a transient heating event in the history of a highlands troctolite from apollo 12 soil 12033 a 1 5 mm clast of a highlands troctolite attached to a glassy alkali rich soil breccia was identified in a thin section of 1 2 mm particles from apollo 12 soil sample 12033 the troctolite consists of euhedral olivines fo89 in a groundmass of granulitic plagioclase an95 each olivine grain is rimmed by a thin selvage of olivine plagioclase glass containing vesicles and minute crystallites of spinel olivine and plagioclase this unique texture records a complex history beginning with the formation of the troctolite as a plutonic cumulate followed by subsolidus metamorphism partial remelting vesculation crystallite growth and quenching experimental runs on plagioclase olivine melting rates show that at temperatures above incipient melting the grain boundary selvages in the lunar troctolite would have formed very rapidly in less than about 10 min preservation of selvage glass required rapid cooling the troctolite was subject to a heat pulse most likely accompanying an impact event the same event or more probably a later one welded the troctolite to the soil breccia inasmuch as this particle was found on oceanus procellarum at a site crossed by a ray from copernicus and because olivine has been identified by remote sensing experiments as the dominant mafic mineral in the central peak of copernicus we suggest that the troctolite is a fragment of copernicus ejecta

radiative transfer modeling of near infrared reflectance of lunar highland and mare soils 1 with near infrared hyperspectral data sets returned from kaguya selene and chandrayaan 1 s moon mineralogic mapper m3 accurate evaluation and interpretation of lunar data sets with higher spectral resolution has never been more critical here we test a new radiative transfer spectral modeling algorithm to determine composition from hyperspectral reflectance spectra of lunar soils data for 19 lunar mare and highland soil samples previously characterized by the lunar soil characterization consortium are used for validation spectral fits are made using a goodness of fit metric considering spectral shape spectral contrast spectral slope and iron abundance high precision fits are achieved for nearly every soil with this algorithm using a plot of spectral shape relative to the ratio mg i e molar mg mg fe 100 determines the winning model and composition mg is determined with an average difference of 11 15 and 3 8 units before and after a correction is applied respectively mineralogy is determined with an average difference of 5 15 vol depending upon the mineral constituent

quantitative analysis and paleoecology of earliest mississippian microbial reefs gudman formation queensland australia not just post disaster phenomena small 30 m diameter 9 m thick reefs in the gudman formation of queensland australia are the oldest known mississippian reefs occurring very near the devonian carboniferous boundary following late devonian extinction events they occur in high energy shallow oolitic grainstones and consist of 70 microbialite and bound detritus on the basis of point count analysis skeletal organisms including potential frame building rugose and tabulate corals ramose bryozoans crinoids and algae occur in growth position but account for only 4 4 of sampled framework the microbial framework was syndepositionally rigid on the basis of 1 vertical and overhanging relief in a high energy setting 2 export of framework intraclasts 3 hard substrate encrusting organisms 4 abundant hard rock borings and 5 neptunian dikes unusually for mississippian reefs stromatolites make up a large part of the framework 32 but more typical thrombolites are equally abundant interfingering of skeletal organisms and microbialites suggests that they grew in welloxygenated normal marine waters and that microbial biofilms competed effectively with skeletal organisms for available substrate abundant and diverse co occurring skeletal flora and fauna are inconsistent with interpretations of gudman stromatolites as post extinction disaster taxa hence gudman reefs are stromatolite rich examples of a larger class of microbialite dominated phanerozoic reefs that occurred with abundant skeletal metazoans in normal marine settings

metal silicate mixtures spectral properties and applications to asteroid taxonomy the reflectance spectra of combinations of olivine orthopyroxene and iron meteorite metal show systematic variations in spectral properties which can be used to constrain many of the physical and chemical properties of the assemblages the presence of metal most noticeably affects band area ratios peak peak and peak minimum reflectance ratios and band widths these parameters are also affected to varying degrees by the abundance and grain size of the metal and silicates and the composition of the silicates band width and band areas are useful for determining metal abundance in olivine metal and orthopyroxene metal assemblages respectively mafic silicate grain size variations are best determined using band depth criteria band centers are most useful for determining mafic silicate composition analysis of the reflectance spectrum of the s class asteroid 8 flora on the basis of these spectral parameters indicates a surface composed of approximately 50 wt metal 40 wt olivine fa 35 10 10 wt orthopyroxene fs 30 25 35 and perhaps a few weight percent of clinopyroxene a substantial amount of the surface seems to consist of a fine grained 45 m size component analysis of the reflectance spectrum of the a class asteroid 446 aeternitas suggests a surface assemblage of approximately 35 wt metal 55 wt olivine fa 20 10 7 wt clinopyroxene fs 17 and 3 wt orthopyroxene fs 45 a substantial fine grained 45 m size surface component is also indicated for this asteroid

new results and implications for lunar crustal iron distribution using sensor data fusion techniques remote measurements of the moon have provided iron maps and thus essential constraints for models of lunar crustal formation and mare basalt petrogenesis a bulk crustal iron map was produced for the equatorial region from apollo gamma ray agr spectrometer measurements and a global iron variation map from recent clementine spectral reflectance csr measurements both iron maps show bimodal distribution but have significantly different peak values and variations in this paper csr data have been recalibrated to pyroxene in lunar landing site soils a residual iron map is derived from the difference between agr bulk and recalibrated csr pyroxene iron abundances the most likely interpretation is that the residual represents ferrous iron in olivine this residual iron is anticorrelated to basin age with older basins containing less olivine suggesting segregation of basin basalt sources from a progressively fractionating underlying source region at the time of basin formation results presented here provide a quantitative basis for 1 establishing the relationship between direct geochemical gamma ray x ray and mineralogical near ir remote sensing data sets using sensor data fusion techniques to allow 2 simultaneous determination of elemental and mineralogical component distribution on remote targets and 3 meaningful interpretation of orbital and ground based spectral reflectance measurements when calibrated data from the lunar prospector mission are available mapping of bulk crustal iron and iron bearing soil components will be possible for the entire moon similar analyses for data from the near earth asteroid rendezvous near mission to asteroid 433 eros will constrain models of asteroid formation

