travertine deposits of soda dam new mexico and their implications for the age and evolution of the valles caldera hydrothermal system uranium thorium disequilibrium dates and stable isotope analyses of travertine deposits at soda dam new mexico have been used to determine the age and to document the evolution of the valles caldera hydrothermal system soda dam discharges from paleozoic and precambrian rocks in san diego canyon southwest of the caldera and the canyon was filled with several hundred metres of upper bandelier tuff during formation of valles caldera 1 12 ma according to the dates the valles hydrothermal system is at least 106 yr old or nearly as old as the caldera the basic hydrology of the system has thus remained virtually unchanged during this time travertine ages indicate pulses in travertine deposition from 1 0 to 0 48 ma from 0 107 to 0 058 ma and from 0 005 ma to present the volume of various travertine deposits suggests that the hot spring system at soda dam was once larger than it is today possibly discharging as much as 5 to 10 times more fluid of na hco3 cl composition stable isotopes of the travertines indicate however that the hot spring system has probably never been more than about 10 c hotter than the present maximum temperature of 48 c stable isotopes also show that the 13c of co2 and 18o of h2o in hot spring waters has remained relatively constant for 106 yr the similar ages between caldera formation and the onset of large scale hydrothermal circulation and travertine deposition on pre bandelier tuff rocks imply that incision rates by the jemez river in bandelier tuff were relatively rapid as much as 400 m of tuff were cut by the ancestral jemez river in 105 yr or less

four climate regimes on a land planet with wet surface effects of obliquity change and implications for ancient mars abstract series of numerical experiments are performed using a general circulation model to gain insights on the hydrologic cycle on ancient mars since the state of the ancient mars atmosphere is not well constrained we did not try to simulate an ancient mars climate under warm and wet condition in stead we used an idealized model and tried to extract general features of the hydrologic cycle by modeling an ideal land planet that has no ocean on its surface four different climate regimes warm upright warm oblique frozen upright and frozen oblique regimes are recognized depending on the inclination of the spin axis obliquity and average surface temperature the period of active hydrologic cycle suggested from the geomorphology on mars seems to be consistent with that at the warm oblique regime which appears at warm above freezing environment with high obliquity higher than about 30 condition

the use of hydrochemical sections to identify recharge areas and saline intrusions in alluvial aquifers southeast queensland australia abstract alluvial ground waters used for irrigation in the southwest lockyer valley queensland experience varying salinity problems samples were taken on three occasions along transects in the valleys of the tenthill and ma ma creeks during the dry season august 1984 the wet season february 1985 and during a period of drought january 1987 the waters are categorized by chemical type and hydrochemical sections are plotted for major cation data magnesium calcium and sodium the interpretation of the sections permits the identification of recharge areas for the alluvial aquifers and the location of saline intrusions into the alluvium from underlying sandstone aquifers it is also possible with the assistance of chemical type to correlate some saline intrusions in adjacent valleys as issuing from the same sandstone aquifers a diagram to summarize the locations and magnitudes of salinity changes along transects is given

geochemistry and isotopes of fluids from sulphur springs valles caldera new mexico abstract detailed geochemistry supported by geologic mapping has been used to investigate sulphur springs an acid sulfate hot spring system that issues from the western flank of the resurgent dome inside valles caldera the most intense activity occurs at the intersection of faults offsetting caldera fill deposits and post caldera rhyolites three geothermal wells in the area have encountered pressures 4 8000 mg l these conditions cause argillic alterations throughout a large area non condensible gases consist of roughly 99 co 2 with minor amounts of h 2 s h 2 and ch 4 empirical gas geothermometry suggests a deep reservoir temperature of 215 to 280 c comparison of 13 c and 18 o between caco 3 from well cuttings and co 2 from fumarole steam indicates a fractionation temperature between 200 and 300 c by decarbonation of hydrothermally altered paleozoic limestone and vein calcite in the reservoir rocks tritium concentrations obtained from steam condensed in a mudpot and deep reservoir fluids baca 13 278 c are 2 1 and 1 0 t u respectively suggesting the steam originates from a reservoir whose water is mostly 50 yrs old deuterium contents of fumarole steam deep reservoir fluid and local meteoric water are practically identical even though 18 o contents range through 4 thus precipitation on the resurgent dome of the caldera could recharge the hydrothermal system by slow percolation from analysis of d and 18 o values between fumarol steam and deep reservoir fluid steam reaches the surface either 1 by vaporizing relatively shallow groundwater at 200 c or 2 by means of a two stage boiling process through an intermediate level reservoir at roughly 200 c although many characteristics of known vapor dominated geothermal systems are found at sulphur springs fundamental differences exist in temperature and pressure of our postulated vapor zone we propose that the reservoir beneath sulphur springs is too small or too poorly confined to sustain a true vapor dominated system and that the sulphur springs system may be a dying vapor dominated system that has practically boiled itself dry

observations of thermospheric horizontal neutral winds at watson lake yukon territory λ 65 n fabry perot interferometer observations of the thermospheric o i 6300 a emission have been conducted from an airglow observatory at a dark field site in the southeastern yukon territory canada for the period november 1991 to april 1993 the experiment operated in an unattended remote fashion has resulted in a substantial data set from which mean neutral winds have been determined dependent upon geomagnetic activity the nocturnal location of the site is either equatorward of the auroral oval or within the oval boundaries the data set is rich enough to permit hourly binning of neutral winds based upon the kp geomagnetic disturbance index as well as the season for cases of low geomagnetic activity the averaged vector horizontal neutral wind exhibits the characteristics of a midlatitude site displaying antisunward pressure gradient driven winds as the geomagnetic activity rises the late afternoon and evening winds slowly rotate sunward in an anticlockwise direction initially remaining near 100 m s in speed but eventually increasing to 300 m s for kp 5 for the higher levels of activity the observed neutral wind flow pattern resembles a higher latitude polar cap pattern characterized by ion drag forcing of thermospheric neutral gases in addition rotational coriolis forcing on the dusk side enhances the ion drag forcing resulting in dusk winds which trace out the clockwise dusk cell plasma flow on the dawn side the neutral winds also rotate in an anticlockwise direction as the strength of geomagnetic disturbances increase since the site is located at a transition latitude between the midlatitude and the polar cap the data set provides a sensitive test for general circulation models which attempt to parameterize the contribution of magnetospheric processes a comparison with the vector spherical harmonic vsh model indicates several regions of poor correspondence for december solstice conditions but reasonable agreement for the vernal equinox

new isotopic evidence for the origin of groundwater from the nubian sandstone aquifer in the negev israel the geochemistry and isotopic composition h o s osulfate c sr of groundwater from the nubian sandstone kurnub group aquifer in the negev israel were investigated in an attempt to reconstruct the origin of the water and solutes evaluate modes of water rock interactions and determine mean residence times of the water the results indicate multiple recharge events into the nubian sandstone aquifer characterized by distinctive isotope signatures and deuterium excess values in the northeastern negev groundwater was identified with deuterium excess values of 16 which suggests local recharge via unconfined areas of the aquifer in the negev anticline systems the d 18 oh2o and d 2 h values 6 5 and 35 4 of this groundwater are higher than those of groundwater in the sinai peninsula and southern arava valley 7 5 and 48 3 that likewise have lower deuterium excess values of 10 based on the geochemical differences between groundwater in the unconfined and confined zones of the aquifer a conceptual geochemical model for the evolution of the groundwater in the nubian sandstone aquifer has been reconstructed the isotopic composition of shallow groundwater from the unconfined zone indicates that during recharge oxidation of pyrite to so4 d 34 sso4 13 d 18 oso4 7 7 and dissolution of caco3 87 sr 86 sr 0 70787 d 13 cdic 3 7 occur in the confined zone of the aquifer bacterial so4 reduction removes a significant part of dissolved so 2

use of isotopic signatures for the determination of natural recharge and chemical characterization of groundwaters the case of horombe plateau area sw madagascar the necessity for accurate determination of groundwater recharge is an important issue for the smart mining of groundwater resources especially in hydrologically sensitive regions different techniques and methods have been widely reported in literature and isotope hydrology has found to be one of the major fields of the study this paper presents the combination of different techniques for analyzing the recharge discharge mechanisms within a large catchment area in sw madagascar by correlating different isotopic signatures piezometric conditions major ion water chemistry from ground and surface water samples including their physical characteristics from in situ measurements and also geological structures present within the study area it provides among others a detailed description on the geologic and hydrogeologic regime of the horombe plateau based on field data obtained from a well distributed monitoring network within the study area which is envisaged to serve as the conceptual model for future groundwater modeling studies

stratigraphic relations and lithologic variations in the jemez volcanic field new mexico over 100 radiometric dates and recent detailed geologic mapping allow some refinements of the stratigraphic relations of major units and generalization of temporal lithologic variations in the jemez volcanic field volcanism had begun in the area by about 16 5 ma with episodic eruptions of alkaline basalts by 13 ma alkaline volcanism had been replaced with eruptions of more voluminous olivine tholeiite high silica rhyolite derived from melts of lower crust also was erupting by about 13 ma basalt and high silica rhyolite continued to be erupted until about 7 and 6 ma respectively but effusions of dominantly andesitic differentiates of basalt that began as early as about 12 ma volumetrically overshadowed all other eruptive products between 10 and 7 ma from 7 to 3 ma the dominant erupted lithology was dacite which appears to have been generated by mixing of magmas whose compositions are approximated by earlier andesites and high silica rhyolites less than 4 3 ma volcanism was dominated by eruption of rhyolitic tuffs field relations geochemistry and dates specifically indicate the following with regards to stratigraphie relations 1 distinctions among basalt of chamisa mesa paliza canyon formation basalts and lobato basalt for other than geographic reasons are artificial basaltic volcanism was continuous in volcanic field from 13 to 7 ma 2 canovas canyon and bearhead rhyolites form a continuum of high silica rhyolite volcanism from 13 to 6 ma 3 hypabyssal and volcanic rocks of the cochiti mining district probably represent the exhumed interior of a keres group volcano s 4 temporal overlaps exist among the major stratigraphie groups which may imply some genetic relations and 5 the tewa group formation cerro rubio quartz latite may more appropriately be considered part of the tschicoma formation of the polvadera group preliminary analysis of hydrothermal alteration in the context of the volcanic stratigraphy suggests at least three distinct hydrothermal events have occurred in the volcanic field s history

