oxygen isotope and geochemical variations in the missouri river oxygen isotope ratios in streamflow of the missouri river basin vary geographically due to differences in source precipitation and the integration of waters from upstream regions average 18o values in the missouri river main stem systematically increase from less than 17 in the headwaters to about 9 in the lower basin seasonal variations at a given location result from fluctuations in meteoric precipitation residence time in reservoirs and groundwater systems evaporation and snowmelt average water chemistry values are successfully predicted for the upstream stations of two reaches on the lower missouri river based on changes in discharge along each reach and water quality measurements collected at the downstream stations source regions for some dissolved ions found in the lower missouri river are also identified sodium and sulfate originate predominantly from the basin above sioux city iowa while nitrate is largely derived from agricultural regions below sioux city

the fluvial geochemistry of the rivers of eastern siberia i tributaries of the lena river draining the sedimentary platform of the siberian craton abstract the response of continental weathering rates to changing climate and atmospheric pco 2 is of considerable importance both to the interpretation of the geological sedimentary record and to predictions of the effects of future anthropogenic influences while comprehensive work on the controlling mechanisms of contemporary chemical and mechanical weathering has been carried out in the tropics and to a lesser extent in the strongly perturbed northern temperate latitudes very little is known about the peri glacial environments in the subarctic and arctic thus the effects of climate essentially temperature and runoff on the rates of atmospheric co 2 consumption by weathering are not well quantified at this climatic extreme to remedy this lack a comprehensive survey has been carried out of the geochemistry of the large rivers of eastern siberia the lena yana indigirka kolyma anadyr and numerous lesser streams which drain a pristine high latitude region that has not experienced the pervasive effects of glaciation and subsequent anthropogenic impacts common to western eurasia and north america the scale of the terrain sampled in terms of area is comparable to that of the continental united states or the amazon orinoco and includes a similarly diverse range of geologic and climatic environments in this paper the chemical fluxes from the western region the very large ancient and geologically stable sedimentary basin precambrian to quaternary of the siberian platform will be presented and compared to published results from analogous terrains in the tropical basins of china while the range in the chemical signatures of the various tributaries included here 60 sampled is large this mainly reflects lithology rather than the weathering environment the areal chemical fluxes are comparable to those of the chinese rivers being dominated by the dissolution of carbonates and evaporites the net consumption of atmospheric co 2 by aluminosilicate weathering is minor as it is in the tropical basins it is much smaller than in active orogenic belts in similar latitudes e g the fraser and yukon but comparable to those of the mackenzie tributaries that drain the eastern slope of the rockies lithology exerts the dominant influence in determining the weathering yield from sedimentary terrains and for a largely carbonate evaporite terrain climate does not have a direct effect

geochemical characteristics of fluoride in groundwater of gimcheon korea lithogenic and agricultural origins the occurrence of fluoride in groundwaters can be influenced by many factors in korea the fluoride rich groundwaters are normally associated with rock types especially granite and gneiss in gimcheon high fluoride groundwaters up to a maximum of 2 15 mg l were observed with bimodal distribution of concentrations the groundwater in this area showed relatively high concentrations of anthropogenic chemicals such as nitrate chloride and sulfate statistical analysis showed that fluoride is positively correlated with ph alkalinity sodium and lithium indicating that the interaction with granite is the main cause enriching its concentration in gimcheon 18o data of groundwater showed a negative correlation with nitrate and can be used as an indicator of groundwater age the four samples of fluoride rich groundwater were plotted in the light d and 18o region showing that they were the result of long water rock reaction however other groundwater with a low fluoride concentration was evenly distributed throughout all d and 18o ranges and did not show a statistically significant correlation with nitrate indicating possible mixing with another source of fluoride considering the influence from the surface on the geochemical characteristics of groundwater in this area anthropogenic sources including phosphate fertilizer containing fluoride and pesticides may also have partly contributed to the concentrations of fluoride in the low fluoride groundwater the scattered distribution of fluoride rich groundwater and the significant correlation with lithium suggest that pegmatite is the main rock type increasing fluoride concentration in this area

water geochemistry controlled by carbonate dissolution a study of the river waters draining karst dominated terrain guizhou province china concentrations of major ions and sr and sr isotopic compositions of two major river systems wujiang river and yuanjiang river in karst dominated regions and during winter were measured the rivers and their tributaries have high total dissolved solid concentrations with tz ranging from 2 1 to 6 3 meq l which are significantly higher than that of the global river average calcium and hco3 followed by mg2 and so42 dominate the chemical composition of major ions in the river waters both na k and cl si account for 5 10 of the cations and anions respectively the waters of the wujiang river have high sr2 concentrations and lower 87sr 86sr ratios 0 7077 0 7110 while those of the qingshuijiang river one of two major tributaries of the yuanjiang river system show higher sr isotopic ratios 0 7090 0 7145 and low sr concentrations the lithology and geography of the river basins largely control the chemical and isotopic compositions of these rivers analyses of the stoichiometry of the river waters show that the water chemistry is controlled by carbonate dissolution by both carbonic and sulfuric acid especially of the wujiang river and suggest an origin of sulfate mainly from atmospheric input because of coal combustion and or oxidation of sulfide minerals in the catchments we identify three main weathering sources limestone dolomite and silicates chemical and sr isotopic composition of wujiang river waters are characterized mainly by limestone weathering while those of the qingshuijiang river waters mainly by dolomite and silicate weathering chemical weathering rates of carbonate and silicate are estimated and the results indicate that the chemical weathering rates of carbonate in the catchments are remarkably high significantly higher than most large rivers it is considered that presence of sulfuric acid in the rock weathering overuse of land and deterioration of vegetation are most likely the key factors responsible for the high weathering rates of carbonate in the catchments

study of harmonic site position variations determined by very long baseline interferometry 1 position variations of 40 very long baseline interferometry vlbi stations at 32 tidal frequencies were obtained from analysis of 3 million measurements of group delays from 1980 to 2002 residual displacements after the removal of the effect of solid earth tides were studied the purpose of this study is to investigate a harmonic signal at any frequency where it is expected and to assess quantitatively whether the models of vertical and horizontal site position variations agree with the observations it was found that the estimates of station displacements are generally in good agreement with the ocean loading computed on the basis of ocean tide models for the main diurnal and semidiurnal tides moreover vlbi results allow us to discriminate between different ocean tide models however discrepancies between vlbi results and all models of ocean loading for k1 k2 and s2 tides exceed both the errors of the vlbi estimates and the errors of ocean loading displacements based on the reported formal uncertainties of ocean tide models it was found that there is a significant nontidal signal at diurnal and annual frequencies applying a model of hydrological loading reduces the variance of the residual vertical displacements at the annual frequency by 30 using an empirical model of harmonic site position variations in vlbi processing provides a better fit and improves the baseline length repeatability

