hydrogen and carbon abundances and isotopic ratios in apatite from alkaline intrusive complexes with a focus on carbonatites we report h and c contents and d and 13 c values of apatites from 15 alkaline intrusive complexes ranging in age from 110 ma to 2 6 ga sampling focused on carbonatites but included silicate rocks as well heating at temperatures up to 1500 c is needed to extract fully h 2o and co 2 from these apatites apatites from carbonatite rich intrusive complexes contain 0 2 1 1 wt h 2o and 0 05 0 70 wt co 2 apatites from two silicate rich alkaline complexes with little or no carbonatite are generally poorer in both volatile components 0 1 0 2 h 2o and 0 01 0 11 co 2 d h ratios in apatites from these rocks are bimodally distributed group i d 51 to 74 and group ii d 88 to 104 we suggest that the d values of group i apatites represent primitive mantle derived values and that the group ii apatites crystallized from degassed magmas resulting in lower h 2o contents and d values although many factors influence the extent of degassing the depth of emplacement could represent a major control in contrast to h 2o contents and d values co 2 contents and 13 c values of gas released at high temperatures from multiple aliquots of these apatite samples are variable this suggests the presence of more than one c bearing component in these apatites one of which is proposed to be dissolved carbonate the other with 13 c 25 could be associated with hydrocarbons group i apatites have d values similar to those of primitive mantle derived basaltic magmas and overlap with but cover a narrower range than mantle derived mica amphibole and whole rocks 13 c values also overlap typical upper mantle these results suggest that igneous apatites can retain their primary d and 13 c values

apatite as a monitor of late stage magmatic processes at volcan irazu costa rica apatite phenocrysts from the 1963 and 1723 eruptions of irazu volcano costa rica record a volatile evolution history that confirms previous melt inclusion studies and provides additional information concerning the relative and absolute timing of subvolcanic magmatic events measurements of h cl and f by secondary ion mass spectrometry reveal multiple populations of apatite in both 1723 and 1963 magmas assuming nominal apatite melt partition coefficients allows us to compare the pattern of melt inclusions and apatites in ternary space demonstrating the fidelity of the record preserved in apatite and revealing a complex history of magma mixing with at least two components the preservation of heterogeneous populations of apatite and of internally heterogeneous crystals requires short timescales days to years for these magmatic processes to occur

volatiles in lunar felsite clasts impact related delivery of hydrous material to an ancient dry lunar crust abstract in this detailed geochemical petrological and microstructural study of felsite clast materials contained in apollo breccia samples 12013 14321 and 15405 little evidence was found for relatively enriched reservoirs of endogenic lunar volatiles nanosims measurements have revealed very low volatile abundances 2 18 ppm hydrogen in nominally anhydrous minerals nams plagioclase potassic alkali feldspar and sio2 that make up a majority of these felsic lithologies yet these mineral assemblages and clast geochemistries on earth would normally yield relatively high volatiles contents in their nams 20 to 80 ppm hydrogen this difference is particularly notable in felsite 14321 1062 that exhibits extremely low volatile abundances 2 ppm hydrogen and a relatively low amount of microstructural evidence for shock metamorphism given that it is a clast of the most evolved 74 wt sio2 rock type returned from the moon if taken at face value wet felsic magmas 1 2 1 7 wt water are implied by the relatively high hydrogen contents of feldspar in felsite clasts in apollo samples 12013 and 15405 but these results are likely misleading these felsic clasts have microstructural features indicative of significantly higher shock stress than 14321 1062 these crustal lithologies likely obtained no more water from the lunar interior than the magma body producing 14321 1062 rather we suggest hydrogen was enriched in samples 12013 and 15405 by impact induced exchange and or partial assimilation of volatiles added to the surface of the moon by a hydrated impactor asteroid or comet or the solar wind thus the best estimate for magmatic water contents of felsic lunar magmas comes from 14321 1062 that leads to a calculated magmatic water content of 0 2 wt this dry felsic magma has a slightly greater but comparable water content to the ancient mafic magmas implied by the other lithologies that we have studied based on this and expanding evidence for a significantly dry ancient or early degassed moon it is likely that some recent estimates 100 s ppm of the water abundances in the lunar parental magma ocean have been overestimated

lunar apatite with terrestrial volatile abundances the moon is thought to be depleted relative to the earth in volatile elements such as h cl and the alkalis nevertheless evidence for lunar explosive volcanism has been used to infer that some lunar magmas exsolved a co rich and co 2 rich vapour phase before or during eruption although there is also evidence for other volatile species on glass spherules until recently there had been no unambiguous reports of indigenous h in lunar rocks here we report quantitative ion microprobe measurements of late stage apatite from lunar basalt 14053 that document concentrations of h cl and s that are indistinguishable from apatites in common terrestrial igneous rocks these volatile contents could reflect post magmatic metamorphic volatile addition or growth from a late stage interstitial sulphide saturated melt that contained 1 600 parts per million h 2o and 3 500 parts per million cl both metamorphic and igneous models of apatite formation suggest a volatile inventory for at least some lunar materials that is similar to comparable terrestrial materials one possible implication is that portions of the lunar mantle or crust are more volatile rich than previously thought

estimating the lunar mantle water budget from phosphates complications associated with silicate liquid immiscibility abstract the discovery of water within the lunar mantle has broad implications for the formation of the earth moon system differentiation of the moon and the magmatic evolution of lunar basalts as well as the highland rocks recently there has been considerable interest in using combined water abundances and h isotope systematics of lunar apatites from mare basalts to quantify the origin and extent of water within the moon s mantle however the petrologic and geochemical conditions that govern apatite crystallization are not well constrained especially for high feo basaltic melts that crystallize at fo2 values below the iron wustite buffer apatites are typically located within the late stage interstitial regions in this contribution we present detailed textural descriptions of late stage inter cumulus residual liquid pockets i e mesostasis pockets in order to understand the petrogenesis of lunar apatite results from five mare basalts demonstrate that the majority of the residual liquids in mesostasis regions have undergone silicate liquid immiscibility sli splitting into si k rich felsic and fe rich fe basaltic conjugate liquids we demonstrate the complexity of these residual liquids by documenting a wide range of water contents for apatites in several mesostasis pockets within a single mare basalt a complexity common to many basalts these data illustrate that individual apatite hosting mesostasis pockets behave as independent sub systems even within a single rock furthermore we present water concentrations for another phosphate phase merrillite indicating additional uncertainties during considerations of water partitioning into apatite fractional crystallization trends have been used in order to assess the conditions under which magmas are likely to undergo sli predicted liquid lines of descent indicate that it is the late stage residual liquids of lunar basalts with relatively low mg e g 50 may not intersect the two liquid field depending upon the fractionation trends in the late stage mesostasis pockets for samples that undergo sli the apatite melt partition coefficients required for back calculating water abundances of the parental melts are compromised by the generation of two populations of apatites merrillites from conjugate immiscible liquids this process highlights an important complexity inherent to all water back calculations that use apatite as this requires an additional set of partition coefficients we emphasize that the complex petrologic nature and common development of sli of apatite bearing late stage mesostasis pockets have not been considered in published apatite volatile data these factors in additional to other considerations illustrate why water back calculations to model the primary melts from such data must be viewed with caution

