nominally hydrous magmatism on the moon for the past 40 years the moon has been described as nearly devoid of indigenous water however evidence for water both on the lunar surface and within the lunar interior have recently emerged calling into question this long standing lunar dogma in the present study hydroxyl as well as fluoride and chloride was analyzed by secondary ion mass spectrometry in apatite ca5 po4 3 f cl oh from three different lunar samples in order to obtain quantitative constraints on the abundance of water in the lunar interior this work confirms that hundreds to thousands of ppm water of the structural form hydroxyl is present in apatite from the moon moreover two of the studied samples likely had water preserved from magmatic processes which would qualify the water as being indigenous to the moon the presence of hydroxyl in apatite from a number of different types of lunar rocks indicates that water may be ubiquitous within the lunar interior potentially as early as the time of lunar formation the water contents analyzed for the lunar apatite indicate minimum water contents of their lunar source region to range from 64 ppb to 5 ppm h2o this lower limit range of water contents is at least two orders of magnitude greater than the previously reported value for the bulk moon and the actual source region water contents could be significantly higher

the provenance formation and implications of reduced carbon phases in martian meteorites this review is intended to summarize the current observations of reduced carbon in martian meteorites differentiating between terrestrial contamination and carbon that is indigenous to mars indeed the identification of martian organic matter is among the highest priority targets for robotic spacecraft missions in the next decade including the mars science laboratory and mars 2020 organic carbon compounds are essential building blocks of terrestrial life so the occurrence and origin biotic or abiotic of organic compounds on mars is of great significance however not all forms of reduced carbon are conducive to biological systems this paper discusses the significance of reduced organic carbon including methane in martian geological and astrobiological systems specifically it summarizes current thinking on the nature sources and sinks of martian organic carbon a key component to martian habitability based on this compilation reduced organic carbon on mars including detections of methane in the martian atmosphere is best described through a combination of abiotic organic synthesis on mars and infall of extraterrestrial carbonaceous material although conclusive signs of martian life have yet to be revealed we have developed a strategy for life detection on mars that can be utilized in future life detection studies

hydrous melting of the martian mantle produced both depleted and enriched shergottites the search for water in our solar system is one of the primary driving forces for planetary science and exploration because water plays an important role in many geologic processes and is required for biologic processes as we currently understand them excluding earth mars is the most promising destination in the inner solar system to find water as it is undoubtedly responsible for shaping many geomorphologic features observed on the present day martian surface however the water content of the martian interior is currently unresolved much of our information about the martian interior comes from studies of the basaltic martian meteorites shergottites in this study we examined the water contents of magmatic apatites from a geochemically enriched shergottite the shergotty meteorite and a geochemically depleted shergottite the queen alexandria range 94201 meteorite from these data we determined that there was little difference in water contents between the geochemically depleted and enriched shergottite magmas the water contents of the apatite imply that shergottite parent magmas contained 730 2870 ppm h 2 o prior to degassing furthermore the martian mantle contains 73 290 ppm h 2 o and underwent hydrous melting as recently as 327 ma in the absence of plate tectonics the presence of water in the interior of mars requires planetary differentiation under hydrous conditions this is the first evidence of significant hydrogen storage in a planetary interior at the time of core formation and this process could support elevated h abundances in the interiors of other terrestrial bodies like the moon mercury venus large differentiated asteroids and earth

early plate tectonics versus single plate tectonics on mars evidence from magnetic field history and crust evolution 1 the consequences of an early epoch of plate tectonics on mars followed by single plate tectonics with stagnant lid mantle convection on both crust production and magnetic field generation have been studied with parameterized mantle convection models thermal history models with parameterized mantle convection not being dynamo models can provide necessary but not sufficient conditions for dynamo action it is difficult to find early plate tectonics models that can reasonably explain crust formation as is required by geological and geophysical observations and allow an early magnetic field that is widely accepted as the cause for the observed magnetic anomalies dating of crust provinces and topography and gravity data suggest a crust production rate monotonically declining through the noachian and hesperian and a present day crust thickness of more than 50 km plate tectonics cools the mantle and core efficiently and the core may easily generate an early magnetic field given a sufficiently weak mantle rheology plate tectonics can explain a field even if the core is not initially superheated with respect to the mantle because the crust production rate is proportional to temperature however an early efficient cooling will frustrate later crust production and therefore cannot explain for example the absence of prominent magnetic anomalies in the northern crustal province and the northern volcanic plains in the early hesperian voluminous crust formation following plate tectonics is possible if plate tectonics heat transfer is inefficient but then the crust growth rate has a late peak about 2 ga b p which is not observed these models also require a substantial initial superheating of the core to allow a dynamo if one accepts the initial superheating then as we will show a simple thermal evolution model with monotonic cooling of the planet due to stagnant lid mantle convection underneath a single plate throughout the evolution can better reconcile early crust formation and magnetic field generation

halogen chemistry and hydrogen isotopes of apatite from the 3 7 ga isua supracrustal belt sw greenland abstract the origin and evolution of volatiles particularly water in the abiotic early earth environment have been intensively studied and this is a topic of high relevance when considering the timing and conditions of life s emergence investigation of hydrogen isotopes in the oldest crystals of minerals from the apatite group ca10 po4 6 f cl oh 2 should bring new insight to this topic as the d h ratio of apatite has proved useful for establishing the evolution of volatiles in other solar system bodies apatite crystals from metasedimentary and metavolcanic rocks collected from a low strain domain of the eoarchean isua supracrustal belt have been investigated for their d h signatures using secondary ion mass spectrometry and for major and trace element abundances using epma and laser ablation icp ms apatite crystals from isua have a broad range in volatile compositions both within samples from the same lithology e g banded iron formation bif and between different lithologies bif metacarbonate mafic dyke most of the crystals are chlorine rich which is in contrast to typical modern sedimentary apatite that is predominantly carbonate fluorapatite we have used the ree distribution patterns from isua apatite to distinguish those crystals having sedimentary metasomatic and magmatic origins the d h ratios for all samples were determined to be very low with dvsmow values falling within the range from 93 to 56 d values of isua apatite do not correlate with ree signatures of crystals nor could we relate d to the host lithologies we conclude that this geochemical system has been reset during long and multi phase geologic history making it difficult if not impossible to use hydrogen isotopes for assessment of the primary signatures of the archean hydrosphere

hydrogen isotope evidence for loss of water from mars through time 1 the high d h of the martian atmosphere 5 6 terrestrial is considered strong evidence for the loss of martian water to space the timing and magnitude of the loss of water from mars can be constrained by measurements of d h in martian meteorites previous studies of martian meteorites have shown a large range in d h from terrestrial values to as high as the current martian atmosphere here we show that the ancient 4 ga mars meteorite alh84001 has a d h 4 terrestrial and that the young 0 17 ga shergotty meteorite has a d h 5 6 terrestrial we also find that the young los angeles shergottite has zoning in d h that can be correlated to igneous growth zoning strongly suggesting assimilation of d enriched water during igneous crystallization near the martian surface in contrast to previous studies we find higher and less variable d h ratios in these three meteorites our results suggest a two stage evolution for martian water a significant early loss of water to space prior to 3 9 ga followed by only modest loss to space in the last 4 billion years the current martian atmospheric d h has remained essentially unchanged for the last 165 ma

constraints on martian differentiation processes from rbsr and smnd isotopic analyses of the basaltic shergottite que 94201 isotopic analyses of mineral leachate and whole rock fractions from the martian shergottite meteorite que 94201 yield rb sr and sm nd crystallization ages of 327 12 and 327 19 ma respectively these ages are concordant although the isochrons are defined by different fractions within the meteorite comparison of isotope dilution sm and nd data for the various que 94201 fractions with in situ ion microprobe data for que 94201 minerals from the literature demonstrate the presence of a leachable crustal component in the meteorite this component is likely to have been added to que 94201 by secondary alteration processes on mars and can affect the isochrons by selectively altering the isotopic systematics of the leachates and some of the mineral fractions initial 87sr 86sr of 0 701298 14 nd143 of 47 6 1 7 and whole rock nd142 of 0 92 0 11 indicate that que 94201 was derived from a source that was strongly depleted in 87rb 86sr and enriched in 147sm 144nd early in its history modeling demonstrates that the sm nd isotopic compositions of que 94201 can be produced by either four episodes of melting at 327 ma of cumulates crystallized from a magma ocean at 4 525 ga or five episodes of melting of an initially solid mars at 4 525 ga and 327 ma the neodymium isotopic systematics of que 94201 are not consistent with significant melting between 4 525 ga and 327 ma the estimated timing of these events is based on initial neodymium isotopic ratios and is independent of differentiation of the que 94201 parental magma rb sr based partial melting models are unable to reproduce the composition of que 94201 using the same model parameters employed in the sm nd based models implying a decoupling of rb sr and sm nd isotopic systems the initial decoupling of the two isotopic systems can be attributed to either cumulate or crust formation processes which are able to more efficiently fractionate rb from sr compared to sm from nd the fact that all martian meteorites analyzed so far define a rb sr whole rock isochron age of 4 5 ga suggests that virtually all rb was partitioned out of their mantle source regions and into either fractionated residual liquids trapped in the cumulate pile or into the crust at that time thus the martian mantle cumulates and restites are not expected to evolve past 87sr86sr of 0 700 and could not have been significantly enriched in incompatible elements by crustal recycling processes all martian meteorites have initial 87sr86sr values that are higher than 0 700 and are therefore likely to be produced by mixing between evolved crustal like and depleted mantle reservoirs the absence of crustal recycling processes on mars may preserve the geochemical evidence for decoupling of the rb sr and sm nd isotopic systems underscoring one of the fundamental differences between geologic processes on mars and the earth

thermal and compositional evolution of the martian mantle effects of water abstract we present numerical models of the thermochemical evolution of the mantle of mars with particular attention paid to the effects of water with a two dimensional anelastic compressible convection algorithm in combination with a parameterized model of composition and thermoelastic properties we consider how water in nominally anhydrous minerals may have influenced the melting and rheology of the martian mantle and how it may have been redistributed by melting melt extraction and convection over a period of 4 gy the strongest effect of water is found to be a marked increase in convective vigor due to the lower viscosity which leads to faster cooling of the mantle but nonetheless enhances melt production modeling results are compared with observations and independent inferences from spacecraft observations and martian meteorite analyses some models with radionuclide concentrations from wanke and dreibus 1994 but with initial mantle water concentrations between their estimate of 36 ppm by weight and 10 times this value combined with 50 degassing of crust forming material partly match observed crustal concentrations of k th and water in order to account for the observed chemical variation in crustal rocks however the formation and survival of ancient mantle heterogeneities appears to have been necessary water loss from the mantle since the end of the magma ocean stage has been minor elevated water contents notwithstanding the depth variation of viscosity in the sublithospheric mantle of a given model is likely minor depths to the curie temperature at the end of the noachian range from 40 to 60 km for magnetite and hematite in the models and present day total crustal thicknesses lie between 75 and 100 km the depth to the brittle ductile transition increases from values around 30 km in the early stages of the models to 170 240 km at present an estimate of total core entropy renders the existence of a basal perovskite ferropericlase layer unlikely the absence of stable superplumes in all of our preferred models suggests that the volcanic provinces of tharsis and elysium were formed by a succession of more short lived events such as transient plumes from specific regions at the core mantle boundary