recent glacier mass changes in the gulf of alaska region from grace mascon solutions the mass changes of the gulf of alaska goa glaciers are computed from the gravity recovery and climate experiment grace inter satellite range rate data for the period april 2003 september 2007 through the application of unique processing techniques and a surface mass concentration mascon parameterization the mass variations in the goa glacier regions have been estimated at high temporal 10 day and spatial 2 2 arc degrees resolution the mascon solutions are directly estimated from a reduction of the grace k band inter satellite range rate data and unlike previous grace solutions for the goa glaciers do not exhibit contamination by leakage from mass change occurring outside the region of interest the mascon solutions reveal considerable temporal and spatial variation within the goa glacier region with the largest negative mass balances observed in the st elias mountains including the yakutat and glacier bay regions the most rapid losses occurred during the 2004 melt season due to record temperatures in alaska during that year the total mass balance of the goa glacier region was 84 5 gt a 1 contributing 0 23 0 01 mm a 1 to global sea level rise from april 2003 through march 2007 highlighting the large seasonal and interannual variability of the goa glaciers the rate determined over the period april 2003 march 2006 is 102 5 gt a 1 which includes the anomalously high temperatures of 2004 and does not include the large 2007 winter balance year snowfall the mascon solutions agree well with regional patterns of glacier mass loss determined from aircraft altimetry and in situ measurements

deterioration mechanisms of tuffs in midas monument slightly weathered white and pink tuffs of the midas monument have deterioration problems in this study depths and characteristics of the weathering zones developed within the tuffs are investigated through optical microscopy x ray diffractometry xrd chemical analyses scanning electron microscopy sem and some index parameters accelerated weathering tests including wetting drying freezing thawing and salt crystallization are performed and durability assessment methods are used to predict the durabilities of the tuffs the findings are compared with field observations by examining quantitative weathering indices and comparing them with thin section studies it is found that thin section analyses of the crystals loi and wpi are good indicators to quantify the depth of weathering for the tuffs however thin section studies have limited value for fine grained tuffaceous matrix the chemical weathering of the tuffs produces weathered zones that are 4 5 cm thick within the white tuff and 2 5 cm thick within the pink tuff physical weathering causes scaling of outer layers of the tuffs and fracturing of feldspars along their cleavage planes however variations of the index properties of the tuffs due to weathering are not so significant to quantify the weathering depths in the tuffs among the accelerated weathering tests salt crystallization is found to be the most destructive environmental condition pigeon droppings rich in no3 are found to be the main source of soluble salt at the midas monument the salt transported up by capillary rise due to surface water causes spalling of the tuffs in the capillary zone surface water and salt of any kind in the close vicinity of the monument should be totally eliminated for the purpose of conservation field observations and the durability equations reveal that the white tuff is less durable than the pink tuff wet to dry strength ratio yields a better stone durability assessment among various durability methods used in this study d 2002 elsevier science b v all rights reserved

quality and durability assessments of the armourstones for two rubble mound breakwaters mersin turkey due to economic reasons natural stones armourstones of various sizes and qualities are very frequently used for the constructions of the breakwaters to protect coastal engineering structures from wave actions deterioration of the armourstones with time in the form of abrasion and disintegration may end up with the damage of the structures therefore it is necessary to investigate the long term performance and quality of the armourstones which should be sound and durable mersin and kumkuyu harbours were constructed using four different limestones obtained from two quarries the limestones have different characters and site performances in this study the material and mass properties of the limestones taken from the quarries with known site performances as armourstones are investigated the site performances and durability of the limestones are compared with the field measurements and laboratory works thus the information obtained is used to assess long term durability of the armourstones the long term performance of the degirmencayi and tirtar upper level limestones are observed to be good whereas it is rather poor for the tirtar middle and lower level limestones comparison between the predicted and observed durabilities of the armourstones indicated that ciria cur rdid rers and wet to dry strength ratio give better results based on their field performances however the prediction of the durability of the limestones is poor in case rdis average pore diameter and saturation coefficient are used

rock for breakwater construction in western australia its availability and influence on design abstract small boat harbours protected by rubble mound breakwaters are currently being built along the exposed western and southern coasts of western australia the properties that rocks must have to be suitable for armour blocks on breakwaters are discussed particular reference is made to the special problems produced by the remoteness of heavy armour material from the sites of 6796 of breakwaters recently built or being considered in western australia fuller geotechnical investigations for quarries are warranted in these circumstances

natural and anthropogenic so4 sources in the arno river catchment northern tuscany italy a chemical and isotopic reconnaissance abstract the 34 s isotope signature of aqueous so 4 2 in the main river arno and principal tributaries was investigated along with major ion chemistry in order to check the pollution effects in the water network of a heavily industrialized and densely urbanized catchment extending in tuscany over an area of 8228 km 2 from the apennine ridge to the tyrrhenian sea major towns include florence and pisa analyses are presented for 29 water samples from the arno river and 36 water samples from the tributaries all collected in 1996 1997 during low flow hydrologic conditions samples from the arno are distributed from source to mouth and those from tributaries upstream from the confluence points the arno river solutes consist mainly of ca 2 and hco 3 but the proportions of na cl and so 4 2 increase downstream in keeping with the basically anthropogenic origin of the latter the 34 s so 4 2 signature also increases downstream with the most depleted values in the source zone the seawater ingression into the river is documented by distinctly higher chemical and isotopic parameters at about 13 km from the mouth in general the tributaries behave similarly to the arno for both their chemical and isotopic compositions with increasing 34 s na cl and so 4 2 downstream the 34 s of so 4 2 in natural inputs is estimated to range approximately between 15 and 4 from oxidation of pyrite disseminated in country rocks and between 15 and 23 from dissolution of evaporites whereas the 34 s of anthropogenic so 4 2 should be variable within the range 1 8

major ion chemistry of the ganga brahmaputra river system weathering processes and fluxes to the bay of bengal the ganga brahmaputra one of the world s largest river systems is first in terms of sediment transport and fourth in terms of water discharge a detailed and systematic study of the major ion chemistry of these rivers and their tributaries as well as the clay mineral composition of the bed sediments has been conducted the chemistry of the highland rivers upper reaches of the ganga the yamuna the brahmaputra the gandak and the ghaghra are all dominated by carbonate weathering ca mg and hco3 account for about 80 of the cations and anions in the lowland rivers the chambal the betwa and the ken hco3 excess over ca mg and a relatively high contribution of na k to the total cations indicate that silicate weathering and or contributions from alkaline saline soils and groundwaters could be important sources of major ions to these waters the chemistry of the ganga and the yamuna in the lower reaches is by and large dictated by the chemistry of their tributaries and their mixing proportions illite is the dominant clay mineral about 80 in the bedload sediments of the highland rivers kaolinite and chlorite together constitute the remaining 20 of the clays in the chambal betwa and ken smectite accounts for about 80 of the clays this difference in the clay mineral composition of the bed sediments is a reflection of the differences in the geology of their drainage basins the highland rivers weather acidic rocks whereas the others flow initially through basic effusives the ganga brahmaputra river system transports about 130 million tons of dissolved salts to the bay of bengal which is nearly 3 of the global river flux to the oceans the chemical denudation rates for the ganga and the brahmaputra basins are about 72 and 105 tons km yr 1 respectively which are factors of 2 to 3 higher than the global average the high denudation rate particularly in the brahmaputra is attributable to high relief and heavy rainfall