apatite in granitoids related to polymetallic mineral deposits in southeastern hunan province shi hang zone china implications for petrogenesis and metallogenesis abstract the area of southeastern hunan province china located within the southwestern part of the shi hang metallogenic zone is characterized by abundant cu pb zn w and sn polymetallic ore deposits that are closely associated with coeval late mesozoic granodiorite porphyries and biotite granites respectively here we present new major and trace element concentrations and 87 sr 86 sr ratios of apatites from six ore bearing granitic rocks as determined by electron microprobe laser ablation inductively coupled plasma mass spectrometry and thermal ionization mass spectrometer which allow us to determine the main controls on the formation of these different types of mineralization and to explore how these controls are reflected in variations in apatite chemical and isotopic compositions the apatite data indicate that granodiorite porphyry intrusions related to cu pb zn mineralization are oxidized and formed as a result of slab dehydration melting of the mantle wedge overlying a subducted slab and the partial melting of crustal material the release of abundant cl and h 2 o rich fluids from the slab triggered mantle melting and the extraction of metals that were precipitated within the deposits in comparison granites related to w and sn deposits are moderately oxidized to reduced and were generated by the partial melting of crustal material with only limited input from mantle derived magmas granites associated with the w and sn mineralization formed in an intra arc rifting related tectonic environment the fact that these numerous polymetallic ore deposits formed in the same area during two successive periods of mineralization the first from 180 to 160 ma and the second from 160 to 140 ma indicates that the tectonic environment of southeastern hunan province evolved from a continental arc associated with the subduction of the paleo pacific plate and the formation of cu pb zn deposits to a later intra arc rifting environment associated with the formation of w and sn deposits as a consequence of slab roll back and mantle upwelling during the late jurassic this study reveals that apatite compositions can be used as a proxy to reflect the differences between granitoids and their associated mineralization and identify regional metallogeny and tectonic evolution

plate boundary deformation and man made subsidence around geothermal fields on the reykjanes peninsula iceland abstract we present interferometric synthetic aperture radar insar data from 1992 1999 and 2003 2008 as well as gps data from 2000 2009 for the active plate boundary on the reykjanes peninsula southwest iceland the geodetic data reveal deformation mainly due to plate spreading anthropogenic subsidence caused by geothermal fluid extraction and possibly increasing pressure in a geothermal system subsidence of around 10 cm is observed during the first 2 years of production at the reykjanes geothermal power plant which started operating in may 2006 we model the surface subsidence around the new power plant using point and ellipsoidal pressure sources in an elastic halfspace short lived swarms of micro earthquakes as well as aseismic fault movement are observed near the geothermal field following the start of production possibly triggered by the stresses induced by geothermal fluid extraction

correlated δ 18 o and ti in lunar zircons a terrestrial perspective for magma temperatures and water content on the moon zircon grains were separated from lunar regolith and rocks returned from four apollo landing sites and analyzed in situ by secondary ion mass spectrometry many regolith zircons preserve magmatic 18o and trace element compositions and although out of petrologic context represent a relatively unexplored resource for study of the moon and possibly other bodies in the solar system the combination of oxygen isotope ratios and ti provides a unique geochemical signature that identifies zircons from the moon the oxygen isotope ratios of lunar zircons are remarkably constant and unexpectedly higher in 18o 5 61 0 07 vsmow than zircons from earth s oceanic crust 5 20 0 03 even though mare basalt whole rock samples are nearly the same in 18o as oceanic basalts on earth 5 6 thus the average fractionation of oxygen isotopes between primitive basalt and zircon is smaller on the moon 18o wr zrc 0 08 0 09 than on earth 0 37 0 04 the smaller fractionations on the moon suggest higher temperatures of zircon crystallization in lunar magmas and are consistent with higher ti in lunar zircons phase equilibria estimates also indicate high temperatures for lunar magmas but not specifically for evolved zircon forming melts if the solidus temperature of a given magma is a function of its water content then so is the crystallization temperature of any zircon forming in that melt the systematic nature of o and ti data for lunar zircons suggests a model based on the following observations many of the analyzed lunar zircons are likely from k rare earth elements p kreep zr rich magmas zircon does not saturate in normal mafic magmas igneous zircons in mafic rocks are typically late and formed in the last most evolved portion of melts even if initial bulk water content is moderately low the late zircon forming melt can concentrate water locally in general water lowers crystallization temperatures in which case late igneous zircon can form at significantly lower temperatures than the solidus inferred for a bulk rock composition although lunar basalts could readily lose h2 to space during eruption lowering water fugacity the morphology large size and presence in plutonic rocks suggest that many zircons crystallized at depths that retarded degassing in this case the crystallization temperatures of zircons are a sensitive monitor of the water content of the parental magma as well as the evolved zircon forming melt if the smaller 18o zircon mare basalt values reported here are characteristic of the moon then that would suggest that even highly evolved zircon forming magmas on the moon crystallized at higher temperature than similar magmas on earth and that magmas though not necessarily water free were generally drier on the moon

behavior of tungsten and hafnium in silicates a crystal chemical basis for understanding the early evolution of the terrestrial planets 1 the short lived isotopic system involving the decay of 182hf to 182w half life of 9 ma has been used to establish a time scale for planetary assembly and core formation the w isotope signature of lunar and martian basalts appears to be correlated to characteristics of their source on the moon the small amount of excess 182w is associated with basalts that may be derived from an ilmenite and clinopyroxene bearing mantle that was produced during late stages of lunar magma ocean crystallization on mars excess 182w is associated with a depleted mantle source our experimental measurements for the partitioning behavior of hf and w between silicates and melt suggest that the early fractionation of hf from w by phases such as ilmenite high ca clinopyroxene and garnet may be significant enough to account for the generation of all or part of the radiogenic w signatures in the mantle sources for these basalts the duration and nature of early mantle differentiation events on the moon and mars may be calculated by combining hf w fractionation with the extent of radiogenic w enrichment

early dinantian evaporites of the easton 1 well solway basin onshore cumbria england abstract an early visean anhydrite rich carbonate clastic succession of vertical thickness 3784 feet no base was found in 1990 at the easton 1 well in the solway basin onshore cumbria the succession is stratigraphically located in the lower border group where only traces of evaporites had been found at outcrop it is proposed to name the succession the easton anhydrite facies of the lower border group abbreviated to ea beds the ea beds are divided into three units unit 1 at the top about 400 feet thick contains two sequences of upwardly thickening anhydrite beds within mixed lithologies unit 2 about 2100 feet thick consists of nine cyclic sequences of limestones shales and sandstones with numerous interbeds of anhydrite overall similarity of several of the sequences suggests similar origins unit 2 sequences are grouped into three megacycles two of approximately 750 feet and one 590 feet thick deposition is interpreted to have taken place in arid or partly arid climatic conditions within a shallow and rapidly but uniformly subsiding basin with glacio eustatically controlled rise and fall of sea level many of the unit 2 anhydrite beds are interpreted to be of subaqueous origin unit 3 about 1500 feet thick displays complex patterns of cyclicity with sedimentation apparently responding directly to solar insolation under orbitally induced control within milankovitch periodicities of 100 000 and 400 000 years seismic interpretation indicates that the regional extent of the ea beds is greater than 1000 km 2

constraints on the flux of meteoritic and cometary water on the moon from volatile element n ar analyses of single lunar soil grains luna 24 core abstract we report new nitrogen and argon isotope and abundance results for single breccia clasts and agglutinates from four different sections of the luna 24 drill core in order to re evaluate the provenance of n trapped in lunar regolith and to place limits on the flux of planetary material to the moon s surface single luna 24 grains with 40ar 36ar ratios 10 1126 science 188 4184 162 is no longer apparent when the luna and apollo data are combined instead the n isotope signatures corrected for cosmogenic 15n are consistent with binary mixing between isotopically light solar wind sw n and a planetary n component with a 15n value of 100 to 160 the lower 15n values of luna 24 grains compared to apollo samples reflect a higher relative proportion of solar n resulting from the higher sw fluence in the region of mare crisium compared to the central near side of the moon carbonaceous chondrite like micro impactors match well the required isotope characteristics of the non solar n component trapped in low antiquity lunar regolith in contrast a possible cometary contribution to the non solar n flux is constrained to be 3 13 based on the mixing ratio of sw to planetary n obtained for recently exposed lunar soils we estimate the flux of micro impactors to be 2 2 5 7 103 tons yr 1 at the surface of the moon our estimate for luna 24 agrees well with that for young apollo regolith indicating that the supply of planetary material does not depend on lunar location thus the continuous influx of water bearing cosmic dust may have represented an important source of water for the lunar surface over the past 1 ga provided that water removal rates i e by meteorite impacts photodissociation and sputtering do not exceed accumulation rates

