 11 13 tetraene simonellite and c5 phenanthrene samples higher in rank about 1 1 rr provide fully aromatized and partly desalkylated phenanthrene homologues generation of 1 methylphenanthrene from retene during maturation affects molecular rank parameters like mpr and mpi 1 additionally an intra seam homogenization of resin derived aromatic hydrocarbon is observed in comparison the german wealden coal extracts are dominated by bicyclic aromatic hydrocarbons and they are poor in tricyclic hydrocarbons analyses of hand picked macerals resinites and cutinites by thermodesorption coupled to gc ms indicate the presence of two potential sources for the naphthalene derivatives c4 tetralin is primarily associated with the resins of abietites linkii 1 2 5 trimethylnaphthalene and 1 2 5 6 tetramethylnapthhalene are probably derived from the fluorinite filling of the conifer needles

short term variability in the dates of the indian monsoon onset and retreat on the southern and northern slopes of the central himalayas as determined by precipitation stable isotopes this project launched the first study to compare the stable isotopes 18o and d in daily precipitation at kathmandu located on the southern slope of the central himalayas and tingri located on the northern slope the results show that low 18o and d values of summer precipitation at the two stations were closely related to intense convection of the indian monsoon however summer 18o and d values at tingri were lower than those at kathmandu a result of the lift effect of the himalayas coupled with convection disturbances and lower temperatures at tingri in winter the relatively high 18o and d values at the two stations appears to have resulted from the influence of the westerlies compared with those during the summer the subsidence of the westerlies and northerly winds resulted in relatively high 18o and d values of the winter precipitation at tingri winter 18o and d values at kathmandu far exceeded those at tingri due to more intense advection of the southern branch of the westerlies and higher temperatures and relative humidity at kathmandu the detailed differences in stable isotopes between the two stations follow short term variability in the onset date of the indian monsoon and its retreat across the central himalayas during the sampling period the indian monsoon onset at tingri occurred approximately 1 week later than that at kathmandu however the retreat at tingri began roughly 3 days earlier clearly the duration of the indian monsoon effects last longer at kathmandu than that at tingri our findings also indicate that the india monsoon travels slowly northward across the central himalayas due to the blocking of the himalayas but retreats quickly

extension in high grade terranes of the southern omineca belt british columbia evidence from paleomagnetism paleomagnetic observations are used to construct a map of structural tilts in metamorphic and plutonic rocks of the southern omineca belt in southeastern british columbia during eocene extension midcrustal rocks were exhumed in footwalls of low to moderate angle normal faults that dip east and west in the eastern and western parts of the study area respectively tilts averaging 30 to 40 are consistent over large areas and generally antithetic to the major faults in the central part of the study area however the eastern half of the coryell pluton is untilted and its western half in the hanging wall of the east dipping kettle river fault is tilted down to the east in the opposite sense to that expected north of the pluton these eastward tilted rocks are juxtaposed against westward tilted rocks to explain the anomalous tilts a major west dipping eocene normal fault arrow lake fault is inferred and a revised kinematic history for the area proposed observations of magnetic polarity 86 normal laboratory unblocking temperatures and isotopic age data suggest that magnetizations in the west were acquired during chron 23n and in the east in chron 23n and or chron 24n unless extension postdated the acquisition of magnetization tilts would not be observed thus it is argued that extension in the west occurred after 50 6 ma and in the east between 51 6 possibly 53 3 and 50 6 ma these time intervals do not correspond to any known global plate reorganization event indicating that the last phase of eocene extension in the southern omineca belt was governed by regional rather than global processes