typhoon induced ground deformation geodetic instruments now offer compelling sensitivity allowing to investigate how solid earth and surface processes interact by combining surface air pressure data nontidal sea level variations model and rainfall data we systematically analyze the volumetric deformation of the shallow crust at seven borehole strainmeters in taiwan induced by 31 tropical cyclones typhoons that made landfall to the island from 2004 to 2013 the typhoon s signature consists in a ground dilatation due to air pressure drop generally followed by a larger ground compression we show that this compression phase can be mostly explained by the mass loading of rainwater that falls on the ground and concentrates in the valleys towards the strainmeter sensitivity zone further our analysis shows that borehole strainmeters can help quantifying the amount of rainwater accumulating and flowing over a watershed during heavy rainfalls which is a useful constraint for building hydrological models

factors controlling carbon isotope ratios of dissolved inorganic carbon in two major tributaries of the han river korea understanding the carbon cycle of the han river system in korea is of prime interest in managing and preserving this valuable water resource for more than 20 million residents in the area as a part of a comprehensive carbon cycling study for the han river system this report focuses on the carbon isotope compositions of dissolved inorganic carbon dic in its two major tributaries the north and the south han rivers the major difference in carbonate chemistry of the tributaries originates primarily from the lithology of the catchment areas the south han river draining a carbonate dominant terrain has much higher alkalinities and dic concentrations whereas the lower concentrations in the north han river indicate little influence of carbonate weathering likewise 13cdic values in the south han river indicate that the dic input from the carbonate rocks is important in controlling carbon isotope ratios of dic for the north han river the oxidation of organic material influences the amount of riverine dic and 13cdic values to a greater extent overall remarkable seasonal and spatial variations of river chemistry and carbon isotope compositions of dic reflect the variability in geo hydrologic characteristics in the water regime and in metabolic activities in the river water and or the drainage areas copyright 2006 john wiley sons ltd

effect of weathering on the geomechanical properties of andesite ankara turkey andesite exposed in different parts of ankara has different weathering categories varying from fresh to residual soil the geomechanical properties of the andesite are significantly affected by weathering buildings constructed especially in completely weathered and residual soil levels of the andesite have some geotechnical problems in this study the variation of the geomechanical properties of the andesite due to weathering is investigated in three selected sites of ankara through optical microscope x ray diffraction analyses major element analyses pressuremeter tests physicomechanical tests and seismic refraction method the data gathered from the field and laboratory studies were used to assess the characteristics of the weathering zones based on the data obtained from this study an idealized weathering profile is assessed no bearing capacity and consolidation settlement problems exist in the area however care should be taken for immediate settlement of the buildings slopes with heights less than 8 m are not expected to cause any significant problems for buildings there exists a ground amplification problem in the study area the natural period of the building should not match that of the weathered rock the ground response analyses reveal that the buildings with four to seven stories may be adversely affected from earthquakes due to resonance phenomenon therefore this has to be taken into account when designing new buildings

analyses of deterioration of the cappadocian tuff turkey the cappadocian tuff contains unique erosional features the so called fairy chimneys some of which in the past were dwelled in and contain valuable wall paintings these historical heritages however are undergoing chemical and physical deterioration due to atmospheric effects for the conservation studies understanding of the deterioration phenomenon of the tuff is essential in this study engineering geological and physicochemical characteristics of the tuff were determined the durability of the tuff was assessed through wetting drying freezing thawing and salt crystallization the test results suggest that chemical weathering may be traced to a depth of 2 cm below lichen covered surfaces and 20 cm adjacent to discolored joint walls based on durability assessment methods the tuff may be classified as having poor to very poor durability

evaluation of andesite source as armourstone for a rubble mound breakwater hisaronu turkey black sea coast line is a hazardous region especially in winter due to the dominant wave action therefore rubble mound breakwaters protected with armourstone used as ship shelters are vital structures especially for the fishermen the deterioration of the armourstone with time in the form of abrasion and disintegration may result in the failure of the breakwater in this study the properties of the armourstone taken from an andesite quarry and used in the hisaronu rubble mound breakwater were studied both in field and laboratory in order to assess their qualities and long term durabilities based on the in situ observations and laboratory tests the andesite is found to be generally marginal rock ciria cur rdis rers and wet dry strength ratio classifications are in good agreement with the in situ observations and the results of the laboratory tests however rdid average pore diameter and saturation coefficient classifications cannot correctly predict long term durability of the armourstone field studies reveal that block size of the andesite in the quarry increases with depth due to the increase in spacing of the cooling joints of the rock

hydrogeochemical and isotopic study of the kumho river korea implications for anthropogenic and seasonal effects the geochemical and isotopic compositions of river water are controlled by different factors the seasonal and spatial variations in the geochemical composition d 18o and 15n no3 of the kumho river were investigated to reveal the geochemical processes occurring at different seasons the kumho river which runs through different geologic terrains with different land use characteristics is the largest tributary of the nakdong river the longest river in south korea the data varied significantly according to the land use and the season each monitoring station showed the lowest concentrations of various ions during july the rainy season due to the increase of precipitation rate the ionic concentrations gradually increased downstream by the mineral weathering and anthropogenic activity at the upper regions of the river ca and hco3 which are closely associated with mineral weathering were the most dominant cation and anion respectively the relatively high si concentration of the headwater samples caused by the weathering of volcanic rocks also showed the importance of weathering in the upper regions mainly composed of volcanic rocks the downstream regions of the kumho river are mainly influenced by sedimentary rocks at the lower reaches of the river especially near the industrial complexes in daegu the third largest city in korea na cl and so4 became the dominant ions indicating that the anthropogenic pollution became more important in regulating the chemical composition of the river the increasing ca mg na k hco3 ratio downstream also indicates that the anthropogenic effects became more important as the river flows downstream the isotopic compositions of d and 18o indicate that the river waters were significantly affected by evaporation during may and july but the evaporation effect was relatively low during october the isotopic composition of 15n no3 increased downstream also confirming that anthropogenic effects became more significant at the lower reach of the river and near daegu

