a model of the primordial lunar atmosphere abstract we create the first quantitative model for the early lunar atmosphere coupled with a magma ocean crystallization model immediately after formation the moon s surface was subject to a radiative environment that included contributions from the early sun a post impact earth that radiated like a mid type m dwarf star and a cooling global magma ocean this radiative environment resulted in a largely earth side atmosphere on the moon ranging from 104 to 102 pascals composed of heavy volatiles na and sio this atmosphere persisted through lid formation and was additionally characterized by supersonic winds that transported significant quantities of moderate volatiles and likely generated magma ocean waves the existence of this atmosphere may have influenced the distribution of some moderate volatiles and created temperature asymmetries which influenced ocean flow and cooling such asymmetries may characterize young tidally locked rocky bodies with global magma oceans and subject to intense irradiation

3d nanopores modeling using tem tomography dolostones upper triassic abstract transmission electron microscopy tomography temt stands as a novel and alternative tool to tridimensionally model the nano scale pores of rocks in this study it is flanked with traditional mercury capillary injection porosimetry micp nitrogen adsorption porosimetry np and scanning electron microscopy sem analysis to test a sample belonging to an upper triassic dolostone cropping out in northern calabria micp revealed low values of porosity and permeability 2 3 and the 0 11 md respectively nanopores account for the 94 of the pore volume whereas the remaining 6 is represented by micropores the integrated micp and np pore size distribution psd shows the presence of a dominant pore diameter population coincident with 50 nm with minor peaks at diameters of 12 m 850 25 13 6 2 nm however since the psd peaks of the two techniques do not match a comparison of the two curves is necessary to better characterized the overlapping area sem imaging analysis showed the presence of nano scale intercrystalline and intracrystalline pores the first corresponds with the spaces among dolomite crystals and as suggested by the np analysis shows a wedge slit morphology the second appears with a prevailing polygonal section or as tight microfractures since sem provides exclusively two dimensional images the morphology and development of these pores was obtained through temt 3d reconstruction the 3d model showed the presence of open cavities fractures and blind isolated pores cavities cross the entire dolomite crystals and can present a constant sub prismatic pores or variable channel section funnel shaped pores that can reduce its aperture as observed of also more than a ten factor e g from 300 nm to 20 nm fractures commonly developing on the existing cleavage surfaces cut the crystal faces for 300 350 nm reducing its aperture maximum of 20 30 nm from the edge towards the inner part of the crystal lastly blind isolated pores can assume diameters and thickness of 250 nm they show a sub cubic morphology and can be filled by solid liquid or gaseous inclusions

a vaporization model for iron silicate fractionation in the mercury protoplanet abstract a study has been carried out of the vaporization of a totally molten silicate magma of chondritic composition heated into the range 2500 3500 k the motivation for this was to determine the changes in the composition of the mantle that would occur in the mercury protoplanet should that body have been subjected to the high temperature phase in the evolution of the primitive solar nebula but the results are of more general interest we have used both ideal and nonideal descriptions of the magma chemistry an empirical model based on ideal mixing of complex components developed by hastie and co workers was used to describe the nonideal magma comparison of our results of the nonideal magma calculations with experimental work on vaporization of chondritic material shows generally good agreement we find that vaporization of about 70 80 of the original amount of silicate from a chondritic planet is required to produce an iron rich body with a mean uncompressed density equal to that deduced for mercury 5 3 g cm3 at this point the silicate is depleted in the alkalis feo and sio2 and enriched in cao mgo al2o3 and tio2 relative to chondritic material we also predict the production of unique trace element abundance patterns which are depleted in easily oxidized elements relative to other trace elements of similar volatilities

