distinguishing high alumina mare basalts using clementine uvvis and lunar prospector grs data mare moscoviense and mare nectaris 1 high alumina ha mare basalts are a unique group of the lunar sample collection sample geochemistry indicates that these basalts are derived from sources composed of late stage cumulates from the lunar magma ocean lmo their aluminous nature suggests their sources contained significant plagioclase which has implications regarding the efficiency of plagioclase separation from earlier forming mafic cumulates in the lmo to form the anorthositic lunar crust and hence the heterogeneity of the lunar mantle the apollo and luna missions sampled ha basalts from four different locations that are separated by 80 equatorial degrees 2400 km radiometric age dating of these samples demonstrates aluminous basaltic volcanism spanned over 1 billion years suggesting ha basalts may be more prevalent on the moon than implied by the sample population knowing their global occurrence would ultimately enhance our understanding of lunar evolution aluminous mare basalts occupy a unique location in th feo compositional space that suggests they can be identified using global remote sensing data of the moon we present our approach for distinguishing exposures of ha basalts using clementine ultraviolet visible infrared uvvis and lunar prospector gamma ray spectrometer lp grs data with constraints based on the feo tio2 and th abundances of apollo and luna ha samples we identified 34 regions of interest rois where ha basalts could be a prominent component of the lunar surface by analyzing the rims and proximal ejecta from small impacts 0 4 4 km in diameter into the mare surface we characterized compositionally distinct basaltic units that make up the mare and thus determined which units represent ha basalt lavas the results were used to generate maps that depict discrete mare units and classify their general basalt type here we focus on two rois mare moscoviense and mare nectaris mare moscoviense is composed of four basaltic units two of which are ha candidates clementine uvvis data of mare nectaris show evidence of up to three mare basalt units one is the remnants of a mid ti unit that capped earlier low ti flows the majority of the basin is filled by a compositionally indistinguishable low fe low ti basalt however spectral profiles suggest there are two units regardless the units both fit the criteria for a ha basalt

submarine groundwater discharge driven nitrogen fluxes to long island sound ny terrestrial vs marine sources abstract bottom waters in smithtown bay long island sound ny are subject to hypoxic conditions every summer despite limited nutrient inputs from waste water and riverine sources while modeling estimates of groundwater inputs are thought to be insignificant terrestrial and marine fluxes of submarine groundwater discharge sgd were quantified to smithtown bay using mass balances of 222 rn 224 ra 226 ra and 228 ra during the spring and summer of 2014 2015 in order to track this seasonal transition period intertidal pore waters from a coastal bluff terrestrial sgd and from a barrier beach marine sgd displayed substantial differences in n concentrations and sources traced using a multi isotope approach 222 rn ra 15 n no 3 18 o no 3 no 3 in terrestrial sgd did not display any seasonality and was derived from residential septic systems and fertilizer marine sgd n concentrations varied month to month because of mixing between oxic seawater and hypoxic saline pore waters n concentrations were greatest during the summer when no 3 was derived from the remineralization of organic matter short lived 222 rn and 224 ra sgd fluxes were used to determine remineralized n loads along tidal recirculation flow paths while long lived 228 ra was used to trace inputs of anthropogenic n in terrestrial sgd 228 ra derived terrestrial n load estimates were between 20 and 55 lower than 224 ra derived estimates excluding spring 2014 228 ra may be a more appropriate tracer of terrestrial sgd n loads terrestrial sgd no 3 derived from 228 ra to smithtown bay varied from 1 40 12 8 10 6 mol n y 1 with comparable marine sgd no 3 fluxes of 1 70 6 79 10 6 mol n y 1 derived from 222 rn and 224 ra remineralized n loads were greater during the summer compared with spring and these may be an important driver toward the onset of seasonal hypoxic conditions in smithtown bay and western long island sound seawater recirculation through the coastal aquifer can rival the n load from terrestrial sgd from a heavily polluted aquifer

isotopic and ree studies of lunar basalt 12038 implications for petrogenesis of aluminous mare basalts we report sr nd and sm isotopic studies of lunar basalt 12038 one of the so called aluminous mare basalts a precise internal rb sr isochron yields a crystallization age of 3 35 0 09 ae and initial87sr 86sr 0 69922 2 2 error limits 1ae 109 years 87rb 0 0139ae 1 an internal sm nd isochron yields an age of 3 28 0 23ae and initial143nd 144nd 0 50764 28 present day143nd 144nd is less than the chondritic value i e nd 0 2 3 0 4 where nd is the deviation of143nd 144nd from chondritic evolution expressed as parts in 104 at the time of crystallization nd 3 2ae 1 5 0 6 we have successfully modeled the evolution of the sr and nd isotopic compositions and the ree abundances within the framework of our earlier model for apollo 12 olivine pigeonite and ilmenite basalts the isotopic and trace element features of 12038 can be modeled as produced by partial melting of a cumulate mantle source which crystallized from a lunar magma ocean with a chondrite normalized ree pattern of constant negative slope chondrite normalized la yb 2 2 for this hypothetical magma ocean pattern a plot of i sr versus nd for the apollo 12 basalts clearly shows the influence of varying proportions of olivine clinopyroxene orthopyroxene and plagioclase in the basalt source regions a small percentage of plagioclase 5 in the 12038 source apparently is responsible for low i sr and nd in this basalt aluminous mare basalts from mare crisium luna 24 and by inference mare fecunditatis luna 16 occupy locations on the i sr nd plot similar to that of 12038 implying that some basalts from three widely separated lunar regions came from plagioclase bearing source regions a summary of model calculations for mare basalts shows a record of lunar mantle solidification during the period when ree abundances in the lunar magma ocean increased from 20 chondritic to 100 chondritic although there is a general trend from olivine to clinopyroxene dominated source regions with progressive magma ocean evolution significant mineralogical heterogeneities in mantle composition apparently formed at any given stage of evolution as evidenced in particular by the three apollo 12 magma types