the chlorine isotopic composition of martian meteorites 1 chlorine isotope composition of martian mantle and crustal reservoirs and their interactions the martian meteorites record a wide diversity of environments processes and ages much work has been done to decipher potential mantle sources for martian magmas and their interactions with crustal and surface environments chlorine isotopes provide a unique opportunity to assess interactions between martian mantle derived magmas and the crust we have measured the cl isotopic composition of 17 samples that span the range of known ages martian environments and mantle reservoirs the 37cl of the martian mantle as represented by the olivine phyric shergottites nwa 2737 chassignite and shergotty basaltic shergottite has a low value of approximately 3 8 this value is lower than that of all other planetary bodies measured thus far the martian crust as represented by regolith breccia nwa 7034 is variably enriched in the heavy isotope of cl this enrichment is reflective of preferential loss of 35cl to space most basaltic shergottites less shergotty nakhlites chassigny and allan hills 84001 lie on a continuum between the martian mantle and crust this intermediate range is explained by mechanical mixing through impact fluid interaction and assimilation fractional crystallization

phosphate minerals in ll chondrites a record of the action of fluids during metamorphism on ordinary chondrite parent bodies ordinary chondrites contain two phosphate minerals merrillite and chlorapatite both of which are secondary minerals that developed in response to metamorphism on the chondrite parent bodies we have studied the phosphate mineralogy of four ll chondrites of petrologic types 3 9 6 in order to determine the petrogenesis of the two minerals and interpret the conditions under which they formed characterization of merrillite and apatite includes textural observations mineral compositions determined by electron probe microanalysis and ion microprobe analyses of trace element and volatile anion elemental abundances initial formation of phosphate minerals during mild metamorphism to petrologic type 4 conditions resulted in oxidation of p that was originally incorporated in metal and growth of merrillite as inclusions within metal grains subsequent development of both phosphate minerals occurred in response to diffusional equilibration possible precipitation from fluids as well as replacement reactions resulting from interactions with fluids porosity and vein filling textures in both merrillite and chlorapatite as well as textures indicating replacement of merrillite by chlorapatite support a model in which fluid played a significant role and suggest an interface coupled dissolution reprecipitation mechanism during metasomatism some associations of phosphate minerals with chromite plagioclase assemblages suggest that phosphate minerals could also be related to impact processes either as precipitation from an impact melt or as a result of interactions with a fluid or vapor derived from an impact melt fluid compositions may have been water bearing initially at low temperatures of metamorphism but later evolved to become halogen rich and very dry late stage halogen rich fluids that dominated during cooling of ll chondrite material may have been derived from vaporization of partial melts in the interior of the parent body overall the ll chondrite parent body underwent a complex chemical evolution in which metasomatism played a significant role

volatiles in the martian crust and mantle clues from the nwa 6162 shergottite abstract martian meteorites of various petrogeneses retain a record of volatiles on mars from the hydrosphere crustal water to the mantle sputtering of the martian atmosphere by solar wind after the loss of mars magnetic field enriched it in deuterium which exchanged with martian crustal water recent studies show that the hydrogen isotopic composition of the martian crustal water reservoir varies from 3000 to 7000 but requires better constraints melt inclusion glasses maskelynite and fusion crust from the depleted olivine phyric shergotite nwa 6162 were analyzed using nanosims providing a unique insight into the hydrogen isotopic and volatile elemental content of both the martian crustal water reservoir and the mantle source the h2o s and cl contents of the melt inclusion glasses are 0 3137 14 239 and 16 967 ppm respectively d values vary from 560 to 6137 the water content positively correlates with the d values in both the melt inclusion glasses and maskelynite in a two end member mixing trend one end member is the magmatic water with a d value of 0 and the other end member is the martian crustal water with d ranging from 5000 to 6000 nwa 6162 a depleted olivine phyric shergottite originated from a different mantle source to the enriched lherzolitic shergottites however both types of shergottites exchanged with martian crustal water with the same d values indicating a homogeneous martian crustal water hydrogen isotopic composition 5000 6000 most melt inclusion glasses from nwa 6162 have low water content 0 234 ppm except for two enriched locations as micron sized bands and dendrites the low water content in most melt inclusion glasses the dendritic shaped water enriched areas in melt inclusions and the martian crustal water diffusion profile recorded in maskelynite collectively suggest short lived water rock interactions in the nwa 6162 parent rock that was probably induced by impact furthermore a great contribution up to 98 of surface cl accompanying d enriched water was recorded in the melt inclusions supported by the positive correlation between cl and h2o the presence of sulfide and s rich hot spots and low d end member of the magmatic water indicate that the degassing during post entrapment crystallization and ascent of the melt inclusion is negligible h2o s and cl contents of the martian mantle reservoir are estimated to be 0 1 3 0 5 15 and 0 5 4 ppm respectively after the correction of fractional crystallization of the melt inclusions and contribution from the martian surface reservoir the martian mantle reservoir estimated from nwa 6162 was water s and cl poorer than the earth s interior

a petrogenetic model for the origin and compositional variation of the martian basaltic meteorites the major element trace element and isotopic compositional ranges of the martian basaltic meteorite source regions have been modeled assuming that planetary differentiation resulted from crystallization of a magma ocean the models are based on low to high pressure phase relationships estimated from experimental runs and estimates of the composition of silicate mars from the literature these models attempt to constrain the mechanisms by which the martian meteorites obtained their superchondritic cao al2o3 ratios and their source regions obtained their parent daughter 87 rb 86 sr 147 sm 144 nd and 176 lu 177 hf ratios calculated from the initial sr nd and hf isotopic compositions of the meteorites high pressure experiments suggest that majoritic garnet is the liquidus phase for mars relevant compositions at or above 12 gpa early crystallization of this phase from a martian magma ocean yields a liquid characterized by an elevated cao al2o3 ratio and a high mg olivine pyroxene garnet dominated cumulates that crystallize subsequently will also be characterized by superchondritic cao al2o3 ratios melting of these cumulates yields liquids with major element compositions that are similar to calculated parental melts of the martian meteorites furthermore crystallization models demonstrate that some of these cumulates have parent daughter ratios that are similar to those calculated for the most incompatible element depleted source region i e that of the meteorite queen alexandra que 94201 the incompatible element abundances of the most depleted que 94201 like source region have also been calculated and provide an estimate of the composition of depleted martian mantle the incompatible element pattern of depleted martian mantle calculated here is very similar to the pattern estimated for depleted earth s mantle melting the depleted martian mantle composition reproduces the abundances of many incompatible elements in the parental melt of que 94201 e g ba th k p hf zr and heavy rare earth elements fairly well but does not reproduce the abundances of rb u ta and light rare earth elements the source regions for meteorites such as shergotty are successfully modeled as mixtures of depleted martian mantle and a late stage liquid trapped in the magma ocean cumulate pile melting of this hybrid source yields liquids with major element abundances and incompatible element patterns that are very similar to the shergotty bulk rock

determination of volatile concentrations in fluorapatite of martian shergottite nwa 2975 by combining synchrotron ftir raman spectroscopy empa and tem and inferences on the volatile budget of the apatite host magma we combined the focused ion beam sample preparation technique with polarized synchrotron based ftir fourier transform infrared spectroscopy laser raman spectroscopy electron microprobe analysis empa and transmission electron microscope tem analysis to identify and quantify structurally bound oh f cl and co3 groups in fluorapatite from the northwest africa 2975 nwa 2975 shergottite in this study the first ftir spectra of the oh stretching region from a martian apatite are presented that show characteristic oh bands of a f rich hydroxyl bearing apatite depending on the method of apatite formula calculation and whether charge balance is assumed or not the ftir based quantification of the incorporated oh expressed as wt h2o is in variably good agreement with the h2o concentration calculated from electron microprobe data emp analyses yielded between 0 35 and 0 54 wt h2o and ir data yielded an average h2o content of 0 31 0 03 wt consistent with the lower range determined from emp analyses the tem observations implied that the volatiles budget of fluorapatite is magmatic the water content and the relative volatile ratios calculated for the nwa 2975 magma are similar to those established for other enriched or intermediate shergottites it is difficult to define the source of enrichment either martian wet mantle or crustal assimilation comparing the environment of parental magma generation for nwa 2975 with the terrestrial mantle in terms of water content it displays a composition intermediate between enriched and depleted morb

constraints on the depth and thermal vigor of melting in the martian mantle studies of rocks in gale crater and clasts within the martian meteorite breccia northwest africa nwa 7034 and paired stones have expanded our knowledge of the diversity of igneous rocks that make up the martian crust beyond those compositions exhibited in the meteorite collection or analyzed at any other landing site therefore the magmas that gave rise to these rocks may have been generated at significantly different conditions in the martian mantle than those derived from previously studied rocks here we build upon our previous models of basalt formation based on rocks analyzed in gusev crater and meridiani planum to the new models of basalt formation for compositions from gale crater and a clast in meteorite nwa 7034 estimates for the mantle potential temperature tp based on noachian age rock analyses in gale crater gusev crater and bounce rock in meridiani planum and a vitrophyre clast in nwa 7034 are within error which suggests that the calculated average tp of 1450 70 c may represent an average global mantle temperature during the noachian the tp estimates for the hesperian and amazonian based on orbital analyses of the chemistry of the crust are lower in temperature than our estimates for the noachian which is consistent with simple convective cooling of the interior of mars however the tp estimates from the young meteorites are significantly higher than the estimates based on surface chemistry and are consistent with localized hot spot melting and not heating up of the interior