oceanographic and eustatic control of carbonate platform evolution and sequence stratigraphy on the cretaceous valanginian campanian passive margin northern gulf of mexico an integrated sequence stratigraphic study based on outcrop core and wireline log data documents the combined impact of cretaceous eustacy and oceanic anoxic events on carbonate shelf morphology and facies distributions in the northern gulf of mexico the diverse facies and abundant data of the comanche platform serve as a nearly complete global reference section and provide a sensitive record of external processes affecting cretaceous platform development regional cross sections across the shoreline to shelf margin profile provide a detailed record of mixed carbonate siliciclastic strata for the hauterivian to lower campanian stages ca 136 to 80 ma the study window on the slowly subsiding passive margin allows the stratigraphic response to external forcing mechanisms to be isolated from regional structural processes three second order supersequences comprised of eight composite sequences are recognized in the valanginian barremian the aptian albian and the cenomanian campanian the valanginian barremian supersequence transitioned from a siliciclastic ramp to carbonate rimmed shelf and is a product of glacial ice accumulation and melting as well as variable rates of mid ocean ridge volcanism the aptian albian supersequence chronicles the drowning and recovery of the platform surrounding oceanic anoxic events 1a and 1b the cenomanian campanian supersequence similarly documents shelf drowning following oceanic anoxic event 1d after which the platform evolved to a deep subtidal system consisting of anoxic dysoxic shale and chalk in the time surrounding oceanic anoxic event 2 each period of oceanic anoxia is associated with composite sequence maximum flooding termination of carbonate shelf sedimentation and deposition of condensed shale units in distally steepened ramp profiles composite sequences unaffected by oceanic anoxic events consist of aggradational to progradational shelves with an abundance of grain dominated facies and shallow subtidal to intertidal environments because they are products of eustacy and global oceanographic processes the three supersequences and most composite sequences defined in the south texas passive margin are recognizable in other carbonate platforms and published eustatic sea level curves

cooling rates of lunar orange glass beads abstract it is widely accepted that the apollo 17 orange glass beads are of volcanic origin the degree of degassing of the glass beads depends on their cooling rates so the estimation of volatile contents in the parental magmas of these lunar pyroclastic glasses also depends on the cooling rates the cooling rate can be estimated using the calorimetric properties of the glass across the glass transition in this study a series of heat capacity measurements were carried out on hand picked lunar volcanic orange glass beads during several cycles of heating to temperatures above their glass transition using a differential scanning calorimeter the cooling rate of orange glass beads sample 74220 867 was calculated to be 101 k min using the correlation between glass cooling rates and fictive temperatures estimated from their heat capacity temperature paths this cooling rate is close to the lower end of the range that best fits the diffusion profiles of several volatile species in the glass beads and at the upper end of the cooling rate range recorded in glasses quenched subaerially on earth the cooling rate is likely to be controlled by the cooling environment cooling medium such that the lunar volcanic glass beads could have been cooled in a gaseous medium released from volcanic eruptions on the moon but not during free flight in vacuum the existence of a gas medium suggests in turn that there may have been at least a short lived or episodic atmosphere on the early moon at around 3 5 ga

crystals stirred up 2 numerical insights into the formation of the earliest crust on the moon 1 this is the second paper in a two part series examining the fluid dynamics of crystal settling and flotation in the lunar magma ocean in the first paper we develop a direct numerical method for resolving the hydrodynamic interactions between crystals and their feedback on the flow field in magmatic liquid in this paper we use this computational technique to test the leading model for the formation of the earliest crust on the moon the anorthositic lithology of the lunar crust is thought to have been formed by the flotation of buoyant plagioclase crystals at a time when the lunar mantle was still wholly or largely molten this model is appealing from an observational point of view but its fluid dynamical validity is not obvious because 1 plagioclase probably started crystallizing very late i e when the magma ocean was already 80 solidified and 2 a significant portion of the shallow lunar crust consists of almost pure plagioclase 90 vol requiring very efficient plagioclase segregation the goal of this study is to better understand the fluid dynamical conditions that hinder or facilitate crystal settling or flotation our approach complements earlier studies by explicitly linking the petrological and fluid dynamical evolution and by focusing on the effect of increasing crystal fraction we find that crystal settling was probably possible throughout the entire solidification history of the lunar magma ocean as long as crystal sizes were sufficiently large r 1 mm and crystal fraction sufficiently low 13

extraction of uranium and thorium from swiss granites and their microdistribution 2 microdistribution of uranium and thorium abstract this work is concerned with the extraction at the laboratory level of uranium and thorium from swiss granites the mittagfluh bergell and rotondo granites and the giuv syenite offered a wide range of u and th concentrations 7 7 20 0 ppm u and 25 5 67 0 ppm th u and th were determined in leachates by the fission track method and by spectrophotometry respectively samples containing g u and 4 g th could be measured with an accuracy of 10 for u and 5 for th leaching experiments were performed during which the following parameters were varied granite type grain size acid type acid concentration temperature and time there were large leaching differences between the granites studied grain size caused no great variation the extracted percentages of u and th were practically the same for any particular rock with either 12 coarse or 71 fine of the grain size finer than 0 125 mm the leached fraction with h 2 so 4 was somewhat smaller than with hcl or hno 3 the difference in leaching with 2 5 and 10 m hcl was negligible temperature was the most important parameter sharp differences in extraction occurred between 20 50 and 80 c at 80 c more than 85 of the u and th were extracted the extraction curve percent extracted as a function of time of aliquots sampled after 1 2 4 8 12 and 24 hr showed a plateau after 8 hr as a general rule th was more easily extracted than u the granites investigated showed widely different u and th leachability 13 75 u 32 75 th upon treatment of rock powder in 5 m hcl at 20 c for 24 hr a separate study was devoted to relate these differences to peculiarities in the u and th microdistribution in these rocks part 2

