intraplate extension prior to continental extrusion along the ailao shan red river shear zone left lateral movement of the ailao shan red river shear zone lends support to the hypothesis of continental extrusion resulting from the collision of india with asia our new observations from northwestern yunnan china and northwestern vietnam on different sides of the shear zone demonstrate that the sinistral offset was 600 km according to correlations of permian triassic flood basalt successions and late paleogene highly potassic mafic magmas we conclude that the shear was propagating on the south china continental margin and does not correspond to a suture between south china and indochina furthermore the highly potassic magmas were emplaced from ca 40 to 30 ma before the shear movement which was caused by the late oligocene to early miocene ca 27 22 ma extrusion activity this suggests that a late eocene to early oligocene intraplate extension possibly induced by delamination of thickened continental lithosphere took place in northwestern yunnan or eastern tibet as a response to the india asia collision this extension and sea floor spreading of the south china sea that began ca 30 ma could have accounted for the initiation of the ailao shan red river shear zone

a noachian source region for the black beauty meteorite and a source lithology for mars surface hydrated dust the martian surface is covered by a fine layer of oxidized dust responsible for its red color in the visible spectral range bibring et al 2006 morris et al 2006 in the near infrared the strongest spectral feature is located between 2 6 and 3 6 m and is ubiquitously observed on the planet jouglet et al 2007 milliken et al 2007 although this absorption has been studied for many decades its exact attribution and its geological and climatic implications remain debated we present new lines of evidence from laboratory experiments orbital and landed missions data and characterization of the unique martian meteorite nwa 7533 all converging toward the prominent role of hydroxylated ferric minerals martian breccias so called black beauty meteorite nwa7034 and its paired stones nwa7533 and nwa 7455 are unique pieces of the martian surface that display abundant evidence of aqueous alteration that occurred on their parent planet agee et al 2013 these dark stones are also unique in the fact that they arose from a near surface level in the noachian southern hemisphere humayun et al 2013 we used ir spectroscopy fe xanes and petrography to identify the mineral hosts of hydrogen in nwa 7533 and compare them with observations of the martian surface and results of laboratory experiments the spectrum of nwa 7533 does not show mafic mineral absorptions making its definite identification difficult through nir remote sensing mapping however its spectra are virtually consistent with a large fraction of the martian highlands abundant nwa 7034 7533 and paired samples lithologies might abound on mars and might play a role in the dust production mechanism

the western ailaoshan volcanic belts and their se asia connection a new tectonic model for the eastern indochina block the western ailaoshan wal volcanic belts mark the western boundary of the south china indochina suture zone along the ailaoshan fold belt geochronological and geochemical evidence suggests that the wal volcanic belts vary in ages and origins and includes 1 l carboniferous earliest m permian ca 300 270 ma incipient backarc basin magmatism 2 m permian ca 265 ma island arc mature backarc basin magmatism 3 early l permian ca 260 255 ma wal indochina arc continent collision and the associated syn collisional granitic magmatism as well as subsequent 4 e triassic ca 250 245 ma post collisional magmatism regional geological comparison indicates that the post l carboniferous wal tectonic evolution was closely related to the eastern indochina block we present a new g plate geodynamic evolution model for the ailaoshan fold belt and its surrounding south china indochina region based on new and published u pb zircon ages together with whole rock and pb isotope geochemical data

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

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

rb sr and sm nd isotopic and ree studies of igneous components in the bulk matrix domain of martian breccia northwest africa 7034 the bulk matrix domain of the martian breccia nwa 7034 was examined petrographically and isotopically to better understand the provenance and age of the source material that make up the breccia both 147sm 143nd and 146sm 142nd age results for mineral separates from the bulk matrix portion of breccia nwa 7034 suggest that various lithological components in the breccia probably formed contemporaneously 4 44 ga ago this old age is in excellent agreement with the upper intersection ages 4 35 4 45 ga for u pb discordia and also concordia defined by zircon and baddeleyite grains in matrix and igneous textured clasts consequently we confirm an ancient age for the igneous components that make up the nwa 7034 breccia substantial disturbance in the rb sr system was detected and no age significance could be gleaned from our rb sr data the disturbance to the rb sr system may be due to a thermal event recorded by bulk rock k ar ages of 1 56 ga and u pb ages of phosphates at about 1 35 1 5 ga which suggest partial resetting from an unknown thermal event s possibly accompanying breccia formation the nwa 7034 bulk rock is lree enriched and similar to kreep rich lunar rocks which indicates that the earliest martian crust was geochemically enriched this enrichment supports the idea that the crust is one of the enriched geochemical reservoirs on mars that have been detected in studies of other martian meteorites