the clementine mission to the moon scientific overview in the course of 71 days in lunar orbit from 19 february to 3 may 1994 the clementine spacecraft acquired just under two million digital images of the moon at visible and infrared wavelengths these data are enabling the global mapping of the rock types of the lunar crust and the first detailed investigation of the geology of the lunar polar regions and the lunar far side in addition laser ranging measurements provided the first view of the global topographic figure of the moon the topography of many ancient impact basins has been measured and a global map of the thickness of the lunar crust has been derived from the topography and gravity

using natural distributions of short lived radium isotopes to quantify groundwater discharge and recharge radium activity in pore water of wetland sediments often differs from the amount expected from local production decay and exchange with solid phases this disequilibrium results from vertical transport of radium with groundwater that flows between the underlying aquifer and surface water in situations where groundwater recharge or discharge is significant the rate of vertical water flow through wetland sediment can be determined from the radium disequilibrium by a combined model of transport production decay and exchange with solid phases we have developed and tested this technique at three sites in the freshwater portion of the everglades by quantifying vertical advective velocities in areas with persistent groundwater recharge or discharge and estimating a coefficient of dispersion at a site that is subject to reversals between recharge and discharge groundwater velocities v were determined to be between 0 and 20 5 cm d 21 for a recharge site and 1 5 6 0 4 cm d 21 for a discharge site near levee 39 in the everglades strong gradients in 223 ra and 224 ra usually occurred at the base of the peat layer which avoided the problems of other tracers e g chloride for which greatest sensitivity occurs near the peat surface a zone readily disturbed by processes unrelated to groundwater flow this technique should be easily applicable to any wetland system with different production rates of these isotopes in distinct sedimentary layers or surface water the approach is most straightforward in systems where constant pore water ionic strength can be assumed simplifying the modeling of radium exchange

mapping iron in the lunar mare an improved approach 1 previous methods for mapping iron lucey et al 1995 1998 2000a give inconsistent results in terms of suppressing the effects of maturity making it difficult to distinguish true units of contrasting iron from regions that simply show the residual effects of incomplete separation of maturity these methods rely on an assumption that materials of similar iron content but varying maturity form radial trends on a plot of vis reflectance versus nir vis ratio recently the assumption of radial behavior of maturity trends in mare regions has been called into question by staid and pieters 2000 they observed trends in the mare that appeared more parallel in nature in this work we study nearly 10 000 craters in six mare regions and model the effects of maturity with radiative transfer theory to quantify and better understand the spectral behavior of maturity variations in the mare we confirm that the maturity trends in mare regions are more parallel than radial and we exploit this fact to develop a new algorithm for determination of iron content in mare regions this new mare iron algorithm better compensates for maturity than previous methods and uncertainties due to maturity variations are less than 0 5 wt feo absolute uncertainties are similar to previous algorithms 1 5 wt feo results from this work provide the ability to detect iron anomalies in the ejecta of craters and as a result more confidently map vertical stratigraphy in the lunar mare in terms of iron composition

evaluation of 224 ra as a tracer for submarine groundwater discharge in long island sound ny abstract the approach to quantify submarine groundwater discharge using ra isotopes generally involves developing a ra mass balance in an estuary bay or lagoon in this work we present a 224ra mass balance used to evaluate the importance of the submarine groundwater discharge sgd in long island sound ny us the third most important estuary in us located between long island and connecticut that is usually affected by summertime hypoxia in the western basin three surveys were conducted between april 2009 and august 2010 where 25 water stations were sampled for ra isotopes oxygen and mn stations were oriented along 4 transects one axial extending from the western to the eastern sound and three longitudinal transects in the western central and eastern sound the inventory of 224ra in the water column in summer was circa 2 times greater than in winter suggesting an increased 224ra flux to the sound in summer a mass balance for 224ra was constructed considering tidal exchange inputs from rivers desorption from resuspended particles diffusive fluxes including bioirrigation from bottom sediments and radioactive decay in the water column fluxes of 224ra from bottom sediments were measured by incubating cores under oxic conditions in a continuous flow mode such that the overlying water was circulated through a mn oxide fiber to maintain a constant activity of 224ra fluxes from muddy sediments comprising 67 of the sound bottom ranged from 127 to 312 dpm m 2 d 1 and were 60 dpm m 2 d 1 in sandy sediments 33 of the sound incubations under hypoxic conditions showed variable fluxes depending on reduction and mobilization of mn the 224ra mass balance shows a net input of ra to the sound of 106 50 1012 dpm y 1 in spring and 244 112 1012 dpm y 1 in the summer that is attributed to sgd elevated 224ra values were observed near shore and in the pore fluids of the coarse beach sands along the long island and connecticut coasts suggesting that sgd driven by tidal recirculation through the beach face is a major source of 224ra to the sound seasonal variation in this source seems unlikely and the calculated 224ra sgd fluxes for spring and summer overlap within the uncertainties nevertheless we conclude that variations in the 224ra water column inventories could be produced by seasonal changes in bioirrigation and or redox cycling of mn as well as sediment resuspension and desorption of 224ra from resuspended particles and that our mass balance underestimates these terms particularly in the summer 224ra fluxes from sediments in estuaries especially those with significant areas of muddy sediments and seasonal hypoxia are important and should be well constrained in future uses of this isotope as a tracer for sgd

apollo 14 mare basalts petrology and geochemistry of clasts from consortium breccia 14321 eleven mare basalt clasts have been extracted from polymict lunar breccia 14321 for a combined petrologic and geochemical study by our consortium ten of these clasts are high al low ti mare basalts similar to those discovered previously at apollo 14 the other is a highly evolved tridymite ferrobasalt with low al and intermediate ti contents a high al ilmenite ferrobasalt from lunar breccia 14305 is the most evolved high al basalt described from the apollo 14 site the major and trace element characteristics of the basalts studied here allow them to be grouped into five compositional types that range from lree depleted to lree enriched some of these types may be related by varying percents of partial melting of the same source but at least two separate sources that differ by a factor of two in incompatible trace element concentrations are required the 14321 type basalts and vitrophyres have steep chondritenormalized hree slopes and may have formed by assimilation of intermediate k fra mauro kreep which is presumed to represent a partial melt of the lower crust the age of these basalts 3 9 aeons suggests that mare volcanism played an important role in the evolution of the early lunar crust