a review of the nature and origin of limestone microporosity abstract limestone microporosity is ubiquitous and extensively developed in most phanerozoic limestones from an economic perspective microporosity is important because it contributes substantially to the carbonate pore system which can host significant volumes of water and hydrocarbons therefore determining the presence and distribution of limestone micropores is necessary for accurate hydrocarbon estimations reservoir characterization and fluid flow simulations from an academic standpoint microporosity is important because its genesis is intimately linked with the mineralogical stabilization of metastable sediments a fundamental process in carbonate diagenesis many types of micropores contribute to what has been referred to as microporosity but the vast majority is hosted among low magnesium calcite lmc microcrystals that are present in limestone matrix and allochems geochemical textural and mineralogical data from natural settings and laboratory experiments indicate that lmc microcrystals are diagenetic in origin more specifically these data support a diagenetic model of mineralogical stabilization that involves dissolution of precursor sediments dominated by aragonite and high magnesium calcite hmc minerals and precipitation of lmc microcrystal cements the stabilization process is inferred to take place in the meteoric marine and burial diagenetic realms although it has not been directly observed carbon and oxygen isotopes as well as trace element data suggest that lmc microcrystals form during burial diagenesis in marine like fluids evidence suggests that porosity is not generated during this dissolution precipitation process but rather inherited from the precursor sediments the final arrangement of the micropores in a limestone however depends on the precise diagenetic pathway lmc microcrystals exhibit a range of microcrystalline textures that are classified on the basis of crystal morphology and size the three main textural classes granular framework fitted mosaic and clustered have been recognized across a wide range of ages depositional settings burial depths and precursor types and are characterized by distinct petrophysical properties such as porosity permeability and pore throat size observations from modern sediments also support the hypothesis that lmc microcrystals develop from aragonite and hmc dominated lime mud the origin of lime mud has been extensively studied but still highly debated of particular interest to the discussion of microporosity are proposed secular variations in the dominant mineralogy of carbonate sediments through the phanerozoic microporous limestones comprised of lmc microcrystals are equally abundant during times of aragonite seas and calcite seas which suggests that no special mineral precursor is required microporous textures are also observed in deep marine chalks where micropores are hosted between chalk constituents unlike shallow marine limestones deep marine sediments start out as mostly lmc therefore mineralogical stabilization is not a significant process in chalk diagenesis

on lunar asymmetries 1 tilted convection and crustal asymmetry 1 it is proposed that lunar crustal asymmetries are the result of convective processes acting early in the moon s history during the magma ocean phase and after synchronous rotation was established buoyant anorthositic crystals were transported to the farside by a large scale circulation called tilted convection known to occur spontaneously in chaotic convective systems the circulation was oriented toward the farside of the moon by a small temperature contrast produced by radiative thermal shielding due to the proximity of earth crustal thickening near the equator resulted from the modification of tilted convection by the coriolis force the anorthosite that was transported to the farside and equator may be a major cause of the observed crustal asymmetries and of the associated offset of the center of figure from the center of mass and bimodal hyposgram the selective transport may have resulted in a nearside excess of incompatible elements leading to the formation of the procellarium kreep terrane

lunar volatile depletion due to incomplete accretion within an impact generated disk the moon may have accreted from a disk of debris after a giant impact simulations suggest that part of the moon derives from volatile poor melt in the hot inner disk with most of the volatile elements condensing later and accreting to earth