evidence for influence of mineral weathering on stream water sulphate in vermont and new hampshire usa mass balance studies in forested catchments in the northeastern usa show that s losses via streamwater so4 2 exceed measured atmospheric s inputs possible sources of the excess s loss include underestimated dry deposition mineralization of organic s in soils desorption of soil sulphate oxidation of recently formed sulphides and mineral weathering evaluating the relative contribution of these sources and processes to so4 2 export is important to our understanding of s cycling as well as to policy makers in their evaluation of the efficacy of s emission controls in order to evaluate the potential for mineral weathering contributions to so4 2 export we measured concentration and isotopic composition 34 sa nd 18 o of so4 2 in stream water and concentration and 34 s values of four s fractions in bedrock and soil parent material in catchments of varying geological composition geological substrates with low s concentrations were represented by catchments underlain by quartzite and granite whereas geological substrates with high s concentrations were represented by catchments underlain by sulphidic slate schist and metavolcanic rocks catchments with s poor bedrock had stream water so4 2 concentrations 100 eq l 1 and isotopic values consistent with those of atmospheric so4 2 that had been cycled through the organic soil pool catchments with s rich bedrock had stream water so4 2 concentrations ranging from 56 to 229 eq l 1 isotopic values deviated from those of so4 2 in atmospheric deposition clearly indicating a mineral weathering source in some cases whereas in others spatial variability of mineral 34 s values precluded the isotopic detection of a weathering contribution these results along with evidence suggesting formation of secondary sulphate minerals in bedrock weathering rinds indicate that mineral weathering may be an important source of s in the surface waters of some forested catchments in the northeastern usa copyright 2004 john wiley sons ltd

hydrochemistry to delineate groundwater flow conditions in the mogher al mer area damascus basin southwestern syria the hydrochemistry of groundwater from the mogher al mer area located in southwestern syria has been used as a tool to identify and assess the hydrogeological systems and associated conditions in this arid region of syria groundwater is considered as the main source of water supply for both drinking and irrigation purposes the detailed description of hydrogeochemical conditions including major ions physico chemical and in situ field parameters has underlined the very complex variability of the stratigraphic sequences and hence the numerous hydrogeological units within the study area on the one hand groundwater chemical signature is found to be mainly controlled by the water rock interaction processes in the mountainous western part of the study area on the other hand anthropogenic influences are observed in the eastern plain in terms of recharge mechanisms the region can be considered as a part of a main intermediate or even regional flow system instead of a local one

the effect of acid rain and altitude on concentration δ34s and δ18o of sulfate in the water from sudety mountains poland abstract the analyses of sulfate content 34s and 18o of dissolved sulfate and 18o of water were carried out in a 14 km2 crystalline massif located in the sudety mountains sw poland to 1 assess the amount of the sulfate delivered to the surface and groundwater systems by modern atmospheric precipitation 2 determine the effect of altitude on these parameters and 3 investigate their seasonal variations in april and november of 2002 august 2003 and march and september of 2005 samples of water were collected from springs and streams of the massif during these seasons sulfate contents and 18o so42 values varied from 5 80 to 18 00 mg l and from 3 96 to 8 23 respectively showing distinctively higher values of 18o so42 in wet seasons the 34s so42 values had a relatively narrow range from 4 09 to 5 28 and were similar to those reported for organic matter in soil and the canopy throughfall in the sudety mountains sulfate content 34s so42 18o so42 and 18o h2o values revealed a remarkable dependence on the altitude the calculated altitude effects for five season averages of these parameters were 1 00 mg l 100 m 0 18 100 m 0 27 100 m and 0 17 100 m respectively this dependence on the altitude resulted mainly from the mixing of sulfates of different origins such as anthropogenic sulfate sulfate produced in the soil within the weathered zone of the massif and that one from the tree canopy the oxygen isotope mass balance indicates that in the study area about one third of the sulfate delivered to the surface and groundwater by modern precipitation comes from anthropogenic pollution further interaction of meteoric water within the weathered rocks causes a continuous decrease of 18o so42 values resulting from biological transformation of the sulfate due to plant vegetation and decomposition of organic matter

spatial evolution of frictional heating and the predicted thermospheric wind effects in the vicinity of an auroral arc measured with the sondrestrom incoherent scatter radar and the reimei satellite 1 simultaneous observation with the sondrestrom incoherent scatter is radar and the reimei satellite was conducted on 3 october 2007 the objective was to measure horizontal patterns of the ionospheric structure in the vicinity of an auroral arc the is radar was scanned azimuthally with a fixed elevation angle and the satellite narrow view camera 557 7 nm was directed downward taking pictures every 0 12 s a stationary auroral arc was captured at 05 17 ut 02 54 mlt with both instruments simultaneously gross ionospheric features measured with the is radar around the arc were in good agreement with the expected magnetosphere ionosphere current system of particular interest was the horizontal pattern in the ion speed and temperature in the f region the ion speed within the arc was close to zero by contrast the larger ion speed 350 400 m s 1 on the poleward side was parallel to the arc and almost no horizontal shear within about 20 km width perpendicular to the arc this area was separated into two parts by the ion temperature one was associated with clear enhancements in excess of 1200 k and another was with more moderate enhancements less than 1000 k the widths of the two areas were approximately 10 km each the horizontal shear seen in the ion temperature suggested the presence of a narrow thermospheric wind shear of about 10 km width this paper suggests that the possible cause for the thermospheric wind shear was ion drag associated with localized soft particle precipitation or f region ionization

gas geochemistry of the valles caldera region new mexico and comparisons with gases at yellowstone long valley and other geothermal systems abstract noncondensible gases from hot springs fumaroles and deep wells within the valles caldera geothermal system 210 300 c consist of roughly 98 5 mol co 2 0 5 mol h 2 s and 1 mol other components 3 he 4 he ratios indicate a deep magmatic source r r a up to 6 whereas 13 c co 2 values 3 to 5 do not discriminate between a mantle magmatic source and a source from subjacent hydrothermally altered paleozoic carbonate rocks regional gases from sites within a 50 km radius beyond valles caldera are relatively enriched in co 2 and he but depleted in h 2 s compared to valles gases regional gases have r r a values 1 2 due to more interaction with the crust and or less contribution from the mantle carbon sources for regional co 2 are varied during 1982 1998 repeat analyses of gases from intracaldera sites at sulphur springs showed relatively constant ch 4 h 2 and h 2 s contents the only exception was gas from footbath spring 1987 1993 which experienced increases in these three components during drilling and testing of scientific wells vc 2a and vc 2b present day valles gases contain substantially less n 2 than fluid inclusion gases trapped in deep early stage post caldera vein minerals this suggests that the long lived valles hydrothermal system ca 1 myr has depleted subsurface paleozoic sedimentary rocks of nitrogen when compared with gases from many other geothermal systems valles caldera gases are relatively enriched in he but depleted in ch 4 n 2 and ar in this respect valles gases resemble end member hydrothermal and magmatic gases discharged at hot spots galapagos kilauea and yellowstone

integrated fe and s isotope study of seafloor hydrothermal vents at east pacific rise 9 10 n abstract in this study we report on coupled fe and s isotope systematics of hydrothermal fluids and sulfide deposits from the east pacific rise at 9 10 n to better constrain processes affecting fe isotope fractionation in hydrothermal environments we aim to address three fundamental questions 1 is there significant fe isotope fractionation during sulfide precipitation 2 is there significant variability of fe isotope composition of the hydrothermal fluids reflecting sulfide precipitation in subsurface environments 3 are there any systematics between fe and s isotopes in sulfide minerals the results show that chalcopyrite precipitating in the interior wall of a hydrothermal chimney displays a limited range of 56fe values and 34s values between 0 11 to 0 33 and 2 2 to 2 6 respectively the 56fe values are on average slightly higher by 0 14 relative to coeval vent fluid composition while 34s values suggest significant s isotope fractionation 0 6 0 2 during chalcopyrite precipitation in contrast systematically lower 56fe and 34s values relative to hydrothermal fluids by up to 0 91 and 2 0 respectively are observed in pyrite and marcasite precipitating in the interior of active chimneys these results suggest isotope disequilibrium in both fe and s isotopes due to s isotopic exchange between hydrothermal h2s and seawater so42 followed by rapid formation of pyrite from fes precursors thus preserving the effects of a strong kinetic fe isotope fractionation during fes precipitation in contrast 56fe and 34s values of pyrite from inactive massive sulfides which show evidence of extensive late stage reworking are essentially similar to the hydrothermal fluids multiple stages of remineralization of ancient chimney deposits at the seafloor appear to produce minimal fe isotope fractionation similar affects are indicated during subsurface sulfide precipitation as demonstrated by the lack of systematic differences between 56fe values in both high temperature fe rich black smokers and lower temperature fe depleted vents

an empirical model of the earth s horizontal wind fields hwm07 1 the new horizontal wind model hwm07 provides a statistical representation of the horizontal wind fields of the earth s atmosphere from the ground to the exosphere 0 500 km it represents over 50 years of satellite rocket and ground based wind measurements via a compact fortran 90 subroutine the computer model is a function of geographic location altitude day of the year solar local time and geomagnetic activity it includes representations of the zonal mean circulation stationary planetary waves migrating tides and the seasonal modulation thereof hwm07 is composed of two components a quiet time component for the background state described in this paper and a geomagnetic storm time component dwm07 described in a companion paper

chemical and isotopic compositions of minerals and waters from the campi flegrei volcanic system naples italy abstract based on their 34 s signature sulfate minerals and native sulfur around fumaroles and hot water pools from the campi flegrei volcanic area derive from supergenic oxidation of volcanic h 2 s their mean 34 s value 0 2 1 7 matches with that of fumarolic h 2 s at solfatara 0 3 0 3 as well as with the 34 s of 1 4 obtained for total sulfur in fresh trachyte from the area all 34 s values indicate a mostly deep seated origin for sulfur thermal waters were analysed for major and minor chemistry and for oxygen hydrogen and sulfur isotope compositions pools at pisciarelli are filled with evaporated meteoric water heated by rising magmatic gases the water 18 o 3 8 1 3 and 2 h 6 5 2 2 values in these steam heated waters are controlled by mixing and evaporation effects and the 34 s value of dissolved sulfate 1 3 0 3 basically agrees with supergenic oxidation of deep seated h 2 s as the major source of sulfur instead water from thermal springs and wells elsewhere in the campi flegrei appears to be a mixture between dilute meteoric and saline marine components the latter may be local seawater from the bay of pozzuoli the 18 o and 2 h values of waters sampled during 1993 1994 range from 5 6 to 0 3 and from 33 to 3 4 respectively the 34 s values of dissolved sulfate range between 0 1 and 19 5 in general sulfate is probably derived essentially from two sources both within the volcanic cover i e oxidation dissolution of pyrite and anhydrite and marine water an occasional source of water and sulfate is represented by magmatic gases which directly interact with shallow meteoric water as in the case of the hotel tennis well yielding steam heated water with 18 o 1 5 0 2 2 h 17 1 and 34 s 0 1