major element chemistry of the changjiang yangtze river the chemistry of major elements ca mg na k hco3 so4 cl and si in the river water of the changjiang yangtze river was studied based on continuously monitored data at 191 stations in the drainage basin for the period 1958 1990 the results show that the total dissolved solid tds concentration of the changjiang varies over an order of magnitude throughout the basin 49 7 518 1 mg l with a medium tds concentration of 205 9 mg l about three times the global average in contrast the tds at a given main channel station varies only slightly in different seasons with a variation factor less than 2 0 despite a substantial water dilution in the summer flood season the major element chemistry of the changjiang is mainly controlled by rock weathering with the anion hco3 and the cation ca dominating the major ion composition due to the abundance of carbonate rocks in the basin a persistently increasing trend has been observed in the concentrations of so4 and to a lesser extent cl in the changjiang a signature of considerable anthropogenic impacts e g acid deposition flux calculations at datong the most downstream main channel station without tidal influence indicate that the changjiang transports ca 154 106 tons year of tds to the sea second only to the amazon in the world

the fluvial geochemistry of the rivers of eastern siberia ii tributaries of the lena omoloy yana indigirka kolyma and anadyr draining the collisional accretionary zone of the verkhoyansk and cherskiy ranges fundamental to the global carbon cycle over geologic time scales is the control of atmospheric co2 by aluminosilicate weathering much of the information on the rates of this process comes from rivers in the tropics and subtropics to understand the possible climatic influences systematic studies are needed for the arctic subarctic regions this is the second in a series of papers addressing this problem by systematic studies of the pristine rivers of the russian far east the region to the east of the siberian platform huh et al 1998 is a geologically complex terrain formed by the mesozoic collision and accretion of the siberian and kolyma plates because of the arid continental climate it has not been glaciated in the recent past thus it is possible to study weathering processes in an arctic environment dominated solely by cryogenic interactions without contamination by heterogeneous components derived from scouring glaciers all the major rivers and their tributaries in this area have been sampled on expeditions to individual basins 100 samples on a reconnaissance basis at falling stage usually in july and august the total dissolved cation levels tz are moderate up to 3 100 eq and the major ion chemistry is indicative of ca aluminosilicate and carbonate weathering with significant contributions from black shales in some tributaries the si tz si na k and 87sr 86sr ratios indicate that the weathering is superficial i e only to cation rich secondary minerals the areal total dissolved solid fluxes range from 0 04 to 0 39 106 mol km2 yr up to an order of magnitude lower than for the amazon orinoco draining the andes in the tropics 0 6 4 1 106 mol km2 yr the co2 consumption by aluminosilicate weathering 18 230 103 mol km2 yr is also at the lower end of the range observed in the amazon orinoco headwaters 143 1 000 103 mol km2 yr however as the north american counterparts in similar latitudes and with comparable relief the mackenzie yukon and fraser draining the rockies also have high dissolved solids 0 2 2 9 106 mol km2 yr and co2 19 1 750 103 mol km2 yr fluxes these low values seem to be more a function of lithology than simply climate ice action in cold environments appears to overcome the inhibiting effects of the decreased temperatures and lack of precipitation in producing a high chemical yield but results in superficial weathering in the case of aluminosilicates

precise three dimensional stereo localization of corner reflectors and persistent scatterers with terrasar x this paper reports on the absolute 3 d localization of radar corner reflectors and persistent scatterers pss by stereo synthetic aperture radar sar carried out with terrasar x and tandem x the novel combination of rigorously linearized range doppler equations with thorough sensor modeling consideration of atmospheric delays geodynamic signals satellite dynamics and geometrical calibration allows a direct target localization at the centimeter level therefore there is no need for the application of geocoding since our approach delivers 3 d positions directly in the international terrestrial reference frame itrf 2008 four radar corner reflectors located at the wettzell geodetic observatory metsahovi geodetic observatory and german antarctic receiving station o higgins were localized in 3 d with a precision better than 4 cm by introducing an updated geometrical calibration of terrasar x and tandem x the absolute accuracy of the same level becomes possible which was demonstrated by externally validating the reflector positions at metsahovi and wettzell against results of terrestrial geodetic surveying furthermore pss located in berlin were retrieved with a precision of 10 cm making the method a suitable tool for radar positioning in urban environments potential fields of application for our approach are the joint analysis with phase based methods geometrical calibration of radar satellites and direct integration of sar observations into global navigation satellite system networks

combination of multisatellite altimetry and tide gauge data for determining vertical crustal movements along northern mediterranean coast sea level variations slv can be measured by tide gauges tg at the coast and by altimeters onboard satellites the former measures the slv relative to the coast whereas altimetry provides the slv with respect to a geocentric reference frame the differences between slv measurements from these two techniques can be used as an indirect assessment of vertical crustal motions at the tg sites in this study we exploit this idea analyzing differences between sea level signals as measured by altimetric missions topex poseidon and jason 1 and by 47 tg stations along northern mediterranean coasts for the period 1993 2007 this allows us to estimate the vertical land motion along these coasts at the tg sites in this time window for those sites where the tg is co located or has a nearby global positioning system gps station these estimates are compared with the vertical rates derived from gps measurements our results on vertical ground motion along the mediterranean coast provide a useful source of data for studying contrasting and constraining tectonic models for the region

displacements of the earth s surface due to atmospheric loading effects on gravity and baseline measurements atmospheric mass loads and deforms the earth s crust by performing a convolution sum between daily global barometric pressure data and mass loading green s functions we estimate the time dependent effects of atmospheric loading including those associated with short term synoptic storms on surface point positioning measurements and surface gravity observations we calculate the response for both an oceanless earth and an earth with an inverted barometer ocean load responses for near coastal stations are significantly affected by the inclusion of an inverted barometer ocean peak to peak vertical displacements are frequently 15 20 mm with accompanying gravity perturbations of 3 6 gal baseline changes can be as large as 20 mm or more the perturbations are largest at higher latitudes and during winter months these amplitudes are consistent with the results of rabbel and zschau 1985 who modeled synoptic pressure disturbances as gaussian functions of radius around a central point deformation can be adequately computed using real pressure data from points within about 1000 km of the station knowledge of local pressure alone is not sufficient rabbel and zschau s hypothesized corrections for these displacements which use local pressure and the regionally averaged pressure prove accurate at points well inland but are in general inadequate within a few hundred kilometers of the coast

correlation of conductivity and stable isotope 18o for the assessment of water origin in river system when working on wetlands or other surface and subsurface water systems with multiple water sources it is not always easy to identify the mixing between the different waters here we have tried to adapt an easy technique i e conductivity but regularly standardised against stable natural isotope 18o to immediately give a glimpse on the field site of the percentage the two kinds of water in certain cases this method is also valid to discriminate a third source of water the first experimental site to be described is in a meander of the garonne river in south west france where there exists an interesting case of active paleo channels the second site is located in north india in the himalayas mountains garhwal at the source of the ganges river here the samples were taken to discriminate between snow and glacier melt