ophiolite genesis and global tectonics geochemical and tectonic fingerprinting of ancient oceanic lithosphere ophiolites and discussions on their origin and significance in earth s history have been instrumental in the formulation testing and establishment of hypotheses and theories in earth sciences the definition tectonic origin and emplacement mechanisms of ophiolites have been the subject of a dynamic and continually evolving concept since the nineteenth century here we present a review of these ideas as well as a new classification of ophiolites incorporating the diversity in their structural architecture and geochemical signatures that results from variations in petrological geochemical and tectonic processes during formation in different geodynamic settings we define ophiolites as suites of temporally and spatially associated ultramafic to felsic rocks related to separate melting episodes and processes of magmatic differentiation in particular tectonic environments their geochemical characteristics internal structure and thickness vary with spreading rate proximity to plumes or trenches mantle temperature mantle fertility and the availability of fluids subduction related ophiolites include suprasubduction zone and volcanic arc types the evolution of which is governed by slab dehydration and accompanying metasomatism of the mantle melting of the subducting sediments and repeated episodes of partial melting of metasomatized peridotites subduction unrelated ophiolites include continental margin mid ocean ridge plume proximal plume distal and trench distal and plume type plume proximal ridge and oceanic plateau ophiolites that generally have mid ocean ridge basalt morb compositions subduction related lithosphere and ophiolites develop during the closure of ocean basins whereas subduction unrelated types evolve during rift drift and seafloor spreading the peak times of ophiolite genesis and emplacement in earth history coincided with collisional events leading to the construction of supercontinents continental breakup and plume related supermagmatic events geochemical and tectonic fingerprinting of phanerozoic ophiolites within the framework of this new ophiolite classification is an effective tool for identification of the geodynamic settings of oceanic crust formation in earth history and it can be extended into precambrian greenstone belts in order to investigate the ways in which oceanic crust formed in the archean

water on mars insights from apatite in regolith breccia northwest africa 7034 abstract determining the source of planetary water from the hydrogen isotope compositions of crustal samples is complicated by the overprinting of isotopically diverse source material by geologic and atmospheric processes as mars has no plate tectonics crustal material which may have isotopically exchanged with the martian atmosphere is not recycled into the mantle keeping the water reservoirs in the mantle and atmosphere mostly isolated buffered by the crust as the only known martian samples that are regolith breccias with a composition representative of the average crust of mars northwest africa nwa 7034 and its paired stones provide an important opportunity to investigate the water content and hydrogen isotope composition of the martian crust in particular apatites in distinct clasts as well as the brecciated matrix of nwa 7034 record a complex history including magmatic and impact processes and exchange with crustal fluids

strong water isotopic anomalies in the martian atmosphere probing current and ancient reservoirs we measured maps of atmospheric water h2o and its deuterated form hdo across the martian globe showing strong isotopic anomalies and a significant high deuterium hydrogen d h enrichment indicative of great water loss the maps sample the evolution of sublimation from the north polar cap revealing that the released water has a representative d h value enriched by a factor of about 7 relative to earth s ocean vienna standard mean ocean water vsmow certain basins and orographic depressions show even higher enrichment whereas high altitude regions show much lower values 1 to 3 vsmow our atmospheric maps indicate that water ice in the polar reservoirs is enriched in deuterium to at least 8 vsmow which would mean that early mars 4 5 billion years ago had a global equivalent water layer at least 137 meters deep

fore arc basalts and subduction initiation in the izu bonin mariana system recent diving with the jamstec shinkai 6500 manned submersible in the mariana fore arc southeast of guam has discovered that morb like tholeiitic basalts crop out over large areas these fore arc basalts fab underlie boninites and overlie diabasic and gabbroic rocks potential origins include eruption at a spreading center before subduction began or eruption during near trench spreading after subduction began fab trace element patterns are similar to those of morb and most izu bonin mariana ibm back arc lavas however ti v and yb v ratios are lower in fab reflecting a stronger prior depletion of their mantle source compared to the source of basalts from mid ocean ridges and back arc basins some fab also have higher concentrations of fluid soluble elements than do spreading center lavas thus the most likely origin of fab is that they were the first lavas to erupt when the pacific plate began sinking beneath the philippine plate at about 51 ma the magmas were generated by mantle decompression during near trench spreading with little or no mass transfer from the subducting plate boninites were generated later when the residual highly depleted mantle melted at shallow levels after fluxing by a water rich fluid derived from the sinking pacific plate this magmatic stratigraphy of fab overlain by transitional lavas and boninites is similar to that found in many ophiolites suggesting that ophiolitic assemblages might commonly originate from near trench volcanism caused by subduction initiation indeed the widely dispersed jurassic and cretaceous tethyan ophiolites could represent two such significant subduction initiation events