sulfur isotopic effects in the disproportionation reaction of sulfur dioxide in hydrothermal fluids implications for the δ 34 s variations of dissolved bisulfate and elemental sulfur from active crater lakes sulfur isotope effects during the so 2 disproportionation reaction to form elemental sulfur 3so 2 3h 2 o 2hso 4 s 2h at 200 330 c and saturated water vapor pressures were experimentally determined initially a large kinetic isotopic fractionation takes place between hso 4 and s followed by a slow approach to equilibrium the equilibrium fractionation factors estimated from the longest run results are expressed by 1000 in hso 4 s 6 21 10 6 t 2 3 62 the rates at which the initial kinetic fractionation factors approach the equilibrium ones were evaluated at the experimental conditions 34 s values of hso 4 and elemental sulfur were examined for active crater lakes including noboribetsu and niseko hokkaido japan khloridnoe bannoe and maly semiachik kamchatka poas costa rica ruapehu new zealand and kawah ijen and keli mutu indonesia hso4 s values are 28 for keli mutu 26 o for kawah ijen 24 c for ruapehu 23 for poas 22 for maly semiachik 21 for yugama 13 for bannoe 9 for niseko 4 o for khloridonoe and 0 for noboribetsu in the decreasing order the so 2 disproportionation reaction in the magmatic hydrothermal system below crater lakes where magmatic gases condense is responsible for high hso4 s values whereas contribution of hso 4 produced through bacterial oxidation of reduced sulfur becomes progressively dominant for lakes with lower hso4 s values currently noboribetsu crater lake contains no hso 4 of magmatic origin a 40 year period observation of 34 s hso4 and 34 s s values at yugama indicated that the isotopic variations reflect changes in the supply rate of so 2 to the magmatic hydrothermal system this implies a possibility of volcano monitoring by continuous observation of 34 s hso4 values the 18 o values of hso 4 and lake water from the studied lakes covary indicating oxygen isotopic equilibration between them the covariance gives strong evidence that lake water circulates through the sublimnic zone at temperatures of 140 30 c

sulfur isotopic study of sulfate in the aquifer of costa de hermosillo sonora mexico in relation to upward intrusion of saline groundwater irrigation pumping and land cultivation abstract groundwater from the costa de hermosillo aquifer has been used extensively for irrigation over the past 60 a in the sonora region of northwestern mexico resulting in salinization of fresh groundwater resources salinization of groundwater is most pronounced on the western coastal side of the aquifer with an aerial extent of 26 7 km2 where maximum values are reported for conductivity 31 ms cm and cl concentrations 16 271 mg l salinization is likely to increase if groundwater pumping continues at levels comparable to the present time upward incursion of marine water into the aquifer is inferred from 2h 7 2 and 18o 1 6 compositions of groundwater samples with the highest conductivity compared to modern seawater in the gulf of california ratios of so4 cl and cl br are small 0 01 and 33 respectively and the s isotopic composition of so 4 2 is high 32 7 in the most saline portions of the costa de hermosillo this saline groundwater is inferred to result from an earlier phase of dissimilatory bacterial so 4 2 reduction coupled to decomposition of organic matter in marine blue clays deposited during the miocene pliocene transgression the isotopic composition of present day surface discharge from agricultural fields is substantially enriched in 32s due to widespread application of nh4 2so4 fertilizers and potential mobilization of s from mineral resources surface water discharging from irrigated fields has 34s values ranging from 2 1 to 3 3 which are distinctly different from groundwater and surface water in adjacent non agricultural areas with 34s values ranging from 5 2 to 13 5 prolonged irrigation pumping that promotes the incursion of air to the subsurface could enhance the weathering of s bearing minerals such as magmatic sulfides producing 32s enriched so 4 2

spatial structure in the thermospheric horizontal wind above poker flat alaska during solar minimum a new all sky imaging wavelength scanning fabry perot spectrometer was used to record high resolution r 200 000 spectra of the 630 nm thermospheric optical emission above poker flat alaska these spectra were used to derive spatially resolved maps of the horizontal wind vector at approximately 250 km altitude we describe the procedure used to infer vector winds from line of sight doppler shifts along with its limitations we present the time evolution of the vector wind fields obtained from this method for 6 nights of observation five of the 6 nights contained periods when we inferred the existence of significant curvature divergence or shear in the thermospheric wind across our instrument s 1000 km diameter field of view the sixth night exhibited little spatial structure and is shown for comparison we compare these results with a generic solar minimum winter time run of the national center for atmospheric research s thermosphere ionosphere and electrodynamics general circulation model while agreement was good at the start and end of the night considerable differences were found in the late evening and midnight sectors some possible origins for these discrepancies are proposed in particular we suggest that the f region horizontal wind may be deflected by upwelling vertical winds which are in turn driven by e region heating in the auroral zone we note that both the instrument used and our high latitude implementation of the analysis procedure are new experimental techniques thus the data presented here should be regarded as preliminary and if possible be validated by comparison with results from other techniques

mineralogy of an ancient lacustrine mudstone succession from the murray formation gale crater mars the mars science laboratory curiosity rover has been traversing strata at the base of aeolis mons informally known as mount sharp since september 2014 the murray formation makes up the lowest exposed strata of the mount sharp group and is composed primarily of finely laminated lacustrine mudstone intercalated with rare crossbedded sandstone that is prodeltaic or fluvial in origin we report on the first three drilled samples from the murray formation measured in the pahrump hills section rietveld refinements and fullpat full pattern fitting analyses of x ray diffraction patterns measured by the msl chemin instrument provide mineral abundances refined unit cell parameters for major phases giving crystal chemistry and abundances of x ray amorphous materials our results from the samples measured at the pahrump hills and previously published results on the buckskin sample measured from the marias pass section stratigraphically above pahrump hills show stratigraphic variations in the mineralogy phyllosilicates hematite jarosite and pyroxene are most abundant at the base of the pahrump hills and crystalline and amorphous silica and magnetite become prevalent higher in the succession some trace element abundances measured by apxs also show stratigraphic trends zn and ni are highly enriched with respect to average mars crust at the base of the pahrump hills by 7 7 and 3 7 times respectively and gradually decrease in abundance in stratigraphically higher regions near marias pass where they are depleted with respect to average mars crust by more than an order of magnitude in some targets the mn stratigraphic trend is analogous to zn and ni however mn abundances are close to those of average mars crust at the base of pahrump hills rather than being enriched and mn becomes increasingly depleted moving upsection minerals at the base of the pahrump hills in particular jarosite and hematite as well as enrichments in zn ni and mn are products of acid sulfate alteration on earth we hypothesize that multiple influxes of mildly to moderately acidic pore fluids resulted in diagenesis of the murray formation and the observed mineralogical and geochemical variations the preservation of some minerals that are highly susceptible to dissolution at low ph e g mafic minerals and fluorapatite suggests that acidic events were not long lived and that fluids may not have been extremely acidic ph 2ph 2 alternatively the observed mineralogical variations within the succession may be explained by deposition in lake waters with variable eh and or ph where the lowermost sediments were deposited in an oxidizing perhaps acidic lake setting and sediments deposited in the upper pahrump hills and marias pass were deposited lake waters with lower eh and higher ph

isotopic and geochemical evolution of ground and surface waters in a karst dominated geological setting a case study from belize central america abstract analysis of stable isotopes and major ions in groundwater and surface waters in belize central america was carried out to identify processes that may affect drinking water quality belize has a subtropical rainforest savannah climate with a varied landscape composed predominantly of carbonate rocks and clastic sediments stable oxygen 18 o and hydrogen d isotope ratios for surface and groundwater have a similar range and show high d excess 10 40 8 the high d excess in water samples suggest secondary continental vapor flux mixing with incoming vapor from the caribbean sea model calculations indicate that moisture derived from continental evaporation contributes 13 to overhead vapor load in surface and groundwater concentrations of dissolved inorganic carbon dic ranged from 5 4 to 112 9 mg c l and 13 c dic ranged from 7 4 to 17 4 so 4 2 ca 2 and mg 2 in the water samples ranged from 2 163 2 6593 and 2 90 mg l respectively the dic and 13 c dic indicate both open and closed system carbonate evolution combined 13 c dic and ca 2 mg 2 and so 4 2 suggest additional groundwater evolution by gypsum dissolution and calcite precipitation the high so 4 2 content of some water samples indicates regional geologic control on water quality similarity in the range of 18 o d and 13 c dic for surface waters and groundwater used for drinking water supply is probably due to high hydraulic conductivities of the karstic aquifers the results of this study indicate rapid recharge of groundwater aquifers groundwater influence on surface water chemistry and the potential of surface water to impact groundwater quality and vise versa

tectonics of the jemez lineament in the jemez mountains and rio grande rift the jemez lineament is a ne trending crustal flaw that controlled volcanism and tectonism in the jemez mountains and the rio grande rift zone the fault system associated with the lineament in the rift zone includes from west to east the jemez fault zone southwest of the valles toledo caldera complex a series of ne trending faults on the resurgent dome in the valles caldera a structural discontinuity with a high fracture intensity in the ne jemez mountains and the embudo fault zone in the espanola basin the active western boundary faulting of the espanola basin may have been restricted to the south side of the lineament since the mid miocene the faulting apparently began on the sierrita fault on the east side of the nacimiento mountains in the late oligocene and stepped eastward in the early miocene to the canada de cochiti fault zone at the end of the miocene about 5 ma the active boundary faulting again stepped eastward to the pajarito fault zone on the east side of the jemez mountains the north end of the pajarito fault terminates against the jemez lineament at a point where it changes from a structural discontinuity zone of high fracture intensity on the west to the embudo fault zone on the east major transcurrent movement occurred on the embudo fault zone during the pliocene and has continued at a much slower rate since then the relative sense of displacement changes from right slip on the western part of the fault zone to left slip on the east the kinematics of this faulting probably reflect the combined effects of faster spreading in the espanola basin than the area north of the lineament abiquiu embayment and san luis basin the right step in the rift that juxtaposes the san luis basin against the picuris mountains and counterclockwise rotation of various crustal blocks within the rift zone no strike slip displacements have occurred on the lineament in the central and eastern jemez mountains since at least the mid miocene although movements on the still active jemez fault zone in the western jemez mountains may have a significant strike slip component basaltic volcanism was occurring in the jemez mountains at four discrete vent areas on the lineament between about 15 ma and 10 ma and possibly as late as 7 ma indicating that it was being extended during that time