palaeoenvironmental control on sponge microbialite reefs and contemporaneous deep shelf marl limestone deposition late oxfordian southern germany abstract the late oxfordian bimammatum zone deep shelf deposits of southern germany are characterised by abundant reefs that laterally pass into marl limestone alternations the bioconstructions are made from three main components sponges microbialites and allochthonous sediment a detailed morphological analysis of sponge microbialite reefs in the plettenberg section swabian alb southern germany is combined with investigation of calcareous nannofossil assemblages in laterally correspondent marl limestone alternations in order to trace the evolution of palaeoenvironmental conditions during reef development fluctuations of caco3 content in deep shelf deposits provides evidence of a succession of small scale lithological units generally formed by five to six marl limestone couplets within a small scale lithological unit a close link is observed between growth patterns of sponge microbialite reefs and the changes in the nannofossil assemblage composition phases of expansion of the build ups correspond to carbonate deposits characterised by a relative dominance of large oligotrophic nannoplankton species large watznaueria britannica watznaueria manivitiae and schizosphaerella spp marly intervals reveal a high relative abundance of small sized taxa mainly lotharingius hauffii small w britannica and subordinated biscutum dorsetensis and bioconstructions show a net reduction in size or a total demise this suggests that the same palaeoenvironmental parameters controlled at the same time marl versus limestone deposition reef growth phases and calcareous nannofossil assemblage composition successive reef growth phases recognized within a bioherm are correlated to the limestone hemi couplets each reef growth phase is composed of several stacked elementary sequences comprising the following succession i sponge ii microbialites and iii carbonate mud in turn the microbialitic crust is formed of three successive microbial layers 1 a fine crust of dense to clotted micrite 2 a centimetre scale to multicentimetric columnar layer of clotted to peloidal micrite 3 a centimetre scale stromatolitic crust the passage from an initial dense microbial layer with numerous microencrusters to a final stromatolitic crust is interpreted as resulting from an increase of the microbial growth rate mainly driven by changes in the accumulation rate deep shelf deposits resulted from changes in platform carbonate production and export basinwards controlled both by sea level and climate changes climate controlled the intensity of carbonate production in shallow platform environments and export towards the deep shelf as well as the trophic conditions of the deep shelf marine waters low trophic conditions favoured platform carbonate production and export basinwards and a large development of the sponge microbialite reefs in the deep shelf however a high carbonate accumulation rate in the deep shelf was also commonly responsible for the demise of sponge microbialite reefs during unfavourable and higher trophic conditions during marl deposition reduced development and frequent demise of the sponge microbialite reefs is observed

production of subtidal tubular and surficial tempestites by hurricane kate caicos platform british west indies abstract storm infilling of deep open callianassa burrows with molluscan to peloidal packstone was the dominant style of preservable sedimentation produced by the passage of hurricane kate across caicos platform british west indies on 18 november 1985 this moderate hurricane was the first to affect an actively studied portion of the carbonate platform environments of the south florida bahama region in 19 years a time during which many of our concepts of storm sedimentation have evolved prior to hurricane kate much of the shallow platform interior peloidal packstone to grapestone grainstone had a sparse seagrass cover and a highly irregular bottom caused by abundant callianassa mounds hurricane kate flattened the mounded bottom of the platform interior and caused minor smothering and erosion of the seagrass beds a thin surficial tempestite though deposited over much of the platform was difficult to identify because it lacked a coarse base instead much of the reworked surface sediment poured down the large callianassa burrow entrances and filled the vast burrow networks with either a coarse molluscan packstone or peloidal skeletal packstone storm burrow filling tubular tempestites effectively removed the coarse fraction from contributing to a surficial storm layer ten percent of the upper 75 cm of platform interior sediment consists of tubular tempestites from hurricane kate

pyroxene spectroscopy revisited spectral compositional correlations and relationship to geothermometry the authors wish to thank the various agencies which have provided the necessary support for this project including grants in aid of research from sigma xi the scientific research society to e a c the geological society of america grant 3741 87 to e a c and nasa planetary geology and geophysics grant nagw 642 to m j g

sea level changes an integrated approach sea level changes an integrated approach in october 1985 sepm sponsored a four day conference entitled sea level changes an integrated approach the purpose of the conference was to provide a forum for an interdisciplinary exchange of ideas on sea level changes and to provide an opportunity for integrating various types of evidence in approaching unresolved issues the conference was successful in bringing together scientists from industry academia and government representing all of the major geosciences disciplines presentations of many new papers plus significant releases of data that were previously held proprietary provided fertile ground for discussion this much cited volume represents the best of the material presented at the conference includes the early vail chart

aeolian cliff top deposits and buried soils in the white river badlands south dakota usa aeolian deposits in the north american great plains are important sources of holocene palaeo environmental records although there are extensive studies on loess and dune records in the region little is known about records in aeolian cliff top deposits these are common on table mesa edges in the white river badlands these sediments typically have loam and sandy loam textures with dominantly very fine sand 0 5 1 organic carbon and 0 5 5 caco3 some of these aeolian deposits are atypically coarse and contain granules and fine pebbles buried soils within these deposits are weakly developed with a c and a ac c profiles beneath these are buried soils with varying degrees of pedogenic development formed in fluvial aeolian or colluvial deposits thickness and number of buried soils vary however late holocene soils from several localities have ages of approximately 1300 2500 and 3700 14c yrs bp the 1300 14c yr bp soil is cumulic with a thicker and lighter a horizon soils beneath the cliff top dep