an attempt to understand the behavior of dissolved organic carbon in coastal aquifers of pondicherry region south india groundwaters of the coastal region are significant and serve as a fragile ecosystem in the sedimentary terrain the pondicherry region is characterized by different geological formations of distinct geological epochs cretaceous tertiary and quaternary ninety three samples were collected from specific aquifers with respect to spatial distribution alluvium 31 upper cuddalore 13 lower cuddalore 13 other tertiary 7 cretaceous 24 and mixed multiple completion aquifer 5 the collected samples were analyzed for major ions ca2 mg2 na k hco3 cl po42 so42 f and doc stables isotopes of 18o d and 13c were also analyzed along with heavy metals like al ba fe sr cd and zn the 18o ranges between 6 85 and 2 15 and d ranges between 43 94 and 19 41 the distribution of these environmental isotopes in groundwater of this layered aquifer sequence was also attempted a comparison of the isotopic data with the rainfall local meteoric water line with a equation of d 7 398 18o 5 067 indian meteoric water line and global meteoric water line was performed the 13c values for groundwater ranges from 5 3 to 18 1 the result indicates that the groundwater in the study area is mainly meteoric in origin and few samples show evidence of evaporation the dissolved organic carbon doc is a very important component in biogeochemical cycling of elements characterized by high susceptibility to leaching the range of the doc in the study area is 0 16 mg l factor analysis was applied to classify the groundwater samples and to identify geochemical processes controlling groundwater geochemistry the alluvium aquifers show a complex hydrogeochemistry than the older aquifers the major factor influencing the hydrogeochemistry of the region is rock water interaction and anthropogenic processes hence metal mobility of the groundwater shows the correlation of metal bonding and doc the relation between the doc and heavy metal concentration in the aquifers was also identified

understanding groundwater systems and their functioning through the study of stable water isotopes in a hard rock aquifer maheshwaram watershed india summary groundwater degradation through abstraction contamination etc shows a world wide increase and has been of growing concern for the past decades in this light the stable isotopes of the water molecule 18 o and 2 h from a hard rock aquifer in the maheshwaram watershed andhra pradesh india were studied this small watershed 53 km 2 underlain by granite is endorheic and representative of agricultural land use in india with more than 700 bore wells in use in such a watershed the effect of overpumping can be severe and the environmental effects of water abstraction and contamination are of vital importance a detailed and dynamic understanding of groundwater sources and flow paths in this watershed thus is a major issue for both researchers and water managers especially with regards to water quality as well as the delimitation of resources and long term sustainability to this end the input from monsoon precipitation was monitored over two cycles as well as measuring spatial and temporal variations in 18 o and 2 h in the groundwater and in precipitation individual recharge from the two monsoon periods was identified leading to identification of periods during which evaporation affects groundwater quality through a higher concentration of salts and stable isotopes in the return flow such evaporation is further affected by land use rice paddies having the strongest evapotranspiration

correlation between hydrogen isotope ratios of lipid biomarkers and sediment maturity abstract we investigated the influence of thermal maturity on the hydrogen isotope ratios of sedimentary hydrocarbons to prove that the isotope ratio of hydrocarbons mirrors paleoclimate signatures d values from n alkanes and acyclic isoprenoids of two sediment sections kupferschiefer ks 258 ma and posidonienschiefer ps 184 ma with different maturation history were investigated both covered thermal maturity from 0 48 to 1 3 rc vitrinite reflectance and reflectance calculated from mpi1 sediment burial up to 4500 m caused thermal maturation of organic matter in the ks horizon from the early zechstein basin of poland whereas contact metamorphic thermal maturation originated in the early toarcian ps posidonienschiefer of the north german vlotho massif the d values of the extracted n alkanes positively correlate with thermal maturity in the ks y 56 mpi1 x 160 vsmow and in the ps y 104 mpi1 x 200 vsmow the d values of isoprenoids i e pristane phytane were even more enriched with increasing maturity y 179 mpi1 x 341 vsmow in the ks y 300 mpi1 x 415 vsmow in ps these results explain why isotope ratios of n alkanes and isoprenoids in mature sediments are generally enriched in d and do not have the expected isotopic difference between n alkanes and isoprenoids of 190 moreover the correlation between sediment maturity parameters and d values suggests that after correction the d values of n alkanes can be used to reconstruct climate and environment in the geological past