differences between reservoirs in the intra platform and platform margin reef shoal complexes of the upper ordovician lianglitag formation in the tazhong oil field nw china and corresponding exploration strategies abstract the upper ordovician lianglitag formation in the tazhong oil field nw china is dominantly composed of shallow marine carbonates and it can be subdivided into five members lithologically unclear understanding of the reservoir evolution in the platform margin and intra platform reef shoal complexes resulted in difficulty in locating reservoirs and poor drilling success in the intra platform by comparing the basic characteristics diagenesis and porosity evolution of the two types of reservoirs this study established their development patterns and proposed corresponding exploration strategies based on comprehensive analysis of core thin section well logging three dimensional seismic and geochemistry data the major difference between the platform margin and intra platform reservoirs lied in their pore types the platform margin reservoirs had fabric selective intragranular dissolution pores intergranular dissolution pores moldic pores and non fabric selective karst fractures and caves and tectonic fractures whereas the intra platform ones only had tectonic fractures intercrystalline dissolution pores and intergranular vugs in terms of distribution the platform margin reservoirs were mainly distributed in the parasequence top and landform highlands of the highstand system tract in members 3 to 1 appearing in two to six cycles with large single layer and accumulative thicknesses and a quasi bedded continuous distribution in the lateral however the distribution of the intra platform ones was not obviously correlated with sedimentary facies and paleogeomorphology with smaller single layer and accumulative thicknesses and poorer lateral continuity the evolution and distribution of high quality reservoirs in the platform margin were jointly controlled by eogenetic marine diagenetic and meteoric dissolution including karst burial dissolution and tectonic fractures in comparison eogenetic marine diagenetic and meteoric dissolution in the intra platform reef shoal complexes were weak accompanied by persistent cementation the favorable reservoirs were primarily controlled by fractures and later burial dissolution hence for the exploration of the platform margin reef shoal complex reservoirs the priority should be given to the areas with the superimposition of eogenetic marine diagenetic and meteoric dissolution burial dissolution and tectonic fracturing for the exploration of intra platform reef shoal complex reservoirs more attention should be paid to areas with overlapped fractures and burial dissolution especially where hercynian strike slip faults and early fractures were superimposed less attention should be paid to the areas with eogenetic marine diagenetic and meteoric dissolution

facies independent reservoir characterization of the micropore dominated word field edwards formation lavaca county texas micropore dominated carbonate reservoirs remain challenging for accurate hydrocarbon evaluation and production as conventional reservoir models using depositional textures and petrophysical properties to distribute porosity and permeability cannot be applied nevertheless understanding the distribution of pore systems and predicting the fluid flow behavior of microporous reservoirs is fundamental as micropores constitute a significant percentage of the total porosity and storage capacity we present the results from an integrated study on the producing micropore dominated word field characterized by a facies independent diagenetically controlled pore system that approaches 100 microporosity four cored wells through the albian edwards formation were described and correlated using stacking patterns and vertical facies trends pore type characterization was done through thin section petrography routine core analyses sem and micp data this study is an example of a permeable reservoir in which intergrain pores are cemented during burial diagenesis and micropores being more resistant to cementation remain open to depths greater than 4000 m 13 000 ft a unique relationship exists between porosity permeability median pore throat size and microcrystalline textures independent of facies and fabrics cumulative gas production data show there is a correlation between the total porosity and the structural position of the wells wells high on the structure have the highest production we demonstrate that an equally well connected micropore network exists in mud dominated rocks via the matrix and via grain to grain contacts in grain dominated rocks the here described intragrain micropore network through grain to grain contacts in cemented grainstones is a new carbonate flow path that will likely become more important as more unconventional carbonate reservoirs are explored

origin of micro rhombic calcite matrix within cretaceous reservoir rock west stuart city trend texas abstract cores from four wells from the west stuart city trend in la salle and webb counties texas were analyzed to define depositional and diagenetic facies and to determine factors controlling porosity distribution in all 1187 ft 362 m of core and 220 thin sections were examined in detail and supplemented by sem analyses of fractured surfaces and plastic casts of pore systems a comparison of lithofacies and ecologic facies to permeability and porosity values compiled from core data revealed that zones with permeabilities greater than 0 1 md and porosities of at least 6 were associated with rudistid grainstones cemented by isopachous submarine cement and packstones with a finely crystalline rhombic calcite matrix isotopic and trace element analyses of both isopachous submarine cements and micro rhombic matrix suggest a common origin the precursor to the micro rhombic calcite is believed to have been peloidal high magnesian calcite this internal marine sediment may be analogous to the peloidal fabrics that have been reported from holocene and pleistocene carbonates diagenetic equilibration of both submarine cements and peloidal infill is believed to have occurred during burial either in marine pore waters at elevated temperatures or in restricted flow phreatic freshwaters