model near infrared optical constants of olivine and pyroxene as a function of iron content the imaginary coefficients of the complex index of refraction of olivine low ca orthopyroxene and high ca clinopyroxene are derived as a function of iron content and wavelength over the spectral region 0 4 to 2 5 m from reflectance spectra of powders and hapke radiative transfer theory reflectance spectra as a function of composition and grain size are computed and compared i find that while spectral effects of variations in these parameters are similar they are distinguishable variations in iron content do not explain all the observed spectral variations in the spectra of the samples investigated

global occurrence trend of high ca pyroxene on lunar highlands and its implications we present details of the global distribution of high ca pyroxene hcp rich sites in the lunar highlands based on the global data set of hyperspectral reflectance obtained by the selene spectral profiler most hcp rich sites in the lunar highlands are found at fresh impact craters in each crater most of the detection points are distributed on the ejecta rim and floor of the impact craters rather than the central peaks while the central peaks are dominated by purest anorthosite pan this indicates that hcp rich materials originate from relatively shallower regions of the lunar crust than pan in addition while all ray craters with sizes larger than 40 km possess hcp rich materials small fresh craters with sizes less than 6 10 km do not indicating that the uppermost mixing layers in the lunar crust are not dominated by hcp based on these results we propose that in the upper lunar crust a hcp rich zone overlying the pan layer exists below the uppermost mixing layer this hcp rich zone may originate from interstitial melt during the formation of the flotation anorthositic cumulate while an impact ejecta origin impact melt origin and or magmatic intrusion into the upper lunar crust may also account for the occurrence of hcp rich sites in the highlands

on the appearance of cyanobacterial calcification in modern stromatolites abstract in august 1991 calcified magnesian calcite filamentous cyanobacteria scytonema mirabile appeared on the surface of a modern lacustrine stromatolite lake r2 rangiroa atoll tuamotu archipelago french polynesia previously the topmost photosynthetic layer of this sediment was devoid of such microbial biomineralisers the calcified cyanobacteria are accompanied by magnesian calcite grains which are evocative of bacterial precipitates although the appearance of cyanobacterial calcification might be related to environmental changes in the lake in particular a decrease in water salinity the persistence of non calcified specimens of a filamentous cyanobacteria phormidium crossbyanum which was once a dominant species of the lake benthos shows that calcification and environmental conditions might be only indirectly related thus attempts to use the fossil record of calcareous cyanobacterial skeletons to infer changes in the chemical composition of past oceans cannot be made without due regard of biological processes like the appearance of new competitors

integrated sequence stratigraphy facies stable isotope and palynofacies analysis in a deeper epicontinental carbonate ramp late jurassic sw germany abstract sequence stratigraphy in deeper water epicontinental carbonates such as in the upper jurassic of southern germany is difficult because the recognition of parasequences sequences and sequence boundaries is impeded by the paucity in diagnostic sedimentological criteria or stratal surfaces using the genetic stratigraphic approach and integrating facies stable isotope c o and palynofacies analysis two types of genetic depositional sequences can be discriminated small scale sequences are stacked into medium scale sequences which may record a 400 kyr milankovitch signal the medium scale sequences were correlated regionally using both gamma ray logs and stable isotope records regional correlations show that the depocentres are controlled by underlying palaeotectonic elements late palaeozoic troughs the rise fall turnarounds of medium scale sequences are marked by negative 18o peaks temperature maxima and reduced absolute palynoclast contents the fall rise turnarounds are marked by positive 18o peaks temperature minima and high absolute palynoclast contents the initiation and termination of sponge microbial mounds show characteristic patterns thrombolitic microbialites form during intervals of 1 reduced input of terrestrial palynomorphs interpreted as an increase in distality 2 decreasing 13c trends interpreted to be related to decreasing nutrient supply and 3 decreasing 18o values interpreted as phases of warming and rising relative sea level in contrast thrombolitic stromatolitic microbialites were found to occur during phases of 1 increasing input of terrestrial palynomorphs interpreted as an increase in proximality 2 increasing 13c values interpreted to reflect increasing terrestrial input and nutrient supply as well as increasing 18o values interpreted as phases of cooling and relative sea level falls isotopic and palynofacies evidence suggests that bioherms were terminated by sudden input of nutrients during relative sea level falls sedimentological criteria were clearly not sufficient to delineate a robust sequence stratigraphic framework

manganese rich olivines identification from spectral reflectance properties this work was supported by grants in aid of research from the geological society of america and sigma xi the scientific research society