metasomatic products of the lunar magma ocean the role of kreep dissemination the origin of the incompatible element rich lunar component kreep is in the lunar magma ocean lmo the fractionated residual melt after crystallization of the lmo represents urkreep after warren and wasson 1979 the percentage of this residual melt is low enough to be within the realm of silicate liquid immiscibility sli this process has the ability to split the kreep signature into k and reep fractions which are manifest as lunar granite k and phosphate phases present in highland lithologies or as quartz ferrotroctolite in lunar soils reep we envisage this as a localized but significant process since only a small portion of urkreep undergoes sli norms of experimental and apollo 15 basaltic immiscible glasses suggest that thevreep fraction found in the lunar highlands has undergone post sli fractionation of at least fayalite this significantly reduces the density of the reep fraction and coupled with its low viscosity 10 15 poise it can percolate upward metasomatizing the lunar crust the higher viscosity of the granitic melt 30000 poise inhibits its mobility and it forms pods in the lower rust as required for vhk basalt petrogenesis with the identification of kreepy components the composition of urkreep can be calculated using experimental evidence the kreep components may be recombined to give the pre sli composition or liquid liquid kd s can be used to calculate a pre sli composition from lunar granite both calculated urkreep compositions are lower in mgo and al2o3 and higher in feo and p2o5 than reported low and high k kreep compositions the calculated ree abundances are higher and the ree profiles are slightly more lree enriched than the previously reported kreep compositions however the ree profile calculated using liquid liquid kd s is concave upwards compared to the lree enriched profile produced by recombining the kreep components pre sli whitlockite apatite fractionation occurred prior to immiscibility in order to generate the concave upwards profile the lree enriched profile represents the pre sli magma prior to phosphate fractionation the presence of superkreepy rock types can be accounted for by k and reep fraction assimilation and the compositions of olivine vitrophyres can now be modeled using analyzed lunar rock types without the inference of a mythical high mg component other more widespread kreepy rocks e g apollo 14 breccias apollo 15 kreep basalts lkfm basalts are produced by incorporation of the more widespread pre sli urkreep component the splitting of kreep into identifiable lithological components allows the petrogenesis and role of kreep in lunar evolution to be better understood

high fluxes of radium and barium from the mouth of the ganges brahmaputra river during low river discharge suggest a large groundwater source the annual flux of sediment from the ganges brahmaputra river is among the highest in the world the desorption of226ra and ba from this sediment produces a major point source of226ra and ba input to the ocean highest226ra and ba fluxes are expected to occur during high river flow june september when most of the sediment is discharged surprisingly during low discharge of the ganges brahmaputra river fluxes of226ra and ba to the northern bay of bengal are comparable to expected river derived fluxes during peak river discharge a large non riverine source of ra and ba is required to explain the high fluxes during low river discharge i suggest that this source is submarine discharge of groundwater containing high concentrations of226ra and ba total annual fluxes of226ra and ba to the ocean from this system are significantly greater than estimated previously

lunar surface geochemistry global concentrations of th k and feo as derived from lunar prospector and clementine data abstract accurate estimates of global concentrations of th k and feo have an important bearing on understanding the bulk chemistry and geologic evolution of the moon we present empirical ground truth calibrations transformations for lunar prospector gamma ray spectrometer data k and th and a modified algorithm for deriving feo concentrations from clementine spectral reflectance data that incorporates an adjustment for tio 2 content the average composition of soil samples for individual landing sites is used as ground truth for remotely sensed data among the apollo and luna sites apollo 12 and 14 provide controls for the incompatible element rich compositions apollo 16 and luna 20 provide controls for the feldspathic and incompatible element poor compositions and apollo 11 15 and 17 and luna 16 and 24 provide controls for fe rich compositions in addition to these apollo and luna sample data we include the composition of the feldspathic lunar meteorites as a proxy for the northern farside highlands to extend the range of the calibration points thus providing an additional anorthositic end member composition these empirical ground truth calibrations for lunar prospector th and k provide self consistency between the existing derived data and lunar sample data clementine spectral reflectance data are used to construct a tio 2 sensitive feo calibration that yields higher feo concentrations in areas of high fe low ti mare basalt rich surfaces than previous feo algorithms the data set so derived is consistent with known sample compositions and regolith mixing relationships

the isotopic record of lunar volcanism abstract the timing and extent of lunar volcanism was determined primarily by the internal thermal evolution of the moon a late heavy bombardment produced most of the observable lunar basins easily recognized stratigraphic markers and also may have influenced lunar volcanism most of the nearside basins seem to have been produced 3 8 4 0 ga ago during a period often referred to as the lunar cataclysm the pre cataclysm period was characterized by formation of the lunar crust plutonic rocks within the crust and pre mare volcanism isotopic analysis of breccia clasts pre dating the cataclysm has yielded an outline of this period the isotopic record of post cataclysm mare volcanism is clear but incomplete because samples from the youngest mare areas are lacking specifically the isotopic data show that some lunar anorthosites formed 4 45 ga ago consistent with early formation of an anorthositic lunar crust some mg suite norites troctolites and dunites also formed approximately contemporaneously with the oldest anorthosites but others are up to 200 300 ma younger more evolved rocks granites and quartz monzodiorites also formed between 4 4 and 4 0 ga ago the earliest known pre mare volcanism at 4 25 ga ago included aluminous mare like basalts and an olivine gabbronorite similar to apollo 12 basalts kreep basalt volcanism began at least 4 1 ga ago approximately contemporaneously with that of the ancient mare like basalts and continued during the cataclysm recorded instances of high ti mare basalt volcanism began during or immediately after the cataclysm low ti mare basalt volcanism is the most recent for which samples are available the isotopic data record an early primary lunar differentiation during which mare basalt sources formed probably by crystallization of cumulus minerals from a lunar magma ocean the isotopic record of post cataclysm basalts indicates a heterogeneous lunar mantle and can be explained by partial melting of cumulate sources but more complex petrogenesis also has been suggested more complex petrogenetic processes including assimilation and assimilation fractional crystallization afc seem to be required for pre mare volcanics the isotopic data contain a hint that petrogenesis of the oldest pre mare volcanics may be linked to formation of the so called procellarum basin possibly the oldest and largest lunar basin such a basin would provide a geologic context for the pre mare volcanics and its formation may have been a defining moment in lunar history