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

phosphate and feldspar mineralogy of equilibrated l chondrites the record of metasomatism during metamorphism in ordinary chondrite parent bodies in ordinary chondrites ocs phosphates and feldspar are secondary minerals known to be the products of parent body metamorphism both minerals provide evidence that metasomatic fluids played a role during metamorphism we studied the petrology and chemistry of phosphates and feldspar in petrologic type 4 6 l chondrites to examine the role of metasomatic fluids and to compare metamorphic conditions across all three oc groups apatite in l chondrites is cl rich similar to h chondrites whereas apatite in ll chondrites has lower cl f ratios merrillite has similar compositions among the three chondrite groups feldspar in l chondrites shows a similar equilibration trend to ll chondrites from a wide range of plagioclase compositions in petrologic type 4 to a homogeneous albitic composition in type 6 this contrasts with h chondrites which have homogeneous albitic plagioclase in petrologic types 4 6 alkali and halogen rich and likely hydrous metasomatic fluids acted during prograde metamorphism on oc parent bodies resulting in albitization reactions and development of phosphate minerals fluid compositions transitioned to a more anhydrous cl rich composition after the asteroid began to cool differences in secondary minerals between h and l ll chondrites can be explained by differences in fluid abundance duration or timing of fluid release phosphate minerals in the regolith breccia kendleton show lithology dependent apatite compositions bulk cl f ratios for ocs inferred from apatite compositions are higher than measured bulk chondrite values suggesting that bulk f abundances are overestimated and that bulk cl f ratios in ocs are similar to ci

exploring fractionation models for martian magmas 1 martian primary compositions i e magmas that did not experience fractionation and or contamination after extraction from the mantle occur as a subset of martian meteorites and a few lavas analyzed on the planet s surface by rovers eruptions of primary magmas are rare on earth and presumably on mars previous studies of fractional crystallization of martian primary magmas have been conducted under isobaric conditions simulating idealized crystallization in magma chambers polybaric fractionation which occurs during magma ascent has not been investigated in detail for martian magmas using the melts algorithm and the pmelts revision we present comprehensive isobaric and polybaric thermodynamic calculations of the fractional crystallization of four primary or parental martian magmas humphrey fastball y 980459 shergottite and nakhlite parental melts using various pressure temperature paths oxygen fugacities and water contents to constrain how these magmas might evolve we then examine whether known martian alkaline rock compositions could have formed through fractional crystallization of these magmas under the simulated conditions we find that isobaric and polybaric crystallization paths produce similar residual melt compositions but given sufficient details we may be able to distinguish between them we calculate that backstay gusev crater likely formed by fractionation of a primary magma under polybaric conditions while jake m gale crater may have formed through melting of a metasomatized mantle crustal assimilation or fractional crystallization of an unknown primary magma the best fits for the backstay composition indicate that consideration of polybaric crystallization paths can help improve the quality of fit when simulating liquid lines of descent

petrology on mars petrologic investigations of martian rocks have been accomplished by mineralogical geochemical and textural analyses from mars rovers with geologic context provided by orbiters and by laboratory analyses of martian meteorites igneous rocks are primarily lavas and volcaniclastic rocks of basaltic composition and ultramafic cumulates alkaline rocks are common in ancient terranes and tholeiitic rocks occur in younger terranes suggesting global magmatic evolution relatively uncommon feldspathic rocks represent the ultimate fractionation products and granitic rocks are unknown sedimentary rocks are of both clastic mudstone sandstone conglomerate all containing significant igneous detritus and chemical evaporitic sulfate and less common carbonate origin high silica sediments formed by hydrothermal activity sediments on mars formed from different protoliths and were weathered under different environmental conditions from terrestrial sediments metamorphic rocks have only been inferred from orbital remote sensing measurements metabasalt and serpentinite have mineral assemblages consistent with those predicted from low pressure phase equilibria and likely formed in geothermal systems shock effects are common in martian meteorites and impact breccias are probably widespread in the planet s crustal rocks the martian rock cycle during early periods was similar in many respects to that of earth however without plate tectonics mars did not experience the thermal metamorphism and flux melting associated with subduction nor deposition in subsided basins and rapid erosion resulting from tectonic uplift the rock cycle during more recent time has been truncated by desiccation of the planet s surface and a lower geothermal gradient in its interior the petrology of mars is intriguingly different from earth but the tried and true methods of petrography and geochemistry are clearly translatable to another world

seismicity in deep gold mines of south africa implications for tectonic earthquakes we have studied induced seismicity associated with five deep gold mines located in the far west rand district republic of south africa focusing on the digital data recorded from january 1994 until february 2000 by in mine arrays of three component geophones the observed seismicity which exceeds 1 000 events per day can be divided into two kinds of events designated as types a and b type a events are tightly clustered in time and space and generally occur within 100 m of an active mining face or development tunnel their spectra are comparatively enriched in high frequencies and they have an upper moment magnitude cutoff at mmax 1 we associate these events with the fracture dominated rupture of com petent rock induced by dynamic stresses during blasting and quasi static stress per turbations from the excavation and closure of individual stopes in contrast type b events are temporally and spatially distributed throughout the active mining region they represent friction dominated slip in existing shear zones such as faults or dikes and have source scaling properties that agree well with extrapolations from tectonic earthquakes in the far west rand region type b events can have large magnitudes m 3 but they show a distinct lower magnitude cutoff at mmin 0 we interpret this cutoff in terms of a critical patch size for nucleation of shear failure and we show that the data are consistent with a rate and state dependent friction model in which the critical slip distance d c 10 4 m both the spectral predictions of this model and accelerograms of type b events agree that f max 200 hz

microseismicity derived fault planes and their relationship to focal mechanism stress inversion and geologic data general stress and faulting trends have been retrieved through the analysis of mining induced microseismic events m 0 at two sites related to an mn 2 6 rockburst and an excavation at depth a comparison of results obtained through principal component analysis pca of seismicity focal mechanism and stress inversion with in situ measurements of stress and structural mapping data show that under stable stress conditions the p b t and stress inversion axes are consistent with in situ measurements of stresses stress inversion and pca fault planes lie within 10 to 20 of the most significant mapped features at the sites and the pca technique provides a robust approach for the determination of fault planes

resampling methods for evaluating the uncertainty of the nonparametric magnitude distribution estimation in the probabilistic seismic hazard analysis abstract the cumulative distribution function cdf of magnitude of seismic events is one of the most important probabilistic characteristics in probabilistic seismic hazard analysis psha the magnitude distribution of mining induced seismicity is complex therefore it is estimated using kernel nonparametric estimators because of its model free character the nonparametric approach cannot however provide confidence interval estimates for cdf using the classical methods of mathematical statistics to assess errors in the seismic events magnitude estimation and thereby in the seismic hazard parameters evaluation in the nonparametric approach we propose the use of the resampling methods resampling techniques applied to a one dataset provide many replicas of this sample which preserve its probabilistic properties in order to estimate the confidence intervals for the cdf of magnitude we have developed an algorithm based on the bias corrected and accelerated method bca method this procedure uses the smoothed bootstrap and second order bootstrap samples we refer to this algorithm as the iterated bca method the algorithm performance is illustrated through the analysis of monte carlo simulated seismic event catalogues and actual data from an underground copper mine in the legnica glogow copper district in poland the studies show that the iterated bca technique provides satisfactory results regardless of the sample size and actual shape of the magnitude distribution

the polymodal frequency magnitude relationship of earthquakes earthquake frequency magnitude relationships can be well described as a polymodal composite of normal distributions a pattern consistent with varying causal mechanisms in different tectonic settings and or magnitude ranges but a pattern also in conflict with the assumption of self similarity or the fractal nature of earthquakes from the giardini catalog 4660 deep 350 km worldwide earthquakes presumably homogeneous with respect to causal mechanism are well described as a single normally distributed population analysis of 10 341 earthquakes ranging in magnitude from 2 0 to 8 2 from the 1989 to 1991 national earthquake information center quick epicenter determination catalogue yields three populations each of whose magnitude frequency is expressed in terms of probability some nonsimilar frequency magnitude distributions for low magnitudes are also explicable as the result of one or more normally distributed populations in our model b is a measure of the dispersion of the population

a method for multidimensional analysis of earthquake frequency magnitude distribution with an application to the vrancea region of romania abstract a novel method is proposed for the time space analysis of the frequency magnitude distribution of earthquakes fmd the fmd is calculated using a non parametric technique based on the nearest neighbourhood statistics and the fmd parameters namely the occurrence rate at a reference magnitude and the b value are subsequently estimated by a parametric log linear regression the method s potential is examined by using a microearthquake catalogue of the intermediate depth h 60 km seismicity in the vrancea region romania spanning 18 yr for the magnitude intervals of ml 2 8 4 0 and 4 0 5 2 the calculated occurrence rates exhibited different linear decays with increasing magnitude on a log linear scale quasi linear correlations were found between the fmd parameters over selected time space intervals in several cases the results showed that changes in the b values were inversely related to changes in the occurrence rates of magnitudes at the limits of the first magnitude interval the three large events mw 7 reported in the catalogue were preceded by time space regions of relatively low b values lasting for a few years at the depth of these events three episodes of distinct behaviour were identified i b values are inversely related to changes in the occurrence rates of magnitudes at the limits of the first study range ml 2 8 and 4 0 ii a decrease in the b value occurs when an increase in the occurrence rate of relatively larger magnitude events ml 4 0 is observed iii the occurrence rate of larger events tends to saturate whereas the rate of small events tends to fluctuate the results suggest that multi dimensional b values and occurrence rates over selected magnitudes have the potential to outline characteristic trends in the recorded seismicity and provide relative constraints for the modelling of the earthquake cycle

the role of static stress transfer in mining induced seismic events occurrence a case study of the rudna mine in the legnica glogow copper district in poland summary seismicity accompanying mining exploitation results from changes in the stress field in the rock mass near the mining excavations caused by human activity many studies of the temporal and spatial distribution of mining induced seismicity have provided evidence for interrelations among events although a variety of techniques have been applied to quantify the interdependences of mining induced seismic events the physical mechanism of interactions has not been unequivocally identified based on the premise that one possible cause of interactions among seismic events can be static stress transfer we have verified statistically the role of coulomb stress transfer in the generation process of mining induced seismicity using a series of seismic

the abundance and isotopic composition of water in eucrites volatile elements play a key role in the dynamics of planetary evolution extensive work has been carried out to determine the abundance distribution and source s of volatiles in planetary bodies such as the earth moon and mars a recent study showed that the water in apatite from eucrites has similar hydrogen isotopic compositions compared to water in terrestrial rocks and carbonaceous chondrites suggesting that water accreted very early in the inner solar system given the ancient crystallization ages 4 5 ga of eucrites here the measurements of water reported as equivalent h2o abundances and the hydrogen isotopic composition d of apatite from five basaltic eucrites and one cumulate eucrite are reported apatite h2o abundances range from 30 to 3500 ppm and are associated with a weighted average d value of 34 67 no systematic variations or correlations are observed in h2o abundance or d value with eucrite geochemical trend or metamorphic grade these results extend the range of previously published hydrogen isotope data for eucrites and confirm the striking homogeneity in the h isotopic composition of water in eucrites which is consistent with a common source for water in the inner solar system