delineating sequence stratigraphic patterns in deeper ramp carbonates quantitative palynofacies data from the upper jurassic kimmeridgian of southwest germany abstract the delineation of sequence stratigraphic patterns in deeper ramp carbonates is notoriously difficult using sedimentological criteria hence in an effort to better understand the processes controlling the formation of deeper water carbonate ramps fully quantitative palynofacies analyses were carried out on two cores from the upper jurassic kimmeridgian of the swabian marl basin sw germany to eliminate the effect of variable carbonate content absolute palynoclast abundances i e particles per gram of sediment were calculated with respect to the non carbonate fraction of the original sediment the palynofacies data were supplemented by bulk sediment oxygen isotope data and sedimentological information terrestrial and marine palynoclast groups show in phase cyclical absolute abundance patterns in both cores investigated highest carbonate adjusted absolute abundances of terrigenous palynoclasts are interpreted to indicate sea level lowstands and vice versa the in phase distribution of marine and terrestrial palynoclast groups points towards a coupling between the terrestrial and marine realms increased absolute abundances of terrigenous palynoclasts are interpreted to represent intervals of enhanced land derived nutrient input into the marine system such higher nutrient availability would have caused higher phytoplankton productivity as evidenced in increased absolute abundances of marine palynomorphs hence marine productivity in the epeiric setting of the swabian marl basin was strongly controlled by the nutrient flux from the surrounding landmasses in the palynofacies and bulk sediment 18o records two hierarchies of sequences are recognized well pronounced medium scale sequences with thicknesses of 5 20 m are built by the stacking of smaller scale sequences with thicknesses of 3 7 m heavier 18o values coincide with high absolute abundances of terrigenous palynoclasts based on this observation a model for environmental fluctuations is proposed time intervals with high sea level were characterized by relatively high water temperatures whereas time intervals with low sea level coincided with relatively low water temperatures estimates of ammonite zone ages available from the literature were used to constrain the duration of medium scale sequences when taking into account the range of dating uncertainties the obtained value of ca 370 kyr appears reasonably close to the duration of the 400 kyr eccentricity cycle we speculate that the formation of medium scale sequences as evidenced in our palynoclast and 18o records may be related to eccentricity driven insolation changes that caused sea level changes with higher insolation leading to a sea level rise this would imply that the regional record of sea level and temperature fluctuations within the epeiric swabian marl basin reflects climatic changes that occurred on a more global scale the integration with sedimentological data shows that marl dominated intervals were deposited during early sea level rise and under cooler conditions whereas limestone dominated intervals formed during intervals of high sea level and under warmer conditions

oxfordian reef architecture of the la manga formation neuquen basin mendoza province argentina abstract the neuquen back arc basin is located on the west margin of the south american platform between latitudes 36 and 40 s the basin is famous for its continuous sedimentary record from the late triassic to cenozoic comprising continental and marine clastic carbonate and evaporitic deposits up to 2 600 m in thickness the stratigraphical and paleontological studies of the outcrops of the la manga formation argentina located near the bardas blancas region mendoza province 35 s and 69 o allow the reconstruction of the sedimentary environments of an oxfordian carbonate ramp where outer ramp middle ramp inner ramp oolitic shoal inner ramp margin patch reef lagoon and paleokarst were differentiated the reefs consist of back reef facies and in situ framework of coral boundstones that was formed at the top of shallowing upward succession coral reefs were analyzed by defining coral colonies shapes paleontological content coral diversity and taphonomy studies in some studied sections abundant fragments of gryphaeids encrusting bryozoans and isolated sponges provided a suitable substrate for coral colonization however other sections show an increase in the proportions of ooids peloidal and coral intraclasts the core reef facies is composed of white grey unstratified and low diversity scleractinian coral limestone dominated by robust and thinly branching corals with cerioid phocoid growths and massive coral colonies with meandroid thamnasteroid growth forms the assemblage is characterized by actinastraea sp australoseris sp thamnasteria sp and garateastrea sp internal facies organization and different types of coral colonies allow to recognize the development of varying framework as well as intercolony areas a superstratal growth fabric characterizes the coral assemblage on the basis of coral growth fabric branche and domal types the reef of la manga formation is considered a typical mixstones the intercolony areas consist of biomicrites and biomicrorudites containing abundant coral fragments parautochthonous gryphaeids and another bivalves ctenostreon sp gastropods harpagodes sp natica sp echinoderms test and spines plegiocidaris sp miliolids cayeuxia sp acicularia sp salpingoporella sp intraclasts ooids peloids and coated grains the domal growth forms are probably more protected against biological and physical destruction meanwhile delicate branching growth forms with very open and fragile framework were more affected and fragmented due to wave action and bioerosion the reef fabric shows different intervals of truncation as consequence of erosion resulting from coral destruction by storm waves or currents the maximum flooding surface separates oolitic shoal facies below from the aggradational and progradational coralline limestones facies above subsequent sea level fall and karstification 148 ma affected reef and oolitic facies

surveying the south pole aitken basin magnetic anomaly for remnant impactor metallic iron abstract the moon has areas of magnetized crust magnetic anomalies the origins of which are poorly constrained a magnetic anomaly near the northern rim of south pole aitken spa basin was recently postulated to originate from remnant metallic iron emplaced by the spa basin forming impactor here we remotely examine the regolith of this spa magnetic anomaly with a combination of clementine and lunar prospector derived iron maps for any evidence of enhanced metallic iron content we find that these data sets do not definitively detect the hypothesized remnant metallic iron within the upper tens of centimeters of the lunar regolith

pleistocene wind system in eastern austria and its impact on landscape evolution abstract during cold periods in the quaternary the intracontinental pannonian basin was part of the european periglacial zone and aeolian erosion had a profound effect in shaping the landscape geomorphologically most effective winds were channelled between the alps and carpathians and entered the pannonian basin from the nw to assess the nature of meteorological conditions producing these winds field studies were carried out in the foreland of the basin entrance in eastern austria as a result we report on the first bedrock ventifacts from austria and aeolian sand occurrence in the bohemian massif through a compilation of published data and field work the distribution of ventifacts was mapped and appears to be controlled primarily by available lithologies palaeo wind directions were identified using mesoforms of bedrock ventifacts especially flutes the acquired air flow directions are accordant with the orientation of erosional landforms on soft sediments and form a coherent system with westerly to north westerly winds in the west which turn towards the entrance of the pannonian basin in the east there are no directions referring to the direct influence of katabatic winds produced on the ice sheet instead the wind system must have been driven by synoptic scale patterns like the polar front the narrow distribution of wind directions suggests that the low altitude air flow system was relatively stable even without a funnelling topography as in the pannonian basin though the alps could have acted to deflect the winds osl data from the bohemian massif indicate aeolian sand movement during the late pleistocene the results provide data for aeolian transport studies among them for loess provenance analyses and can be used as input for climate models