the east irish sea basin from caterpillar to butterfly a thirty year metamorphosis in the thirty years since the award of the first licenses the east irish sea basin has emerged as a significant hydrocarbon province this paper first lists some of the occasionally almost arbitrary events that led to the first success in the basin the discovery of the morecambe field in 1974 an attempt is made to review progress over those thirty years in certain topics namely 1 stratigraphy 2 structure 3 sedimentology 4 diagenesis the platy illite problem and others 5 uplift and inversion 6 hydrocarbon sources and types 7 east irish sea basin analogues the paper concludes by summarizing the current state of knowledge 1995 represented the thirtieth anniversary of the first award of licences in the east irish sea basin eisb the twenty sixth anniversary of the drilling of the first wells and the twenty first anniversary of the discovery of the south morecambe field it is perhaps appropriate to look back on some of the crucial events of the last thirty years and on some of the earlier concepts and interpretations with a view to seeing how these last have progressed or been found wanting undoubtedly the biggest spur to exploration was the discovery in 1974 by the british gas corporation subsidiary hgb ltd of the south morecambe field how a fledgling organization came to discover this 5 tcf gas accumulation in its first venture is itself noteworthy key events that led to this discovery might be summarized as follows 1 the wish of the government in power in 1969 to foster a national presence in the exploration of british waters by allowing the then gas council to take 100 interests in eisb blocks 2 the readiness of the gas council to exploit this opportunity 3 the unwillingness of the council s main north sea partner to participate in the proposed application with its offer of a firm well 4 the unwillingness of other majors to join the application 5 the informal gift by gulf in 1973 of the logs of wells 110 8 1 and 2 on the basis of a gentleman s agreement that hgb would likewise make data available from any wells it

the constitution and structure of the lunar interior the current state of understanding of the lunar interior is the sum of nearly four decades of work and a range of exploration programs spanning that same time period missions of the 1960s including the rangers surveyors and lunar orbiters as well as earth based telescopic studies laid the groundwork for the apollo program and provided a basic understanding of the surface its stratigraphy and chronology through a combination of remote sensing surface exploration and sample return the apollo missions provided a general picture of the lunar interior and spawned the concept of the lunar magma ocean in particular the discovery of anorthite clasts in the returned samples led to the view that a large portion of the moon was initially molten and that crystallization of this magma ocean gave rise to mafic cumulates that make up the mantle and plagioclase flotation cumulates that make up the crust smith et al 1970 wood et al 1970 this model is now generally accepted and is the framework that unifies our knowledge of the structure and composition of the moon the intention of this chapter is to review the major advances that have been made over the past decade regarding the constitution of the moon s interior much of this new knowledge is a direct result of data acquired from the successful clementine and lunar prospector missions as well as the analysis of new lunar meteorites as will be seen results from these studies have led to many fundamental amendments to the magma ocean model much of what we know from sample analyses has been previously summarized elsewhere and only their most important aspects will be discussed in this chapter the reader is referred to the relevant chapters in the books basaltic volcanism on the terrestrial planets basaltic volcanism study project 1981 the

phosphate halogen metasomatism of lunar granulite 79215 impact induced fractionation of volatiles and incompatible elements in the last decade it has been recognized that the moon contains significant proportions of volatile elements h f cl and that they are transported through the lunar crust and across its surface here we document a significant segment of that volatile cycle in lunar granulite breccia 79215 impact induced remobilization of volatiles and vapor phase transport with extreme elemental fractionation 79215 contains 1 volume of fluorapatite ca 5 po 4 3 f cl oh in crystals to 1 mm long which is reflected in its analyzed abundances of f cl and p the apatite has a molar f cl ratio of 10 and contains only 25 ppm oh and low abundances of the rare earth elements ree the chlorine in the apatite is isotopically heavy at 37 cl 32 7 1 6 hydrogen in the apatite is heavy at d 1060 180 much of that d came from spallogenic nuclear reactions and the original d was lower between 350 and 700 unlike other p rich lunar rocks e g 65015 79215 lacks abundant k and ree and other igneous incompatible elements characteristic of the lunar kreep component here we show that the p and halogens in 79215 were added to an otherwise normal granulite by vapor phase metasomatism similar to rock alteration by fumarolic exhalations as observed on earth the ultimate source of the p and halogens was most likely kreep it being the richest reservoir of p on the moon and 79215 having h and cl isotopic compositions consistent with kreep a kreep rich rock was heated and devolatilized by an impact event this vapor was fractionated by interaction with solid phases including merrillite a volatile free phosphate mineral a fe ti oxide and a zr bearing phase these solids removed ree th zr hf etc from the vapor and allowed the vapor to transport primarily p f and cl with lesser proportions of ba and u into 79215 vapor deposited crystals of apatite to 30 m are known in some lunar regolith samples but lunar vapor has not before this been implicated in significant mass transfer it seems unlikely however that phosphate halogen metasomatism is related to the high th sm abundance ratios of this and other lunar magnesian granulites the metasomatism of 79215 emphasizes the importance of impact heating in the lunar volatile cycle both in mobilizing volatile components into vapor and in generating strong elemental fractionations

pristine lunar glasses criteria data and implications major element analyses of several thousand glasses from all of the apollo landing sites have resulted in the identification of 25 groups of pristine i e volcanic glass the nickel in these pristine glasses is shown to be indigenous not meteoritic contamination and to be correlated with mg the chemical data indicate that these glasses are consistently better candidates for primary magmas than the majority of crystalline mare basalts the pristine glasses support the view that assimilative processes ringwood and kesson 1976 involving two cumulate systems in the differentiated mantle operated during mare petrogenesis the reality of those assimilative interactions is evident by the occurrence of two linear arrays among the chemistries of the glasses data suggest that these cumulate components in the differentiated mantle persist for lateral distances of at least 1000 km and therefore appear to be products of a vast magma ocean that existed early in lunar history alternative hypotheses claiming that the highlands crust and mare source regions were produced by serial magmatism without a magma ocean have not yet considered all of the constraints derived from the pristine glasses

direct measurement of hydroxyl in the lunar regolith and the origin of lunar surface water remote sensing discoveries of hydroxyl and water on the lunar surface have reshaped our view of the distribution of water and related compounds on airless bodies such as the moon the origin of this surface water is unclear but it has been suggested that hydroxyl in the lunar regolith can result from the implantation of hydrogen ions by the solar wind here we present fourier transform infrared spectroscopy and secondary ion mass spectrometry analyses of apollo samples that reveal the presence of significant amounts of hydroxyl in glasses formed in the lunar regolith by micrometeorite impacts hydrogen isotope compositions of these glasses suggest that some of the observed hydroxyl is derived from solar wind sources our findings imply that ice in polar cold traps could contain hydrogen atoms ultimately derived from the solar wind as predicted by early theoretical models of water stability on the lunar surface we suggest that a similar mechanism may contribute to hydroxyl on the surfaces of other airless terrestrial bodies where the solar wind directly interacts with the surface such as mercury and the asteroid 4 vesta

early degassing of lunar urkreep by crust breaching impact s current models for the moon s formation have yet to fully account for the thermal evolution of the moon in the presence of h2o and other volatiles of particular importance is chlorine since most lunar samples are characterised by unique heavy 37cl values significantly deviating from those of other planetary materials including earth for which 37cl values cluster around 0 in order to unravel the cause s of the moon s unique chlorine isotope signature we performed a comprehensive study of high precision in situ cl isotope measurements of apatite from a suite of apollo samples with a range of geochemical characteristics and petrologic types the cl isotopic compositions measured in lunar apatite in the studied samples display a wide range of 37cl values reaching a maximum value of 36 which are positively correlated with the amount of potassium k rare earth element ree and phosphorous p kreep component in each sample using these new data integrated with existing h isotope data obtained for the same samples we are able to place these findings in the context of the canonical lunar magma ocean lmo model the results are consistent with the urkreep reservoir being characterised by a 37cl 30 such a heavy cl isotope signature requires metal chloride degassing from a cl enriched urkreep lmo residue a process likely to have been triggered by at least one large crust breaching impact event that facilitated the transport and exposure of urkreep liquid to the lunar surface