fe and mn levels regulated by agricultural activities in alluvial groundwaters underneath a flooded paddy field abstract iron and mn concentrations in fresh groundwaters of alluvial aquifers are generally high in reducing conditions reflecting low so4 concentrations the mass balance and isotopic approaches of this study demonstrate that reduction of so4 supplied from agricultural activities such as fertilization and irrigation is important in lowering fe and mn levels in alluvial groundwaters underneath a paddy field this study was performed to investigate the processes regulating fe and mn levels in groundwaters of a point bar area which has been intensively used for flood cultivation four multilevel groundwater samplers were installed to examine the relationship between geology and the vertical changes in water chemistry the results show that fe and mn levels are regulated by the presence of no3 at shallow depths and by so4 reduction at the greater depths isotopic and mass balance analyses revealed that no3 and so4 in groundwater are mostly supplied from the paddy field suggesting that the fe and mn rich zone of the study area is confined by the agricultural activities for this reason the geologic conditions controlling the infiltration of agrochemicals are also important for the occurrence of fe mn rich groundwaters in the paddy field area

columnar joint morphology and cooling rate a starch water mixture experiment 1 an analogue experiment using a starch water mixture has been carried out in order to understand the effect of cooling rate on the morphological characteristics of a basalt columnar joint if the contraction of material is essential for the formation of columnar joint structure the water loss rate by desiccation hereafter referred to as desiccation rate in the experiment is analogous to the cooling rate in solidifying basalt in the experiment the desiccation rate is controlled by varying the distance between the starch water mixture and a lamp used as the heat source we find that there are three regimes in the relation between joint formation and desiccation rate 1 at desiccation rates higher than 1 4 10 2 g cm 2 h 1 normal columnar joint regime the average cross sectional area s of a column is inversely proportional to the average desiccation rate i e s with 1 2 between that desiccation rate and a critical desiccation rate 0 8 10 2 g cm2h s approaches infinity as decreases close to a critical desiccation rate i e exponent monotonically increases from unity to infinity critical regime 3 below the critical desiccation rate no columnar structure forms no columnar joint regime forms applying the present experimental result to the formation of basalt column the basalt columnar cross sectional area is inversely proportional to the cooling rate with factors including elasticity crack growth coefficient thermal expansion glass transition temperature and crack density ratio at stress maximum also it can be predicted that there exists a critical cooling rate below which the columnar joint does not form the presence of a critical regime between the normal columnar jointing and no columnar jointing during a certain cooling rate range can also be predicted we find that at higher cooling rate the preferred column shape is a pentagon whereas at lower cooling rate it is a hexagon

study of the atmospheric pressure loading signal in very long baseline interferometry observations 1 redistribution of air masses due to atmospheric circulation causes loading deformation of the earth s crust which can be as large as 20 mm for the vertical component and 3 mm for horizontal components rigorous computation of site displacements caused by pressure loading requires knowledge of the surface pressure field over the entire earth surface a procedure for computing three dimensional displacements of geodetic sites of interest using a 6 hourly pressure field from the national centers for environmental prediction numerical weather models and the ponte and ray 2002 model of atmospheric tides is presented we investigated possible error sources and found that the errors of our pressure loading time series are below the 15 level we validated our model by estimating the admittance factors of the pressure loading time series using a data set of 3 5 million very long baseline interferometry observations from 1980 to 2002 the admittance factors averaged over all sites are 0 95 0 02 for the vertical displacement and 1 00 0 07 for the horizontal displacements for the first time horizontal displacements caused by atmospheric pressure loading have been detected the closeness of these admittance factors to unity allows us to conclude that on average our model quantitatively agrees with the observations within the error budget of the model at the same time we found that the model is not accurate for several stations that are near a coast or in mountain regions we conclude that our model is suitable for routine data reduction of space geodesy observations

atmospheric pressure loading corrections applied to gps data at the observation level 1 space geodetic techniques can detect elastic deformation of the earth caused by atmospheric pressure loading atml however it has not yet been demonstrated whether these surface displacements should be accounted for at the time of reduction of the observations or by applying time averaged values to the coordinates after the analysis of the observations an analysis of the power spectral density of the atml predicted vertical deformation shows that aside from the diurnal and semi diurnal periods there is very little power in the sub daily frequencies the present tidal atml models improve the analysis at sites near the equator but seem to degrade the height estimates elsewhere the majority of the non tidal deformation can be modelled by applying a daily averaged correction to daily estimates of coordinates but a greater improvement in height rms is found if non tidal atml is applied at the observation level

weathering processes in the ganges brahmaputra basin and the riverine alkalinity budget abstract we present river chemistry data for a network of rivers draining the western and central nepal himalaya our sampling locations cover the system from the sources of rivers in tibet to the gangetic plain water samples were collected throughout the year including the monsoon season for rivers in nepal and for the ganges and brahmaputra in bangladesh rivers draining the north himalaya are characterized by low discharge under a cold and arid climate main stream waters have 13 c dic near 0 and high so42 so42 hco3 ratios xso4 with values around 40 eq and high cl ca is the dominant cation ca2 cations 55 to 75 eq after correction of sodium by chloride dissolved sulfate is produced in waters from the tethian sedimentary series whereas chlorine is related to thermal waters dissolved sulfate is primarily derived from sulfide oxidation rather than evaporite dissolution 13 c dic values of up to 3 9 show that metamorphic co2 is an important weathering agent rivers of the north himalayan basins have about 50 of their alkalinity derived from carbonate dissolution 20 from biogenic activity and 30 from metamorphic co2 on the south flank of the himalaya rivers are more depleted in 13 c and have on average lower xso4 most rivers have 13 c dic and xso4 values compatible with a simple mixing between soil co2 and sulfate derived from sulfide oxidation during the monsoon discharge increases by a factor 20 but the total dissolved concentration is only slightly reduced xso4 and 13 c decrease while ca cations increases implying enhanced dissolution of pedogenic calcite as a whole the g b riverine flux of alkalinity derived from silicate weathering is around 2 7 1011 mol year modest at the global scale sulphuric acid controls 20 30 of the weathering reaction in the brahmaputra and 6 to 9 in the ganges na and k balance 60 to 65 of the silicate derived alkalinity flux and the long term co2 consumption by ganges and brahmaputra is near 6 4 1010 mol year the flux of metamorphic co2 converted to alkalinity via weathering reactions is ca 1 1010 mol year