moon near infrared spectral reflectance a first good look a positive identification of the minerals olivine plagioclase and several types of pyroxenes were made at several locations on the lunar surface by using remote measurements for example the crater aristarchus is found to have an average pyroxene composition of augite and plagioclase is obviously present a dark mantle deposit in the crater j herschel is at least partly composed of a mixture of 70o7o olivine and 30o7o pyroxene these determinations were possible because the reflectance spectra for 10 20 km diameter lunar areas have been measured for the first time in the ir spectral region 0 65 2 5 m with sufficient spectral resolution and photometric precision to define mineral electronic absorption bands the reflectance for all lunar regions observed over 100 to present continues to increase toward longer wavelengths to at least 2 5 m and several mineral absorption bands appear the telescopic spectra are of similar quality and contain features similar to laboratory spectra of lunar samples the absorption features in several spectra have been quantitatively analyzed using newly developed computer processing techniques including thermal flux removal and absorption band fitting to produce these mineral identifications detection and quantitative analysis of these absorptions provide a much improved basis for remotely determining and mapping surface mineralogy quantitatively from the ground or using airborne or spacecraft platforms

olivine carbonate mineralogy of the jezero crater region a well preserved ancient delta deposit in combination with ample exposures of carbonate outcrops makes jezero crater in nili fossae a compelling astrobiological site we use compact reconnaissance imaging spectrometer for mars crism observations to characterize the surface mineralogy of the crater and surrounding watershed previous studies have documented the occurrence of olivine and carbonates in the nili fossae region we focus on correlations between these two well studied lithologies in the jezero crater watershed we map the position and shape of the olivine 1 m absorption band and find that carbonates are found in association with olivine which displays a 1 m band shifted to long wavelengths we then use thermal emission imaging spectrometer themis coverage of nili fossae and perform tests to investigate whether the long wavelength shifted redshifted olivine signature is correlated with high thermal inertia outcrops we find that there is no consistent correlation between thermal inertia and the unique olivine signature we discuss a range of formation scenarios for the olivine and carbonate associations including the possibility that these lithologies are products of serpentinization reactions on early mars these lithologies provide an opportunity for deepening our understanding of early mars and given their antiquity may provide a framework to study the timing of valley networks and the thermal history of the martian crust and interior from the early noachian to today

gaussian analysis of temperature effects on the reflectance spectra of mafic minerals in the 1 μm region gaussian band fitting analysis has been applied to the reflectance spectra of mafic silicates which are of geologic importance throughout much of the solar system reflectance spectra obtained over a sample temperature range of 80 to 448 k of olivine clinopyroxene and orthopyroxene were used in order to characterize the spectral changes in the 1 m wavelength region of these minerals as a function of temperature four gaussians are required to characterize the olivine while two gaussians are necessary to characterize both the orthopyroxene and clinopyroxene the trends of the individual gaussian parameters integrated area width and center position are presented as a function of temperature for each mineral the characterization by gaussian analysis of the 1 m absorption feature of all minerals yields consistent trends in center position integrated area and width that may prove useful in quantitative determination of these minerals in mineral mixtures the gaussian analysis of olivine for the three primary band components is qualitatively consistent with previous crystal field transition assignments of fe2 in the m 1 and m 2 crystallographic sites the trends of the determined olivine gaussian center positions imply that site symmetry is more important in determining transition energies than metal oxygen distances the result of the gaussian analysis for orthopyroxene is consistent with the need for two gaussians to describe an asymmetric band the gaussian analysis of the clinopyroxene is consistent with previous assignments of crystal field transitions due to fe2 in the m 1 and m 2 crystallographic sites

stratigraphic architecture and gamma ray logs of deeper ramp carbonates upper jurassic sw germany abstract the objective of this paper is to contribute to the development of sequence stratigraphic models for extensive epicontinental carbonate systems deposited over cratonic areas epicontinental carbonates of the sw german upper jurassic were analysed in terms of microfacies sedimentology and sequence stratigraphy based on 2 5 km of core 70 borehole gamma ray logs and 24 quarries facies analysis revealed six major facies belts across the deeper parts of the carbonate ramp situated generally below fair weather wave base and mostly below average storm wave base but in the reach of occasional storm events observed stratigraphic patterns differ in some aspects from widely published sequence stratigraphic models 1 elementary sedimentary cycles are mostly more or less symmetrical and are thus referred to as genetic sequences or genetic units aaapg bull 55 1971 1137 frazier d e 1974 depositional episodes their relationship to the quaternary stratigraphic framework in the northwestern portion of the gulf basin university of texas austin bureau of economic geology geologicalo circular 71 1 aapg bull 73 1989 125 galloway w e hobday d k 1996 terrigenous clastic depositional systems 489 pp springer cross t a baker m r chapin m s clark m s gardner m h hanson m s lessenger m a little l d mcdonough k j sonnenfeld m d valasek d w williams m r witter d n 1993 applications of high resolution sequence stratigraphy to reservoir analysis edition technip 1993 11 33 bull cent rech explor prod elf aquitaine 16 1992 357 homewood p mauriaud p lafont f 2000 best practices in sequence stratigraphy elf ep mem 25 81 pp homewood p eberli g p 2000 genetic stratigraphy on the exploration and production scales elf ep mem 24 290 pp in contrast to the asymmetrical shallowing upward parasequences of the exxon approach 2 neither sequence boundaries nor maximum flooding surfaces could be clearly delineated cycle boundaries are generally not represented by sharp stratal surfaces but are always transitional and thus referred to as turnarounds nor pet soc spec publ 8 1998 171 several types of genetic sequences were delineated both major types of facies and sequences show characteristic gamma ray log signatures based on the cycle stacking and the gamma ray patterns a hierarchy of sequences was recognized probably driven in part by 100 000 and 400 000 year milankovitch signals the cyclicity allowed regional correlations across various depositional environments such as sponge microbial bioherms and coeval basins the basin wide correlation revealed evidence for a subtle clinoform type stratigraphic architecture along very gentle slopes rather than a so far assumed simple layer cake pattern