a universal classification scheme for the microcrystals that host limestone microporosity abstract microporosity is recognized as a significant concern in phanerozoic age limestone reservoirs throughout the world because its presence can severely complicate hydrocarbon evaluation and production numerous studies have documented the occurrence and abundance of micropores their physical appearance and diagenetic origins in specific reservoirs but no published study has been systematic and global in its approach presented here is a global assessment of limestone microporosity that is based on scanning electron microscope crystal size distributions helium porosimetry and mercury injection capillary pressure data collected from 12 microporous limestone reservoirs spanning a broad range of geologic ages depositional facies and burial depths results indicate that the vast majority of limestone microporosity is hosted within a framework of low magnesium calcite microcrystals in general crystal size distributions are narrow and positively skewed compiled data indicate that 99 of all microcrystals measure between 0 5 and 9 0 m in diameter with a mode at ca 2 0 m based on microcrystal shape packing and edge density microporous limestones can be classified into three major textural classes which we term granular clustered and fitted granular textures which include subhedral and euhedral subclasses are characterized by a framework of unconsolidated rhombic to polyhedral microcrystals that exhibit straight to curvilinear boundaries and intermediate crystal edge densities clustered textures which include loose and fused subclasses are characterized by a framework of irregularly shaped microcrystals with relatively high densities of discontinuous curvilinear crystal edges fitted textures which include partial and fused subclasses are characterized by a dense mosaic of slightly larger microcrystals with mostly curvilinear boundaries and relatively low edge densities these textural classes have unique mean crystal sizes average pore throat radii bulk porosities and permeabilities furthermore textural classes and their characteristic pore throat radii fall along a single log normal transform in porosity permeability space based on these relationships three petrophysical microporosity types are distinguished type 1 is associated with granular subhedral crystal fabrics and typically exhibit relatively large average pore throat radii ca 0 7 m as well as high porosity 20 and permeability 1 20 md type 2 includes granular euhedral and clustered fabrics which most commonly exhibit intermediate average pore throat radii ca 0 2 m porosity 10 20 and permeability 0 1 1 md type 3 includes fitted crystal fabrics which are generally characterized by smaller average pore throat radii ca 0 06 m and relatively low porosity 10 and permeability 0 1 md

petrogenesis of picritic mare magmas constraints on the extent of early lunar differentiation calculations of isobaric batch polybaric batch and polybaric fractional melting have been carried out on a variety of proposed lunar and terrestrial source region compositions results show that magmas with a generally tholeiitic character plagioclase and high ca pyroxene crystallize before low ca pyroxene reflecting relatively high al2o3 concentrations 12 wt are the inevitable consequence of anhydrous partial melting of source regions composed primarily of olivine and two pyroxenes with an aluminous phase on the solidus low al2o3 magmas 10 wt as typified by the green picritic glasses in the lunar maria require deep 700 1000 km low al2o3 source regions without an aluminous phase the difference between primitive and depleted mantle beneath mid ocean ridges amounts to less than 0 1 wt al2o3 whereas formation of the green glass source region requires a net loss of between 1 5 and 2 5 wt al2o3 basalt extraction cannot account for fractionations of this magnitude accumulation of olivine and pyroxene at the base of a crystallizing magma ocean is however an effective method for producing the necessary al2o3 depletions both olivine rich and pyroxene rich source regions can produce the picritic magmas but mixing calculations show that both types of source region are likely to be hybrids consisting of an early to intermediate stage cumulate olivine plus enstatite and a later stage cumulate assemblage mass balance calculations show that refractory element enriched bulk moon compositions contain too much al2o3 to allow for the deep low al2o3 source regions even after extraction of an al2o3 rich 26 30 wt crust between 50 and 70 km thick

the role of microbialitic facies in the micro and nano pore system of dolomitized carbonate platforms upper triassic southern italy abstract the pore system of two dolomitized triassic carbonate platforms named lower and upper unit and cropping out in southern italy has been investigated through mercury porosimetry and electron microscopy despite their variability all facies show micro to nano pores systems composed of intra and inter crystal pore types this is due to the prevalence of microbialites in the inner platform margin settings together with an homogenous diagenetic history porosity and permeability are generally very low 60 the porosity derived from nanopores is significant in all facies and particularly in the shallow water environments a positive correlation between nanopores volume and porosity is present in the whole upper unit and in the shallow water facies of the lower unit moreover different sub environments of the platforms show separated amount of nanopores and porosity on the contrary permeability does not seem to be influenced by the nanopores distribution regardless a wide spectrum of fabric and morphologies microbialitic facies of both units show a confined range of porosity average 1 0 standard deviation 0 6 and permeability average 0 4 standard deviation 0 2 most probably because composed of syn sedimentary microbial dolomite which presents a high resistance to compaction during the burial history finally despite the complete dolomitization porosity and permeability ratio varies in function of the main depositional environments and less of the precursor sedimentary facies suggesting a control of the final pore size distribution mainly linked with the presence absence of the microbial primary dolomitic facies instead of the native fabrics of the other sedimentary facies