δ18o and δd systematics in the surficial waters of the gaula river catchment area kumaun himalaya india abstract the 18 o and d measurements of surface waters streams springs lakes and precipitation from the gaula river catchment area of kumaun himalaya are reported the d and 18 o values are positively correlated as has been the case with waters from several other regions the lake waters are found to be enriched in 18 o and d compared with the neighbouring regions owing to evaporation estimates of mean total evaporation during the dry season range from 10 to 25 spring water samples collected from various altitudes from 915 m to 2150 m display variations in values showing an altitude effect of 0 1491 per 100m elevation

analysis of columnar joint patterns from three dimensional stress modeling 1 we consider a crack pattern penetrating into a solid material forming a columnar structure as observed in basalts tuffs and also in starches using the finite element method we calculate the strain field ahead of the crack front in the presence of a uniform lateral expansion simulating the strain induced by cooling in rocks or drying in starches we observe the tendency of the cracks to adapt dynamically in order to reach a stable polygonal pattern the polygons have different numbers of sides and different areas with slightly curved borders we find that the tendency of the cracks to shift laterally upon penetration depends on the geometry of the neighbor cracks but it is independent of the global scale of the pattern we suggest that the mean width of the columns is determined by two different effects the typical size of the irregular crack pattern at the free surface from which the polygonal pattern develops upon penetration and the further possibility of terminate some cracks during advance which leads to a thickening of the columns as a function of depth

relationship between density compressive strength tensile strength and aggregate properties of andesites from hungary aggregate properties and strength parameters of four andesites from two operating hungarian quarries of nogradkovesd one lithotype and gyongyossolymos three lithotypes are presented in this paper air dry water saturated and freeze thaw subjected specimens were tested on core drilled cylindrical specimens and the aggregate properties were also determined from the remaining part of the drilled rock blocks tensile strength values rapidly decreased from air dry to water saturated and finally to freeze thaw subjected specimens linear relationships between air dry and water saturated bulk densities and between ucs and modulus of elasticity were found micro fabric influences strength and aggregate parameters of studied andesites fine porphyritic andesite has the highest ucs and tensile strength and the best micro deval results while coarser porphyritic andesite has lower strength and aggregate parameters test results were compared with previously published rock mechanical data of intermediate and basic igneous rocks a good exponential correlation was found between micro deval and ucs values of this paper and previously published data sets but there was no indication that micro deval values correlate well with los angeles values

ocean loading deformations caused by storm surges on the northwest european shelf 1 a model of the non tidal ocean loading deformations caused by storm surges on the northwest european shelf has been developed using the output from a 12 km grid storm surge model the spatial distributions of displacements and gravity variations caused by a typical storm surge event are computed in order to show the magnitudes of the effects that can be expected in space geodetic or gravity measurements a storm surge of just over 2 m in the southern north sea produces vertical displacements of 20 to 30 mm and increases of gravity of 6 to 8 gal in the coastal areas of denmark germany the netherlands and the east coast of england it is shown that the loading deformations due to surges affect a wide area of northwest europe and that high resolution non tidal loading models are required for correcting geodetic measurements made in areas near shallow continental shelves

conductive cooling of lava columnar joint diameter and stria width as functions of cooling rate and thermal gradient abstract much evidence exists that column diameter and stria width of columnar joints in lava flows vary inversely with cooling rate t t and thermal gradient t x at the point of fracture as the flow cools some evidence suggests that lava flows cool conductively a conductive cooling model yields cooling rate and thermal gradient through space and time for cooling igneous bodies both for extrusive and intrusive settings thermal gradient and cooling rate are then linked to stria width and column diameter with faster cooling leading to narrower columns and steeper gradients to narrower striae this model shows large regions within a body where the ratio of thermal gradient to cooling rate is nearly constant and predicts that the ratio of stria width to column diameter is also nearly constant this prediction is consistent with field observations both in this and other works the model also suggests that if conductive cooling dominates then joint spacing i e column diameter should increase inward from the margins of the body as should stria width

characteristics of isotope in precipitation river water and lake water in the manasarovar basin of qinghai tibet plateau the stable hydrogen and oxygen of lake river rain and snow waters were investigated to understand the water cycle characteristics of the drainage basin of manasarovar lake in tibet both d and 18o of river water are larger than those of lake water and the effect of altitude on both d and 18o is not very significant this phenomenon was suggested to occur because manasarovar basin is located in qinghai tibet plateau which has low latitude high altitude abundant glaciers thin air and intensive solar radiation resulting in higher evaporation in lake water

a reassessment of global and regional mean sea level trends from topex and jason 1 altimetry based on revised reference frame and orbits 1 mean sea level trends from topex and jason 1 altimeter data are recomputed using unified geophysical modeling and the new itrf2005 terrestrial reference frame for the entire altimetric time series with consistent orbits based on satellite laser ranging slr and doris tracking data we obtain a global rate of 3 36 0 41 mm yr over the 14 year period from 1993 to 2007 the regional sea level trends computed with the new reference frame show significant north south hemispherical offsets of 1 5 mm yr relative to trends based on the previous 1995 era frame regional sea level trend comparisons for the time periods of 1993 1999 and 1999 2005 reveal strong basin scale polarities and pronounced inter decadal variability with a relative increase in the global mean sea level trend of 1 5 0 7 mm yr in the latter seven years

oxygen isotope composition of fjord and river water in the sognefjorden drainage area western norway implications for paleoclimate studies abstract during two cruises and one field expedition from 1996 to 1998 32 water samples from 10 stations in sognefjorden and tributary fjords and six samples from rivers draining into the fjord were obtained for oxygen isotope measurements in addition ctd profiles were obtained from all of the fjord locations the river samples show a large gradient in the oxygen isotopic composition from the outer fjord region to the rivers at the fjord head the difference is more than 6 with highest values recorded at the fjord mouth decreasing inward along the fjord the low oxygen isotope values are found in areas with a high altitude from the watershed the gradient in the river water is explained by distance to the moisture source topographic effects and temperature of precipitation the isotopic composition of the fjord waters suggest a mixing line for sognefjorden of 0 31 for a salinity change of 1 which is slightly higher than the north sea mixing line israelson buchardt 1991 and lower than the north atlantic mixing line craig gordon 1965 the river samples are not used in the calculation of the mixing because of the large differences in the isotopic composition of river water along the fjord and large seasonal differences of precipitation

quality assessment of armourstone for a rubble mound breakwater sinop turkey helaldi is a fishing town in the central black sea region where construction of a rubble mound breakwater is being planned the construction of the breakwater requires good quality durable armourstone several laboratory tests are performed for the quality assessment of the two potential armourstone namely limestone and sandstone the quality evaluation of the stones is done on the basis of ciria cur criteria saturation coefficient wet to dry strength ratio and the rock durability index the quality evaluations are then compared with the field performance of both rocks laboratory test results durability assessments and field performance of the rocks indicate that the limestone is a good quality armourstone and it can be used for the breakwater construction however the sandstone is marginal to poor material with very poor field performance and should not be used for the breakwater construction