near infrared spectral reflectance of mineral mixtures systematic combinations of pyroxenes olivine and iron oxides near infrared spectral reflectance data are presented for systematic variations in weight percent of two component mixtures of ferromagnesian and iron oxide minerals mixtures were chosen for application to the study of the dark materials on mars but the results are equally applicable to mafic and ultramafic assemblages elsewhere in the solar system olivine spectral features are greatly reduced in contrast by admixture of other phases but remain distinctive even for low olivine contents clinopyroxene and orthopyroxene mixtures show resolved pyroxene absorptions near 2 m the addition of limonite greatly modifies pyroxene and olivine reflectance but does not fully eliminate distinctive spectral characteristics using only spectral data in the 1 m region it is difficult to differentiate orthopyroxene and limonite goethite in a mixture additional spectral coverage or other evidence may be required for a unique interpretation all composite mineral absorptions observed in this study are either weaker than or intermediate in strength to the end member absorptions and have bandwidths greater than or equal to those for the end members in general spectral properties in an intimate mixture combine in a complex nonadditive manner with features demonstrating a regular but usually nonlinear variation as a function of end member phase proportions

dynamics of a holocene cliff top dune along mountain river northwest territories canada abstract the dynamics of a cliff top dune system located at the foot of the mackenzie mountains was reconstructed by radiocarbon dating and tree ring analysis of forest paleosols in eolian sediments the first evidence of eolian activity dates to ca 3000 yr b p when the breaching of a bedrock sill initiated the erosion of glaciofluvial deposits that resulted in the exposure of a 75 m high cliff of erodible sediment sandy sediment eroded from the cliff by katabatic winds from the mackenzie mountains buried a mature forest growing on alluvial sediments despite a minor eolian event between 750 and 860 cal yr a d dune development began ca 1100 cal yr a d and has been marked by two major sedimentation periods between ca 1100 cal yr a d and 1460 a d and from 1865 to present detailed analysis of tree morbidity and mortality indicates that the dune progressed at an average rate of 78 cm yr for the last century dune dynamics are directly related to slope activity that controls the episodic nature of sediment availability and to the katabatic wind regime comparison of the dune dynamics and paleoclimatic data suggest a possible influence of warm climate on eolian activity

relation of the spectroscopic reflectance of olivine to mineral chemistry and some remote sensing implications using high resolution visible and near infrared diffuse spectral reflectance we have systematically investigated apparent wavelength shifts as a function of mineral chemistry in the fe mg olivine series from fo11 to fo91 the study also shows that trace amounts of nickel can be spectrally detected in the olivine structure we show that significant compositional information can only be extracted at relatively high resolution because the overall spectral characteristics of the olivines change only subtly as a function of the fe mg ratio significant spectral variation as a function of grain size is also demonstrated adding a further complication to the interpretation of remotely sensed data from olivine rich surfaces this laboratory study is expected to aid in the interpretation of remotely sensed data from both terrestrial and extraterrestrial bodies terrestrial applications may include the recognition of ultramafic ultrabasic and basaltic terrains which in themselves may have mineral potential among extraterrestrial applications the asteroids are obvious candidates for further examination if instrumentation can provide the necessary wavelength coverage resolution and signal to noise ratio so that spectra can be compared to those laboratory data discussed here some permutations of fe mg ni relations in olivines are discussed as they apply to the interpretation of asteroid surfaces and other extraterrestrial bodies

sequence stratigraphy of the jurassic new data from the paris london basin compiled on well logs a sequence stratigraphic analysis of the jurassic sedimentary succession in paris basin is derived from an integration of subsurface log correlations field observations and reinterpretations of field descriptions the analysis is presented on two log sections one crossing the basin from northeast to southwest and the other from northwest to southeast approximately 80 logs a vast quantity of field data collected all around the parsi basin english dorset french normandy manche ardennes lorraine bourgogne allowed the sequences and system tracts boundaries to be traced and dated at the same time or prior to being recognized on well log data in comparison with the haq et al 1987 cycle chart 16 new sequences have been added three for the lias seven for the dogger and six for the malm occasionally ages of some of the already recognized sequences boundaries have been slightly modified to fit new biostratal data these biostratal data were usually at the scale of the ammonite sub zone and the actual give ages all tie with the 1987 haq et al chart time scale

alternation of microbial mounds and ooid shoals middle jurasssic morocco response to paleoenvironmental changes abstract the occurrence of neritic microbial carbonates is often related to ecological refuges where grazers and other competitors are reduced by environmental conditions or to post extinction events e g in the late devonian early triassic here we present evidence for middle jurassic bajocian microbial mounds formed in the normal marine shallow neritic setting of an inner ramp system from the high atlas of morocco the microbial mounds are embedded in cross bedded oolitic facies individual mounds show low relief domal geometries up to 3 m high and 4 5 m across but occasionally a second generation of mounds exhibits tabular geometries