magnitude frequency relation for small earthquakes a clue to the origin of ƒmax of large earthquakes in order to test the hyothesis that the max of large earthquakes is due to the source effect and is causally related to the corner frequency of small earthquakes when it becomes constant below magnitude about 3 we constructed the frequency magnitude relation for earthquakes with magnitude range from 1 3 to 4 recorded at a borehole seismograph station operated by the university of southern california at baldwin hills in the middle of the newport inglewood fault a procedure was developed for an accurate estimation of moment magnitude from the measurement of coda amplitude as a function of lapse time the cumulative number of earthquakes per unit time period and area was estimated by finding the detection limit for ts p for each magnitude we found a clear depature of the observed log frequency magnitude relation for m 3 the observed frequency of earthquakes with m 0 5 is almost 10 times less than that expected from the extrapolation of empirical relation for earthquakes with magnitudes larger than 3 we conclude that the observed frequency magnitude relation departs from self similarity for earthquakes with magnitude smaller than about 3 this departure coincides with the widely observed departure of the moment corner frequency relation from self similarity these observations are consistent with the interpretation of max of large earthquakes in terms of the slip weakening instability model in which the critical slip may be a few tenths of a meter to a few meters and the cohesive zone size may be a few hundred meters to a few kilometers

insights into martian water reservoirs from analyses of martian meteorite que94201 the martian atmospheric d h value of 5 2 times terrestrial is significantly higher than any found on earth and has been ascribed to preferential loss of h relative to d from the atmosphere through jeans escape over time here based on ion microprobe analyses of apatite grains from martian meteorite que94201 it is shown that the pre jeans escape martian water reservoir has a d h value twice that of terrestrial water rather than the terrestrial value that has been assumed in prior work the data support a two stage history for martian volatiles in which early hydrodynamic escape enriched martian water to 2x terrestrial d h values subsequent jeans escape to produce the current atmospheric values has thus been responsible for less d enrichment than previously thought a martian crust containing 2 3 times more water than previously proposed is implied by the results

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

onset of solid state mantle convection and mixing during magma ocean solidification energy sources involved in the early stages of planetary formation can cause partial or even complete melting of the mantle of terrestrial bodies leading to the formation of magma oceans upon planetary cooling solidification is expected to take place from the bottom upwards because of the steeper slope of the liquid adiabat with respect to the liquidus elkins tanton 2012 solomatov 2015 fractional solidification in particular can lead to the formation of a compositional layering that can play a fundamental role for the subsequent long term dynamics and evolution of the interior tosi et al 2013 plesa et al 2014 in order to assess to what extent primordial compositional heterogeneities generated upon magma ocean solidification can be preserved we investigate the cooling and solidification of a whole mantle magma ocean along with the conditions that allow solid state convection to start mixing the mantle before solidification has completed to this end we run 2 d numerical simulations in cylindrical geometry using the finite volume code gaia huttig et al 2013 we treat the liquid magma ocean in a parametrized fashion while we self consistently solve the conservation equations of thermochemical convection in the growing solid mantle accounting for pressure temperature and melt dependent rheology we consider two end member cases fractional crystallization where melt is instantaneously extracted into the overlying liquid leaving beneath a differentiated mantle and batch crystallization where melt remains in contact with the silicate matrix throughout solidification causing no differentiation by testing the effects of different cooling rates and rayleigh numbers we show that for a lifetime of the liquid magma ocean between 1 and 10 myr lebrun et al 2013 the onset of solid state convection prior to complete mantle crystallization is possible and that part or even all of the compositional heterogeneities generated upon fractionation can be erased by efficient mantle stirring figure 1 we discuss the consequences of our findings in relation to the early and long term evolution of compositional heterogeneities generated via fractional crystallization of magma oceans in terrestrial bodies with emphasis on mars thermochemical history

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

core formation in earth s moon mars and vesta stimulated by new experimental results on metal silicate partitioning of elements at elevated temperatures and pressures we have revisited the question of core formation in earth s moon mars and vesta the probable source of the eucritic meteorites earlier studies suggested metal silicate equilibrium in mars but led to the paradox that mars accreted homogeneously while the earth accreted heterogeneously using new elevated pressure and temperature metal silicate partition coefficients we show that abundances of the moderately siderophile elements in the mantles of the moon mars and vesta are consistent with early magma oceans on these bodies the most successful model for explaining the lunar mantle siderophile element abundances requires a core of 5 of the mass of the moon 500 km radius siderophile element abundances in mars are consistent with intermediate pressure metal silicate equilibrium as has also been recently suggested for the earth the most successful model for explaining the martian siderophile element abundances requires a bulk planetary composition that has greater than ci chondritic abundances of the moderately siderophile elements and a core of 30 of the mass of mars siderophile element abundances in the mantle of vesta are consistent with low pressure liquid metal liquid silicate equilibrium as expected for an asteroid sized body and a core of 10 of the mass of vesta comparison of our best fit oxygen fugacities for vesta with thermodynamic calculations of oxygen fugacity for silicate bearing iron meteorites indicates that parts of the inner solar system were homogeneous with respect to redox state at 4 5 ga approximately 2 log fo2units below the fe feo buffer much higher than estimates for the solar nebula similar comparisons for mars and the earth indicate that these bodies have undergone oxidation since 4 5 ga because the oxygen fugacities associated with metal silicate equilibrium in both mars and the earth moon system are much lower than those recorded in martian and terrestrial basaltic and periodotitic samples the oxidation on mars is most likely due to atmospheric effects whereas earth s much wider range of oxygen fugacities must be due to both atmospheric and plate tectonic effects

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 age of the martian meteorite northwest africa 1195 and the differentiation history of the shergottites samarium neodymium isotopic analyses of unleached and acid leached mineral fractions from the recently identified olivine bearing shergottite northwest africa 1195 yield a crystallization age of 347 13 ma and an end143 value of 40 1 0 9 maskelynite fractions do not lie on the sm nd isochron and appear to contain a martian surface component with low 147sm 144nd and 143nd 144nd ratios that was added during shock the rb sr system is disturbed and does not yield an isochron terrestrial sr appears to have affected all of the mineral fractions although a maximum initial 87sr 86sr ratio of 0 7016 is estimated by passing a 347 ma reference line through the maskelynite fraction that is least affected by contamination the high initial end143 value and the low initial 87sr 86sr ratio combined with the geologically young crystallization age indicate that northwest africa 1195 is derived from a source region characterized by a long term incompatible element depletion the age and initial sr and nd isotopic compositions of northwest africa 1195 are very similar to those of queen alexandra range 94201 indicating these samples were derived from source regions with similar sr nd isotopic systematics these similarities suggest that these two meteorites share a close petrogenetic relationship and might have been erupted from a common volcano the meteorites yamato 980459 dar al gani 476 sayh al uhaymir 005 008 and dhofar 019 also have relatively old ages between 474 and 575 ma and trace element and or isotopic systematics that are indicative of derivation from incompatible element depleted sources this suggests that the oldest group of meteorites is more closely related to one another than they are to the younger meteorites that are derived from less incompatible element depleted sources closed system fractional crystallization of this suite of meteorites is modeled with the melts algorithm using the bulk composition of yamato 980459 as a parent these models reproduce many of the major element and mineralogical variations observed in the suite in addition the rare earth element systematics of these meteorites are reproduced by fractional crystallization using the proportions of phases and extents of crystallization that are calculated by melts other shergottites that demonstrate enrichments in incompatible elements and have evolved sr and nd isotopic systematics have some geochemical systematics that are similar to those observed in the depleted group most notably although they exhibit a very limited range of incompatible trace element and isotopic compositions they have highly variable major element compositions this is also consistent with evolution from a common mantle source region by variable amounts of fractional crystallization if this scenario is correct it suggests that the combined effects of source composition and fractional crystallization are likely to account for the major element trace element and isotopic diversity of all shergottites

fracture coalescence as a mechanism for earthquakes observations based on mining induced microseismicity abstract microseismic events with magnitudes less than zero recorded within a volume at depth in an underground mine are used to evaluate failure conditions associated with a magnitude 2 9 event rockburst the approach incorporated several independent methods of analysis including the principal component analysis pca of seismicity focal mechanisms stress inversion underground in situ stress measurements and structural mapping and three dimensional numerical modelling derived stresses a good correlation was found between stress inversion and pca derived microseismic failure planes and structural mapping and between the in situ principal stress orientations and those obtained through stress inversion and numerical modelling a few days prior to the large event and during the aftershock sequence a change in microseismic failure plane orientation to a shallower dip angle than mapped underground was found to coincide with the numerical modelling derived plane of maximum slip potential this orientation along with measured fracture characteristics persistence and spacing and an increase in event clustering into the plane suggests that the formation of the large event plane of rupture was likely related to the coalescence of mapped fractures an observed reduction in stress release accompanying the increased tendency towards planarity prior to the large event indicates that the development of a large rupture surface occurred under an increased effective shear stress build up as part of the earthquake generation process and the process of coalescence can be considered as the breakage of barriers new fracture growth accompanied by an increase in the effective shear stress on the remaining asperities pre existing fractures

a reinterpretation of the precursory seismic b value anomaly from fracture mechanics summary a new model is presented which can explain the major temporal fluctuations in seismic b value in terms of the underlying physical processes of time varying applied stress and crack growth under conditions of constant strain rate the model predicts two minima in the b value separated by a temporary maximum of inflexion point a corollary being that a single broad maximum would be expected in scattering attenuation these fluctuations in b value are consistent with reported intermediate term and short term earthquake precursors separated by a period of seismic quiescence we present preliminary results from controlled laboratory experiments and report recent field observations both of which are consistent with the predicted form and in particular exhibit the distinctive second short term anomaly which reaches a value bc 0 5 during the critical phase