geochemical and isotopic characterization of groundwater from shallow and deep limestone aquifers system of aleppo basin north syria stable isotopes 18o 2h and 13c and radioactivity 3h 14c have been used in conjunction with chemical data to evaluate the processes generating the chemical composition reconstruct the origin of the water and groundwater residence time the aleppo basin is comprised of two main limestone aquifers the first one is unconfined of paleogene age and the second is confined of upper cretaceous age the chemical data indicate that the dissolution of minerals and evaporation are the main processes controlling groundwater mineralization the groundwater from the two aquifers is characterized by distinctive stable isotope signatures this difference in water isotopes is interpreted in terms of difference origin and recharge period fresh and brackish shallow groundwater were mostly recharged during the holocene period the presence of 3h in several groundwater samples of this aquifer gives evidence that groundwater recharge is going on brackish water of the deep confined aquifer has depleted stable isotope composition and very low 14c activity that indicates recharge during the late pleistocene cold period

acidic volatiles and the mars soil large portions of mars surface are covered with deposits of fine homogeneous weathered dusty soil material nanophase iron oxides silicate mineraloids and salts prevail in the soil the mode of formation of this somewhat peculiar type of soil is still far from being clear one scenario suggests that weathering took place during early epochs when mars may have been warm and wet the properties of the soil are not easily reconciled with this scenario we propose another possible scenario that attributes in part the peculiar nature of the martian dust and soil to a relatively young weathering product formed during the last few hundreds of millions of years in a process that involves acidic volatiles we tested this hypothesis in an experimental study of the first step of acidolytic weathering of a partly palagonitized volcanic tephra of hawaiitic lava origin using sulfuric hydrochloric and nitric acids and their mixtures the tephra effectively neutralize the added acidity the protonic acidity added to the tephra attacks the primary minerals releasing fe al and mg which control the ph acting as lewis acid species of varying acid strengths the full amount of acidity added to the tephra is stored in it but only a very small fraction is preserved as the original protonic acidity the majority of the added sulfate and chloride were present as salts and easily solubilized minerals well crystallized sulfate salt minerals of aluminum and calcium were detected by powder x ray diffractometry whereas secondary magnesium and iron minerals were not detected due probably to lack of crystallinity the presence of gypsum caso4 2 h2o and alunogen al2 so4 3 17 h2o is probably responsible for the observed increased hygroscopicity of the acidified tephra and their tendency to form hardened crusts we suggest that if this mechanism is of importance on mars then the chemically weathered component of the martian soil consists of a salt rich mineral mixture containing the salts of the anionicligands so4 and cl resulting from volatiles emitted from volcanoes during more recent eruptions up to 109 years b p the lack of liquid water on mars surface during that time slowed or halted mineralogical evolution into highly crystallized minerals having large mineral grains the chemically weathered components are mixed with the products of physical weathering the recently formed soil may cover and coat more evolved hydrothermally modified mineral deposits formed in earlier epochs of mars

formation of hydrothermal vents in the north fiji basin sulfur and lead isotope constraints abstract hydrothermal sulfides were recovered from the 16 50 s triple junction area in the north fiji basin at a water depth of ca 1900 m the chimney samples can be divided into three groups based on their major metal contents 1 type 1 fe cu rich 2 type 2 fe cu rich with minor zn and 3 type 3 zn rich chimneys type 1 chimneys are mainly composed of chalcopyrite and pyrite and are enriched in elements commonly precipitated under high temperature conditions 300 c such as cu co mo and se type 3 chimneys consist dominantly of sphalerite and marcasite with traces of pyrite and chalcopyrite and are enriched in elements commonly associated with relatively low temperatures 150 to 250 c such as zn cd pb as and ga type 2 chimneys have a mineralogy similar to that of type 1 chimneys although their trace metal contents range between those of type 1 and type 3 samples type 2 chimneys appear to be the products of low temperature replacement which might be related to formation of type 3 chimneys of type 1 chimneys the trace element composition of basaltic rocks indicates that magma generation in the triple junction area was influenced by two different sources n morb and e morb sulfur and lead isotope patterns of the hydrothermal chimneys show distinct differences between the type 1 and type 3 chimneys the type 1 sulfides 34 s 2 8 1 2 206 pb 204 pb 18 082 to 18 132 207 pb 204 pb 15 440 to 15 481 208 pb 204 pb 37 764 to 37 916 are depleted in 34 s and have lower pb isotope ratios compared to types 2 and 3 chimneys 34 s 4 1 0 9 206 pb 204 pb 18 122 to 18 193 207 pb 204 pb 15 475 to 15 554 208 pb 204 pb 37 882 to 38 150 the higher 34 s values for types 2 and 3 sulfides than type 1 sulfides can be explained by mixing of hydrothermal fluids with ambient seawater the more radiogenic pb isotope composition of types 2 and 3 chimneys compared to type 1 chimneys suggest that the formation of types 2 and 3 chimneys were possibly related to e morb volcanism that shows higher pb isotope composition than n morb rocks however ferromanganese crust samples have radiogenic pb isotope compositions that are identical to those of e morb therefore input of hydrogenous pb is also a possible source for radiogenic pb isotopes in the types 2 and 3 chimneys

the 40ar 39ar age constraints on the duration of resurgence at the valles caldera new mexico 1 the 40ar 39ar ages for rocks from the valles caldera new mexico imply that resurgent uplift of the caldera floor occurred within 27 27 ka of caldera collapse the structural resurgent dome of the valles caldera was uplifted approximately 1000 m above the surrounding caldera floor during resurgence the upper bandelier tuff which yields an age of 1 256 0 010 ma 2 ages relative to fish canyon tuff sanidine at 28 02 ma is the lower constraint on the timing of resurgence the oldest postcollapse ring fracture dome cerro del medio is the upper time constraint and yields an age of 1 229 0 017 ma for one of its oldest flow lobes therefore resurgent uplift probably occurred within 54 ka at a minimum rate of 1 9 cm yr sanidine phenocrysts from rhyolites of the postcollapse intracaldera deer canyon and redondo creek members yield 40ar 39ar single crystal laser fusion ages ranging from 1 229 0 013 ma to 1 283 0 017 ma deer canyon member n 8 and 1 208 0 017 ma to 1 239 0 017 ma redondo creek member n 4 with one exception from each unit these ages are statistically indistinguishable from the upper bandelier tuff indicating that eruption of these postcollapse rhyolites probably commenced shortly after caldera formation melt inclusion hosted excess argon was not found to have a measurable effect on the age of sanidine from the upper bandelier tuff or the deer canyon member

use of hydrochemistry and environmental isotopes for evaluation of groundwater in the paleogene limestone aquifer of the ras al ain area syrian jezireh atmospheric precipitation and groundwaters from the paleogene aquifer system in northeastern syria jezireh have been investigated using major ions and environmental isotope methods to interpret the hydrogeological features characterizing this system based on the chemical ratios and isotopic compositions the groundwater bodies are differentiated into three main groups 1 fresh cold and shallow groundwater 2 brackish thermal and deep groundwater and 3 an admixed groundwater the fractions of deep thermal water in the total discharge of admixed groundwaters were estimated and the elevations of recharge zones for the paleogene aquifer were determined based on tritium content in atmospheric precipitation and by adopting a model with exponential time distribution function the mean residence time of groundwater is evaluated radiocarbon groundwater ages were calculated and corrected according to the most commonly used models the extensive declining of major karst springs discharge in the ras al ain area is the consequence of a severe groundwater pumping from the paleogene aquifer the remaining groundwater resources in this aquifer are subject to be exhausted in the future years in the absence of any real rational treatment and suitable management strategies

acid sulfate weathering of synthetic martian basalt the acid fog model revisited the acid fog model has received considerable attention as a model of soil formation on mars previous evaluations of this model have focused on experimental weathering of terrestrial basalt samples however these samples differ significantly from what now is thought to be typical of martian basalt the acid fog model is tested here using synthetic basaltic analogs derived from mars pathfinder soil and rock compositions reaction of synthetic basalt with various acidic solutions and subsequent evaporation has led to the formation of several putative secondary mineral phases many of these phases were not produced in prior experimental studies aimed at aqueous interactions on mars of these alteration phases mg fe ca and al sulfates were identified in addition secondary ferric oxide phases formed via rapid fe oxidation under relatively high ph levels buffered by basalt dissolution amorphous silica is a ubiquitous product in these experiments and has formed by precipitation from solution and by the dissolution of minerals and glasses leaving behind leached surface layers composed of residual silica the secondary products formed in these experiments demonstrate the importance of primary mineralogy when testing models of aqueous interactions on mars new constraints are placed on both the reactivity of primary basalt and the secondary mineralogy present at the martian surface copyright 2004 by the american geophysical union

evaluation of meteorites as habitats for terrestrial microorganisms results from the nullarbor plain australia a mars analogue site unambiguous identification of biosignatures on mars requires access to well characterized long lasting geochemical standards at the planet s surface that can be modified by theoretical martian life ordinary chondrites which are ancient meteorites that commonly fall to the surface of mars and earth have well characterized narrow ranges in trace element and isotope geochemistry compared to martian rocks given that their mineralogy is more attractive to known chemolithotrophic life than the basaltic rocks that dominate the martian surface exogenic rocks e g chondritic meteorites may be good places to look for signs of prior life endemic to mars in this study we show that ordinary chondrites collected from the arid australian nullarbor plain are commonly colonized and inhabited by terrestrial microorganisms that are endemic to this mars analogue site these terrestrial endolithic and chasmolithic microbial contaminants are commonly found in close association with hygroscopic veins of gypsum and mg calcite which have formed within cracks penetrating deep into the meteorites terrestrial bacteria are observed within corrosion cavities where troilite fes oxidation has produced jarosite kfe so oh where terrestrial microorganisms have colonized primary silicate minerals and secondary calcite these mineral surfaces are heavily etched our results show that inhabitation of meteorites by terrestrial microorganisms in arid environments relies upon humidity and ph regulation by minerals furthermore microbial colonization affects the weathering of meteorites and production of sulfate carbonate fe oxide and smectite minerals that can preserve chemical and isotopic biosignatures for thousands to millions of years on earth meteorites are thus habitable by terrestrial microorganisms even under highly desiccating environmental conditions of relevance to mars they may therefore be useful as chemical and isotopic standards that preserve evidence of life thereby providing the possibility of universal context for recognition of microbial biosignatures on earth mars and throughout the solar system