iron and titanium abundance and maturity degree distribution on the lunar nearside new digital images of the lunar nearside albedos at 0 42 0 65 0 75 and 0 95 m derived from telescopic data were used to map the abundance and distribution of iron titanium and maturity degree on the lunar nearside developing the approach by p luceyet al 1995 science268 1150 a method of separating contributions of the fe and ti abundance and maturity degree to spectral properties of the lunar surface is presented the main objective of the method is an analysis of the 3d correlation diagram of optical characteristics of regolith material with the aim of choosing a coordinate system providing the best correlations of these characteristics with fe and ti abundance data for the surveyor luna and apollo landing sites and with maturity degree laboratory measurements of lunar samples by e fischer and c pieters e g 1996 j geophys res 101 2225 to find the coordinates a geometrical optics model of light scattering in particulate media enabling to calculate the absorption coefficient from albedo measurements is used an analysis of the correlation diagram feo tio2provides two maps characterizing optical types of the lunar nearside in particular the maps show that the basalts of mare serenitatis and mare tranquillitatis are not widely extended on the lunar nearside the maturity degree parameteris feo was also mapped regions withis feo 50 are young craters surrounded by ray systems whereas the conditionis feo 70 corresponds to regions associated with copernicus ejecta western boundaries of mare tranquillitatis and mare serenitatis and a portion of the south highland the new map of feo distribution on the lunar nearside was used to study a correlation between iron content and distribution of remanent magnetism over the lunar surface the relationship obtained has a reverse behavior the lower the iron content the higher the magnetism

solute transport into the jiulong river estuary via pore water exchange and submarine groundwater discharge new insights from 224ra 228th disequilibrium abstract pore water exchange pex and submarine groundwater discharge sgd represent two mechanisms for solute transport from the seabed into the coastal ocean however their relative importance remains to be assessed in this study we pursued the recently developed 224ra 228th disequilibrium approach to quantify pex fluxes of 224ra into the jiulong river estuary china by constructing a full mass balance of water column 224ra we were allowed to put various source terms i e sgd diffusive and advective pore water flow pex and river input in a single context this led to the first quantitative assessment of the relative importance of pex vs sgd in the delivery of solutes into an estuary we carried out two surveys in the jiulong river estuary one in january 2014 winter survey the other in august 2014 summer survey by virtue of a 1 d mass balance model of 224ra in the sediment column we demonstrated that pex fluxes of 224ra were highly variable both temporally and spatially and can change by 1 2 orders of magnitude in our study area moreover we identified a strong correlation between 224ra based irrigation rate and 234th based sediment mixing rate our results highlighted irrigation as the predominant pex process for solute transfer across the sediment water interface total pex flux of 224ra in 1010 dpm d 1 into the jiulong river estuary was estimated to be 22 3 3 0 and 33 7 5 5 during the winter and summer surveys respectively in comparison total sgd flux of 224ra in 1010 dpm d 1 was 11 3 8 6 and 49 5 16 3 in the respective seasons by multiplying the pex fluxes of 224ra by the ratio of the concentration gradients of component 224ra at the sediment water interface we quantified the total pex fluxes of dissolved inorganic carbon dic and nutrients nh4 no3 and h4sio4 into the jiulong river estuary in the meantime net export of dic and nutrients via sgd were estimated by multiplying the sgd fluxes of 224ra by the dic nutrients 224ra ratios in the sgd end members around this area our results revealed that pex driven fluxes of solutes rival net sgd input and river input in an estuary an additional new finding is that water column no3 in the surface estuary was effectively sequestered due to sgd probably as a result of intense denitrification occurring in the anoxic subterranean estuary

estimating groundwater discharge into the northeastern gulf of mexico using radon 222 abstract submarine groundwater discharge sgd may provide important chemical constituents to the ocean but the dispersed nature of this process makes locating and quantifying its input extremely difficult since groundwater contains 3 4 orders of magnitude greater radon than seawater 222rn may be a useful tracer of this process if all other sources of radon to bottom waters can be evaluated we report development of a sgd tracing tool based on radon inventories in a coastal area of the northeastern gulf of mexico we evaluated factors that influence the concentration of radon in the water column i e production decay horizontal transport and loss across the pycnocline using a linked benthic exchange horizontal transport model total 222rn benthic fluxes 2420 dpm m 2 day 1 measured with in situ chambers are of the magnitude required to support measured sub pycnocline 222rn inventories while estimates of molecular diffusion show that this input is relatively small 230 dpm m 2 day 1 using this model approach together with measurements of the radon inventory we estimated a regional subsurface fluid flow ranging from 180 to 710 m3 sec 1 into the 620 km2 study area this discharge equivalent to an upward advective velocity of approximately 2 10 cm day 1 dispersed over this entire study area is equivalent to approximately 20 first magnitude springs

a 24 000 year period climate signal in 1 7 2 0 million year old death valley strata continental records of plio pleistocene climatic fluctuations are often confined to fragmentary localized basins and not easily dated one exception is the confidence hills of southern death valley in this study we present a detailed description of a plio pleistocene section of interfingering alluvial fan and saltpan sediments from the confidence hills southern death valley this well exposed section accumulated with an average deposition rate of 25 cm 1000 yr with no bioturbation permitting more precise paleomagnetic dating than in oceanic records 1 we interpret the sequence of facies changes in the olduvai normal polarity zone of the confidence hills to represent alternations between wetter and drier regional climatic regimes the frequency of this variation 24 000 yr appears to correspond to the milankovitch precessional cycle 23 000 yr we believe this section records a milankovitch driven climatic variation in the death valley basin annual precipitation about 1 7 2 0 ma this is the first report of the precessional cycle in continental sediments of this age in the united states