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

the sources of water in martian meteorites clues from hydrogen isotopes abstract h isotope measurements of carbonate phosphate feldspathic and mafic glasses and post stishovite silica phase in the shergottites zagami shergotty sau 005 dag 476 alha 77005 and eeta 79001 as well as in chassigny and alh 84001 show that all these phases contain deuterium enriched water of extraterrestrial origin the minerals and glasses analyzed may contain an initial primary hydrogen component but their isotopic composition was modified to varying degrees by three different processes interaction with a fractionated exchangeable water reservoir on mars hydrogen devolatilization by impact melting and terrestrial contamination positive correlations between d and water abundance in feldspathic glass and post stishovite silica in zagami shergotty and sau 005 is indicative of mixing of a high d component 3000 4000 and a less abundant low d component 0 the high d component is primarily derived from the martian exchangable reservoir but may also have been influenced by isotopic fractionation associated with shock induced hydrogen loss the low d component is either a terrestrial contaminant or a primary magmatic component the negative correlation between d and water abundances in mafic and feldspathic glasses in alh 84001 alha 77005 and eeta 79001 is consistent with the addition of a low d terrestrial contaminant to a less abundant high deuterium martian component the low d of magmatic glass in melt inclusions suggests that the d of martian parent magma was low and that the initial h isotope signature of mars may be similar to that of earth

ejection of martian meteorites we investigated the transfer of meteorites from mars to earth with a combined mineralogical and numerical approach we used quantitative shock pressure barometry and thermodynamic calculations of post shock temperatures to constrain the pressure temperature conditions for the ejection of martian meteorites the results show that shock pressures allowing the ejection of martian meteorites range from 5 to 55 gpa with corresponding post shock temperature elevations of 10 to about 1000 c with respect to shock pressures and post shock temperatures an ejection of potentially viable organisms in martian surface rocks seems possible a calculation of the cooling time in space for the most highly shocked martian meteorite allan hills alh 77005 was performed and yielded a best fit for a post shock temperature of 1000 c and a meteoroid size of 0 4 to 0 6 m the final burial depths of the sub volcanic to volcanic martian rocks as indicated by textures and mineral compositions of meteorites are in good agreement with the postulated size of the potential source region for martian meteorites during the impact of a small projectile 200 m as defined by numerical modeling artemieva and ivanov 2004 a comparison of shock pressures and ejection and terrestrial ages indicates that on average highly shocked fragments reach earth crossing orbits faster than weakly shocked fragments if climatic changes on mars have a significant influence on the atmospheric pressure they could account for the increase of recorded ejection events of martian meteorites in the last 5 ma

tau migration and velocity analysis theory and synthetic examples prestack migration velocity analysis in the time domain reduces the velocity depth ambiguity usually hampering the performance of prestack depth migration velocity analysis in prestack migration velocity analysis we keep the interval velocity model and the output images in vertical time this allows us to avoid placing reflectors at erroneous depths during the velocity analysis process and thus avoid slowing down its convergence to the true velocity model using a 1d velocity update scheme the prestack migration velocity analysis performed well on synthetic data from a model with a complex near surface velocity accurate velocity information and images were obtained using this time domain method problems occurred only in resolving a thin layer where the low resolution and fold of the synthetic data made it practically impossible to estimate velocity accurately in this layer this 1d approach also provided us reasonable results for synthetic data from the marmousi model despite the complexity of

magmatic water in the martian meteorite nakhla abstract mars does not recycle crustal materials via plate tectonics for this reason the magmatic water reservoir of the martian mantle has not been affected by surface processes and the deuterium hydrogen d h ratio of this water should represent the original primordial martian value following this logic hydrous primary igneous minerals on the martian surface should also carry this primordial d h ratio assuming no assimilation of martian atmospheric water during crystallization and no major hydrogen fractionation during melt degassing hydrous primary igneous minerals such as apatite and amphibole are present in martian meteorites here on earth providing these minerals have not been affected by terrestrial weathering martian atmospheric water or shock processes after crystallization they should contain a good approximation of the primordial martian d h ratio as nakhla was seen to fall in the egyptian desert in 1911 terrestrial contamination is minimized in this meteorite the nakhlites are also among the least shocked of the martian meteorites therefore apatite within nakhla could contain primordial martian hydrogen isotope ratios we produced in situ measurements of the d h ratios in nakhla apatite grains using a cameca ims 1280 ion microprobe our measurements produced d h values in nakhla apatite similar to terrestrial values despite strong evidence that our samples were not significantly contaminated by terrestrial hydrogen these results suggest that water trapped in the martian mantle has a similar d h to that of the earth therefore the water of these two planets may have originated from the same source material the d h ratios of the carbonaceous chondrite meteorites and the jupiter family comet 103p hartley 2 are similar to the d h of the two planets making both these primitive inner solar system materials strong candidates for the source of the terrestrial planets water these results support recent dynamical models of the formation of the solar system which suggest material in the inner solar system was homogenized by the migration of jupiter