recharge mechanisms and geochemical processes in a semi arid sedimentary basin eastern cape south africa abstract stable isotope 18 o and 2 h and geochemical signatures are used to gain some insight into recharge processes and groundwater salinization mechanisms in a semi arid rangeland catchment the 665 km 2 catchment is underlain by fractured lower beaufort sandstones and mudstones and is intruded by several dolerite dykes chloride and isotopic relationships suggest that chloride ions in ground water are of meteoric origin the hypothesized recharge and salinization mechanism is that large storm events periodically dissolve accumulated surficial meteoric salts and after a period of evaporative enrichment at or near the soil surface leach them into the ground water geochemical variations imply that spatial differences exist in recharge volumes in evaporative enrichment or in the extent of leaching of surficial salts meteoric sodium chloride contributes greater than 90 of the dissolved sodium except at low salinities where cation exchange processes yield additional sodium inputs in exchange for dissolved calcium and magnesium at high salinities this process reverses and sodium is adsorbed releasing calcium and magnesium this process accounts for up to 40 of the dissolved calcium and magnesium contributions from geochemical weathering are relatively uniform in spite of highly variable salinities which implies that residence times are also relatively uniform

explosive rhyolitic volcanism in the jemez mountains vent locations caldera development and relation to regional structure the jemez volcanic field straddles the western margin of the rio grande rift where the rift is intersected by the jemez lineament in north central new mexico the field has a record of volcanism extending back to before 13 ma initial basaltic activity was related to active rifting with minor rhyolitic eruptions occurring along n s rift bounding faults between 10 and 7 ma voluminous andesitic volcanism took place in the central jemez mountains area overwhelming contemporaneous basaltic and rhyolitic magmatism an apparent tectonic lull took place from 7 to 4 ma accompanied by lower eruption rates during this interval dacitic magmas were erupted to form the tschicoma volcanic center but mafic and rhyolitic volcanism virtually ceased since 4 ma accompanying resumption of rifting a growing silicic magma system has been present under the central part of the jemez mountains ultimately evolving to the magma body that produced the voluminous rhyolitic bandelier tuffs explosive rhyolitic eruptions from this large magma body have occurred many times since 3 to 4 ma early eruptions 3 6 2 8 ma produced high silica rhyolite ignimbrites restricted to the southwest part of the jemez mountains formation of these units may have been accompanied by caldera collapse these events were followed by the two caldera forming bandelier tuff ignimbrite eruptions 1 45 and 1 12 ma post caldera explosive and effusive rhyolite eruptions have also tapped the magma body from vents generally located along ring fractures after both bandelier events vent and caldera locations for the rhyolitic eruptions during 3 4 ma have been inferred from grain size characteristics dispersal patterns and facies variations in the plinian deposits and ignimbrites lithic breccia zones of the pre bandelier ignimbrites indicate possible caldera sources in the southwest part of the present valles caldera during the eruption of both bandelier tuffs initial plinian falls and early pyroclastic flows emanated from vents centrally located in the jemez mountains in the lower bandelier tuff eruption a transition to ring fracture vents occurred before the emission of later pyroclastic flows but there is no strong evidence to suggest such a transition occurred during the upper bandelier eruption calderas associated with the lower and upper bandelier tuffs toledo and valles respectively are almost identical in location as are the plinian vent sites for these two large eruptions the toledo embayment northeast of the valles caldera contains lava domes from up to 3 6 ma and may be a caldera or crater associated with early explosive dacitic volcanism in the tschicoma volcanic center post 1 4 ma lava domes also fill this depression the main volcanic features of the jemez mountains field including the valles caldera complex eruption vents and the apical graben of the post valles redondo resurgent block appear to be aligned along the ne sw trending jemez fault zone this zone the local expression of a precambrian basement feature the jemez lineament has exerted strong control on the location and style of eruptions from the bandelier rhyolitic magma system

isotopic evidence for processes of sulfur retention release in 13 forested catchments spanning a strong pollution gradient czech republic central europe sulfur isotope systematics were studied in 13 small catchments in the czech republic similar in topography v shaped valley and vegetation norway spruce the sites differed in elevation rainfall bedrock soil type and s pollution across the sites 34 5 values decreased in the order bulk deposition runoff spruce throughfall c horizon soil a b horizon soil 0 horizon soil bedrock means of 5 5 4 8 4 7 4 6 4 2 3 1 and 1 5 o respectively some of the sites had a net export of s while others accumulated s sites exporting s were located in the polluted north where atmospheric s input started to decrease in 1987 sites retaining s were located in the relatively unpolluted south sulfur isotope composition of runoff depended on whether the catchment accumulated or released s sites releasing s had runoff 34 s values lower than deposition in contrast sites retaining s had runoff 34 s values higher than deposition across the sites the 34 5 values of runoff were not correlated with 34 s values of bedrock indicating that the contribution of bedrock to s in runoff was negligible the 34 s values of runoff were strongly positively correlated with the 34 s values of soil sulfur present in the c horizon of soils was mainly derived from atmospheric deposition not bedrock sulfur isotope mass balances were constructed for each catchment making it possible to quantify the difference between 34 s values of the within catchment source sink of s and runoff s sulfur isotope mass balances indicated that the sink for the retained s at unpolluted sites and the source of the released s at polluted sites were isotopically fractionated by the same amount relative to runoff s inorganic and organic processes were considered as possible causes for this observation biological s cycling involves a variety of reactions some of which fractionate s isotopes in contrast adsorption desorption of inorganic sulfate in soil and weathering of s containing minerals do not fractionate s isotopes therefore the within catchment source sink of s must be largely a result of biological s cycling organic s cycling played an important role over a wide range of atmospheric s inputs from 13 to 130 kg s ha 1 yr 1

sulfur during early diagenesis in sphagnum peat insights from δ34s ratio profiles in 21pb dated peat cores pb chronologies and depth profiles of stable s isotope ratios 834s and concentrations of organic and inorganic s fractions were determined in peat cores from nine sites in the u s and the czech republic results indicate that depth profiles in s concentrations s accumulation and 634s ratios in peat deposits are affected not only by historical patterns in atmospheric s deposition but also by ongoing depth dependent changes in s reduction oxidation and s immobilization mineralization processes within a peat deposit these processes impart a certain degree of mobility to s in peat bringing into question the validity of reconstructing historical records of s accumulation using dated peat profiles over long term diagenesis isotopically light s may be continually released from deep peat this release may result in redistribution of s and s isotopes in peat and suggests that short term patterns in s accumulation may not persist over much longer time scales

sulfur isotope signatures in gypsiferous sediments of the estancia and tularosa basins as indicators of sulfate sources hydrological processes and microbial activity abstract in order to reconstruct paleo environmental conditions for the saline playa lakes of the rio grande rift we investigated sediment sulfate sources using sulfur isotope compositions of dissolved so 4 2 ions in modern surface water groundwater and so 4 2 precipitated in the form of gypsum sediments deposited during the pleistocene and holocene in the tularosa and estancia basins the major sulfate sources are lower and middle permian marine evaporites 34s of 10 9 14 4 but the diverse physiography of the tularosa basin led to a complex drainage system which contributed sulfates from various sources depending on the climate at the time of sedimentation as inferred from sulfur isotope mass balance constraints weathering of sulfides of magmatic hydrothermal and sedimentary origin associated with climate oscillations during last glacial maximum contributed about 35 50 of the sulfates and led to deposition of gypsum with 34s values of 1 2 to 2 2 which are substantially lower than permian evaporates in the estancia basin microbial sulfate reduction appears to overprint sulfur isotopic signatures that might elucidate past groundwater flows a rayleigh distillation model indicates that about 3 18 of sulfates from an inorganic groundwater pool 34s of 12 6 13 8 have been metabolized by bacteria and preserved as partially to fully reduced sulfur bearing minerals species elemental sulfur monosulfides disulfides with distinctly negative 34s values 42 3 to 20 3 compared to co existing gypsum 3 8 to 22 4 for the tularosa basin microbial sulfate reduction had negligible effect on 34s value of the gypsiferous sediments most likely because of higher annual temperatures 15 33 c and lower organic carbon content median 0 09 in those sediments leading to more efficient oxidation of h2s and or smaller rates of sulfate reduction compared to the saline playas of the estancia basin 5 28 c median 0 46 of organic carbon the white sands region of the tularosa basin is frequently posited as a hydrothermal analogue for mars high temperatures of groundwater 33 3 c and high 18o h2o values 1 1 in white sands however are controlled predominantly by seasonal evaporation rather than the modern influx of hydrothermal fluids nevertheless it is possible that some of the geochemical processes in white sands such as sulfide weathering during climate oscillations and upwelling of highly mineralized waters might be considered as valid terrestrial analogues for the sulfate cycle in places such as meridiani planum on mars

hydrochemical investigation of shallow groundwater in northwest margin of lop nur northwest china a hydrochemical investigation was conducted in northwest margin of lop nur to evaluate the groundwater chemical patterns and the main hydrological processes occurring in the groundwater system fourteen representative groundwater samples were collected from different springs and boreholes hydrochemical data of the groundwater showed that so4 cl na and cl so4 na water types were dominant in this area and the total dissolved solid tds content rose along the flow path of the groundwater ionic relation analysis was used in conjunction with geochemical modeling to investigate the evolution of the chemical composition of groundwater phreeqc was used for inverse geochemical modeling it is demonstrated that the groundwater recharged mainly in the northern low mountains acquired its mineralization properties principally from water rock interactions i e dissolution of evaporates and reverse cation exchange the dissolution of halite glauber s salt dolomite and calcite determined the na cl mg2 ca2 so4 2 and hco3 chemistry but evaporation and precipitation also influenced the water composition the shallow groundwater of lop nur was characterized by high salinity and slow circulation

sulfur species and biosignatures in sulphur springs valles caldera new mexico implications for mars astrobiology abstract a biogeochemical so 4 2 cycle was investigated in the acid hot springs of valles caldera new mexico using s isotopes and distribution of amino acids in 2007 a major contribution of so 4 2 in this modern volcanic setting came from oxidation of h 2 s from hydrothermal sources which largely increased so 4 2 concentrations up to 2550 mg l 1 and decreased ph down to 2 27 in surface water a relatively small variation of 34 s among the analyzed s bearing minerals 2 1 to 4 0 fumarole h 2 s 1 7 to 4 6 and dissolved so 4 2 in modern surface and groundwater 2 5 to 7 9 indicates poor evidence of s isotope biosignatures related to microbial disproportionation of elemental s to h 2 s and so 4 2 which in turn are not effectively captured in the hydrothermal minerals of the studied volcanic setting this is mainly due to prevailing contribution of reduced s forms from magmatic hydrothermal sources and considerably smaller microbial activity in acid hot spring areas although hydrothermal gypsum and elemental s effectively trap amino acids their preservation lifetimes in s bearing hydrothermal minerals appear to be small the minimal lifetimes are inferred to be the result of increased temperatures and rapid recycling time of s materials in hydrothermal settings landed missions to the martian surface at sites inferred to have experienced active hydrothermal activity similar to the one studied in valles caldera e g elevated volcanic s flux may provide valuable insight into geological and geochemical processes that have influenced the martian surface but may provide minimal potential for recording either amino acid or s isotopic biosignatures of an extinct martian ecosystem