new exploration concepts for the edwards and sligo margins cretaceous of onshore texas we examined the potential in onshore texas of the most prolific reservoirs found to date in the gulf of mexico basin cretaceous carbonates and in particular the edwards and sligo formations two dimensional 2 d and three dimensional 3 d seismic data with lithologic and biostratigraphic information led to a detailed sequence stratigraphic framework this framework resulted in a concentrated exploration effort in lavaca county a redefinition of the edwards shelf margin and confirmation of a major sequence boundary in the sligo the youngest edwards margin appears to have stepped seaward a distance of more than 3 mi 4 8 km from the position of the margin as indicated by the word field this seaward shift and repositioning of the margin is shown in 3 d seismic and well data recognized within the progradational package are distal slope wackestones reef and bank complexes and back reef lagoonal deposits that are offset seaward across sequence boundaries reef and grainstone deposits are located far seaward of the commonly recognized margin and numerous exposure surfaces occur in the shelf deposits proximity to faulting after burial ensures the development of a plumbing system that enhances secondary porosity and provides a migration pathway for hydrocarbons a sligo debris play is based on a sequence boundary within the upper part of the sligo in ferred from seismic geometry and surface exposures in mexico the seismic portrays a wedge geometry positioned downslope from the sligo margin base level change about the sequence boundary would have initiated coarse carbonate debris and grain flow deposition seaward of the sligo shelf margin rapid deposition may have helped preserve porosity within the thick debris wedge data from reservoir analogs confirm that downslope carbonates can retain reservoir quality porosity facies variation and slump faulting on the foreslope creates the potential for trapping and juxtaposition to deep water carbonates sets up the source and migration pathway this undrilled wedge extends for hundreds of miles along the sligo margin

the nature and origin of rims on lunar soil grains abstract space weathering processes that operate in the lunar regolith modify the surfaces of lunar soil grains transmission electron microscope analysis of the lunar soil grains from the fine size fraction of several lunar soils show that most grains are surrounded by thin 60 200 nm thick rims the microstructure and chemical compositions of the rims can be used to classify rims into four broad categories amorphous inclusion rich multiple and vesicular amorphous rims are noncrystalline generally lack crystalline inclusions show evidence for preferential sputtering of cations and are produced largely by solar wind irradiation damage inclusion rich rims contain abundant nanometer sized grains of fe metal as randomly dispersed inclusions or as distinct layers embedded in an amorphous silica rich matrix inclusion rich rims are compositionally distinct from their host grains and typically contain accumulations of elements that are not indigenous to the host inclusion rich rims are formed largely by the deposition of impact generated vapors with a contribution from the deposition of sputtered ions a continuum in the chemical and microstructural properties exists between typical amorphous rims and typical inclusion rich rims multiple rims consist of a distinct radiation damaged layer up to 50 nm thick that is overlain by vapor deposited material of comparable thickness vesicular rims are compositionally similar to their hosts and are characterized by an abundance of small the formation of rims on lunar soils is complex and involves several processes whose effects may be superimposed from this study it is shown that one process does not dominate and that the relative importance of vapor deposition is comparable to radiation damage in the formation of rims on lunar silicate grains the presence of rims on lunar soil grains particularly those with nanometer sized fe metal inclusions may have a major influence on the optical and magnetic properties of lunar soils