circular polarization ratio characteristics of impact craters from mini rf observations and implications for ice detection at the polar regions of the moon 1 in an attempt to reduce the ambiguity on radar detection of water ice at the permanently shadowed regions near the lunar poles radar echo strength and circular polarization ratio cpr of impact craters are analyzed using the miniature radio frequency mini rf radar data from the lunar reconnaissance orbiter mission eight typical craters among over 70 craters are selected and classified into four categories based on their locations and cpr characteristics polar anomalous polar fresh nonpolar anomalous and nonpolar fresh the influences on cpr caused by surface slope rocks and dielectric constant are analyzed quantitatively using high resolution topography data and optical images a two component mixed model for cpr that consists of a normal surface and a rocky surface is developed to study the effect of rocks that are perched on lunar surface and buried in regolith our analyses show that inner wall of a typical bowl shaped crater can give rise to a change of about 30 in local incidence angle of radar wave which can further result in a cpr difference of about 0 2 there is a strong correlation between mini rf cpr and rock abundance that is obtained from high resolution optical images and predictions from the two component mixed model match well with the observed cprs and the estimated rock abundances statistical results show that there is almost no apparent difference in cpr characteristics between the polar and nonpolar anomalous craters or between the polar and nonpolar fresh craters the enhanced cpr in the interior of anomalous craters is most probably caused by rocks that are perched on lunar surface or buried in regolith instead of ice deposits as suggested in previous studies

hydrogen and d h analysis of apatite by elemental analyzer chromium high temperature conversion isotope ratio mass spectrometry ea cr htc irms abstract hydrogen and d measurements of the mineral apatite have been used to measure volatile contents of planets and planetesimals and to infer the sources and evolution of water throughout the solar system all of these studies use secondary ion mass spectrometry sims which necessitates the use of apatite mineral standards to correct for matrix effects which have previously been measured by mass spectrometry for hydrogen isotopes here we present a new technique of elemental analyzer chromium high temperature conversion isotope ratio mass spectrometry ea cr htc irms for the measurement of hydrogen and hydrogen isotopes of apatite this technique presents greater technical advantages over tc ea due to ability of chromium to bind with phosphorus in the high temperature reactor and prevent this elemental p from clogging the instrument components we also show that removal of adsorbed moisture of nominally hydrous minerals and glasses becomes increasingly important with decreasing grain size of materials and present experiments on moisture removal from nominally anhydrous quartz we report hydrogen and hydrogen isotope results of five fluorapatite and two hydroxylapatite samples including durango apatite we show that our results of hydrogen content of durango apatite are similar to published values using the tc ea technique our recommended values for hydrogen using a cr reactor for h2o and dvsmow slap for durango apatite are 608 102 ppm h2o and dvsmow slap 86 4 2

preservation of primordial signatures of water in highly shocked ancient lunar rocks abstract spurred by the discovery of water in lunar volcanic glasses about a decade ago the accessory mineral apatite became the primary target to investigate the abundance and source of lunar water this is due to its ability to contain significant amounts of oh in its structure along with the widespread presence of apatite in lunar rocks there is a general understanding that crustal cumulate rocks of the lunar magnesian mg suite are better candidates for recording the original isotopic compositions of volatile elements in their parental melts compared to eruptive rocks such as mare basalts consequently water bearing minerals in mg suite rocks are thought to be ideal candidates for discerning the primary hydrogen isotopic composition of water in the lunar interior mg suite rocks and most other apollo samples that were collected at the lunar surface display variable degrees of shock deformation in this study we have investigated seven apollo 17 mg suite samples that include troctolite gabbro and norite lithologies in order to understand if shock processes affected the water abundances and or h isotopic composition of apatite the measured water contents in apatite grains range from 31 to 964 ppm with associated d values varying between 535 134 and 147 194 2 considering the full dataset there appears to be no correlation between h2o and d of apatite and the level of shock each apatite grain has experienced however the lowest d was recorded by individual water poor 100 ppm h2o regardless of the complexity of the shock induced nanostructures there appears to be no evidence of water loss or alteration in their d the weighted average d value of 24 such water rich apatites is 192 71 and of all 36 analyzed spots is 209 47 indistinguishable from that of other kreepy lunar lithologies or the earth s deep mantle despite experiencing variable degrees of shock deformation at a later stage in lunar history water rich apatite in some of the earliest formed lunar crustal material appears to retain the original isotopic signature of h in the moon

the development of a regional scale intraplate strike slip fault system alpine deformation in the north of ireland abstract a paucity of displacement markers can make constraining the kinematics and interaction of regional scale strike slip faults difficult in this study a high resolution aeromagnetic survey allows quantitative analysis of kilometre scale paleogene faulting in the north of ireland mapping offset dykes and igneous centres reveals the presence of two orientations of cenozoic strike slip faults attributed to broadly n s alpine shortening arising from the convergence of africa and europe reactivated ne sw striking faults accommodated up to 2 3 km of sinistral displacement mainly during the paleocene following tectonic quiescence up to 2 5 km of oligocene aged dextral movement was accommodated on newly formed nnw sse striking faults displacement analysis suggests that the faults were kinematically linked and experienced a switch in polarity of the predominantly active fault orientation during the paleogene forming an apparent conjugate system with asymmetric displacement distributions the switch in fault polarity is attributed to a rotation in the regional maximum horizontal stress orientation and the locus of deformation moving from pre existing reactivated structures to newly formed faults the analysis also illustrates that despite low strain rates the interaction of the principal components of the fault system controlled the formation of sedimentary basins and defined the present day geography of the region far from an active plate boundary

origin of basalt fire fountain eruptions on earth versus the moon fire fountain eruptions of basaltic magma occur on earth at centers such as kilauea hawaii and deposits from apparently similar eruptions have been found on the lunar surface the driving force for terrestrial fire fountain eruptions is the exsolution of dissolved co 2 based on gases dissolved in melt inclusions trapped in olivine phenocrysts and the relatively high oxidation state of these magmas gases released at the vent show that so 2 and eventually h 2 o are partitioned into the co 2 rich gas adding to the gas volume in contrast analytical and experimental studies of lunar samples indicate that the gas phase responsible for driving the lunar eruptions was co rich and produced by the oxidation of c graphite carried in the slowly ascending low f o 2 basalt the graphite oxidation occurs when the pressure in the ascending lunar magma reaches that of the graphite gas reaction surface 40 1 mpa or 8 km depth for the apollo 17 orange glass magma as graphite is oxidized some feo is reduced potentially forming a fe rich metal phase and fe rich metal spherules are present in beads in lunar glass deposits other gas species such as s cl and f partitioned variously into co rich lunar volcanic gas and appear in surface coatings on the glass spherules modeling of the magma flow from 8 km depth to the lunar surface shows that the gas bubble volume fraction assuming initial c at 50 500 ppm levels ranges from 0 5 to 0 8 at the surface the exit velocity ranges from 15 to 35 m s and the low viscosity magma fragments only as it erupts at the lunar surface

deep generation of magmatic gas on the moon and implications for pyroclastic eruptions 1 lunar pyroclastic beads are interpreted to represent primitive magmas derived from great depths and rapidly erupted to the surface in explosive events however a detailed mechanism for gas generation at great depth and rapid magma transport to the surface has not yet been described furthermore the pyroclastic beads are not petrogenetically related to basalts erupted near the sampling sites we propose a model in which these conundrums are resolved through gas build up in a low pressure micro environment near the tip of a magma filled crack dike propagating rapidly from the magma source depth to the surface the gas rich region consists of a free gas cavity overlying a foam extending vertically for 20 km eruption of the foam results in the widespread emplacement of unfractionated pyroclastic beads subsequent ascent of the underlying gas free picritic magma is unlikely to occur perhaps accounting for the lack of sampled eruptive equivalents