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

techniques and parameters to analyze seismicity patterns associated with large earthquakes a pattern recognition algorithm is developed to provide potential improvements over existing earthquake prediction practices the parameters employed in the analysis include degree of spatial nonrandomness in two distance ranges spatial correlation dimension spatial repetitiveness of earthquakes with a similar size average depth of events time interval for the occurrence of a constant number of events and ratio of the numbers of events in two magnitude intervals the parameter temporal variations are compared quantitatively with the time series of large events using a technique of association in time the significance of the association frequencies is evaluated by comparison with chance associations estimated from corresponding simulated random time series the developed techniques differ from existing approaches in the following aspects the parameters here emphasize the spatial distribution of earthquakes possible correlations among the parameters are evaluated to determine the final set of parameters to be monitored threshold values for the assumed anomalies are chosen with consideration of properties of the available earthquake catalogs such as the number of large events to be retrospectively predicted equal weight is given to both locally high and locally low parameter values care is taken to distinguish between anomalies preceding large events and those following previous events it is shown that the relationship between precursory local extrema and precursory trends is nonunique with precursory local extrema of the same type frequently associated with opposite observable precursory trends the application of the seismicity parameters and pattern recognition techniques is demonstrated using synthetic earthquake catalogs generated by models of segmented fault systems in a three dimensional elastic solid ben zion 1996

the magnitude frequency distribution of earthquakes recorded with deep seismometers at cajon pass southern california abstract the cumulative b value the slope of the gutenberg richter relationship between earthquake occurrence rate and magnitude is commonly found to be constant 1 network catalogues however reveal a decrease at small magnitudes b value is not just an artifact of catalogue incompleteness but that small earthquakes are really not as numerous as a constant b value extrapolated from larger events would predict in the cajon pass area southern california the b value of seismicity recorded by the local network scsn appears to decrease below about m l 1 6 in order to investigate whether this decrease is real or simply represents the network detection threshold we use seismicity recorded by the deep 1 5 and 2 5 km seismometers deployed in the cajon pass scientific drillhole between april 1992 and october 1994 the maximum amplitudes recorded downhole are compared to scsn magnitudes for events recorded by the network to determine the relationship between amplitude and m l as a function of hypocentral distance from the borehole magnitudes are then calculated for 1300 earthquakes which occurred within 40 km of the borehole magnitude frequency curves are calculated for those events within 18 km of the borehole and a constant b value is observed to m l 0 5

copper enrichments in the kimberley formation in gale crater mars evidence for a cu deposit at the source copper quantification with laser induced breakdown spectroscopy libs using a univariate calibration model enables the chemcam instrument onboard the curiosity rover to measure unusually elevated cu concentrations in potassic sandstones and mn oxide bearing fracture fills in the kimberley region of gale crater mars mostly the copper phases occurring in sedimentary bedrock are associated with detrital silicates including feldspars pyroxenes and k phyllosilicates likely coming from a potassic igneous source near the northern crater rim while those present in the fractures are likely adsorbed on the surface of manganese oxides these two different mineralogical associations imply at least two distinct processes cu enrichment in bedrock at the source likely during crystallization of the igneous silicates and adsorption of cu on mn oxides precipitated from groundwater that encountered oxidizing conditions within fractures in the bedrock the potassic sediments enriched in copper may be evidence of a porphyry copper deposit or an impact induced hydrothermal deposit in the source region

apatites in lunar kreep basalts the missing link to understanding the h isotope systematics of the moon recent re analyses of lunar samples have undoubtedly measured indigenous water challenging the paradigm of a dry moon and arguing that some portions of the lunar interior are as wet as some regions of the earth s mantle and that water in both planetary bodies likely share a common origin mare basalts indirectly sample the lunar mantle and are affected by petrogenetic processes such as crystallization and degassing that can modify characteristics of indigenous water in primary mantle melts analyses of apatite in phosphorus rich kreep k ree rare earth elements p basalts may provide more reliable estimates for the water content of lunar magmas as some apatites likely crystallized before substantial degassing occurred in lunar kreep basalt sample 15386 apatite h 2 o content and h isotopic composition suggest that degassing occurred during apatite crystallization the lowest d value of 90 100 representing an upper limit for the isotopic composition of water in the parental magma interpretation of the data for kreep basalt 15386 suggests that this basalt is characterized by relatively elevated h 2 o contents and ci chondrite type d values similar to those proposed for other mare basalts and pyroclastic glasses on the other hand most of the apatites in lunar kreep basalt 72275 and lunar meteorite nwa 773 crystallized before degassing and h isotope fractionation and their d h ratios thus directly refl ect those of their source regions these apatites have an average d value of 130 50 suggesting the presence of a water reservoir in the moon characterized by moderate h 2 o contents and h isotopic composition similar to that of earth s interior these fi ndings imply that signifi cant amounts of water in the moon were inherited from the proto earth surviving the purported moon forming impact event

combining meteorites and missions to explore mars laboratory studies of meteorites and robotic exploration of mars reveal scant atmosphere no evidence of plate tectonics past evidence for abundant water and a protracted igneous evolution despite indirect hints direct evidence of a martian origin came with the discovery of trapped atmospheric gases in one meteorite since then the study of martian meteorites and findings from missions have been linked although the meteorite source locations are unknown impact ejection modeling and spectral mapping of mars suggest derivation from small craters in terrains of amazonian to hesperian age whereas most martian meteorites are young 4 5 ga and formation of enriched and depleted reservoirs however the history inferred from martian meteorites conflicts with results from recent mars missions calling into doubt whether the igneous histor y inferred from the meteorites is applicable to mars as a whole allan hills 84001 dates to 4 09 ga and contains fluid deposited carbonates accompanying debate about the mechanism and temperature of origin of the carbonates came several features suggestive of past microbial life in the carbonates although highly disputed the suggestion spurred interest in habitable extreme environments on earth and throughout the solar system a flotilla of subsequent spacecraft has redefined mars from a volcanic planet to a hydrologically active planet that may have harbored life understanding the history and habitability of mars depends on understanding the coupling of the atmosphere surface and subsurface sample return that brings back direct evidence from these diverse reservoirs is essential

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

the origin of alteration orangettes in dhofar 019 implications for the age and aqueous history of the shergottites the shergottites are the largest group of martian meteorites and the only group that has not been found to contain definitive evidence of martian aqueous alteration given recent reports of current liquid water at the surface of mars this study aimed to investigate in detail the possibility of martian phyllosilicate within shergottite dhofar 019 optical and scanning electron microscopy followed by transmission electron microscopy confirmed the presence of alteration orangettes with a layered structure consisting of poorly ordered mg phyllosilicate and calcite these investigations identified maskelynite dissolution followed by mg phyllosilicate and calcite deposition within the dissolution pits as the method of orangette production the presence of celestine within the orangette layers the absence of shock dislocation features within calcite and the mg rich nature of the phyllosilicate all indicate a terrestrial origin for these features on dhofar 019

non similar frequency magnitude distribution for m 1 seismicity a series of 1503 induced seismic events ranging in magnitude from 2 to 1 as computed based on a locally calibrated seismic moment scale were located within a well defined volume at depth the seismicity analysis was carried out over 2 months and included events recorded before during and following the after shock period of a mn 2 6 rockburst a non similar pattern was clearly apparent for both cumulative and non cumulative frequency magnitude distributions showing a relative enhancement of seismicity between magnitudes 0 5 and 0 this supports the existence of non similar scaling at these magnitudes the time variation of the b value as computed for a limited self similar magnitude domain 1 1 to 0 4 did not appear to be related to the rockburst instead it is suggested that the rockburst perturbed the local stress field and consequently the distribution of the very small events no correlations were found between b and space clustering

phosphate minerals in the h group of ordinary chondrites and fluid activity recorded by apatite heterogeneity in the zag h3 6 regolith breccia phosphate minerals in ordinary chondrites provide a record of fluids that were present during metamorphic heating of the chondrite parent asteroids we have carried out a petrographic study of the phosphate minerals merrillite and apatite in metamorphosed h group ordinary chondrites of petrologic type 4 6 to understand development of phosphate minerals and associated fluid evolution during metamorphism in unbrecciated chondrites apatite is cl rich and shows textural evolution from fine grained apatite merrillite assemblages in type 4 toward larger uniform grains in type 6 the cl f ratio in apatite shows a similar degree of heterogeneity in all petrologic types and no systematic change in compositions with metamorphic grade which suggests that compositions in each meteorite are dictated by localized conditions possibly because of a limited fluid rock ratio the development of phosphate minerals in h chondrites is similar to that of l and ll chondrites despite the fact that feldspar equilibration resulting from albitization is complete in h4 chondrites but not in l4 or ll4 chondrites this suggests that albitization took place during an earlier period of the metamorphic history than that recorded by preserved apatite compositions and chemical equilibrium was not achieved throughout the h chondrite parent body or bodies during the late stages of metamorphism a relict igneous clast in the h5 chondrite oro grande has apatite rims on relict phenocrysts of possibly diopside that have equilibrated with the host chondrite apatite in the zag h3 6 regolith breccia records a complex fluid history which is likely related to the presence of halite in this meteorite the porous dark h4 matrix of zag where halite is observed has a high apatite merrillite ratio and apatite is extremely cl rich one light h6 clast contains similarly cl rich apatite in a second light h6 clast apatite compositions are very heterogeneous and more f rich apatites in both h4 matrix and h6 clasts have very low h 2o contents heterogeneous apatite compositions in zag record multiple stages of regolith processing and shock at the surface of the h chondrite parent body and apatite records either the passage of fluids of variable compositions resulting from different impact related processes or the passage of a single fluid whose composition evolved as it interacted with the chondrite regolith unraveling the history of apatite can potentially help to interpret the internal structure of chondrite parent bodies with implications for physical and mechanical properties of chondritic asteroids the behavior of halogens recorded by apatite is important for understanding the behavior of volatile elements in general if impact melt materials close to the surface of a chondritic asteroid are readily degassed the volatile inventories of terrestrial planets could be considerably more depleted than the ci carbonaceous chondrite abundances that are commonly assumed

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

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

meteoritic evidence for a previously unrecognized hydrogen reservoir on mars abstract fluvial landforms on mars suggest that it was once warm enough to maintain persistent liquid water on its surface the transition to the present cold and dry mars is closely linked to the history of surface water yet the evolution of surficial water is poorly constrained based on in situ hydrogen isotope d h analyses of quenched and impact glasses in martian meteorites we provide evidence for the existence of a distinct but ubiquitous water ice reservoir d h 2 3 times earth s ocean water that lasted from at least the time when the meteorites crystallized 173 472 million years ago to the time they were ejected by impacts 0 7 3 3 million years ago but possibly much longer the origin of this reservoir appears to predate the current martian atmospheric water d h 5 6 times earth s ocean water and is unlikely to be a simple mixture of atmospheric and primordial water retained in the martian mantle d h earth s ocean water this reservoir could represent hydrated crust and or ground ice interbedded within sediments our results corroborate the hypothesis that a buried cryosphere accounts for a large part of the initial water budget of mars

a geophysical perspective on the bulk composition of mars we invert the martian tidal response and mean mass and moment of inertia for chemical composition thermal state and interior structure the inversion combines phase equilibrium computations with a laboratory based viscoelastic dissipation model the rheological model which is based on measurements of anhydrous and melt free olivine is both temperature and grain size sensitive and imposes strong constraints on interior structure the bottom of the lithosphere defined as the location where the conductive geotherm meets the mantle adiabat occurs deep within the upper mantle 250 500 km depth resulting in apparent upper mantle low velocity zones assuming an fe fes core our results indicate 1 a mantle with a mg molar mg mg fe of 0 75 in agreement with earlier geochemical estimates based on analysis of martian meteorites 2 absence of bridgmanite and ferropericlase dominated basal layer 3 core compositions 13 5 16 wt s core radii 1640 1740 km and core mantle boundary temperatures 1560 1660 c that together with the eutectic like core compositions suggest the core is liquid and 4 bulk martian compositions that are overall chondritic with a fe si wt ratio of 1 63 1 68 we show that the inversion results can be used in tandem with geodynamic simulations to identify plausible geodynamic scenarios and parameters specifically we find that the inversion results are reproduced by stagnant lid convection models for a range of initial viscosities 1019 1020 pa s and radioactive element partitioning between crust and mantle around 0 001 the geodynamic models predict a mean surface heat flow between 15 25 mw m2