the stable isotope geochemistry of volcanic lakes with examples from indonesia abstract stable isotope compositions d 18o and 34s of volcanic lake waters gas condensates and spring waters from indonesia italy japan and russia were measured the spring fluids and gas samples plot in a broad array between meteoric waters and local high temperature volcanic gas compositions the d and 18o data from volcanic lakes in east indonesia plot in a concave band ranging from local meteoric waters to evaporated fluids to waters heavier than local high temperature volcanic gases we investigated isotopic fractionation processes in volcanic lakes at elevated temperatures with simultaneous mixing of meteoric waters and volcanic gases an elevated lake water temperature gives enhanced kinetic isotope fractionation and changes in equilibrium fractionation factors providing relatively flat isotope evolution curves in 18o d diagrams a numerical simulation model is used to derive the timescales of isotopic evolution of crater lakes as a function of atmospheric parameters lake water temperature and fluxes of meteoric water volcanic gas input evaporation and seepage losses the same model is used to derive the flux magnitude of the keli mutu lakes in indonesia the calculated volcanic gas fluxes are of the same order as those derived from energy budget models or direct gas flux measurements in open craters several 100 m3 volcanic water day and indicate a water residence time of 1 2 decades the 34s data from the keli mutu lakes show a much wider range than those from gases and springs which is probably related to the precipitation of sulfur in these acid brine lakes the isotopic mass balance and s cl values suggest that about half of the sulfur input in the hottest keli mutu lake is converted into native sulfur

the hex experiment determination of the neutral wind field from 120 to 185 km altitude near a stable premidnight auroral arc by triangulating the drift of rocket deployed chemical trails 1 on 25 march 2003 horizontal e region experiment hex released trimethyl aluminum trails from two rockets launched northward from poker flat research range near fairbanks to map the vertical wind field near a stable premidnight auroral arc system they deployed three trails of trimethyl aluminum chemical puffs whose subsequent motion traced the prevailing wind field this motion was determined using triangulation from four ground observation sites position and speed accuracies were estimated to be 1 km and a few meters per second respectively the first rocket followed a novel flat trajectory it released a nearly horizontal trail of length 200 km at an average altitude of 145 km the second rocket was launched 19 min later and released two trails between 125 and 175 km altitude along a conventional steep trajectory all puffs between 130 and 175 km altitude drifted geomagnetic westward almost exactly parallel to the aurora from prior observations and modeling we had expected to observe convective upwelling near the arcs we did not vertical winds were essentially downward throughout the horizontal trail with speeds between 0 and 20 m s 1 although an abatement of downward flow was observed 40 km equatorward of the arcs these data alone do not establish a causal relationship between the abatement and the arcs vertical speeds of 20 m s 1 are relatively modest however because the observed wind field would entrain air parcels in flow parallel to the arc system even vertical speeds around 15 m s 1 could displace individual air parcels by several scale heights if they occurred all along the arcs

winds in the high latitude lower thermosphere dependence on the interplanetary magnetic field 1 wind observations in the summertime lower thermosphere at high southern latitudes measured by the wind imaging interferometer windii on the upper atmosphere research satellite are statistically analyzed in magnetic coordinates and correlated with the interplanetary magnetic field imf to determine influences of imf dependent ionospheric convection on the winds effects are clearly detectable down to 105 km altitude above 125 km the wind patterns show considerable similarity with ionospheric convection patterns and the speed of the averaged neutral wind in the polar cap often exceeds 300 m s the correlation between the imf bz component and the diurnal harmonic of the winds is generally best when the imf is averaged over the preceding 1 4 5 hours the magnetic zonal mean zonal wind below 120 km correlates best with the imf by component when the latter is averaged over approximately the preceding 20 hours the wind has a significantly stronger rotational than divergent component around and above 120 km a dusk side anticyclonic wind vortex is prominent consistent with earlier findings around 140 km and higher the dusk side vortex intensifies for negative bz but around 120 km it is the dawn side cyclonic vortex that responds more strongly to bz variations the dependence of the wind on the imf is nonlinear especially with respect to imf bz for positive bz the difference winds are largely confined to the polar cap while for negative bz the difference winds extend to subauroral latitudes a significant correlation between the diurnal bz dependent neutral and convection velocity components exists above 108 km when the convection velocity is suitably rotated in magnetic local time mlt with respect to the wind the rotation that maximizes the correlation ranges from 1 5 hours at 130 km wind preceding convection to nearly 6 hours at 108 km wind lagging convection the rotated diurnal bz dependent wind pattern projects onto the diurnal bz dependent ionospheric convection pattern with about 60 the amplitude of the latter above 125 km decreasing to about 17 at 108 km on timescales of 20 hours a by dependent magnetic zonal mean zonal wind generally exists with maximum wind speeds at 80 magnetic latitude typically 10 m s at 105 km increasing to about 60 m s at 123 km and 80 m s at 200 km in the southern hemisphere the wind is cyclonic when the time averaged by is positive and anticyclonic when by is negative the wind direction is expected to be opposite in the northern hemisphere

timescales for migration of atmospherically derived sulphate through an alpine subalpine watershed loch vale colorado sulphur 35 a cosmogenically produced radioisotope with a short half life 87 days was measured in snowpack during 1993 1997 and at four locations within the loch vale watershed during 1995 1997 the four sites include the two main drainages in the watershed andrews creek and icy brook a small south facing catchment flowing into andrews creek andrews spring 1 and a similar north facing catchment flowing out of a scree field into icy brook spring 19 concentrations ranged from a high of almost 50 mbq l for a sample from spring 19 in june 1996 to a concentration near the detection limit for a sample from andrews creek in april 1997 sulphur 35 concentrations were normalized to sulphate as mbq mg so4 2 and were decay corrected to a julian day of 90 april 1 for each year snowpack had the highest 35s concentration with an average concentration of 53 mbq mg so4 2 concentrations in the streams were much lower even when corrected for decay relative to jd 90 the large 35s concentrations found in spring 19 were the result of increases in concentration due to sublimation and or evapotranspiration and were lower than snowpack when normalized to sulphate using 35s concentrations found in snowpack as of jd 90 as a beginning concentration the fraction of sulphate in streamflow that was derived from atmospheric deposition within the prior water year was estimated for icy brook and andrews creek the fraction of the sulphate in streamflow derived from that year s snowpack and precipitation was low prior to the beginning of the main spring melt reached a maximum during the period of maximum flow and decreased as the summer progressed a calculation of the seasonal flux indicated that about 40 of the sulphate that flowed out of the watershed was derived from atmospheric sulphate deposited during the previous year this suggests that more than half of the sulphate deposited in the watershed by atmospheric processes during the previous year was removed during the following summer thus sulphate retention in alpine watersheds like loch vale is very limited and changes in sulphate deposition should be quickly reflected in stream chemistry

similarity between c n and s stable isotope profiles in european spruce forest soils implications for the use of δ34s as a tracer abstract stable isotope systematics of c n and s were studied in soils of 5 european forest ecosystems the sites were located along a north south transect from sweden to italy mean annual temperatures from 1 0 to 8 5 c atmospheric deposition from 2 to 19 kg n ha 1 a 1 and from 6 to 42 kg s ha 1 a 1 in picea stands the behavior of c n and s isotopes was similar in 3 aspects 1 assimilation favored the lighter isotopes 12 c 14 n and 32 s 2 mineralization in the soil profile left in situ residues enriched in the heavier isotopes 13 c 15 n and 34 s and 3 no 3 n as well as so 4 s in soil solution was isotopically lighter compared to the same species in the atmospheric input in this study emphasis was placed on s isotope profiles which so far have been investigated to a much lesser extent than those of c and n sulfate in monthly samples of atmospheric input had systematically higher 34 s ratios than total soil s at the 0 5 cm depth on average by 4 0 sulfate in the atmospheric input had higher 34 s ratios than in deep 50 cm lysimeter water on average by 3 2 organic s constituted more than 50 of total soil s throughout most of the profiles 0 20 cm below surface there was a tendency to isotopically heavier organic s and lighter inorganic so 4 s with ester so 4 s heavier than c bonded s at 3 of the 5 sites with an increasing depth 0 to 20 cm below surface 13 c 15 n and 34 s ratios of bulk soil increased on average by 0 9 4 2 and 1 6 respectively reflecting an increasing degree of mineralization of organic matter the isotope effects of c n and s mineralization were robust enough to exist at a variety of climate conditions and pollution levels in the case of s the difference between isotope composition of the upper organic rich soil horizon lower 34 s and the deeper sesquioxide rich soil horizons higher 34 s can be used to determine the source of so 4 in streams draining forests this application of 34 s as a tracer of s origin was developed in the jeze i catchment czech republic a highly polluted site suffering from spruce die back in 1996 1997 the magnitude and 34 s of atmospheric input 20 kg s ha 1 a 1 5 8 and stream discharge 56 kg s ha 1 a 1 3 5 was monitored export of s from the catchment was 3 times higher than contemporary atmospheric input more than 50 of s in the discharge was represented by release of previously stored pollutant s from the soil stable isotope systematics of jeze i soil s mean of 2 5 in the o a horizon 4 8 in the b horizon and 5 8 in the bedrock suggests that most of the soil derived s in discharge must come from the isotopically light organic s present in the upper soil horizon and that mineralized organically cycled s is mainly flushed out during the spring snowmelt the fact that a considerable proportion of incoming s is organically cycled should be considered when predicting the time scale of acidification reversal in spruce die back affected areas