development of a cliff top dune indicated by particle size and geochemical characteristics rubjerg knude denmark particle size and geochemical data have been used to investigate the development of a large cliff top dune at rubjerg knude located on the western coast of jutland denmark textural parameters and geochemical ratios provided useful indicators of the dune sediment provenance and mode of evolution of the dune the dune sediments themselves showed no significant spatial particle size trends and reflect a number of processes including grainfall wind ripple migration and avalanching grainflow which formed a high proportion of the deposits on both the stoss and lee sides of the present dune fine grainfall sediments which have accumulated to form a sandplain in the lee of the dune show fining and improved sorting with distance and extend more than 2 km downwind of the dune crest comparison of the textural and geochemical data from rubjerg knude and other locations on the jutland coast indicates that although there is a contribution of sand to the dune from local marine sources the main source of sand to the cliff top dune and sand plain sediments has been provided by the wind erosion of the underlying cliffs which are composed of weichselian age sandy glaciofluvial and glaciolacustrine deposits optically stimulated luminescence dating indicated an apparent age for the sand at the base of 274 14 years if this date is reliable it suggests that accumulation of the aeolian sand in this area began within approximately the last 300 years map and photographic evidence indicate that the modern high dune only began to form after 1885 apparently associated with an acceleration in the rate of coastal cliff retreat

late quaternary aeolian dunes on the presently humid blue mountains eastern australia abstract sand dunes on the newnes plateau 1000 m a s l west of sydney were active during the last glacial maximum the scattered sand dunes are forested under the modern humid temperate climate regime dune types range from parabolic to transverse lee dunes and sand sheets or patches all point to the presence of conditions marginal for aeolian activity made possible through wind acceleration on windward slopes ready sand supply from the weathered sandstone of the plateau and sparse vegetation cover modern climate envelopes of sand dune activity in australia predict that unrealistically drier conditions are necessary to allow wind transport at this site only additional impediments to plant growth such as lower temperature and lower atmospheric carbon dioxide concentrations appear to allow the necessary conditions for dune formation these observations and conclusions extend our understanding of the extremes of the lgm climate in humid eastern australia confirming that the widespread treeless vegetation was also sparse even in areas that today have annual rainfall above 1000 mm

olivine bearing lithologies on the moon constraints on origins and transport mechanisms from m 3 spectroscopy radiative transfer modeling and grail crustal thickness abstract high resolution hyperspectral data from chandrayaan 1 s moon mineralogy mapper m 3 allow detection of olivine on the lunar surface olivine exposed at the surface may originate as mantle material or igneous products intrusive or extrusive potential transport mechanisms include excavation of the mantle or lower crustal material by impacts that form basins and complex craters differentiation of impact melt sheets or magmatic emplacement of lavas cumulates or xenoliths a sample of the lunar mantle which has not been conclusively identified in the lunar sample collection would yield fundamental new insights into the composition structure and evolution of the lunar interior olivine identified in remote spectral data is generally accepted to originate from the primary mantle because abundant olivine is expected to exist in the mantle and lower crust yet have sparse occurrences in the upper crust in this study we identified 111 m 3 single pixel spectra with characteristic absorption features consistent with olivine at crisium nectaris and humorum basins and near the craters roche and tsiolkovsky in an effort to determine the origins and transport mechanisms that led to these individual exposures we estimated mineral abundances using radiative transfer modeling and examined crustal thickness estimates topography and slope maps and images from the lunar reconnaissance orbiter camera lroc at crisium basin where crustal thickness is near 0 km wieczorek et al 2013 mantle olivine may have been exposed by basin forming impact and deposited on the rim picard crater which is superposed on the floor of crisium also exhibits potential mantle olivine in its ejecta within nectaris basin olivine exposures are confined to the rims of small craters on the mare which are inferred to excavate a layer of olivine rich mare basalt olivine occurrences on the rim of humorum basin including those located on a graben are likely to be cumulates of shallow intrusions that were transported magmatically to the surface near roche crater olivine may have originated in shallow dikes that reached the subsurface and were exposed by impacts in addition to verifying both known and previously unidentified olivine exposures our combined geophysical spectral and radiative transfer modeling investigation has allowed identification of both igneous and mantle derived olivine

messinian stromatolite thrombolite associations santa pola se spain an analogue for the palaeozoic stromatolite thrombolite associations are the dominant facies forming large portions of the santa pola carbonate platform se spain during deposition of the terminal carbonate complex tcc the tcc the last period of marine sedimentation in the western mediterranean associated with the messinian salinity crisis comprises a ne sw trending thrombolite reef with occasionally interlayered stromatolite horizons and a predominantply stromatolite and oolite facies in the back reef area the stromatolites are mainly dome shaped but fine columnar or wavy undulose forms can occur the stromatolites form huge bioherms extending tens to hundreds of metres they are finely laminated with alternating layers of dolomicrite and dolomicrospar the dolomicrite layers appear to be a primary dolomite precipitate whereas the dolomite crystals in the dolomicrospar layers apparently formed around a meta stable nuclei which was subsequently dissolved or degraded the low content of sand sized particles in the stromatolitic layers indicates formation under low energy conditions possibly on a tidal flat as reported from other areas in the western mediterranean deposition of the tcc at santa pola was apparently cyclic whereby stromatolites generally terminate each depositional cycle subtidal conophyton stromatolites possibly the only known occurrence younger than palaeozoic are however found on the reef slope at the base of the first tcc depositional cycle the dolomitic nature of the unadulterated stromatolitic laminations and the association of stromatolites and thrombolites as platform builders were a common feature in the early palaeozoic but are unusual in post ordovician carbonate facies we propose that the conditions during tcc deposition were very restricted possibly reflecting an environment similar to that of the early palaeozoic