partitioning of light lithophile elements during basalt eruptions on earth and application to martian shergottites an enigmatic record of light lithophile element lle zoning in pyroxenes in basaltic shergottite meteorites whereby lle concentrations decrease dramatically from the cores to the rims has been interpreted as being due to partitioning of lle into a hydrous vapor during magma ascent to the surface on mars these trends are used as evidence that martian basaltic melts are water rich mcsween et al 2001 lithium and boron are light lithophile elements lle that partition into volcanic minerals and into vapor from silicate melts making them potential tracers of degassing processes during magma ascent to the surface of earth and of other planets while lle degassing behavior is relatively well understood for silica rich melts where water and lle concentrations are relatively high very little data exists for lle abundance heterogeneity and degassing in basaltic melts the lack of data hampers interpretation of the trends in the shergottite meteorites through a geochemical study of lle volatile and trace elements in olivine hosted melt inclusions from kilauea volcano hawaii it can be demonstrated that lithium behaves similarly to the light to middle rare earth elements during melting magma mixing and fractionation considerable heterogeneity in lithium and boron is inherited from mantle derived primary melts which is dominant over the fractionation and degassing signal lithium and boron are only very weakly volatile in basaltic melt erupted from kilauea volcano with vapor melt partition coefficients 4 wt the observed terrestrial lle partitioning behavior is extrapolated to martian primitive melts through modeling the zoning observed in the shergottite pyroxenes is only consistent with degassing of lle from a martian melt near its liquidus temperature if the vapor melt partition coefficient was an order of magnitude larger than observed on earth the range in lle and trace elements observed in shergottite pyroxenes are instead consistent with concurrent mixing and fractionation of heterogeneous melts from the mantle

geochemistry of martian basalts with constraints on magma genesis abstract over the past decade our knowledge of the geochemical and mineralogical diversity of martian rocks has greatly increased rocks on the surface of mars are older than most martian meteorites and have a wider range in bulk chemistry higher sio 2 higher total alkalis and lower mgo contents recent martian meteorite discoveries nwa 7034 nwa 7635 and nwa 8159 are also significantly older than the shergottites and nwa 7034 contains clasts which have a similar range in chemistry of the surface basalts in this invited review i summarize what is known about the bulk chemistry major elements of martian igneous rocks and use the chemistry to constrain the formation conditions in the interior and how these conditions have changed through time the basalts at gale crater are consistent with forming from a metasomatized mantle source which affected not only the chemistry of the basalts but also the formation conditions basalts at gusev crater bounce rock at meridiani planum and those basalts not affected by metasomatism like those at gale crater have a mantle potential temperature of 1450 c for the noachian conversely martian shergottites have a much higher mantle potential temperature 1745 c which has always been problematic to explain for such young rocks new formation conditions calculations are consistent with previous models of formation by a hot mantle plume but solve the pressure of formation paradox from the previous model combining the calculations for mantle potential temperature with previous estimates for grs measurements of surface volcanics from the hesperian and amazonian i calculate a baseline cooling curve and mantle melting conditions for the martian interior through time

inventory of h2o in the ancient martian regolith from northwest africa 7034 the important role of fe oxides water rich martian regolith breccia northwest africa nwa 7034 was analyzed by fourier transform infrared spectroscopy and transmission electron microscopy to determine the inventory and phase distribution of h2o used herein to refer to both molecular h2o and oh structural components in hydrous minerals hydrous fe oxide phases hydromaghemite and an unidentified nanocrystalline fe bearing oxide phase observed with hydromaghemite and phyllosilicates saponite were identified as the primary mineralogic hosts for h2o with a minor contribution from cl rich apatite based on mass balance calculations and modal abundances of minerals constrained by powder x ray diffraction and petrography we can account for the entire 6000 ppm h2o measured in bulk rock analyses of nwa 7034 this h2o is distributed evenly between hydrous fe rich oxides and phyllosilicates indicating that fe oxides could be as important as phyllosilicates for h2o storage in martian surface material

geochemical evidence for magmatic water within mars from pyroxenes in the shergotty meteorite observations of martian surface morphology have been used to argue that an ancient ocean once existed on mars1 it has been thought that significant quantities of such water could have been supplied to the martian surface through volcanic outgassing but this suggestion is contradicted by the low magmatic water content that is generally inferred from chemical analyses of igneous martian meteorites2 here however we report the distributions of trace elements within pyroxenes of the shergotty meteorite a basalt body ejected 175 million years ago from mars3 as well as hydrous and anhydrous crystallization experiments that together imply that water contents of pre eruptive magma on mars could have been up to 1 8 we found that in the shergotty meteorite the inner cores of pyroxene minerals which formed at depth in the martian crust are enriched in soluble trace elements when compared to the outer rims which crystallized on or near to the martian surface this implies that water was present in pyroxenes at depth but was largely lost as pyroxenes were carried to the surface during magma ascent we conclude that ascending magmas possibly delivered significant quantities of water to the martian surface in recent times reconciling geologic and petrologic constraints on the outgassing history of mars

evidence for the exsolution of cl rich fluids in martian magmas apatite petrogenesis in the enriched lherzolitic shergottite northwest africa 7755 abstract martian meteorite northwest africa 7755 is a new example of an enriched lherzolitic shergottite containing some of the coarsest grained apatite yet identified in shergottite meteorites their size has permitted detailed observations of volatile distributions within single grains we have demonstrated that some apatites have been invaded by shock melts which act to devolatilize parts of grains resulting in significant cl enrichment in the adjacent regions the extent of chemical heterogeneity within single grains must be carefully considered in other shergottites so that the effects of secondary modification of apatites are well constrained prior to interpreting the volatile contents and primary magmatic processes apatite grains unaffected by shock melts are oh f enriched and cl poor f 50 cl 14 oh 36 relative to interstitial apatites reported in other shergottites the volatile compositions are similar to interstitial apatites reported in terrestrial mafic intrusions such apatites in terrestrial intrusions are argued to have formed after significant cl loss due to the exsolution and migration of cl rich brines calculated relative f 2 cl 2 and h 2 o fugacities for nwa 7755 apatites show a trend of degassing rather than fractionation noted in previous studies indeed we interpret the volatile contents of apatites analyzed in the cumulate shergottite nwa 7755 to represent snapshots of the evolving late stage residual liquid during exsolution of a cl rich brine this fluid phase has subsequently been lost from an open magma system migrating upward through the cumulate sequence enriching residual liquids in cl alternatively it formed a hydrothermal system in the martian crust surrounding the intrusion furthermore by comparison with terrestrial examples we suggest that the late stage evolution of volatile bearing phases in nwa 7755 is similar to that of comparable terrestrial mafic rocks primary cumulus apatites are f rich whereas interstitial apatites may be either cl rich forming as a result of modification through the interaction with cl rich brines or oh f rich forming from a magma having exsolved or degassed a cl rich fluid phase

lithium systematics in howardite eucrite diogenite meteorites implications for crust mantle evolution of planetary embryos we present lithium li abundances and isotope compositions in a suite of howardites eucrites and diogenites heds these meteorites most likely originated from asteroid vesta and were delivered to earth by a series of independent impact events the li concentrations show striking differences between li poor diogenites plus cumulate eucrites and li enriched eucrites whilst howardites have li abundances intermediate between eucrites and diogenites contrary to li elemental inter group differences li isotope compositions are irresolvable among these individual groups of hed meteorites despite their wildly distinct petrography attesting to insignificant li isotope fractionation during formation of a thick basaltic crust by melting of the vestan mantle the mean li isotope composition of bulk silicate vesta is estimated at 3 7 0 6 1 intermediate to that of the earth versus mars and moon but identical with these terrestrial bodies within uncertainty this further validates largely homogeneous inner solar system solids from the li isotope perspective and supports the lack of loss of moderately volatile elements from planetary embryos during their magmatic histories because li does not follow depletion trends inferred from more volatile elements pasamonte eucrite has the same li isotope composition as other eucrites although it may not be directly linked to vesta these observations are also important for generating li elemental and isotope signatures in juvenile basaltic crusts of large terrestrial planets and numerous planetary embryos in the early solar system a combination of cv l chondrites may be less suitable for building vesta from li perspective but this may face sampling bias of available data and only further analyses may resolve this issue alternatively significant shift of 1 towards heavier li isotope compositions must have occurred during thermal processing of cv l 2 2 2 8 mixture in order to account for the observed li isotope systematics in hed meteorites no correlation is observed between li versus zn fe or si isotopes respectively implying unrelated processes of forming stable isotope variations observed in hed meteorites

diatoms as indicators of sedimentary processes in burrinjuck reservoir new south wales australia abstract a combination of high and low resolution diatom analysis conducted on a transect of five sediment cores from the downstream section of burrinjuck reservoir southern new south wales australia has revealed that despite complex sedimentation patterns there are precise correlations between diatom stratigraphies spatially dependent variation in diatom sedimentation exists particularly that resulting from density current deposition however sediments deposited in this manner are readily identified from the diatom records the nature of diatom species assemblages and their variability aid in the identification of sediment provenance and the temporal resolution of individual samples respectively the results of this study which provide a complement to other research on the reservoir should in particular allow for more accurate reconstructions of the history of nutrient concentrations in and sediment yield to the reservoir

anhydrous liquid line of descent of yamato 980459 and evolution of martian parental magmas we report the results of nominally anhydrous equilibrium and fractional crystallization experiments on a synthetic yamato 980459 y98 bulk composition at 0 5 gpa these experiments allow us to test a suggested fractional crystallization model calculated using melts by symes et al 2008 in which a y98 like initial liquid yielded a magma closely resembling the bulk composition of que 94201 although the two meteorites cannot be cogenetic owing to their age difference they are thought to represent bona fide magmatic liquids rather than products of crystal accumulation as are most martian basaltic meteorites hence understanding possible petrogenetic links between these types of liquids could be revealing about processes of melting and crystallization that formed the range of martian basalts we find that y98 can in fact generate a residual liquid closely resembling que but only after a very different crystallization process and different degree of crystallization than that modeled using melts in addition both the identity and sequence of crystallizing phases are very different between model and experiments our fractional crystallization experiments do not produce a que like liquid and the crystallizing phases are an even poorer match to the melts calculated compositions than in the equilibrium runs however residual liquids from our experiments define a liquid line of descent that encompasses bulk compositions of parental melts calculated for several martian basaltic meteorites suggesting that the known martian basaltic meteorites had their ultimate origin from the same or very similar source lithologies these are in turn similar to source rocks modeled by previous studies as products of extensive crystallization of an initial martian magma ocean