origin and interactions of fluids circulating over the amik basin hatay turkey and relationships with the hydrologic geologic and tectonic settings abstract we investigated the geochemical features of the fluids circulating over the amik basin se turkey syria border which is crossed by the northern extension of the dsf dead sea fault and represents the boundary area of three tectonic plates anatolian arabian and african plates we collected 34 water samples thermal and cold from natural springs and boreholes as well as 8 gas samples bubbling and gas seepage besides the gases dissolved in the sampled waters the results show that the dissolved gas phase is a mixture of shallow atmospheric and deep components either of mantle and crustal origin coherently the sampled waters are variable mixtures of shallow and deep ground waters the latter being characterised by higher salinity and longer residence times the deep groundwaters from boreholes deeper than 1000 m have a ch 4 dominated dissolved gas phase related to the presence of hydrocarbon reservoirs the very unique tectonic setting of the area includes the presence of an ophiolitic block outcropping in the westernmost area on the african plate as well as basalts located to the north and east on the arabic plate the diffuse presence of co 2 enriched gases although diluted by the huge groundwater circulation testifies a regional degassing activity fluids circulating over the ophiolitic block are marked by h 2 dominated gases with abiogenic methane and high ph waters the measured 3 he 4 he isotopic ratios display contributions from both crustal and mantle derived sources over both sides of the dsf although the serpentinization process is generally independent from mantle type contribution the recorded helium isotopic ratios highlight variable contents of mantle derived fluids due to the absence of recent volcanism over the western side of the basin african plate we argue that co 2 rich volatiles carrying mantle type helium and enriched in heavy carbon are degassed by deep rooted regional faults rather than from volcanic sources

geochemical and isotopic characterization of groundwater from the paleogene limestone aquifer of the upper jezireh syria this research aims to evaluate the groundwater resources of paleogene aquifer in the upper jazireh area syria in terms of chemical water type recharge zones and water ages the results show that the main recharge zones for the paleogene aquifer range between 650 and 900 m a s l which coincide with the outcrop of the karstified limestone in the mardin uplift the chemical and isotopic behaviors of groundwater together with radiometric 14c reflect the existence of three different groundwater groups 1 the fresh and cold water percolating in short and shallow flow paths for which the main replenishment processes are recent 2 the brackish and thermal water containing certain amounts of h2s gas that percolate in longer and deeper flow paths for which the main replenishment processes occurred during the palaeoclimatic humid conditions of pleistocene time placed at 10 18 ka bp 3 the brackish and admixed thermal groundwater with intermediate 14c age which seems to be formed as a result of mixing between the previous two groups

open system degassing of sulfur from krakatau 1883 magma we present the first sulfur and oxygen isotopic data for tephra from the catastrophic 1883 eruption of krakatau sulfur isotopic ratios in unaltered krakatau tephra erupted august 26 27 1883 are markedly enriched in 34s relative to mantle sulfur high 34s values of 6 3 to 16 4 can best be explained by open system or multi stage degassing of so2 from the oxidized rhyodacitic and gray dacitic magmas with 34s enrichment of so2 4 remaining in the melt lower whole rock 34s values of 2 6 and 4 0 in two oxidized gray dacitic samples indicate more primitive subarc mantle sulfur in the 1883 magma chamber initial 34s of the rhyodacitic magma was probably in the 1 5 to 4 0 range and similar to 34s values measured in arc volcanic rocks from the mariana arc

sulfate minerals and organic compounds on mars strong evidence for evaporitic sulfate minerals such as gypsum and jarosite has recently been found on mars although organic molecules are often codeposited with terrestrial evaporitic minerals there have been no systematic investigations of organic components in sulfate minerals we report here the detection of organic material including amino acids and their amine degradation products in ancient terrestrial sulfate minerals amino acids and amines appear to be preserved for geologically long periods in sulfate mineral matrices this suggests that sulfate minerals should be prime targets in the search for organic compounds including those of biological origin on mars

isotopic evidence to characterize the sources of sulfate ions in the carbonate aquifer system in aleppo basin north syria sulfur and oxygen isotopic compositions of sulfate 34sso4 18oso4 and 18oh2o 13cdic have been used in conjunction with chemical data to constrain sulfate sources and geochemical processes in carbonate aquifers of the aleppo basin in north syria the aleppo basin comprises two limestone aquifers the first one is shallow unconfined of paleogene age and the second is deep confined of upper cretaceous age the chemical data indicate that dissolution of carbonate and evaporites is the main process controlling groundwater quality in the mainly unconfined modern groundwater the wide range of 34sso4 values 10 39 17 6 indicates a variety of input sources the likely sources of sulfur include meteoric precipitation and sewage waters which recharge the aquifer through qweik river crossing the area these waters have low so4 2 concentration 20 mg l sulfate increases in deep confined groundwater in some of which gypsum saturation is reached the 34sso4 and 18oso4 are relatively constant with mean values of 18 5 and 13 5 respectively this indicates that gypsum and anhydrite dissolution are the primary sources of sulfate this water is associated with higher depleted value of 18oh2o the heavier 13cdic with mean value 1 8 and high mg2 concentration 100 mg l in the high sulfate deep groundwater indicates that the de dolomitization reactions dominate along flow paths where sulfate concentrations increase

revised global model of thermosphere winds using satellite and ground based observations thermospheric wind data obtained from the atmosphere explorer e and dynamics explorer 2 satellites have been combined with wind data for the lower and upper thermosphere from ground based incoherent scatter radar and fabry perot optical interferometers to generate a revision hwm90 of the hwm87 empirical model and extend its applicability to 100 km comparison of the various data sets with the aid of the model shows in general remarkable agreement particularly at mid and low latitudes the ground based data allow modeling of seasonal diurnal variations which are most distinct at mid latitudes while solar activity variations are now included they are found to be small and not always very clearly delineated by the current data they are most obvious at the higher latitudes the model describes the transition from predominately diurnal variations in the upper thermosphere to semidiurnal variations in the lower thermosphere and a transition from summer to winter flow above 140 km to winter to summer flow below significant altitude gradients in the wind are found to extend to 300 km at some local times and pose complications for interpretation of fabry perot observations

dwm07 global empirical model of upper thermospheric storm induced disturbance winds 1 we present a global empirical disturbance wind model dwm07 that represents average geospace storm induced perturbations of upper thermospheric 200 600 km altitude neutral winds dwm07 depends on the following three parameters magnetic latitude magnetic local time and the 3 h kp geomagnetic activity index the latitude and local time dependences are represented by vector spherical harmonic functions up to degree 10 in latitude and order 3 in local time and the kp dependence is represented by quadratic b splines dwm07 is the storm time thermospheric component of the new horizontal wind model hwm07 which is described in a companion paper dwm07 is based on data from the wind imaging interferometer on board the upper atmosphere research satellite the wind and temperature spectrometer on board dynamics explorer 2 and seven ground based fabry perot interferometers the perturbation winds derived from the three data sets are in good mutual agreement under most conditions and the model captures most of the climatological variations evident in the data

sour gas hydrothermal jarosite ancient to modern acid sulfate mineralization in the southern rio grande rift abstract as many as 29 mining districts along the rio grande rift in southern new mexico contain rio grande rift type rgr deposits consisting of fluorite barite sulfide jarosite and additional rgr deposits occur to the south in the basin and range province near chihuahua mexico jarosite occurs in many of these deposits as a late stage hydrothermal mineral coprecipitated with fluorite or in veinlets that crosscut barite in these deposits many of which are limestone hosted jarosite is followed by natrojarosite and is nested within silicified or argillized wallrock and a sequence of fluorite barite sulfide and late hematite gypsum these deposits range in age from 10 to 0 4 ma on the basis of 40ar 39ar dating of jarosite there is a crude north south distribution of ages with older deposits concentrated toward the south recent deposits also occur in the south but are confined to the central axis of the rift and are associated with modern geothermal systems the duration of hydrothermal jarosite mineralization in one of the deposits was approximately 1 0 my most 18oso4 oh values indicate that jarosite precipitated between 80 and 240 c which is consistent with the range of filling temperatures of fluid inclusions in late fluorite throughout the rift and in jarosite 180 c from pena blanca chihuahua mexico these temperatures along with mineral occurrence require that the jarosite have had a hydrothermal origin in a shallow steam heated environment wherein the low ph necessary for the precipitation of jarosite was achieved by the oxidation of h2s derived from deeper hydrothermal fluids the jarosite also has high trace element contents notably as and f and the jarosite parental fluids have calculated isotopic signatures similar to those of modern geothermal waters along the southern rift isotopic values range from those typical of meteoric water to those of deep brine that has been shown to form from the dissolution of permian evaporite by deeply circulating meteoric water jarosite 34s values range from 24 to 5 overlapping the values for barite and gypsum at the high end of the range and for sulfides at the low end most 34s values for barite are 10 6 to 13 1 and many 34s values for gypsum range from 13 1 to 13 9 indicating that a component of aqueous sulfate was derived from permian evaporites 34s 12 2 the requisite h2so4 for jarosite formation was derived from oxidation of h2s which was likely largely sour gas derived from the thermochemical reduction of permian sulfate the low 34s values for the precursor h2s probably resulted from exchange deeper in the basin with the more abundant permian so42 at 150 to 200 c jarosite formed at shallow levels after the ph buffering capacity of the host rock typically limestone was neutralized by precipitation of earlier minerals some limestone hosted deposits contain caves that may have been caused by the low ph of the deep basin fluids due to the addition of deep seated hf and other magmatic gases during periods of renewed rifting caves in other deposits may be due to sulfuric acid speleogenesis as a result of h2s incursion into oxygenated groundwaters the isotopic data in these sour gas jarosite occurrences encode a record of episodic tectonic or hydrologic processes that have operated in the rift over the last 10 my

separation and recovery of various sulphur species in sedimentary rocks for stable sulphur isotopic determination abstract existing methods to extract particular forms of sulphur in rocks and sediments are reviewed and evaluated for application in a chemical scheme to recover sulphur as either ag2s or baso4 precipitates for isotopic analysis the s species distinguished include acid soluble sulphides and sulphates elemental s pyrite barite and various categories of organically bound s there is no evidence of cross contamination or isotopic fractionation during the separation as applied to mixtures synthesized from internal control samples the precision obtained on repetitive extractions is equivalent to that of the measurement technique itself typically 0 2 in the 34s value the chemical separation scheme is demonstrated by application to sections of peat collected from the howards pass xy deposit in the yukon territory canada

from underplating to delamination retreat in the northern apennines abstract recordings of teleseismic earthquakes from a dense set of temporary and permanent broadband seismic stations reveal the lithospheric structure of the northern apennines and support the scenario of a retreating detachment within the mid crust lithospheric delamination appears crucial to the formation and evolution of the apennines orogen receiver function rf stacks outline a continuous west dipping ps converted phase from a positive velocity jump that we interpret as the top of the lower crust and mantle of the adria continental lithosphere which is descending into the shallow mantle the correlation of seismicity with two rf profiles across the northern apennines suggests distinct stages of lithospheric delamination active penetration of the detachment into the adria lithosphere seems evident in the south east with induced shallow mantle flow facilitated by slab dehydration penetration of the detachment in the north west seems to have arrested and is possibly marked by crustal underplating this layer atop the apennines slab is visible only down to 80 km depth and suspends above an oppositely dipping paired positive negative ps converted phase in stacked receiver functions the break in the west dipping adria lithosphere conflicts with a westward subduction scenario continuous from the oligocene lateral changes of deep structure and seismicity along the northern apennines suggest that underplating of crustal material and delamination retreat are distinct mechanisms active today in the western and eastern sectors respectively of the northern apennines negative ps pulses at 100 120 km depth help to define a seismic lithosphere asthenosphere boundary lab but cross cut a volume of high velocity mantle rock as inferred from tomographic models we hypothesize that this seismic lab is a rheological discontinuity that affects the frequency band of seismic body waves but not the long term viscous response that governs the evolution and eventual detachment of the continental slab