using the radium quartet to quantify submarine groundwater discharge and porewater exchange abstract the specific ingrowth rates of different radium isotopes make them valuable tracers to distinguish processes occurring at different temporal scales here we demonstrate the use of the radium quartet 223ra 224ra 226ra and 228ra to differentiate flows of submarine groundwater discharge and porewater exchange to a coastal embayment alfacs bay nw mediterranean sea based on the assumption that these processes occur on different time scales in order to evaluate the seasonal dynamics of groundwater and porewater inputs to the bay we conducted three seasonal samplings at alfacs bay during which samples for ra isotopes were collected from bay waters groundwater springs porewaters and irrigation channels activities of short lived ra isotopes in the bay showed a strong seasonality e g average 224ra activities in summer 32 dpm 100 l 1 up to 4 times higher than in winter 8 dpm 100 l 1 in contrast the activities of the long lived ra isotopes were fairly constant throughout the year e g activities of 226ra were 16 and 14 dpm 100 l 1 in summer and winter respectively the relatively short exposure to sediments of recirculation fluxes resulted in porewaters significantly enriched in short lived ra isotopes relative to the long lived ones e g 224ra 1100 1300 dpm 100 l 1 226ra 17 99 dpm 100 l 1 whereas coastal groundwaters were enriched in all the ra isotopes e g 224ra 120 150 dpm 100 l 1 226ra 200 400 dpm 100 l 1 the distinct signatures of different sources allowed us to construct seasonal ra mass balances to estimate both groundwater discharge which ranges from 40 60 103 m3 d 1 in summer to 310 200 103 m3 d 1 in winter and porewater exchange fluxes ranging from 1200 120 103 m3 d 1 in summer to 270 40 103 m3 d 1 in winter whereas the seasonal variability of groundwater inputs is likely governed by the terrestrial hydraulic gradient a qualitative evaluation of the drivers of porewater exchange suggested that the strong seasonality of the seawater recirculation inputs is likely mediated by seasonal cycles on the activity of benthic infauna ra isotopes are thus valuable tracers to differentiate fluxes of both submarine groundwater discharge and porewater exchange allowing a more accurate evaluation of the fluxes of freshwater and solutes to coastal ecosystems as well as their implications for coastal biogeochemical cycles

groundwater discharge into an estuary using spatially distributed radon time series and radium isotopes summary quantifying groundwater discharge remains a challenge due to its large temporal and spatial variability here we quantify groundwater discharge into a small estuary using radon 222rn and radium isotopes 223ra and 224ra high temporal resolution 30 min time steps radon observations at 4 time series stations were used to determine where groundwater discharge is prevalent in the estuary and to reduce mass balance model uncertainties a three endmember mixing model was developed based on short lived radium isotopes sampled at a single location to separate the shallow saline and deep fresh sources of the discharging groundwater the results show that using multiple 222rn time series stations decreased the overall uncertainty of groundwater discharge estimates from about 41 to 23 the radon derived groundwater flux was 56 13 and 35 12 cm d 1 in wet and dry conditions respectively the spatially distributed stations detected a well defined small area located four kilometers upstream from the mouth of the estuary as a groundwater discharging hotspot estimates based on a 223ra and 224ra mass balance resulted in groundwater discharge estimates of 65 18 and 84 48 cm d 1 in the wet and 18 5 and 20 6 cm d 1 in the dry the mixing model revealed contrasting results for deep vs fresh groundwater contribution in wet and dry conditions in wet conditions deep fresh groundwater discharging into the estuary contributed 65 compared to the shallow saline groundwater 35 while during dry conditions a larger contribution 80 was related to shallow groundwater a comprehensive spatial and temporal sampling strategy can produce groundwater discharge estimates with lower uncertainty and provides additional insight on where groundwater enters surface waters

global elemental maps of the moon the lunar prospector gamma ray spectrometer lunar prospector gamma ray spectrometer spectra along with counting rate maps of thorium potassium and iron delineate large compositional variations over the lunar surface thorium and potassium are highly concentrated in and around the nearside western maria and less so in the south pole aitken basin counting rate maps of iron gamma rays show a surface iron distribution that is in general agreement with other measurements from clementine and the lunar prospector neutron detectors

isotopic analysis of basaltic fragments from lunar breccia 14321 chronology and petrogenesis of pre imbrium mare volcanism fragments of aluminous mare basalts high potassium hk aluminous mare basalts and very high potassium vhk mare basalts from apollo 14 breccias have been studied extensively rb sr isochron ages of aluminous mare basalts reported herein range from 3 96 to 4 24 and possibly up to 4 33 ga 87rb 0 0139 ga 1 they include and extend the range for the oldest mare basalts reported clasts of aluminous basalts from breccia 14321 though similar to each other in petrography mineralogy and major element composition have widely differing trace element abundances and are separable into chemical subgroups dickinsonet al 1985 shervaiset al 1985a rb sr and sm nd isotopic analysis of the grouped rocks of dicktnsonet al 1985 grouped rocks hereinafter and hk and vhk basalts shihet al 1986a b 1987 indicates that they differ with respect to time of crystallization t vs initial isotopic composition i parameters t i plots in a systematic way data for this set of rocks suggests radiogenic growth of 87sr86sr in the basalt source region corresponding to 87rb86sr 0 06 similar to the whole moon value earlier proposed nyquistet al 1977 tridymite ferrobasalt and olivine basalt from 14321 display parent daughter evolution distinct from the grouped rocks of dickinsonet al 1985 and the hk and vhk rocks and do not appear to be isotopically related to these rocks assimilation of kreep dickinsonet al 1985 does not appear to be a reasonable mechanism for forming the grouped basalts but assimilation of urkreep residuals binder 1985 or a granitic component shihet al 1986a b 1987 by more primitive magma are alternative possibilities for explaining their trace elemental and isotopic characteristics nd values for the three whole rocks that were analyzed are near 0 the value for an undifferentiated moon these rocks may be linked to the mg suite of highland rocks