petrogenesis of the nwa 7320 enriched martian gabbroic shergottite insight into the martian crust northwest africa nwa 7320 is classified as a gabbroic shergottite the second to be recognized in the martian meteorite record this interpretation is based on 1 the calculated bulk rock rare earth element ree concentrations which show the highest eu positive anomaly eu eu 2 2 of all the shergottites reflecting accumulation of plagioclase and 2 the highest modal abundance of maskelynitized plagioclase 50 mod compared to the other shergottites the three phase symplectite fayalite hedenbergite silica is present in nwa 7320 and formed as a result of the breakdown of metastable pyroxene pyroxenoid margins on coarse grained pyroxenes the latter is indicative of metastable overgrowths on pyroxene cores during the final stages of crystallization followed by relatively slow cooling at subsolidus conditions the nwa 7320 parental melt originated from an incompatible trace element enriched and oxidized fmq source as indicated by sm nd lu hf isotope systematics ilmenite titanomagnetite pairs the partition coefficient of cr in pyroxene and merrillite ree compositions the ti al ratio of pyroxene in nwa 7320 indicates an initial crystallization depth of 30 70 km p 4 9 kbar however the largest impact craters on mars are 8 km in depth indicating that nwa 7320 could not have been ejected from this depth and must have had a polybaric formation history we suggest that the pyroxene phenocrysts began to crystallize at depth but were entrained as antecrysts in a basaltic magma ascending to shallower levels in the martian crust in addition plagioclase likely crystallized during magma ascent followed by subsequent accumulation in a shallow magma intrusion or sill resulting in the gabbroic texture furthermore the similarity in the radiogenic isotope composition of nwa 7320 to that of los angeles and nwa 856 suggest that these meteorites were linked to common volcanic system on mars

petrography and composition of martian regolith breccia meteorite northwest africa 7475 the northwest africa nwa 7475 meteorite is one of the several stones of paired regolith breccias from mars based on petrography oxygen isotope mineral compositions and bulk rock compositions its inventory of lithic clasts is dominated by vitrophyre impact melts that were emplaced while they were still molten other clast types include crystallized impact melt rocks evolved plutonic rocks possible basalts contact metamorphosed rocks and siltstones impact spherules and vitrophyre shards record airborne transport and accreted dust rims were sintered on most clasts presumably during residence in an ejecta plume the clast assemblage records at least three impact events one that formed an impact melt sheet on mars 4 4 ga ago a second that assembled nwa 7475 from impactites associated with the impact melt sheet at 1 7 1 4 ga and a third that launched nwa 7475 from mars 5 ma ago mildly shocked pyroxene and plagioclase constrain shock metamorphic conditions during launch to 5 and 15 gpa the mild postshock heating that resulted from these shock pressures would have been insufficient to sterilize this water bearing lithology during launch magnetite maghemite and pyrite are likely products of secondary alteration on mars textural relationships suggest that calcium carbonate and goethite are probably of terrestrial origin yet trace element chemistry indicates relatively low terrestrial alteration comparison of mars odyssey gamma ray spectrometer data with the fe and th abundances of nwa 7475 points to a provenance in the ancient southern highlands of mars gratteri crater with an age of 5 ma and an apparent diameter of 6 9 km marks one possible launch site of nwa 7475

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

water undersaturated mantle plume volcanism on present day mars based on meteorite evidence the present day martian mantle has a combined abundance of up to a few hundred ppm of h2o cl and f which lowers the solidus and enhances the magma production rate adiabatic decompression melting in upwelling mantle plumes is the best explanation for young last 200 myr volcanism on mars we explore water undersaturated mantle plume volcanism using a finite element mantle convection model coupled to a model of hydrous peridotite melting relative to a dry mantle the reduction in solidus temperature due to water increases the magma production rate by a factor of 1 3 1 7 at 50 ppm water and by a factor of 1 9 3 2 at 200 ppm water mantle water also decreases the viscosity and increases the vigor of convection which indirectly increases the magma production rate by thinning the thermal boundary layer and increasing the flow velocity at conditions relevant to mars these indirect effects can cause an order of magnitude increase in the magma production rate using geologic and geophysical observations of the late amazonian magma production rate and geochemical observations of melt fractions in shergottite meteorites present day mars is constrained to have a core mantle boundary temperature of 1750 to 1800 c and a volume averaged thermal rayleigh number of 2 106 to 107 indicating that moderately vigorous mantle convection has persisted to the present day melting occurs at depths of 2 5 6 gpa and is controlled by the rayleigh number at the low pressure end and by the mantle water concentration at high pressure

in search for a relationship between induced microseismicity and larger events in mines abstract pattern recognition techniques are applied to mining induced seismicity data to evaluate the association between microearthquakes and larger events the example given is from creighton mine ontario canada owned by inco ltd more than 20 000 events are studied for the 3 month period october december 1992 within a volume of size 400 400 180 m3 the temporal changes in three parameters based on event locations and occurrence times are calculated two of the parameters characterize the spatial distribution of microearthquakes they include the degree of non randomness over the distance range 0 75 m and the correlation dimension over the distance range 30 120 m both describing the degree of spatial clustering of events the third parameter describes the temporal distribution and represents the time interval for occurrence of a constant number of events thus being opposite to the seismicity rate the time series of these parameters are compared quantitatively with the times of larger events through a specific technique of association in time the significance of association is evaluated using randomly simulated time series the results from this study indicate the existence of significant association of local extrema in the study parameters and the times of occurrence of larger events in particular precursory minima in the spatial clustering and seismicity rates are observed these are however not uniquely related to the observable precursory trends that depend on the time elapsed from the occurrence of local extrema to the impending larger events thus precursory seismic quiescence decreasing values is more readily observable in the seismicity rates but both decreasing and increasing spatial clustering can be seen prior to larger events

hydrogen isotopic composition of the martian mantle inferred from the newest martian meteorite fall tissint the hydrogen isotopic composition of planetary reservoirs can provide key constraints on the origin and history of water on planets the sources of water and the hydrological evolution of mars may be inferred from the hydrogen isotopic compositions of mineral phases in martian meteorites which are currently the only samples of mars available for earth based laboratory investigations previous studies have shown that d values in minerals in the martian meteorites span a large range of 250 to 6000 the highest hydrogen isotope ratios likely represent a martian atmospheric component either interaction with a reservoir in equilibrium with the martian atmosphere such as crustal water or direct incorporation of the martian atmosphere due to shock processes the lowest d values may represent those of the martian mantle but it has also been suggested that these values may represent terrestrial contamination in martian meteorites here we report the hydrogen isotopic compositions and water contents of a variety of phases merrillites maskelynites olivines and an olivine hosted melt inclusion in tissint the latest martian meteorite fall that was minimally exposed to the terrestrial environment we compared traditional sample preparation techniques with anhydrous sample preparation methods to evaluate their effects on hydrogen isotopes and find that for severely shocked meteorites like tissint the traditional sample preparation techniques increase water content and alter the d h ratios toward more terrestrial like values in the anhydrously prepared tissint sample we see a large range of d values most likely resulting from a combination of processes including magmatic degassing secondary alteration by crustal fluids shock related fractionation and implantation of martian atmosphere based on these data our best estimate of the d value for the martian depleted mantle is 116 94 which is the lowest value measured in a phase in the anhydrously prepared section of tissint this value is similar to that of the terrestrial upper mantle suggesting that water on mars and earth was derived from similar sources the water contents of phases in tissint are highly variable and have been affected by secondary processes considering the h2o abundances reported here in the driest phases most likely representing primary igneous compositions and appropriate partition coefficients we estimate the h2o content of the tissint parent magma to be 0 2 wt

petrology and trace element geochemistry of tissint the newest shergottite fall the fall and recovery of the tissint meteorite in 2011 created a rare opportunity to examine a martian sample with a known short residence time on earth tissint is an olivine phyric shergottite that accumulated olivine antecrysts within a single magmatic system coarse olivine grains with nearly homogeneous cores of mg 80 suggest slow re equilibration many macroscopic features of this sample resemble those of lar 06319 including the olivine crystal size distribution and the presence of evolved oxide and olivine compositions unlike lar 06319 however no magmatic hydrous phases were found in the analyzed samples of tissint minor and trace element compositions indicate that the meteorite is the product of closed system crystallization from a parent melt derived from a depleted source with no obvious addition of a lree rich crustal component prior to or during crystallization the whole rock ree pattern is similar to that of intermediate olivine phyric shergottite eeta 79001 lithology a and could also be approximated by a more olivine rich version of depleted basaltic shergottite que 94201 magmatic oxygen fugacities are at the low end of the shergottite range with log fo2 of qfm 3 5 to 4 0 estimated based on early crystallized minerals and qfm 2 4 estimated based on the eu in pyroxene oxybarometer these values are similarly comparable to other depleted shergottites including sau 005 and que 94201 tissint occupies a previously unsampled niche in shergottite chemistry containing olivines with mg 80 resembling the enriched olivine phyric shergottite lar 06319 in its crystallization path and comparable to intermediate olivine phyric shergottite eeta 79001a depleted olivine phyric shergottite dag 476 and depleted basaltic shergottite que 94201 in its trace element abundances and oxygen fugacity the apparent absence of evidence for terrestrial alteration in tissint particularly in trace element abundances in the whole rock and individual minerals confirms that exposure to the arid desert environment results in only minimal weathering of samples provided the exposure times are brief