petrophysical heterogeneity in a lower cretaceous limestone reservoir onshore abu dhabi united arab emirates the upper zone of the lower cretaceous kharaib formation 151 177 ft 46 54 m thick in the studied wells is a major oil reservoir in several giant oil fields wide variations in porosity and permeability of this zone have been shown to result from both the inhibition of burial cementation by oil in the crest of each field and localized cementation adjacent to stylolites combined with the more subtle influence of widely varying depositional mud content and grain size the present study examines these relationships in closer detail using core and petrographic observations from two wells on the oil filled crest and two wells on the water filled flanks of a giant domal oil field although porosities are higher overall in the crestal cores each well shows wide variations within each of seven main groupings of the samples by depositional texture this heterogeneity results mainly from the distribution of clay which is concentrated along depositional laminations and causes widely varying porosity losses in all textures by promoting stylolite development and associated calcite cementation higher clay abundance and lower porosity within the upper and lower 12 17 ft 4 5 m of the reservoir reflects increased influx of siliciclastic fines across the epeiric barremian carbonate platform immediately following and preceding respectively third order falls in global sea level most 95 of porosity permeability data from the studied wells lie within lucia rock fabric class 3 showing distinct but relatively subtle differences between texture groups whereas a subordinate part of the data from the upper relatively mud poor third of the reservoir plot at higher permeabilities development of a predictive model for the petrophysical heterogeneity of this example requires a combination of the following 1 a diagenetic model for porosity controls 2 the use of a modestly higher porosity permeability transform upper class 3 in the upper part of the reservoir than in the lower reservoir lower class 3 and 3 a recognition of the scattered and widely varying occurrences of exceptionally high permeabilities in the upper reservoir

interrelations of the petrophysical sedimentological and microstructural properties of the oolithe blanche formation bathonian saline aquifer of the paris basin abstract the paris basin seems a suitable location for co2 capture and storage given both the amount of co2 produced and the availability of depleted fields and deep saline aquifers this study investigates the petrophysical properties in relation to the sedimentary and diagenetic environment of the oolithe blanche formation middle jurassic a deep saline aquifer considered a potential candidate for co2 storage because of the scarcity of core data in the paris basin our investigation was based on the study of field analogues in the south east part of the paris basin the oolithe blanche formation bathonian is 70 80 m thick eighteen oriented blocks were collected from three outcrops selected for the different sedimentological facies identified in the formation their petrophysical properties were measured porosity pore size distribution derived from mercury injection tests permeability and capillary imbibition parameters the sedimentary and diagenetic facies were defined by using optical microscopy coupled with image analysis on thin sections and sem the oolithe blanche formation is composed of oolitic and bioclastic limestones deposited in a shallow marine setting three main sedimentological facies were defined the oolitic shoal facies the tide dominated facies and the prograding oolitic facies they exhibit subtle variations in composition and in the distribution of carbonate textures porosity measured using the water saturation triple weight method ranges from 6 to 34 permeability values are low between 0 1 md and 9 md the data from mercury intrusion porosimetry show that the distribution of the pore throat diameter is either unimodal microporosity only or bimodal macro and microporosity microporosity is intraparticle intraooid and macroporosity is interparticle and is related to dolo dedolomitization variations of petrophysical parameters can be explained by the microstructure now these latter results calibrated by studying field analogues must be extended to borehole data and core data to optimize our knowledge of the deep saline aquifer of the oolithe blanche formation without such investigations it will be impossible to estimate the suitability of this deep saline aquifer for co2 storage

the tethered moon abstract we address the thermal history of the earth after the moon forming impact taking tidal heating and thermal blanketing by the atmosphere into account the atmosphere sets an upper bound of 100 w m2 on how quickly the earth can cool the liquid magma ocean cools over 2 10 myr with longer times corresponding to high angular momentum events tidal heating is focused mostly in mantle materials that are just beginning to freeze the atmosphere s control over cooling sets up a negative feedback between viscosity dependent tidal heating and temperature dependent viscosity of the magma ocean while the feedback holds evolution of the moon s orbit is limited by the modest radiative cooling rate of earth s atmosphere orbital evolution is orders of magnitude slower than in conventional constant q models which promotes capture by resonances the evection resonance is encountered early when the earth is molten capture by the evection resonance appears certain but unlikely to generate much eccentricity because it is encountered early when the earth is molten and q q tidal dissipation in the earth becomes more efficient q q later when the moon is between 20 r and 40 r if lunar eccentricity grew great this was when it did so perhaps setting the table for some other process to leave its mark on the inclination of the moon