combining radon short lived radium isotopes and hydrodynamic modeling to assess submarine groundwater discharge from an anthropized semiarid watershed to a mediterranean lagoon mar menor se spain summary in highly anthropized watersheds surface water tributaries may carry unexpected high quantities of radon and radium to coastal lagoons investigating submarine groundwater discharge sgd with radionuclide tracers is therefore a complex task in order to quantify sgd and decipher the influence of the different water sources we combined a radon 222 rn and short lived radium 223 ra 224 ra survey with the hydrodynamic modeling of a lagoon we applied it to the mar menor lagoon se spain where surface water tributaries and undocumented emissaries carry water from groundwater drainage and brines from groundwater desalinization we identified the areas of influence of the plume of radionuclides from the river located major areas of sgd and proposed a location for two submarine emissaries porewater i e interstitial water from underlying sediments was found to be the most representative sgd end member compared to continental groundwater collected from piezometers mass balances in winter and summer seasons provided yearly sgd fluxes of water of 0 4 2 2 10 8 m 3 y 222 rn 4 4 19 0 10 8 m 3 y 224 ra and 1 3 10 8 m 3 y 223 ra measured in winter only tidal pumping was identified as a main driver for recirculated saline groundwater while fresh submarine groundwater discharge from the aquifer ranged between 2 and 23 of total sgd

lunar mare volcanism in the eastern nearside region derived from clementine uv vis data clementine uv vis multi spectral data were used to map mare deposits in the eastern lunar nearside region mare tranquillitatis mare fecunditatis mare serenitatis mare crisium mare nectaris to understand the volcanic history of this region an array of clementine and clementine derived data were used to classify mare basalts these include 750 nm albedo uv vis ratio 1 m absorption signatures and clementine derived feo and tio2 contents we have successfully identified several new geological units and have determined their spectral characteristics for example the relatively younger low ti basalts were recognized in the eastern part of mare tranquillitatis the central low ti basalts in mare serenitatis which had been classed as misp were divided into 2 groups in mare nectaris 2 types of mare basalts were identified while only 1 group was recognized in the previous study the stratigraphy constructed from the spectral analysis indicates that the mare deposits tend to become younger in the northern maria including serenitatis and crisium and older in the southern maria including tranquillitatis fecunditatis and nectaris according to the relationship between the titanium contents of the mare units and their stratigraphy the titanium content decreases with time in the early stage but increases toward the end of volcanism in the serenitatis and crisium region while it increases with time but finally decreases in the tranquillitatis and fecunditatis region in connection with the distribution of mare basalts a large amount of high ti mare basalts are found in mare tranquillitatis especially in the western part while other maria are covered by low ti basalts the iron contents show a similar distribution to that of titanium

using ra isotopes to examine transport processes controlling benthic fluxes into a shallow estuarine lagoon measurements of the benthic flux of four naturally occurring radium isotopes in a shallow lagoon in the bega river estuary has provided information on the types and rates of transport processes operating in the lagoon sediments the measurement techniques included ra mass budgets of the lagoon ra fluxes into benthic chambers and modelling of the pore water and solid phase ra profiles in a sediment core the sediment profile of 210pb and the solid phase and pore water profiles of the longer lived ra isotopes 228ra half life 5 7 years and 226ra half life 1600 years indicate bioturbation to a depth of 10 cm a diffusion bioturbation model has been used to assess the relative importance of molecular diffusion and bioturbation as transport processes controlling the benthic flux of ra the flux of the shortest lived isotope 224ra half life 3 7 days is not significantly enhanced by bioturbation and its flux is consistent with diffusion controlled release however bioturbation enhances the 228ra flux by a factor of more than two over the flux due to molecular diffusion alone modelled pore water profiles and flux calculations are consistent with a bioturbation time scale between 0 5 and 2 years the measured benthic flux of 226ra is much greater than can be accounted for by the modelled profile and may be due to slow 226ra desorption from the sediment variable sediment accumulation rates or groundwater flow based on 226ra pore water and flux measurements at the time of this study groundwater flow has an upper limit of 0 3 cm d 1

imaging of lunar surface maturity the physical evolution of the lunar surface with exposure to the space environment is termed maturation and maturity is the degree to which a particular lunar soil possesses quantitative characteristics consistent with that exposure several quantitative measures or indices of maturity have been proposed and employed including the abundance of solar wind gas abundance of various types of agglutinates various measures of grain size and is feo among the changes attendant with space exposure are striking changes in the optical characteristics of soils mature lunar soils are dark red and exhibit reduced spectral contrast relative to immature soils this paper presents an optical maturity index that quantifies the spectral effects of maturation we show that this optical maturity index correlates with other maturity indices about as well as the accepted maturity indices correlate among themselves and is only weakly coupled to composition the modest correlations among maturity indices suggest important controls on individual maturity indices other than age uncorrelated variations in the rates of accumulation of individual indicators or variations in depths over which indicators are emplaced in addition to mixing these effects conspire to reduce the equivalence of maturity and duration of surface exposure optical maturity illustrates some of these effects showing that ejecta of large and small craters mature at different rates and that the interiors and ejecta of large craters exhibit systematically different optical maturities the same or analogous effects are likely to influence other maturity indices

laser argon 40 argon 39 age studies of dar al gani 262 lunar meteorite abstract the laser 40ar 39ar dating technique has been applied to the dar al gani dag 262 lunar meteorite a polymict highland regolith breccia to determine the crystallisation age and timing of shock events experienced by this meteorite laser stepped heating analyses of three dominantly feldspathic fragments dag 1 dag 2 and dag 3 revealed the presence of trapped ar mostly released at intermediate and high temperatures with an 40ar 36ar value of 2 8 trapped ar is most likely released from melt glass present as small veins within the fragments the 40ar 39ar ages determined for the three fragments are 3 0 ga for dag 1 and dag 2 and 2 0 ga for dag 3 and probably relate to major impact events laser spot analyses were performed on a feldspathic clast an impact crystalline melt basalt icmb and the matrix in a polished section of dag 262 the feldspathic and icmb clasts have low contents of trapped ar compared with that in the matrix the feldspathic clast shows a wide range of ages from 3 0 to 1 7 ga similar to those obtained by stepped heating the younger age is interpreted as a minimum age for the last major event that assembled this meteorite the icmb shows two age clusters at 3 37 and 3 07 ga where the older age may be that of the impact event that formed the impact melt several cosmic ray exposure cre ages were obtained as expected for a polymict regolith breccia the cre ages are 106 and 141 ma for the feldspathic clast and the icmb respectively one of the feldspathic fragments dag 2 shows a range between 200 400 ma these cre ages which are similar to those determined for returned samples of the lunar regolith indicate that the different components of dag 262 experienced preexposure prior to assemblage of the meteorite