the moon a personal recollection and memorial for professor lawrence a taylor an apollo stalwart abstract the first geochemical analysis of lunar samples returned by the apollo 11 mission revealed that the moon was highly differentiated and depleted in volatile elements stable isotope compositions show that earth and moon are closely related but they have evolved in totally dissimilar ways probably related to the deficiency of water in the moon as well as the vast differences in size currently available lunar samples come from cumulate source regions making the establishment of a bulk planetary composition more reliant on geophysical rather than geochemical properties

the most reduced rock from the moon apollo 14 basalt 14053 its unique features and their origin the apollo 14 high al basalt 14053 is the most reduced lunar rock examined to date both fayalite in the mesostasis and spinel minerals have been extensively reduced in the exterior of the rock whereas the interior contains relatively limited reduction it is shown that these products are the effects of solar wind hydrogen that was implanted on the exterior of the normal 14053 basalt after it originally crystallized and was weathered to become part of the regolith subsequent reheating probably in an impact ejecta blanket caused extreme subsolidus hydrogen reduction particularly of the weathered exterior of this rock the limited permeability of the rock prevented the entire rock from being subjected to the same degree of reduction it is proposed that this extreme reduction especially of the mesostasis also affected the phosphate minerals f cl apatite and merrillite each of which vary greatly in ree contents this effect on the phosphate minerals could relate to the upset sm nd radiogenetic systematics whereas the rb sr system may have been largely immune to the subsolidus reduction

oriented chromite diopside symplectic inclusions in olivine from lunar regolith delivered by luna 24 mission abstract calcium chromium rich lamellae in olivine grain no 1611 from the luna 24 regolith were studied with feg empa and tem the lamellae consist of a worm like intergrowth of fecr 2 o 4 chromite chr and camgsi 2 o 6 diopside di with a chr di modal proportion of 1 3 the linear extension of the lamellae and crystallographic orientation relationships among the symplectite phases and the olivine suggest that the lamellae nucleated at deformation defects in the olivine host calcium depletion haloes surrounding the lamellae amount to about 75 m and indicate that the chromite diopside lamellae were formed by segregation of calcium and chromium from the host olivine into the lamellae without addition of calcium and or chromium from outside the olivine the segregation of calcium and chromium and consequently the growth of the symplectic lamellae were diffusion controlled the segregation of a calcium chromium component from the host olivine was associated with oxidation of divalent to trivalent chromium oxidation was facilitated by dehydrogenation which was driven by decompression and or a change in redox potential hydrogen point defects in the original olivine with h substituting for divalent cations on the m sites provided the necessary electron acceptors for the oxidation of chromium and after electron transfer left olivine as molecular h 2 the internal microstructure of the lamellae suggests that exsolution of the calcium chromium rich lamellae from the host olivine and formation of the chromite diopside symplectic intergrowth occurred simultaneously the time scale derived from diffusion modeling of the calcium depletion haloes around the lamellae indicates a thermal event on the order of several months to several hundred years at most symplectic inclusions found in olivine from lunar martian and terrestrial rocks are similar with respect to their shape crystallographic orientation relationships and internal microstructure of the spinel clinopyroxene intergrowth these features are inconsistent with dry olivine oxidation that is by the uptake of oxygen dehydrogenation of oh bearing precursor olivine is suggested as a general mechanism of oxidation accompanied by chemical segregation and phase separation resulting in symplectite formation

h and cl isotope systematics of apatite in brecciated lunar meteorites northwest africa 4472 northwest africa 773 sayh al uhaymir 169 and kalahari 009 we have investigated the h and cl systematics in apatite from four brecciated lunar meteorites in northwest africa nwa 4472 most of the apatites contain 2000 6000 ppm h2o with d between 200 and 0 except for one grain isolated in the matrix which contains 6000 ppm h2o with d of 500 900 this low d apatite contains 2500 7500 ppm cl associated with 37cl of 15 20 while the high d grain contains 2500 ppm cl with 37cl of 7 15 in nwa 773 apatites in a first group contain 700 2500 ppm h2o with d values averaging around 0 100 while apatites in a second group contain 5500 16500 ppm h2o with d 250 50 in sayh al uhaymir sau 169 and kalahari kal 009 apatites are similar in terms of their h2o contents 600 3000 ppm and d values 100 to 200 in sau 169 apatites contain 6000 10 000 ppm cl characterized by 37cl of 5 12 overall most of the analyzed apatite grains have d within the range reported for carbonaceous chondrites similar to apatite analyzed in ancient 3 9 ga lunar magmatic one grain in nwa 4472 has h and cl isotope compositions similar to apatite from mare basalts with an age of 4 35 ga this grain could be a representative of the oldest known lunar volcanic activity finally since numerous evolved clasts in nwa 773 formed through silicate liquid immiscibility the apatite grains with extremely high h2o contents reaching pure hydroxylapatite composition could provide insights into the effects of such process on the evolution of volatiles in lunar magmas

water hydrogen in the lunar mantle results from petrology and magma ocean modeling abstract measurements of hydroxyl or water in lunar materials are being used to suggest that melting source regions within the moon contained tens to hundreds of ppm water the compositions of magmatic source regions in the moon can be calculated using magma ocean fractional solidification models given an initial bulk composition our magma ocean models demonstrate that to make a source region with 10 to 200 ppm water the bulk magma ocean must contain 100 to 1000 ppm water or more and in a 1000 km deep lunar magma ocean 1000 ppm water is equivalent to 5 of an earth ocean by weight as solidification of the magma ocean continues water and other incompatible elements are progressively enriched in the evolving liquids the final kreep like liquids would contain the greatest fraction of water we suggest that a bulk magma ocean with over 100 ppm water is prohibited by constraints on these kreep like final magma ocean liquids and by the thermodynamic equilibrium requirement with metallic iron in mare basalts we conclude that bulk lunar interior water contents must be at the low end of the range posited by recent observations

chromite symplectites in mg suite troctolite 76535 as evidence for infiltration metasomatism of a lunar layered intrusion abstract despite the very low chromium concentrations in its cumulus olivine 140 ppm lunar troctolite 76535 contains large amounts of cr sporadically but highly concentrated in symplectite assemblages consisting of mg al chromite and two pyroxenes previously proposed symplectite formation mechanisms include crystallization of trapped interstitial melt diffusion of cr from cumulus olivine and or remobilization of cumulus chromite grains these mechanisms would imply that the highly cr depleted nature of mg suite parental magmas and their source materials inferred from cumulus olivine may be illusory we have conducted a detailed petrologic and textural study of symplectites as well as chromite veins intercumulus assemblages olivine hosted melt inclusions and clinopyroxene troilite veins in 76535 with the goals of constraining the origin of the symplectites and the degree of cr depletion in mg suite magmas relative to other lunar basalts orthopyroxene and clinopyroxene in melt inclusions are depleted in cr relative to their symplectite counterparts averaging 900 and 1200 ppm vs 7400 and 8100 ppm cr 2 o 3 respectively olivine in contact with symplectite assemblages may exhibit a diffusion profile of cr going into olivine whereas olivine boundaries away from symplectites show no diffusion profile there is also a distinct lack of primary chromite as inclusions in cumulus phases and melt inclusions multiple textural observations melt inclusion chemistry and modeling of chromite olivine equilibrium rule out previously proposed symplectite formation mechanisms and strongly suggest that chromite was not a primary crystallization product of the 76535 parental magma accordingly the post cumulus addition of cr and fe is required to produce the symplectites after considering multiple models the addition of cr and fe to 76535 via infiltration metasomatism by an exogenous chromite saturated melt is the model most consistent with multiple textural and geochemical observations failure of models that call upon cr diffusion out of olivine grains imply that the observed cr depleted nature of olivine observed in many mg suite lithologies is a primary feature of the cr depleted nature of the mg suite parental magmas and their source materials this substantial depletion of cr in the magma relative to mare basalt magmas still requires a satisfactory explanation in order to be consistent with mg suite petrogenetic models and currently accepted bulk moon compositions additionally if the intimate interaction of migrating melts with early lunar crustal lithologies was a widespread phenomenon after lmo solidification it provides another mechanism by which to reset or delay closure of radiogenic isotopic systems and explain the mg suite ferroan anorthosite age overlap