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

the age of dar al gani 476 and the differentiation history of the martian meteorites inferred from their radiogenic isotopic systematics samarium neodymium isotopic analysis of the martian meteorite dar al gani 476 yields a crystallization age of 474 11 ma and an initial end143 value of 36 6 0 8 although the rb sr isotopic system has been disturbed by terrestrial weathering and therefore yields no age information an initial 87sr 86sr ratio of 0 701249 33 has been estimated using the rb sr isotopic composition of the maskelynite mineral fraction and the sm nd age the sr and nd isotopic systematics of dar al gani 476 like those of the basaltic shergottite que94201 are consistent with derivation from a source region that was strongly depleted in incompatible elements early in the history of the solar system nevertheless dar al gani 476 is derived from a source region that has a slightly greater incompatible enrichment than the que94201 source region this is not consistent with the fact that the parental magma of dar al gani 476 is significantly more mafic than the parental magma of que94201 and underscores a decoupling between the major element and trace element isotopic systematics observed in the martian meteorite suite combining the end142 end143 isotopic systematics of the martian meteorites yields a model age for planetary differentiation of 4 513 0 033 0 027 ga using this age the parent daughter ratios of martian mantle sources are calculated assuming a two stage evolutionary history the calculated sources have very large ranges of parent daughter ratios 87rb 86sr 0 037 0 374 147sm 144nd 0 182 0 285 176lu 177hf 0 028 0 048 these ranges exceed the ranges estimated for terrestrial basalt source regions but are very similar to those estimated for the sources of lunar mare basalts in fact the range of parent daughter ratios calculated for the martian meteorite sources can be produced by mixing between end members with compositions similar to lunar mare basalt sources two of the sources have compositions that are similar to olivine and pyroxene rich mafic cumulates with variable proportions of a rb enriched phase such as amphibole whereas the third source has the composition of liquid trapped in the cumulate pile i e similar to kreep after 99 crystallization correlation between the proportion of trapped liquid in the meteorite source regions and estimates of fo2 suggest that the kreep like component may be hydrous the success of these models in reproducing the martian meteorite source compositions suggests that the variations in trace element and isotopic compositions observed in the martian meteorites primarily reflect melting of the crystallization products of an ancient magma ocean and that assimilation of evolved crust by mantle derived magmas is not required furthermore the decoupling of major element and trace element isotopic systematics in the martian meteorite suite may reflect the fact that trace element and isotopic systematics are inherited from the magma source regions whereas the major element abundances are limited by eutectic melting processes at the time of magma formation differences in major element abundances of parental magma therefore result primarily from fractional crystallization after leaving their source regions

igneous and shock processes affecting chassignite amphibole evaluated using chlorine water partitioning and hydrogen isotopes amphibole in chassignite melt inclusions provides valuable information about the volatile content of the original interstitial magma but also shock and postshock processes we have analyzed amphibole and other phases from nwa 2737 melt inclusions and we evaluate these data along with published values to constrain the crystallization cl and h2o content of phases in chassignite melt inclusions and the effects of shock on these amphibole grains using a model for the cl oh exchange between amphibole and melt we estimate primary crystallization oh contents of chassignite amphiboles sims analysis shows that amphibole from nwa 2737 currently has 0 15 wt h2o it has lost 0 6 wt h2o from an initial 0 7 0 8 wt h2o due to intense shock chassigny amphibole had on average 0 3 0 4 wt h2o and suffered little net loss of h2o due to shock nwa 2737 amphibole has d 3700 it absorbed martian atmosphere derived heavy h in the aftermath of shock chassigny amphibole with d 1900 incorporated less heavy h low h2o cl ratios are inferred for the primitive chassignite magma which had significant effects on melting and crystallization volatiles released by the degassing of martian magma were more cl rich than on earth resulting in the high cl content of martian surface materials

heterogeneous distribution of h2o in the martian interior implications for the abundance of h2o in depleted and enriched mantle sources we conducted a petrologic study of apatite within 12 martian meteorites including 11 shergottites and one basaltic regolith breccia these data were combined with previously published data to gain a better understanding of the abundance and distribution of volatiles in the martian interior apatites in individual martian meteorites span a wide range of compositions indicating they did not form by equilibrium crystallization in fact the intrasample variation in apatite is best described by either fractional crystallization or crustal contamination with a cl rich crustal component we determined that most martian meteorites investigated here have been affected by crustal contamination and hence cannot be used to estimate volatile abundances of the martian mantle using the subset of samples that did not exhibit crustal contamination we determined that the enriched shergottite source has 36 73 ppm h2o and the depleted source has 14 23 ppm h2o this result is consistent with other observed geochemical differences between enriched and depleted shergottites and supports the idea that there are at least two geochemically distinct reservoirs in the martian mantle we also estimated the h2o cl and f content of the martian crust using known crust mantle distributions for incompatible lithophile elements we determined that the bulk martian crust has 1410 ppm h2o 450 ppm cl and 106 ppm f and cl and h2o are preferentially distributed toward the martian surface the estimate of crustal h2o results in a global equivalent surface layer gel of 229 m which can account for at least some of the surface features on mars attributed to flowing water and may be sufficient to support the past presence of a shallow sea on mars surface

frequency magnitude distribution of earthquakes in vrancea relevance for a discrete model a high resolution analysis of a homogeneous and complete data set of intermediate depth microearthquakes h 60 km extending over an interval of 9 3 years emphasizes a significant deviation at low magnitudes ml 4 in a linear frequency magnitude distribution it appears as a distinct change in the slope of the cumulative distribution and as a seismicity deficit followed by a relative enhancement in the corresponding noncumulative curve this is in agreement with the presence of two characteristic mechanisms and allows the identification of both the magnitude threshold of asperity like earthquakes and the transition zone ml 3 3 3 9 from crack like earthquakes background seismicity to asperity like events these features are better pointed out on well individualized active zones the background seismicity shows a tremendeous decrease in its b slope from 1 03 to 0 57 during a 6 year interval before the occurrence of a major earthquake in 1986 mw 7 3 followed by a fast recovery to 1 03 in 2 years after this event such a behavior could be correlated to the continuous growth of the shear stress free surface on the fault as in a percolation process followed by its sudden diminution due to the locking of the fault the above results provide relevance for the discrete character of faulting and enable a coherent modeling of the earthquake generation process from microearthquake to major event scale lengths

trace element inventory of meteoritic ca phosphates most extraterrestrial samples feature the two accessory ca phosphates apatite group minerals and merrillite which are important carrier phases of the rare earth elements ree the trace element concentrations ree sc ti v cr mn co as rb sr y zr nb ba hf ta pb th and u of selected grains were analyzed by la icp ms and or sims ree only this systematic investigation includes 99 apatite and 149 merrillite analyses from meteorites deriving from various asteroidal bodies including 1 carbonaceous chondrite 8 ordinary chondrites 3 acapulcoites 1 winonaite 2 eucrites 5 shergottites 1 ureilitic trachyandesite 2 mesosiderites and 1 silicate bearing iab iron meteorite although ca phosphates predominantly form in metamorphic and or metasomatic reactions some are of igneous origin as late stage phases that often incorporate the vast majority of their host s bulk ree budget the investigated ca phosphates have ree enrichments of up to two orders of magnitude compared to the host rock s bulk concentrations within a single sample each phosphate species displays a uniform ree pattern and variations are mainly restricted to their enrichment therefore indicating similar formation conditions exceptions are brecciated samples i e the adzhi bogdo ll3 6 ordinary chondrite despite this uniformity within single samples distinct meteorite groups do not necessarily have unique ree patterns four basic shapes dominate the ree patterns of meteoritic ca phosphates 1 flat patterns smoothly decreasing from la lu with prominent negative eu anomalies acapulcoites eucrites apatite from the winonaite and the ureilitic trachyandesite merrillite from ordinary chondrites 2 unfractionated patterns with only minor or no anomalies mesosiderites enriched shergottites iab iron meteorite 3 lree enriched patterns with either positive or slightly negative eu anomalies chondritic apatite and 4 strongly lree depleted patterns with negative eu anomalies depleted shergottites the patterns do not correlate with the grade of metamorphism petrologic type specific adjacent mineral assemblages or with ca phosphate grain size neither the proportions of different ree nor particular ree patterns themselves are universally correlated to a specific formation mechanism yet eu i e magnitude of the eu anomaly is a sensitive indicator to evaluate the timing of plagioclase and phosphate crystallization based on our data u and th abundances in apatite increase almost linearly with the grade of metamorphism as well as with the differentiation of their host rock

differentiation in impact melt sheets as a mechanism to produce evolved magmas on mars abstract asteroid bombardment contributed to extensive melting and resurfacing of ancient 3 5 ga mars evidence from the largest impact structures on earth and the moon suggests that vertically thick impact melt sheets experience chemical differentiation recently observed materials in gale crater are enriched in alkalis up to 14 wt na2o k2o and silica up to 67 wt sio2 with low mgo

martian magmas contained abundant chlorine but little water the martian water cycle a key for the habitability of mars largely relies on the abundance of water in martian magmas and their mantle sources yet martian snc shergottite nakhlite and chassigny classes meteorites contain minimal water however some experimental studies have suggested that martian parental magmas contained as much as 2 h2o here we integrate mineral chemical experimental and cosmochemical constraints to show that martian magmas contained little water but abundant chlorine apatite and amphibole in martian meteorites are chlorine rich and water poor this constrains the chlorine contents in their parental magmas to 0 3 wt and water contents to 0 3 wt our experimental work has shown that large amounts of water are not needed to explain the mineralogy of the martian meteorites because chlorine has effects similar to those of water on crystallization such chlorine rich water poor martian magmas are consistent with mars being chlorine rich 2 5 compared with the earth furthermore the bulk cl composition of martian meteorites shows that they have not preferentially lost cl by degassing of an h2o rich vapor together these results show that chlorine not water was the dominant volatile species in martian basalts and that these basalts contributed little h2o to mars surface environment

nanosims analyses of apatite and melt inclusions in the grv 020090 martian meteorite hydrogen isotope evidence for recent past underground hydrothermal activity on mars abstract we measured the hydrogen isotopes and water contents of melt inclusions and apatite that locate far from shock induced melt veins in the martian meteorite grv 020090 using nano scale secondary ion mass spectrometry nanosims the melt inclusions in olivine show hydration profiles with both the water contents and the d values increasing from the cores 2 170 7 ppm and 3386 126 to the rims 5337 200 ppm and 5519 65 the extremely high d values of the melt inclusions relative to a maximum of 4239 81 of apatite that crystallized from the last residual melt convincingly argue that the observed hydration postdated emplacement of the parent magma of grv 020090 this is also a robust line of evidence for past presence of liquid water on mars diffusion simulation of the hydration profiles of both water contents and d values constrains the duration of liquid water up to 130 000 250 000 years at 0 c or 700 1 500 years at 40 c all analyses of the melt inclusions including the hydration profiles show a logarithmic correlation between the water contents and the d values plotting within a two endmember mixing area the extremely d enriched endmember represents martian underground water with a d value of 6034 72 2 this is the highest d value reported in martian meteorites and it is consistent with the recent analyses of martian soils by the curiosity rover leshin et al 2013 suggestive of more water escaped from mars than previous estimates the analyses of apatite show a distinct positive correlation between the water contents 0 10 0 58 wt and the d values 737 4239 which can be explained by assimilation of d rich martian crustal materials and enhancement of water via fractional crystallization the observed correlation suggests that the water contents of martian mantle reservoirs might have been overestimated from d enriched apatite in previous studies our estimation based on the least contaminated apatite grains from grv 020090 turned out a low water content of the primordial parent magma 380 750 ppm which was likely derived from a relatively dry martian mantle reservoir of grv 020090 38 75 ppm h2o