potential anomalies on a sphere applications to the thickness of the lunar crust a new technique for calculating potential anomalies on a sphere due to finite amplitude relief has been developed we show that by raising the topography to the nth power and expanding this field into spherical harmonics potential anomalies due to topography on spherical density interfaces can be computed to arbitrary precision using a filter for downward continuing the bouguer anomaly we have computed a variety of crustal thickness maps for the moon assuming both a homogeneous as well as a dual layered crust the crustal thickness maps for the homogeneous model give plausible results but this model is not consistent with the seismic data petrologic evidence and geoid to topography ratios all of which suggest some form of crustal stratification several dual layered models were investigated and it was found that only models with both upper and lower crustal thickness variations could satisfy the gravity and topography data these models predict that the entire upper crust has been excavated beneath the major nearside multiring basins additionally significant amounts of lower crustal material was excavated from these basins especially beneath crisium this model also predicts that mantle material should not have been excavated during the south pole aitken basin forming event and that lower crustal material should be exposed at the surface in this basin

clementine uvvis multispectral data and the apollo 17 landing site what can we tell and how well multispectral data obtained by the clementine mission are correlated to compositional and petrographic information for individual sample stations at the apollo 17 landing site the soils contain a variety of fe2 bearing phases in different proportions including low and high ca pyroxene olivine ilmenite and glass in the mare soils ilmenite carries a substantial proportion of the fe2 and in all soils glasses particularly agglutinates carry nearly as much or more fe2 as the silicates using an empirical calibration concentrations of feo and tio2 estimated from the ultraviolet visible uvvis data correlate well with measured compositions of surface soils yielding correlation coefficients of 0 94 and 0 95 respectively the ferrous absorption however is weak in the mostly submature to mature apollo 17 soils thus spectral curvature is useful only for investigating the mafic silicate mineralogy around fresh craters and deposits the effects of local topography cause significant variations in feo and tio2 derived from clementine uvvis data but do not impair first order geologic interpretations parameters derived from the uvvis data allow quantification of the composition and nature of the soils and by inference underlying rock formations and are consistent with the known geologic character of the landing site the highland regions along this part of the serenitatis rim are relatively feo rich partly as a result of abundant mafic impact melt breccia and partly from the addition of basaltic material in the form of impact debris and pyroclastic deposits at high elevations massif soils are rich in a mafic melt breccia component although slopes and areas mixed by small craters reveal a mixture of melt breccia and older highland material of anorthositic norite composition soils developed on hummocky deposits that postdate the massifs such as the sculptured hills have a similar range of compositions as the massifs elevated plains northeast of the sculptured hills are more mafic than the known impact melt breccias suggesting that they may also contain an older volcanic component sources of low ti basalt or very low ti basalt though not present in the immediate vicinity of the landing site occur east and northeast of taurus littrow valley and are readily identified using the uvvis data

argon 40 argon 39 chronology and petrogenesis along the eastern limb of the moon from luna 16 20 and 24 samples eighteen new lithic fragments from the soviet luna missions have been analyzed with electron microprobe and 4oar 39ar methods luna 16 basalt fragments have aluminous compositions consistent with previous analyses but have two distinct sets of wellconstrained ages 3347 24 ma 342 1 f 30 ma these data combined with other luna 16 basalt ages imply that there were multiple volcanic events filling mare fecunditatis the returned basalt fragments have relatively old cosmic ray exposure cre ages and may have been recovered from the ejecta blanket of a young 1 ga nearby crater a suite of highlands rocks troctolites and gabbros is represented in the new luna 20 fragments one fragment is the most compositionally primitive mg 9 1 92 spinel troctolite yet found both troctolites have apparent crystallization ages of 4 19 ga other rocks in the suite have progressively younger ages and lower mg s the age and composition progression suggests that these rocks may have crystallized from a single source magma or from similar sources mobilized at the same time within the new luna 24 basalt fragments is a quench textured olivine vitrophyre with the most primitive composition yet analyzed for a luna 24 basalt and several much more evolved olivine bearing basalts both new and previously studied luna 24 very low ti vlt basalt fragments have a unimodal age distribution 3273 83 ma indicating that most returned samples come from a single extrusive episode within mare crisium much later than the apollo 17 vlt basalts 3 6 3 7 ga

224ra 228th disequilibrium in coastal sediments implications for solute transfer across the sediment water interface national basic research program 973 program of china 2009cb421203 natural science foundation of china nsfc 41076041 41276062 funds for creative research groups of the national natural science foundation of china 41121091

seasonal changes in groundwater input to a well mixed estuary estimated using radium isotopes and implications for coastal nutrient budgets 226ra half life 1 600 yr and 228ra half life 5 75 yr were used as tracers to determine seasonal changes in groundwater input to the pettaquamscutt estuary from june 1999 to june 2000 ra isotopes were observed to be in excess of activities due to input from streams rhode island sound water and particle desorption the source of excess 226ra and 228ra within the estuary is attributed to groundwater transport of ra derived from the weathering of bedrock within the pettaquamscutt watershed short lived 224ra half life 3 66 d was used to calculate an average residence time of the estuary of 8 4 d box models used to constrain seasonal changes in groundwater input to the estuary indicate highest groundwater input in the summer 6 4 20 l m 2 d 1 and lowest values in the winter 2 1 6 9 l m 2 d 1 these ra derived groundwater fluxes are similar to rates of aquifer recharge over the annual cycle using these ra derived groundwater fluxes the input of inorganic nitrogen and phosphorus from groundwater to the pettaquamscutt was estimated at 61 180 mmol m 2 yr 1 and 4 4 13 mmol m 2 yr 1 respectively