analyzing moon rocks the paradigm of a dry moon was recently challenged on the basis of reexamination of lunar samples collected during the apollo missions raising the possibility of a volatile rich lunar interior 1 6 several of these studies measured appreciable quantities of water reported as equivalent h oh or h2o and other volatiles e g cl f in the mineral apatite 4 6 which is ubiquitous in lunar basalts mare basalts see the figure however an accurate estimation of the water content of the magmatic liquid from which apatite formed and ultimately of the mantle source regions of mare basalts depends on a number of parameters in cases where apatite in a mare basalt formed through the process of fractional crystallization when newly formed crystals in a cooling magma are physically separated preventing any further interaction with the remaining melt it may not be possible to obtain any reliable estimates of the water contents of the parental magma and its source region on page 400 of this issue boyce et al 7 present an elegant numerical model applicable to mare basalt apatite formed through fractional crystallization to demonstrate that some of the highest water contents reported for lunar apatite can be reconciled with an original melt containing not much water at all these new results cast doubt on the utility of apatite volatile abundances in reliably estimating the water content of mare basalt source regions

detection of structurally bound hydroxyl in fluorapatite from apollo mare basalt 15058 128 using tof sims fluorapatite grains from apollo 15 mare basalt 15058 128 were analyzed by raman spectroscopy raman spectral imaging time of flight secondary ion mass spectrometry tof sims field emission scanning electron microscopy fe sem and electron probe microanalysis epma in an attempt to detect structurally bound oh in the fluorapatite although oh could not be definitively detected by raman spectroscopy because of ree induced photoluminescence hydroxyl was detected in the fluorapatite by tof sims the tof sims technique is qualitative but capable of detecting the presence of hydroxyl even at trace levels electron microprobe data indicate that on average f and cl f cl fill the monovalent anion site in these fluorapatite grains within the uncertainties of the analyses about 0 07 0 01 atoms per formula unit however some individual spot analyses have f cl deficiencies greater than analytical uncertainties that could represent structural oh on the basis of epma data the fluorapatite grain with the largest f cl deficiency constrains the upper limit of the oh content to be no more than 4600 2000 ppm by weight the equivalent of 2400 1100 ppm water the tof sims detection of oh in fluorapatite from apollo sample 15058 128 represents the first direct confirmation of structurally bound hydroxyl in a lunar magmatic mineral this result provides justification for attributing at least some of the missing structural component in the monovalent anion site of other lunar fluorapatite grains to the presence of oh moreover this finding supports the presence of dissolved water in lunar magmas and the presence of at least some water within the lunar interior

low pressure crystallization of a volatile rich lunar basalt a means for producing local anorthosites the presence of anorthosite in the lunar highlands containing plagioclase that is compositionally less calcic than plagioclase in the ferroan anorthosites cannot be readily explained by the current lunar paradigm in which lunar anorthosite was produced as a floatation cumulate in the lunar magma ocean phase equilibrium experiments were conducted to investigate whether such anorthosite could arise locally from crystallization of aluminous magma at shallow levels within the lunar crust the experiments were conducted on a synthetic analog of cl f and s bearing aluminous highland basalt 14053 at pressures of approximately 1 bar and f o 2 at qif pyroxene and plagioclase an 93 89 saturation occurs early and with continued crystallization the residual liquid evolves to a silica poor halogen fe and ti rich melt with a computed density of 3 1 g ml this liquid remains higher in density than the plagioclase over the crystallization interval providing the possibility of plagioclase melt separation by liquid draining a model is proposed in which alkali anorthosite consisting of sodic anorthite or bytownite coupled with underlying pyroxenite or harzburgite is produced locally during crystallization of plagioclase from al rich magmas at or within roughly a kilometer of the lunar surface in this model segregation of plagioclase would be attained by settling of ferromagnesian minerals to the bottom of a shallow magma chamber and draining of low viscosity low silica fe ti k ree p enriched residual basaltic melt to deeper regions of the crust or into topographic lows such residual melt may be represented by magma compositions similar to some of the intermediate to high ti mare basalts this model would provide a mechanism that can account for the more alkali anorthosite identified in widespread isolated locales on the moon and allow for variable ages for such anorthosite that may extend to ages of the mare basalts

crystal chemistry of merrillite from martian meteorites mineralogical recorders of magmatic processes and planetary differentiation merrillite is a ubiquitous accessory phase in a variety of martian meteorite lithologies the martian merrillites exhibit a positive correlation between mg and na and a negative correlation between mg and both mn and vacancies in the octahedral na site their ree patterns are varied and range from lree depleted to lree enriched the dominant cation substitutions in the martian merrillites are fe2 vi mg sitemg2 vi mg site and ca2 vi na site vi na site2na vi na site the ree substitution into the 8 fold coordinated ca site is accommodated by the coupled substitution caviii ca site na vi na site y3 ree3 viii ca site vi na site the ree substitution is significantly more prevalent in lunar merrillite and can be used as a fingerprint to distinguish lunar from martian meteorites the substitution of oh whitlockite and or f bobdownsite for o2 on one of the phosphate tetrahedrons appears to be rather insignificant the correlations among na mg mn and na site vacancies are linked to the premerrillite crystallization history of the melt and the crystal chemical behavior of the mg and na sites the former reflects the sequence and extent of plagioclase and pyroxene crystallization the differences in ree pattern shapes among the merrillites reflect source regions for the martian basalts and the shapes are not greatly perturbed by the crystallization history the occurrence of merrillite does not imply low volatile component in the martian magmas however the low whitlockite and bobdownsite contents suggest that these samples were not altered by hydrothermal fluids and therefore not reset owing to aqueous fluid interactions consequently the young ages of the shergottites are probably true igneous crystallization ages

density and compressibility of the molten lunar picritic glasses implications for the roles of ti and fe in the structures of silicate melts abstract the density and compressibility of four synthetic molten lunar picritic glasses was investigated from 0 to 10 gpa and 1748 to 2473 k the picritic glasses were collected from the lunar surface during the apollo missions and they are hypothesized to have rapidly quenched as glass beads during pyroclastic fire fountain eruptions the specific melt compositions investigated in the present study are the apollo 15 green glass type c a15c tio 2 0 26 wt the apollo 14 yellow glass a14y tio 2 4 58 wt the apollo 17 orange glass 74220 type a17o tio 2 9 12 wt and the apollo 14 black glass a14b tio 2 16 40 wt these glasses are reported to represent primary unfractionated melts making them a prime candidate for experimental studies into lunar basalt density and compressibility during partial melting of the lunar mantle sink float experiments were conducted on the synthetic molten lunar glass compositions using a piston cylinder apparatus p p 2 5 gpa in order to bracket the density of the melts new sink float data are reported for a15c a14y and a17o which are combined with previously published density and compressibility data on a15c a17o and a14b although the ti rich liquids are highly compressible at lower pressures they become nearly incompressible at much higher pressures when compared to the molten low ti glasses consequently the melts with the most tio 2 a14b are the least dense at higher pressures a reversal of what is seen at lower pressures this change in density and compressibility is attributed to changes in coordination of ti and fe in the silicate melt structure as ti 4 abundances in the silicate melt increase predominantly iv ti 4 and iv fe 2 change to vi ti 4 and vi fe 2 in the melt structure all of the data from the present study were used to calculate a birch murnaghan equation of state bm eos for each melt composition the bm eos model for each composition was then combined with previously published estimates for the residual mantle source mineralogy and depth of origin for each of the glasses to assess the density of the partial melt with respect to its point of origin this information was used to determine whether or not the melt would rise or sink with respect to its source region we determined that all melt compositions with the exception of the a17o melt should have been able to rise to the crust mantle boundary as a result of buoyancy forces alone although different mechanisms are likely required for magma ascent through the lunar crust for the rise of a17o other modes of ascent through the lunar mantle are required to extract this melt composition from the mantle and volatiles are not a plausible solution on the grounds of melt density alone