the lunar magma ocean reconciling the solidification process with lunar petrology and geochronology abstract the moon is thought to have originated with a magma ocean that produced a plagioclase flotation crust as solidification proceeded ages of anorthositic crust range over at least 200 million years the model for solidification presented here integrates chemical and physical constraints of lunar magma ocean solidification to determine 1 the final thickness of flotation crust generated by a fractionally solidifying magma ocean 2 the timescale of crystallization before plagioclase is a stable phase 3 the timescale of solidification after the formation of the plagioclase flotation crust and 4 the post overturn lunar mantle composition and structure we find that magma oceans of as much as 1000 km depth are consistent with creating an anorthositic crust 40 to 50 km in thickness solidification of the magma ocean prior to formation of the flotation crust may occur on the order of 1000 years and complete solidification would require additional ten to tens of millions of years reconciling these short model timescales with radiometric dates of crustal samples requires either a very late forming moon combined with finding older crustal ages to be incorrect or calling on tidal heating of the crust by the early earth to prolong solidification gravitationally driven overturn of cumulates during tidal heating provides a mechanism for creating the compositions and ages of the lunar mg suite of crustal rocks further we find that upon crystallization the moon likely began with an azimuthally heterogeneous gravitationally stable mantle after magma ocean cumulate overturn this result may help explain the experimentally determined origin of picritic glasses at similar depths but from different source materials

massive layer of pure anorthosite on the moon 1 we present a new global survey of the purest anorthosite pan rock using the spectral profiler onboard kaguya we found that pan rocks are widely distributed over the moon including the feldspathic highland terrain and the south and north polar regions all pan sites are associated with huge impact structures with diameters larger than 100 km based on the global distributions of pan and olivine rich sites we propose the existence of a massive pan layer with a thickness of 50 km below an uppermost mafic rich mixed layer with a thickness of 10 km below the pan layer a lower crustal layer with olivine rich materials may be present on the nearside but not on the far side of the moon the existence of a pan layer with a thickness of 50 km suggests an al2o3 abundance of 33 to 34 wt in the lunar crust which is higher than previous estimates of 32 wt our data indicate the massive production event of pan during the early stage of the formation of the moon supporting the lunar magma ocean scenario

heavy rare earth element enrichment in granites of the aar massif central alps switzerland abstract the paper presents rare earth element ree determinations of whole rocks and minerals of the central aar granite a hercynian composite granite intrusion in the aar massif central alps consisting mainly of granodiorites granites and leucogranites their geochemical differentation is characterized by a slight depletion of light ree lree and eu and a clear enrichment of heavy ree hree this evolution leads to hree enriched leucogranites with typical wing shaped distribution patterns in chondrite normalized diagrams these distribution patterns can be explained either by pure fractional crystallization of k feldspar and or by crystallization of accessory phases that did not deplete the melt in hree due to their affinity to highly polymerized high silica melts the latter stayed in the liquid phase until they were incorporated in solids during the final stage of bulk magma crystallization the ree contents of analyzed mineral phases allanite apatite biotite epidote garnet and zircon are used to calculate a ree budget of the whole rock these data suggest that existence of further hree rich accessory mineral phases in the felsic rock compositions which have not been analyzed qualitative x ray and eds analyses revealed the existence of accessory minerals like thorite chernovite an y ca mineral and polycrase these minerals may play an outstanding role in the distribution of ree u and th in high silica melts

post magmatic resetting of rb sr whole rock ages a study in the central aar granite central alps switzerland this study investigates the post magmatic reequilibration of rb sr whole rock isochrons in the central aar granite aar massif central alps a post magmatic prealpine hydrothermal alteration caused rehomogenization of sr isotopes in local subsystems of the granites by subsolidus reactions mainly involving k feldspar the size of these rehomogenized subsystems is dependent on rock mineralogy and chemistry interference between sample size size of the rehomogenized subsystem and undisturbed magmatic system size yields a series of rb sr wholerock ages intermediate between an upper carboniferous intrusion age and the age of a hypothetical triassic liassic alteration event the microscopic reaction textures as well as the rb sr age systematics of this hydrothermal event can be distinguished from alpine metamorphic effects

regional variation of permeability in thamama b reservoirs of abu dhabi abstract to better understand reservoir quality in a major oil producing limestone unit the thamama b zone of the lower cretaceous barremian kharaib formation this study compiles and analyzes average values of porosity and permeability measured on 330 well cores in both onshore and offshore areas of the abu dhabi emirate most average and individual values plot along a single porosity permeability trend which is unaffected by porosity preserving early oil emplacement and only moderately influenced by texture and clay content the main trend corresponds with the established field for mud dominated microporous limestones but a subordinate proportion termed hi k plug samples have significantly higher permeability for given porosity the hi k samples are more abundant in the southwestern part of the study area and also show spatial clustering within individual oilfields the present macro scale view of thamama b reservoir quality is a new resource that can be useful for both exploration and production planning