lunar iron and titanium abundance algorithms based on final processing of clementine ultraviolet visible images the clementine mission to the moon returned global imaging data collected by the ultraviolet visible uvvis camera this data set is now in a final state of calibration and a five band multispectral digital image model dim of the lunar surface will soon be available to the science community we have used observations of the lunar sample return sites and stations extracted from the final dim in conjunction with compositional information for returned lunar soils to revise our previously published algorithms for the spectral determination of the feo and tio2 content of the lunar surface the algorithms successfully normalize the effects of space weathering so that composition may be determined without regard to a surface s state of maturity these algorithms permit anyone with access to the standard archived dim to construct high spatial resolution maps of feo and tio2 abundance such maps will be of great utility in a variety of lunar geologic studies

quantifying groundwater discharge from different sources into a mediterranean wetland by using 222rn and ra isotopes summary groundwater discharge constitutes the main water inflow of many coastal wetlands despite the potential of ra isotopes and 222rn as tracers of groundwater discharge the use of these radionuclides to quantify the groundwater inflow in coastal wetlands has been only scarcely addressed in the literature the main goal of this study is to evaluate the use of 222rn and ra isotopes to estimate the contribution of distinct groundwater sources into a mediterranean coastal wetland the peniscola marsh castello spain the peniscola marsh is a small shallow wetland nourished by groundwater coming from four different flowpaths i a deep flow from the regional carbonate aquifer of el maestrat ii a shallow flow and iii an intermediate flow both from the irta range and the detritic vinaros peniscola aquifer and iv seawater intrusion data on 226ra 222rn and salinity obtained in summer 2007 revealed that the deep groundwater contribution was 15 of the total water inflow whereas the shallow and intermediate flow paths represented 32 and 48 respectively seawater accounted only for the remaining 5 inputs to the wetland ra isotopes also allowed estimating the marsh water age in 1 2 days both the groundwater contributions derived from 222rn measurements and the ra derived marsh water age agreed well with the direct measurements obtained using propeller flow meters evidencing the effectiveness of the used methods an interannual comparison between the estimated groundwater inflow and the precipitation revealed that shallow groundwater flows respond to local precipitation whereas the deep groundwater flow from the carbonate aquifer is dominated by a constant baseflow

a chemical model for generating the sources of mare basalts combined equilibrium and fractional crystallization of the lunar magmasphere abstract it is generally considered that mare basalts were generated by the melting of a cumulate mantle formed in an early moon wide magma ocean or magmasphere however the nature and chemistry of this cumulate mantle and the logistics of its origin have remained elusive extensive studies of terrestrial layered mafic intrusions over the past sixty years have emphasized the imperfection of fractional crystallization and attendant crystal crystal and crystal liquid separation in a convecting magma chamber crystal liquid and crystal crystal separations were similarly inefficient during evolution of the lunar magma ocean lmo allowing for the trapping of interstitial liquid and entrainment of a small proportion of less dense plagioclase into the denser mafic cumulate mush indeed petrography of lunar highlands samples demonstrates this for anorthosites with 1 10 olivine the residual liquid after 80 90 crystallization was very evolved in fact kreepy and even in small proportions 1 5 would have a noticeable effect on the trace element chemistry of melts generated from these cumulates this trapped residual liquid would elevate total ree abundances in the cumulate pile while synchronously deepening the already negative eu anomaly essentially this trapped liquid will make the cumulate more fertile for melting to generate both kreep basalt and mare basalt magmas plagioclase entrained in the mafic cumulate pile adds an essential al component to the high ti basalt source and will moderate the requisite negative eu anomaly in the cumulate early in the evolution of the lunar mantle when the lmo still was largely liquid it is likely that vigorous convection was an important factor in crystallization such convection would allow crystals to remain suspended and in equilibrium with the lmo liquid for relatively long periods of time this extended period of equilibrium crystallization would then have been followed by fractional crystallization once plagioclase became a liquidus phase and began to float to form the lunar highlands crust previous authors have proposed a three component model for the evolution of high ti mare basalt source regions this model includes kreep early olivine rich high mg cumulates and late ilmeniterich low mg cumulates in various proportions however we propose a model for high ti basalt parent magmas which is in accord with studies of terrestrial layered intrusions this model for the high ti source includes trapped instantaneous residual liquid tirl 1 3 and entrainment of a small 2 5 proportion of plagioclase into the late stage cumulate pile in order to account for both the observed al compositions and trace element characteristics of high ti mare basalts melting of this relatively shallow ilmenite and clinopyroxene bearing late stage cumulate can generate high ti mare basalt magmas furthermore we are in agreement with other workers that only through a process of nonmodal melting will the high ti values for the parent magmas be realized large scale convective overturn of the cumulate pile and mixing of kreep with early and late stage cumulates is not required however localized overturn of the upper tenth of the cumulate pile is likely and in fact required to achieve an appropriate major element balance for the high ti mare basalt source region

submarine groundwater discharge revealed by 228 ra distribution in the upper atlantic ocean submarine groundwater discharge estimated from a 228ra inventory across the upper atlantic ocean provides a flux of 2 4 1013 m3 yr 1 equivalent to 80 160 of the influx from rivers into the atlantic ocean

evaluation of salt marsh hydrology using radium as a tracer abstract radium isotopes provide unique and important information concerning water exchange in a salt marsh tidal creek system seasonal radium data collected over five tidal cycles from a creek draining a south carolina salt marsh radium and thorium data from the adjacent marsh sediments and interstitial water radium data from the drainage basin are modeled to yield residence times of water in the upper 10 cm of the marsh sediments ranging from less than one to twenty six hours water residence times derived from chambers which directly measure the flux of ra isotopes to the creek waters agree well with these calculated interstitial water turnover times dissolved radium activities in the tidal creek were greater during the summer than during other times of the year we suspect that seasonal changes in the storage of organic carbon and rates of bioturbation lead to net reduction of radium carrier phases in the marsh sediments during the summer