global mapping functions for the atmosphere delay at radio wavelengths i have developed expressions for calculating the ratios mapping functions of the line of sight hydrostatic and wet atmospheric path delays to their corresponding zenith delays at radio wavelengths for elevation angles down to 3 the coefficients of the continued fraction representation of the hydrostatic mapping function depend on the latitude and height above sea level of the observing site and on the day of the year the dependence of the wet mapping function is only on the site latitude by comparing with mapping functions calculated from radiosonde profiles for sites at latitudes between 43 s and 75 n the hydrostatic mapping function is seen to be more accurate than and of comparable precision to mapping functions currently in use which are parameterized in terms of local surface meteorology when the new mapping functions are used in the analysis of geodetic very long baseline interferometry vlbi data the estimated lengths of baselines up to 10 400 km long change by less than 5 mm as the minimum elevation of included data is reduced from 12 to 3 the independence of the new mapping functions from surface meteorology while having comparable accuracy and precision to those that require such input makes them particularly valuable for those situations where surface meteorology data are not available

chemical weathering of carbonates and silicates in the han river basin south korea abstract a detailed investigation of the fluvial geochemistry of the han river system allows to estimate the rates of chemical weathering and the consumption of co 2 the han river drains approximately 26 000 km 2 and is the largest river system in south korea in terms of both water discharge and total river length it consists of two major tributaries the north han river nhr and the south han river shr distinct differences in basin lithology silicate vs carbonate between the nhr and shr provide a good natural laboratory in which to examine weathering processes and the influence of basin geology on water quality the concentrations of major elements and the sr isotopic compositions were obtained from 58 samples collected in both summer and winter along the han river system in both 2000 and 2006 the concentrations of dissolved loads differed considerably between the nhr and shr compared with the shr the nhr had much lower total dissolved solids tds sr and major ion concentrations but a higher si concentration and 87 sr 86 sr ratio a forward model showed that the dissolved loads in the nhr came primarily from silicate weathering 55 11 with a relatively small portion from carbonates 30 14 whereas the main contribution to the dissolved loads in the shr was carbonate weathering 82 3 with only 11 4 from silicates these results are consistent with the different lithologies of the two drainage basins silicate rocks in the nhr versus carbonate rocks in the shr sulfuric acid derived from sulfide dissolution in coal containing sedimentary strata has played an important role in carbonate weathering in the shr basin unlike in the nhr basin the silicate weathering rate swr was similar between the nhr and shr basins but the rate of co 2 consumption in the shr basin was lower than in the nhr basin due to an important role of sulfuric acid derived from pyrite oxidation

chemical and physical weathering in the min jiang a headwater tributary of the yangtze river abstract the min jiang is a major headwater tributary of the yangtze chang jiang its source is in the undeveloped eastern tibetan plateau but it flows through the heavily populated sichuan four rivers basin on its way to join the yangtze main channel the dissolved major element composition was determined in the tibetan headwaters at the rising stage and at four hydrologic stations in a monthly time series the min jiang is alkaline and has high dissolved load compared to other world rivers carbonate weathering dominates especially in the source region of the min jiang main channel and silicate weathering and evaporite dissolution gain some importance in the dadu he tributary the si na k ratios of the dissolved load and the clay mineralogy of the bed material suggest that silicate weathering in the watershed is superficial i e soluble cations are being preferentially leached many major elements show lower concentrations at high summer discharge but there is also additional input such that the concentration discharge relationship is not purely a result of dilution the discharge weighted total dissolved solid tds flux based on data from the three upstream monitoring stations is 10 10 6 tons year 6 of the yangtze at mouth and the chemical denudation rate as measured by tds yield is 115 tons km 2 year for the min jiang higher than the average yangtze basin 85 tons km 2 year the common extrapolation using annual average discharge and spot sampling of dissolved and suspended material during rising or falling stage can reasonably estimate chemical fluxes to 20 but seriously underestimate the physical flux sampling the peak flash flow is critical for the suspended particulate material concentrations of so 4 cl and ca are significantly elevated as the river debouches onto the populated sichuan basin

improved ice loss estimate of the northwestern greenland ice sheet 1 we estimate ice volume change rates in the northwest greenland drainage basin during 2003 2009 using ice cloud and land elevation satellite icesat laser altimeter data elevation changes are often reported to be largest near the frontal portion of outlet glaciers to improve the volume change estimate we supplement the icesat data with altimeter surveys from nasa s airborne topographic mapper from 2002 to 2010 and nasa s land vegetation and ice sensor from 2010 the airborne data are mainly concentrated along the ice margin and thus have a significant impact on the estimate of the volume change our results show that adding airborne topographic mapper and land vegetation and ice sensor data to the icesat data increases the catchment wide estimate of ice volume loss by 11 mainly due to an improved volume loss estimate along the ice sheet margin furthermore our results show a significant acceleration in mass loss at elevations above 1200m both the improved mass loss estimate along the ice sheet margin and the acceleration at higher elevations have implications for predictions of the elastic adjustment of the lithosphere caused by present day ice mass changes our study shows that the use of icesat data alone to predict elastic uplift rates biases the predicted rates by several millimeters per year at gps locations along the northwestern coast

geochemistry of the amazon 1 precipitation chemistry and the marine contribution to the dissolved load at the time of peak discharge analyses of precipitation and surface water are used to estimate the fluxes of marine cyclic salts through that part of the amazon river system draining past obidos 80 of the basin at the time of peak discharge in june amazon precipitation chemistry can be devided into two principal components marine and terrestrial the marine component determined from analyses of marine rain consists of na k mg ca and cl in approximately sea salt proportions with s doubly enriched the excess sulfur is probably derived from gas phase inputs the terrestrial component makes an important contribution of k ca s and n much of which can be related to biological emissions the emission of reduced sulfur in the marine and terrestrial environment and nitrogen in the terrestrial environment is responsible for a natural acid rain in the amazon region with a ph from 4 7 to 5 7 this is about one tenth the acidity of polluted urban rain the chloride content of lowland rivers which drain regions lacking significant geologic sources of chloride shows a systematic decrease in chloride with increasing distance from the ocean this trend is used to define the cyclic salt background for amazonian surface waters cyclic salts in general make only a minor contribution relative to terrestrial inputs to the chemistry of amazon basin rivers even those draining intensely weathered terrains an estimated 17 6 cl 6 9 na 1 3 mg 3 6 s 0 4 k and 0 1 ca of the dissolved load at obidos during peak discharge is cyclic