fish suggests continental connections between the indochina and south china blocks in middle devonian time a yunnanolepiform antiarch placoderm fish is recorded from the givetian dong tho formation of quang binh province central vietnam this and other fishes from the same locality occur in marginal marine detrital facies with plant remains and lingulid brachiopods that indicate a nearshore to deltaic environment yunnanolepiform antiarchs were hitherto known exclusively from the lower devonian of the south china block the new occurrence of this group well south of the song ma suture suggests close links between the indochina and south china blocks in middle devonian time the massive sandstone exposures of the dong tho formation may be a southern extension of the do son sandstone formation of the hai phong area which is located on the south china block

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

τ migration and velocity analysis application to data from the red sea imaging pre salt reflections for data acquired from the coastal region of the red sea is a task that requires prestack migration velocity analysis conventional post stack time processing lacks the lateral inhomogeneity capability necessary for such a problem prestack migration velocity analysis in the vertical time domain reduces the velocity depth ambiguity that usually hampers the performance of prestack depth migration velocity analysis in prestack t migration velocity analysis the interval velocity model and the output images are defined in r i e vertical time as a result we avoid placing reflectors at erroneous depths during the velocity analysis process and thus avoid inaccurately altering the shape of the velocity model which in turn speeds up the convergence to the true model using a 1d velocity update scheme the prestack migration velocity analysis produces good images of data from the midyan region of the red sea for the first seismic line from this region only three prestack t migration velocity analysis iterations were required to focus pre salt reflections in r however the second line which crosses the first line is slightly more complicated and thus required five iterations to reach the final reasonably focused r image after mapping the images for the two crossing lines to depth using the final velocity models the placements of reflectors in the two 2d lines were consistent at their crossing point some errors occurred due to the influence of out of plane reflections on 2d imaging however such errors are identifiable and are generally small

sensitivity kernel based tomographic migration velocity analysis using reverse time migration angle image gathers abstractsensitivity kernel based tomographic migration velocity analysis tmva provides a means to better update the migration velocity model in complex media for actual seismic data with finite frequency bandwidth migration velocity updated from wave equation based tomography is more suitable and robust than ray based tomography for images obtained from reverse time migration rtm depth residuals in the rtm extracted angle image gathers offer a reliable source of velocity information we have developed cost effective means of calculating the angle domain sensitivity kernel and incorporated it into the tmva approach using rtm angle image gathers the angle domain sensitivity kernels are used to convert the depth residuals from rtm angle image gathers into velocity perturbations which were then used to refine the velocity model we derived an approximate analytical residual moveout function for measuring depth residuals of the rtm angle image gather in isotropic media and also devised a workflow for

paleomagnetism of the earliest cretaceous to early late cretaceous sandstones khorat group northeast thailand implications for tectonic plate movement of the indochina block abstract a total of 400 samples 33 sites were collected from the earliest cretaceous to early late cretaceous sandstones of the khorat group in the indochina block for paleomagnetic study to unravel the tectonic evolution of the region the sites were adopted from 3 traverses located in the northern edge of the khorat plateau northeastern thailand results indicate that almost all the sandstones exhibit similar magnetic values with an average declination d 31 7 inclination i 30 3 59 7 190 9 k 54 4 and a95 3 7 at reference point 17 30 n and 103 30 e the calculated paleolatitude points are inferred to deviate from the present latitude point by 1 2 2 3 only the lowermost part of the cretaceous sandstones can pass a positive fold test at 95 confidence level the relationship between the virtual geomagnetic poles vgps of cretaceous rocks of the indochina plate in thailand and those of the south china plate advocate that there is a major displacement of indochina along the northwest trending red river and associated faults by about 950 150 km with a 16 0 17 0 clockwise rotation relative to the south china plate during earliest cretaceous times paleomagnetic results of the early late cretaceous indochina plate point to a 20 25 clockwise rotation relative to the present occurring since very late cretaceous 65 myrs early neogene times which may be due to the collision between india and asia