crystal chemical and structural characterization of fluorapatites in ejecta from somma vesuvius volcanic complex the mineralogy and crystal chemistry of apatites occurring in 14 ejecta of historical eruptions 1631 and 1872 a d of the somma vesuvius volcanic complex were investigated by a multi methodological approach including polarized optical microscopy scanning electron microscope electron microprobe analysis in wavelength dispersive mode laser ablation inductively coupled plasma mass spectroscopy and single crystal x ray diffraction five different groups of apatite with different mineralogical and crystal chemical features were identified apatite crystals occur with well developed hexagonal prismatic habit and more rarely with skeletal acicular forms the crystals are yellow type 1 transparent and colorless type 2 and type 3 green type 4 and aquamarine colored type 5 with different paragenesis macro crystalline aggregates of clinopyroxenes phlogopite and apatite type 1 type 4 clusters of apatite with micro crystalline clinopyroxene minerals of the cancrinite group feldspars and opaque minerals type 2 aggregates of apatite sellaite wagnerite gypsum and phlogopite type 3 aggregates of davyne nepheline mica group minerals and apatite type 5 chemical analyses of apatites show variable amounts of na ree mg sr and fe replacing ca not negligible amounts of si and s substituting p and a significant substitution of cl and oh instead of f five crystals representative of each apatite type were studied by single crystal x ray diffraction their crystal structure was refined in the hexagonal p 63 m space group a significant variation of the unit cell parameters with the composition was observed a comparative crystal chemical analysis between apatites from somma vesuvius and those from other localities is carried out

factors controlling sulfur concentrations in volcanic apatite apatite crystals from two types of samples were analyzed by electron microprobe for 15 major and trace elements 1 apatite in h2o and s saturated experimental charges of the 1982 el chichon trachyandesite and 2 apatite in volcanic rocks erupted from 20 volcanoes the so3 contents of the experimental apatite increase with increasing oxygen fugacity from 0 04 wt in reduced charges buffered by fayalite magnetite quartz o2 fmq to 1 0 2 6 wt in oxidized charges buffered by manganosite hausmanite mnh or magnetite hematite mth the so3 contents of mnh and mth buffered apatite also generally increase with increasing pressure from 2 to 4 kbar and decreasing temperature from 950 to 800 8c the partition coefficient for so 3 between apatite and oxidized melt increases with decreasing temperature but appears to be independent of pressure apatites in volcanic rocks show a wide range of so3 contents 0 04 to 0 63 wt our sample set includes one group known to contain primary anhydrite and a second group inferred to have been free of primary anhydrite no systematic differences in apatite s contents are observed between these two groups our study was initiated to define the factors controlling s contents in apatite and to evaluate the hypothesis that high s contents in apatite could be characteristic of s rich anhydrite bearing magmas such as those erupted from el chichon in 1982 and pinatubo in 1991 this hypothesis is shown to be invalid probably chiefly a consequence of the slow intra crystalline diffusion that limits re equil ibration between early formed apatite and the evolving silicate melt contributing factors include early crystallization of most apatite over a relatively small temperature interval common late stage magmatic enrichment of s progressive oxidation during magmatic evolution and strong controls on s contents in apatite exerted by temperature and o2 pressure

new evidence for lunar basalt metasomatism by underlying regolith earth like d values reported from lunar mare basalt apatites have typically been interpreted to reflect the intrinsic isotopic composition of lunar mantle water new data indicates that some of these basalts are also characterized by having experienced a slow cooling history after their emplacement onto the lunar surface this suggests that these basalts may have experienced metasomatism by fluxes generated during the degassing of the lunar regolith induced by the long duration high temperature residence times of overlying basalts

d poor hydrogen in lunar mare basalts assimilated from lunar regolith apatite grains in lunar mare basalts contain hydrogen that ranges in d h ratio by more than a factor of two for most of these basalts the d h ratios in their apatite grains decrease with measures of the host basalts time spent at elevated temperature specifically the fe mg homogenization of their pyroxenes most basalts with homogeneous pyroxenes i e with constant fe mg ratio have apatite grains with low d h d 100 whereas most basalts with heterogeneous pyroxenes i e varying or zoned fe mg have apatite with high d h d up to 1100 this relationship suggests that low d h values were acquired during thermal processing i e during fe mg chemical equilibration during or after emplacement this light hydrogen is likely derived from solar wind implanted into the lunar regolith with d from 125 to 800 and could enter basalts either by assimilation of regolith or by vapor transport from regolith heated by the flow if a basalt could not interact with regolith rich in solar wind e g it was emplaced onto other fresh basalts its apatite could retain a magmatic d h signature the high d h component in the apatites of unequilibrated basalts is most reasonably that indigenous magmatic hydrogen i e representing hydrogen in the basalt s source mantles or magmatic hydrogen that was residual after partial degassing of h 2

planetary science water on the moon analysis of the first apollo samples suggested that earth s only satellite was bone dry spacecraft data and improved analysis techniques now indicate that the moon is more volatile rich and complex than previously thought

in situ major and trace element compositions of apatites from luanchuan orecluster implications for porphyry mo mineralization abstract the effects of volatile concentrations and oxidation state of magma on the mo mineralization potential have been explored through petrographic studies and in situ electron probe micro analyzer epma and laser ablation inductively coupled plasma mass spectrometry la icp ms of apatites from coeval economically mo mineralized granite porphyry and quartz diorite and sub economically mineralized granite porphyry at luanchuan orecluster the occurrence of abundant k feldspar xenocrysts possibly entrained from granitic magma in quartz diorite implying a magma mingling process studied apatites are fluorapatites or fluor hydroxyapatites with decreasing oh concentrations from economically mineralized quartz diorite 0 30 0 49 apfu through mineralized granite porphyry 0 14 0 41 apfu to sub economically mineralized granite porphyry 0 01 0 11 apfu chondrite normalized ree patterns of all the apatites are characterized by lree enrichment relative to mree and hree and negative eu anomaly similar to their host magmas indicating a melt composition control strontium concentration of studied apatites are probably controlled by the crystallization of plagioclase or alkali feldspar mineralized quartz diorite formed at a relatively reduced environment compared to other rocks but mineralized granite porphyry and sub economically mineralized granite porphyry formed at a similar oxidation state based on the so3 eu ce and mn content variation of apatites the oh contents of apatites combined with published log h2o hf ratios of melt in equilibrated with biotites reflect that economically mineralized intrusions have higher water contents than the sub economically mineralized intrusions in a porphyry mo system a high magma water content is probably a key parameter controlling mo mineralization mafic magma may supply water and heat to ore forming granitic magmas enhancing their mo mineralization potential

partitioning behavior of chlorine and fluorine in the system apatite silicate melt fluid the partitioning behavior of cl among apatite mafic silicate melt and aqueous fluid and of f between apatite and melt have been determined in experiments conducted at 1066 to 1150 c and 199 205 mpa the value of dclapatite melt wt fraction of cl in apatite cl in melt 0 8 for silicate melt containing less than 3 8 wt cl at higher melt cl contents small increases in melt cl concentration are accompanied by large increases in apatite cl concentration forcing dclapatite melt to increase as well melt containing less than 3 8 cl coexists with water rich vapor that containing more cl coexists with saline fluid the salinity of which increases rapidly with small increases in melt cl content analogous to the dependency of apatite composition on melt cl content this behavior is due to the fact that the solubility of cl in silicate melt depends strongly on the composition of the melt particularly its mg ca fe and si contents once the melt becomes saturated in cl additional cl must be accommodated by coexisting fluid apatite or other phases rather than the melt itself because cl solubility depends on composition the cl concentration at which dclapatite melt and dclfluid melt begin to increase also depends on composition the experiments reveal that dfapatite melt 3 4 in contrast to cl the concentration of f in silicate melt is only weakly dependent on composition mainly on melt ca contents so dfapatite melt is constant for a wide range of composition the experimental data demonstrate that the fluids present in the waning stages of the solidification of the stillwater and bushveld complexes were highly saline the cl rich apatite in these bodies crystallized from interstitial melt with high cl f oh ratio the latter was generated by the combined processes of fractional crystallization and dehydration by its reaction with the relatively large mass of initially anhydrous pyroxene through which it percolated