quantitative geomorphology of the mars eberswalde delta the eberswalde delta is composed of six separate depositional lobes that have prograded some 17 km from their apex crosscutting distributary relationships and compensated depositional lobes are clearly visible in images acquired by the mars global surveyor mars orbiter camera here several lobe systems have been examined for sinuosity radius of channel curvature meander bend width and channel width parameters channel sinuosities of between 1 2 and 1 8 defi ne low to moderate sinuosity systems typical of the type transporting bedload or mixed grain size loads channel systems increase in sinuosity as they get older however some of the younger systems show specifi c reaches of increased sinuosity these localized changes may be due to either abutment against resistant beds of older lobes or rise in base level at the channel system terminus if the former such an effect of older deposits on the morphology of the channels suggests that these older lobes were fairly well indurated prior to the deposition of the youngest progradational lobes eighty six percent of distributaries in the mars eberswalde delta are 100 240 m wide comparatively 62 and 44 of distributaries in the atchafalaya and wax lake deltas of louisiana respectively are of similar size small distributaries may indicate lower average and shorter duration fl ows or coarser sediment in mars distributaries than those typical of the gulf coast systems the volume of the material in the mars deposit suggests long periods of sediment deposition sinuosity indexes meander bend migration and ridge and swale point bar topography suggest periods of stable discharge on the delta surface

auroral zone thermospheric dynamics 1 averages forty four nights of thermospheric neutral wind and temperature measurements were obtained with a ground based fabry perot spectrometer at college alaska 65 invariant latitude mostly during high to moderate levels of solar activity the spectrometer scanned the o i 15 867 k 6300 a emission line yielding line profile measurements that originate from an altitude range between 170 and 280 km the observed average wind direction is to the northwest in the early evening changing to the south near midnight and then to the southeast in the morning the overall wind pattern generally persists but the wind speed increases with increasing geomagnetic activity a change in the zonal wind direction occurs earlier in magnetic local time with increasing magnetic activity the meridional wind pattern also shifts equatorward with the auroral oval during increasing magnetic activity consequently the average wind pattern in the north during low geomagnetic activity is rather similar to the moderate activity average in the south and the moderate geomagnetic activity average wind pattern in the north is similar to the high geomagnetic activity average in the south the observed average thermospheric temperature is found to be governed by geomagnetic activity and the previous day s 10 7 cm solar flux

sulfur cycling in an acid mining lake and its vicinity in lusatia germany the sulfur cycle plays a key role in the hydrochemical development of lignite and coal mining districts which are often characterized by acid mine drainage identification of sulfur sources and transformations is essential if we are to understand the current status of acid lakes and propose successful remediation strategies we utilized stable isotope 34ssulfate 18osulfate 34sdissolved sulfide 18owater and hydrochemical data of lake and groundwater samples as well as the concentrations and isotope ratios of various sedimentary sulfur compounds acid soluble sulfate ass acid volatile sulfur avs chromium reducible sulfur crs in aquifer and lake sediments for assessing the biogeochemical sulfur cycle in a lusatian acidic mining lake ml111 and the surrounding area pyrite oxidation is the dominant source of sulfate and iron in the two aquifers west and east of mining lake ml111 concentration and isotope data for dissolved sulfate suggest that bacterial dissimilatory sulfate reduction became an increasingly important process in the flow direction of the western aquifer thereby improving water quality in contrast bacterial sulfate reduction was only of local importance in the dump aquifer on the eastern side of the lake oxygen isotope ratios of the lake water sulfate and mass and isotope balances demonstrate that 80 of the sulfate in mining lake ml111 is derived via groundwater influx from the dump aquifer with the remainder contributed by the western aquifer in lake pyrite oxidation or bacterial sulfate reduction in the water column are insignificant the latter process is restricted to the monimolimnion which represents less than 1 of the lake volume hence the potential for natural generation of alkalinity by bacterial dissimilatory sulfate reduction is presently low for successful remediation of ml111 it is essential to reduce significantly the continuous input of sulfate and acidity from inflowing dump groundwater

the use of na cl ratios to trace solute sources in a semiarid zone rainwater interaction with soils is a major source of dissolved salts in groundwater the transition zone between the humid and the arid area is characterized by a specific combination of reactions which do not exist elsewhere this combination of caco3 dissolution and base exchange reactions affects the na cl ratio which is the quantitatively most important parameter used for tracing salinity sources of groundwater the increase in the na cl ratio in the coastal plain aquifer of israel from north to south is related to local recharge of na rich water after interaction with soils of loessial origin

stability of mg sulfate minerals in the presence of smectites possible mineralogical controls on h2o cycling and biomarker preservation on mars abstract martian layered deposits and regolith at gale crater may contain multiple hydrated mineral phases tentatively identified as hydrated mg sulfate minerals and smectites we have used humidity buffer experiments to assess the stability of hydrated mg sulfate minerals in the presence of smectites in order to improve our understanding of the probable behavior of mg sulfate minerals within multiphase geological materials on mars a series of long term experiments employed temperature 25 to 23 c and relative humidity rh conditions 7 100 that emulate near equatorial martian surface conditions our results indicate that the hydration state of mg sulfate minerals is affected by the presence of rh sensitive clay minerals i e smectites the formation of gypsum and bassanite in dry mineral mixtures via cation exchange between ca bearing smectite and mg sulfate minerals indicates that ca sulfate minerals may be useful indicators of h 2 o and metal mobility at mars relevant temperatures 25 to 23 c the presence of smectites also suppresses deliquescence of mg sulfate minerals at 100 rh and low but non freezing temperatures co existence of smectites and mg sulfate minerals appears to buffer rh within mixtures of these minerals which can result in production or preservation of mg sulfate phases that are inconsistent with measured values of atmospheric rh consequently hydrated mg sulfate minerals may persist beyond their expected t rh equilibrium fields on longer timescales within smectite mgso 4 mixtures than in the pure mgso 4 h 2 o system dehydration of highly hydrated mg sulfate minerals appears to slow in the presence of smectite which may have important implications for long term preservation of organic biosignatures within mg sulfate crystals on mars together these observations suggest that mg sulfate mineral behavior and thus cycling and bioavailability of h 2 o and metals may be impacted by the presence of smectites within mineralogically complex martian layered deposits and regolith

recent volcano ice interaction and outburst flooding in a mars polar cap re entrant abstract formation of chasms in the polar ice caps of mars has been attributed to meltwater outburst floods but the cause of melting has remained uncertain in a cap re entrant enveloping abalos colles west of casma boreale in the north polar cap we have found possible evidence of recent volcano ice interaction and outburst flooding in this paper we demonstrate that these two mechanisms can have acted together to form or expand the abalos re entrant flat topped ridges and circular rims protruding above the ice cap surface in the re entrant apex may be lava ridges and volcano craters and can have caused melting of 3 3 to 7 7 10 3 km 3 of ice the surrounding cap surface appears to have subsided and the likely volume of missing ice matches the melt estimate outburst flooding from this area may have reached peak discharges of 0 3 to 1 5 10 8 m 3 s 1 according to scour patterns in one of the re entrant channels this required ponding of melt water during lava eruption and catastrophic release through a sub or englacial melt water tunnel the collapse of which has left a chasm in the ice cap margin the flood features are geologically recent and volcano ice interaction may have occurred within the last 20 000 years

hydrogeochemical modeling of the water seepages through tannur dam southern jordan this paper reveals the geochemical processes of dissolution precipitation and cation exchange that took place during water rock interaction between water seepages through the tannur dam the schoeller diagram indicates that there are three major water types originating during water rock interaction the first water type is characterized by low salinity that ranges from 1 300 to 2 800 s cm which represents the reservoir water and the water in the right side of the central gallery the second water type is in the left side of the central gallery which exhibits medium salinity that reaches about 4 400 s cm the third water type is characterized by very high salinity that reaches a value of around 8 500 s cm and represents the water in the right existing adit the increase of salinity can be explained due to the dissolution of carbonate and sulfate minerals that form the matrix of the foundation and the abutment rocks and the dissolution of the grout curtain which is composed of cement and bentonite hydrogeochemical modeling using a computer code phreeqc was used to obtain the saturation indices of specific mineral phases which might be related to interaction with water seepages and to identify the chemical species of the dissolved ions the thermodynamic calculations indicate that most of the water samples were undersaturated with respect to gypsum anhydrite and halite and were saturated and or supersaturated with respect to calcite and dolomite ca hco3 2 is the primary water type as a result of dissolution of carbonate minerals such as calcite and dolomite prevailing at the dam site however cation exchange processes are responsible for the formation of the na2so4 water type from the caso4 type that formed due to the dissolution of gypsum

seasonal dependence of northern high latitude upper thermospheric winds a quiet time climatological study based on ground based and space based measurements this paper investigates the large scale seasonal dependence of geomagnetically quiet time northern high latitude f region thermospheric winds by combining extensive observations from eight ground based optical remote sensing and three space based optical remote sensing and in situ instruments to provide a comprehensive picture of the wind morphology data are assimilated into a seasonal empirical vector wind model as a function of season latitude and local time in magnetic coordinates the model accurately represents the behavior of the constituent data sets there is good general agreement among the various data sets but there are some major offsets between goce and the other data sets especially on the duskside the assimilated wind patterns exhibit a strong and large duskside anticyclonic circulation cell sharp latitudinal gradients in the duskside auroral zone strong antisunward winds in the polar cap and a weaker tendency toward a dawnside cyclonic circulation cell the high latitude wind system shows a progressive intensification of wind patterns from winter to equinox to summer the latitudinal extent of the duskside circulation cell does not depend strongly on season zonal winds show a mainly diurnal variation two extrema around polar and middle latitudes and semidiurnal variation four extrema at auroral latitudes meridional winds are primarily diurnal at all high latitudes the strength of zonal winds channeling through the auroral zone on the duskside is strongest in the summer season the vorticity of the wind pattern increases from winter to summer whereas divergence is maximum in equinox in all three seasons divergence is weaker than vorticity