evidence for a widespread basaltic breccia component in the martian low albedo regions from the reflectance spectrum of northwest africa 7034 northwest africa nwa 7034 is the first breccia meteorite from mars and unlike the shergottite nakhlite and chassignite snc martian meteorites it matches the estimated chemical composition of martian crust here we show that the visible infrared reflectance spectrum of nwa 7034 is unique compared to other sncs and is more similar than them to remotely sensed data from mars suggesting the martian regolith may contain significant brecciated material produced during heavy bombardment of the crust

unique meteorite from early amazonian mars water rich basaltic breccia northwest africa 7034 we report data on the martian meteorite northwest africa nwa 7034 which shares some petrologic and geochemical characteristics with known martian meteorites of the snc i e shergottite nakhlite and chassignite group but also has some unique characteristics that would exclude it from that group nwa 7034 is a geochemically enriched crustal rock compositionally similar to basalts and average martian crust measured by recent rover and orbiter missions it formed 2 089 0 081 billion years ago during the early amazonian epoch in mars9 geologic history nwa 7034 has an order of magnitude more indigenous water than most snc meteorites with up to 6000 parts per million extraterrestrial h2o released during stepped heating it also has bulk oxygen isotope values of 17o 0 58 0 05 per mil and a heat released water oxygen isotope average value of 17o 0 330 0 011 per mil suggesting the existence of multiple oxygen reservoirs on mars

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

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

geologic history of martian regolith breccia northwest africa 7034 evidence for hydrothermal activity and lithologic diversity in the martian crust the timing and mode of deposition for martian regolith breccia northwest africa nwa 7034 were determined by combining petrography shape analysis and thermochronology nwa 7034 is composed of igneous impact and brecciated clasts within a thermally annealed submicron matrix of pulverized crustal rocks and devitrified impact volcanic glass the brecciated clasts are likely lithified portions of martian regolith with some evidence of past hydrothermal activity represented lithologies are primarily ancient crustal materials with crystallization ages as old as 4 4 ga one ancient zircon was hosted by an alkali rich basalt clast confirming that alkalic volcanism occurred on mars very early nwa 7034 is composed of fragmented particles that do not exhibit evidence of having undergone bed load transport by wind or water the clast size distribution is similar to terrestrial pyroclastic deposits we infer that the clasts were deposited by atmospheric rainout subsequent to a pyroclastic eruption s and or impact event s although the ancient ages of igneous components favor mobilization by impact s despite ancient components the breccia has undergone a single pervasive thermal event at 500 800 c evident by groundmass texture and concordance of 1 5 ga dates for bulk rock k ar u pb in apatite and u pb in metamict zircons the 1 5 ga age is likely a thermal event that coincides with rainout breccia lithification we infer that the episodic process of regolith lithification dominated sedimentary processes during the amazonian epoch the absence of pre amazonian high temperature metamorphic events recorded in ancient zircons indicates source domains of static southern highland crust punctuated by episodic impact modification

insights into the martian mantle the age and isotopics of the meteorite fall tissint the recent witnessed fall of the meteorite tissint represents the delivery of a pristine new sample from the surface of mars this meteorite provides an unprecedented opportunity to study a variety of aspects about the planet s evolution using the rb sr and sm nd isotopic systems we determined that tissint a depleted shergottite has a crystallization age of 574 20 ma an initial e 143 nd 42 2 0 5 and an initial 87 sr 86 sr 0 700760 11 these initial nd and sr isotopic compositions suggest that tissint originated from a mantle source on mars that is distinct from the source reservoirs of the other martian meteorites the known crystallization ages geochemical characteristics ejection ages and ejection dynamics of tissint and other similarly grouped martian meteorites suggest that they are likely derived from a source crater up to approximately 90 km in diameter with an age of approximately 1 ma that is located on terrain that is approximately 600 million years old

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

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

kfupm kaust red sea model digital viscoelastic depth model and synthetic seismic data set abstract the red sea is geologically interesting due to its unique structures and abundant mineral and petroleum resources yet no digital geologic models or synthetic seismic data of the red sea are publicly available for testing algorithms to image and analyze the area s interesting features this study compiles a 2d viscoelastic model of the red sea and calculates a corresponding multicomponent synthetic seismic data set the models and data sets are made publicly available for download we hope this effort will encourage interested researchers to test their processing algorithms on this data set and model and share their results publicly as well

ancient geologic events on mars revealed by zircons and apatites from the martian regolith breccia nwa 7034

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

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

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