understanding the origin and evolution of water in the moon through lunar sample studies a paradigm shift has recently occurred in our knowledge and understanding of water in the lunar interior this has transpired principally through continued analysis of returned lunar samples using modern analytical instrumentation while these recent studies have undoubtedly measured indigenous water in lunar samples they have also highlighted our current limitations and some future challenges that need to be overcome in order to fully understand the origin distribution and evolution of water in the lunar interior another exciting recent development in the field of lunar science has been the unambiguous detection of water or water ice on the surface of the moon through instruments flown on a number of orbiting spacecraft missions considered together sample based studies and those from orbit strongly suggest that the moon is not an anhydrous planetary body as previously believed new observations and measurements support the possibility of a wet lunar interior and the presence of distinct reservoirs of water on the lunar surface furthermore an approach combining measurements of water abundance in lunar samples and its hydrogen isotopic composition has proved to be of vital importance to fingerprint and elucidate processes and source s involved in giving rise to the lunar water inventory a number of sources are likely to have contributed to the water inventory of the moon ranging from primordial water to meteorite derived water ice through to the water formed during the reaction of solar wind hydrogen with the lunar soil perhaps two of the most striking findings from these recent studies are the revelation that at least some portions of the lunar interior are as water rich as some mid ocean ridge basalt source regions on earth and that the water in the earth and the moon probably share a common origin

magmatic degassing histories from apatite volatile stratigraphy measurements of oh and cl growth zoning in apatite phenocrysts from the cerro galan ignimbrite describe the tumultuous volatile history of a magma chamber in the days to months prior to a supereruption the chemical stratigraphy in these crystals provides a unique relative time scale not otherwise available when studying pre eruptive volatiles in ancient magma chambers and it allows us to temporally correlate the data within each crystal resulting in a volatile history the five crystals studied show broadly similar volatile histories but distinctive differences between the various crystals suggest that each recorded a specific perspective on the magma chamber prior to eruption perhaps correlating to different depths or laterally separated regions within the 1000 km 3 magma chamber all crystals are consistent with the interpretation of a multistage magmatic history including a period of residence in a quiescent magma and a period of rapid growth under strongly varying conditions several apparent events during this period of growth consistent with two competing processes of h 2 o degassing and recharge are recorded by nearly all of these crystals such zoning could not have survived for more than 400 d prior to eruption suggesting that during the days to months leading up to a supereruption apatite records key aspects of the processes that directly lead to and influence these catastrophic events

sulfur evolution of oxidized arc magmas as recorded in apatite from a porphyry copper batholith uniformly sulfur rich cores abruptly zoned to sulfur poor rims 1 to 0 2 wt so3 in apatite from the yerington batholith nevada indicate that early magma that is crystal poor oxidizing and sulfate rich evolved to sulfate poor magma via crystallization of anhydrite a mineral observed in magmas from pinatubo and el chichon we predict that the characteristic zonation to sulfur poor rims of apatite in the yerington batholith is common in other oxidized hydrous calc alkaline magmas and can be used to track cryptic anhydrite saturation as well as to monitor sulfur evolution sulfate rich arc magmas such as yerington magmas may crystallize to produce hydrothermal fluids rich in chlorine copper and sulfur and porphyry copper ores

rare earth element minerals in martian breccia meteorites nwa 7034 and 7533 implications for fluid rock interaction in the martian crust paired martian breccia meteorites northwest africa nwa 7034 and 7533 are the first martian rocks found to contain rare earth element ree phosphates and silicates the most common occurrence is as clusters of anhedral monazite ce inclusions in apatite occasionally zoned irregular merrillite inclusions are also present in apatite monazite bearing apatite is sometimes associated with alkali feldspar and fe oxide apatite near merrillite and monazite generally contains more f and oh f rich region than the main chlorapatite host and forms irregular boundaries with the main host locally the composition of f rich regions can reach pure fluorapatite the chlorapatite hosts are similar in composition to isolated apatite without monazite inclusions and to euhedral apatite in lithic clasts the u th total pb ages of monazite in three apatite are 1 0 0 4ga 2 1 1 0 5ga 2 and 2 8 0 7ga 2 confirming a martian origin the texture and composition of monazite inclusions are mostly consistent with their formation by the dissolution of apatite and or merrillite by fluid at elevated temperatures 100 c in nwa 7034 we observed a monazite chevkinite perrierite bearing benmoreite or trachyandesite clast anhedral monazite and chevkinite perrierite grains occur in a matrix of sub micrometer ree phases and silicates inside the clast monazite ce and nd and chevkinite perrierite ce and nd display unusual la and ce depletion relative to sm and nd in addition one xenotime y bearing pyrite ilmenite zircon clast with small amounts of feldspar and augite occurs in nwa 7034 one xenotime crystal was observed at the edge of an altered zircon grain and a cluster of xenotime crystals resides in a mixture of alteration materials pyrite ilmenite and zircon in this clast are all highly altered zircon being the most likely source of y and hree now present in xenotime the association of xenotime with zircon low u and th contents and the low yb content relative to gd and dy in xenotime suggest the possible formation of xenotime as a byproduct of fluid zircon reactions on the basis of relatively fresh apatite grains and lithic clasts in the same samples we propose that the fluid rock mineral reactions occurred in the source rocks before their inclusion in nwa 7034 and 7533 additionally monazite bearing apatite and ree mineral bearing clasts are possibly derived from different crustal origins thus our results imply the wide occurrence of hydrothermal fluids in the martian crust at 1 ga or older which were probably induced by impacts or large igneous intrusions

hydrothermal fluid characteristics and implications of the makou ioa deposit in luzong basin eastern china abstract a large number of iron oxide apatite ioa deposits occur in the middle and lower yangtze river metallogenic belt mlyb eastern china proterozoic phosphorus rich strata are also widely exposed in this belt providing a good opportunity to research the relationship between phosphorus rich layers and ioa deposits the makou ioa deposit is located in the central part of the volcanic luzong basin the ore body is developed in the contact zone between gabbro diorite and cretaceous trachyandesite and it is the only ioa deposit in the basin that spatially associated with a dioritic intrusion the main hydrothermal alteration minerals are albite diopside apatite chlorite and carbonate in this study we employed shrimp si to analyse in situ o isotope ratios of magmatic and hydrothermal apatite and in situ s isotope ratios of pyrite from the makou deposit additionally la icp ms was used for trace element analysis the results show that the sulfur in the pyrite of the makou deposit comes from different sulfur phases e g h2s and so2 in the hydrothermal fluid and s34total is similar to that of magmatic sulfur indicating that the hydrothermal fluid was weakly affected by evaporite which is substantially different from other ioa skarn iron deposits in the mlyb both analysed apatite samples are classified as fluorapatite in which the 18oap of the makou magmatic hydrothermal apatite is similar to that of the initial mantle 3 7 5 5 and much lower than that of the susong sedimentary metasomatic apatite 13 7 14 2 the lree hree ratio increase from magmatic to hydrothermal apatite whereas the sr y decreases indicating that the hydrothermal fluid metasomatised the dioritic intrusive rock resulting in a large amount of albite crystallisation and release fe from pyroxene and biotite to hydrothermal fluid indicates that fe rich fluid in ioa deposit could be formed by albitization of the consolidated intrusive rock by combining this finding with the oxygen isotope data we propose that the mineralization of the makou deposit was mainly controlled by a magmatic hydrothermal process the low co2 and so42 contents in the volcanic rock are a key factor leading to apatite precipitation the addition of a phosphorus rich layer or evaporites is not necessary for the formation of ioa type deposits in the mlyb

diachronous variscan late orogenic collapse as a response to multiple detachments a view from the internides in france to the foreland in the irish sea