how can we improve a global ocean tide model at a regional scale a test on the yellow sea and the east china sea a global ocean model has been developed within the context of topex poseidon t p on the basis of a finite element hydrodynamic modeling approach combined with data assimilation based on the representer method the solution produced at global scale represents a spectacular improvement over what was available before the era of t p typically the mean discrepancy between the main tidal components and a hundred in situ tide gauges is 1 7 cm for m2 and 1 cm or less for the other components however the accuracies of this solution and of that produced by different authors within the t p tide working group are all worse near coastlines and over continental shelves this is the case for our finite element solution fes fes94 1 solution over the yellow sea and the east china sea ys ecs where the discrepancy is 33 cm for the m2 tide and 9 cm for the k1 tide when compared to a set of 192 tide gauges distributed along the coastlines this is due largely to the complex geometry of the basin and the limited knowledge of the bathymetry the aim of this paper is to investigate how our fes model can be improved with a dedicated application focused on one of the most energetic coastal basins the ys ecs 180 gigawatts for m2 i e 8 of the global energy dissipated in the whole ocean for this application a finite grid was implemented with a resolution down to 5 km along the coasts and over the continental shelf break particular attention was paid to bathymetry by complementing the etop05 database with regional maps sensitivity tests to the tuning of the bottom friction and the nonlinear interactions between the diurnal and semidiurnal components allow us to investigate the impact of dissipation parameterization and to produce an optimal solution without any data assimilation for nine main components of the tidal spectrum improvement by a factor of 2 m2 distance to the observations is now 17 5 cm global variance of 92 cm and k1 is 4 cm global variance of 21 cm as nonlinear components are significant over these basins the two main quarterdiurnal components are calculated the improvements are explained by five points 1 the choice of a mixed friction 2 a refinement of the mesh 3 a choice of reliable boundary conditions 4 a refined topography and 5 the use of a specific friction coefficient 1 5 10 3 surprisingly the energy budget for the m2 component leads to a dissipation similar to the value estimated by the global fes94 1 this is a major result of this study which leads us to the conclusion that when forcing a regional model with sea level boundary conditions along the open limits the simulated velocity field adjusts to the tuning of friction coefficients in order to dissipate the same amount of energy made available at its open boundaries

gps height time series short period origins of spurious long period signals gps height time series used in geophysical studies are often formed from discrete continuous nonoverlapping 24 hour processing sessions with such a strategy unmodeled periodic ground displacements with approximately semidiurnal and diurnal periods have often been assumed to average close to zero by analyzing several years of continuous gps data from globally distributed sites at which controlled errors were not modeled this paper shows such an assumption to be erroneous it is shown that each unmodeled sub daily periodic displacement can propagate to several spurious long wavelength features in a gps height time series ranging in period from about 2 weeks to 1 year admittances ratio of amplitude of spurious long wavelength output signal in the gps height time series to amplitude of unmodeled periodic ground displacement depend on the coordinate component and the tidal constituent considered for example it is shown that an unmodeled s2 north component periodic ground displacement can propagate to a semiannual height signal with admittance of greater than 100 whereas the height admittance is around 5 10 since model errors in ocean tide loading atmospheric pressure loading and solid earth tide displacement amplitudes can be several millimeters long wavelength spurious signals of up to these amplitudes may be expected to appear in gps height time series this paper provides an indication of how such errors will propagate where such errors are greatest and hence how spurious fortnightly semiannual and in some cases annual effects may be present at some sites copyright 2007 by the american geophysical union

the correlation between 18o 16o ratios of meteoric water and surface temperature its use in investigating terrestrial climate change over geologic time abstract correlations between mean annual temperature mat and the weighted average oxygen isotope composition of yearly precipitation 18opt are well known but the utility of modern relations to make reliable estimates of temperature change over geological time is uncertain this question has been addressed by using seasonal subsets of the global data base of temperature and isotopic measurements to represent two different climate modes a comparison of middle to high latitude 18opt temperature relations for each climate mode reveals 1 a significant offset between them and 2 a difference in the strength of their correlations the offset in relations is due to differences in temperature and water vapor budget in the tropics and can lead to serious underestimates of temperature change differences in the strength of correlations arise from the influence of climate mode specific non temperature factors on 18opt the overall result is that no single relation can be used in all cases to make unambiguous temperature estimates using a temporal record of 18opt values one way to overcome these problems is to reconstruct 18opt temperature relations for the time periods being investigated if an appropriate proxy for 18opt is available it may also be possible to estimate temperature without relying on 18opt temperature relations a promising alternative to these options is to use records of 18opt to test predictions of global climate models an approach that may allow a reliable and more complete reconstruction to be made of climate change over geologic time

assessment of deterioration and collapse mechanisms of dolomitic limestone at hasankeyf antique city before and after reservoir impounding turkey the hasankeyf antique city located in southeastern anatolia turkey includes several historical heritages and man made caves it is mainly located in dolomitic limestone the city will be partly under water after reservoir impounding of the ilisu dam and the limestone will be subjected to cyclic processes such as wetting drying and freezing thawing although a new town is formed and part of the city is transported to a nearby area this cannot be done for many existing historical and cultural values at the site the behavior of the limestone under cyclic processes is not known in this study deterioration mechanisms of the limestone were investigated with field and laboratory studies it is found that the rock is not durable very thin surficial deterioration zone exists on the rock surface discontinuity controlled block failures associated with collapse of man made caves occur at the site before reservoir impounding further discontinuity controlled block failures are expected to occur after reservoir impounding by aggravated deterioration and surface erosion of the rock within the fluctuation zone of the reservoir

hydrogeochemical and isotopic investigations of the han river basin south korea summary the han river the largest river in south korea draining approximately 26 000 km 2 comprises two major tributaries the north and the south han rivers seasonal and spatial variations in the major ion chemistry and isotope compositions of the han river were monitored for one year at 14 23 locations covering about 80 of the entire drainage basin compared to the south han river shr the north han river nhr was much lower in total dissolved solids tds sr and major ion concentrations but higher in si concentration 34 s so 4 values and 87 sr 86 sr ratios these observations suggest strong influence of prevailing rock types in the drainage basins on the chemical and isotopic compositions of the river waters these are silicate rocks in the nhr basin and carbonate rocks in the shr basin the headwaters of the nhr basin where several flood control dams have been constructed show enrichment in deuterium and oxygen 18 indicating evaporative loss the 34 s so 4 data suggest dissolved sulfates in the nhr and shr are mostly derived from atmospheric deposition and variable mixtures of atmospheric deposition and sulfide oxidation respectively the 87 sr 86 sr ratios are much higher in the nhr 0 71793 0 72722 than in the shr 0 71495 0 71785 with one exception indicating weathering of precambrian and mesozoic granitic rocks and marine carbonates respectively