a continuous record of holocene eolian activity in west greenland eolian landforms are widespread alongside proglacial valley sandurs in west greenland and comprise low relief sand sheets climbing dunes and upland loess sedimentary facies mainly reflect distance to outwash source zones and the influence of vegetation cover the sediments show stratification types typical for poorly to moderately vegetated sand sheets alternately laminated silt peat sequences and unstratified loess twenty five accelerator mass spectrometry 14c dates provide the basis for the chronostratigraphy of the inland eolian deposits 14c dates from interstratified sand sheets suggest that the bulk of eolian sands were deposited prior to 3400 cal yr b p and after 550 cal yr b p this two phase formation for the inland dunes most likely reflects local changes in proglacial floodplain development and meltwater rerouting associated with a significant recession of the greenland ice sheet during the mid holocene climate optimum subsequent floodplain regeneration and renewed sand sheet formation after 550 cal yr b p followed when the ice margin readvanced to its present position in contrast atmospheric deposition of regionally derived silt in upland peat mires has been continuous since at least 4750 cal yr b p silt influx data demonstrate a strongly episodic history of the intensity of eolian activity over the past five millennia which tentatively reflects alternating periods of winter aridity associated with the variable incursion of maritime air masses over the interior ice free areas of west greenland

the tatahouine diogenite mineralogical and chemical effects of sixty three years of terrestrial residence comparison between clasts of the tatahouine diogenite collected the day of the fall in 1931 and 63 years later in 1994 allows the evaluation of mineralogical and chemical effects of terrestrial residence on meteorites secondary minerals are found in the 1994 samples iron stains and carbonate rosettes major and trace element abundances have been determined on fallen and found clasts no significant differences have been observed for most elements with the exception of rb sr and in a single case the light rare earth elements lree in this case the ree pattern of a 1994 clast displays a weak positive ce anomaly probably linked to the presence of iron hydroxide the contents of rb and sr are significantly higher in the 1994 samples than in the 1931 clasts and reflect the formation of calcite inside some of the clast fractures these results demonstrate that weathering processes may change the chemistry of meteorites in a very short time

complex explosive volcanic activity on the moon within oppenheimer crater abstract oppenheimer crater is a floor fractured crater located within the south pole aitken basin on the moon and exhibits more than a dozen localized pyroclastic deposits associated with the fractures localized pyroclastic volcanism on the moon is thought to form as a result of intermittently explosive vulcanian eruptions under low effusion rates in contrast to the higher effusion rate hawaiian style fire fountaining inferred to form larger regional deposits we use lunar reconnaissance orbiter camera images and diviner radiometer mid infrared data chandrayaan 1 orbiter moon mineralogy mapper near infrared spectra and clementine orbiter ultraviolet visible camera images to test the hypothesis that the pyroclastic deposits in oppenheimer crater were emplaced via vulcanian activity by constraining their composition and mineralogy mineralogically we find that the deposits are variable mixtures of orthopyroxene and minor clinopyroxene sourced from the crater floor juvenile clinopyroxene and juvenile iron rich glass and that the mineralogy of the pyroclastics varies both across the oppenheimer deposits as a whole and within individual deposits we observe similar variability in the inferred iron content of pyroclastic glasses and note in particular that the northwest deposit associated with oppenheimer u crater contains the most iron rich volcanic glass thus far identified on the moon which could be a useful future resource we propose that this variability in mineralogy indicates variability in eruption style and that it cannot be explained by a simple vulcanian eruption a vulcanian eruption should cause significant country rock to be incorporated into the pyroclastic deposit however large areas within many of the deposits exhibit spectra consistent with high abundances of juvenile phases and very little floor material thus we propose that at least the most recent portion of these deposits must have erupted via a strombolian or more continuous fire fountaining eruption and in some cases may have included an effusive component these results suggest that localized lunar pyroclastic deposits may have a more complex origin and mode of emplacement than previously thought

near infrared spectroscopy of probable impact melt from three large lunar highland craters abstract the composition of small areas within three large lunar highland craters are compared using near infrared earth based telescopic data spectra from many areas in the walls and central peaks of the craters indicate the presence of crystalline components which include olivine two types of pyroxene and sometimes fe bearing feldspar spectra from other regions suspected of being impact melt deposits located on the floors and walls of the three craters have remarkably similar yet anomalous features these features are interpreted to indicate the presence of pyroxene fe bearing glass and fe bearing feldspar pyroxene and feldspar are believed to occur primarily in the form of lithic clasts and rapidly recrystallized impact melt the fe bearing glass is interpreted as impact melt glass

ilmenite mapping of the lunar regolith over mare australe and mare ingenii regions an optimized multisource approach based on hapke radiative transfer theory 1 we model lunar ilmenite abundances over mare australe and mare ingenii regions using a new approach we integrate lunar reconnaissance orbiter wide angle camera wac and clementine uv visible near infrared uvvis nir data to obtain a 14 band mosaic 320 2000 nm we use hapke s radiative transfer equations to compute spectra for various mixtures of orthopyroxene clinopyroxene plagioclase olivine and ilmenite with varying grain size chemistry and degree of maturity and find the closest match between the modeled spectra and the spectra of the less mature pixels optical maturity 0 2 in the 14 band mosaic we calculate a maximum stoichiometrically possible ilmenite content using clementine derived tio2 abundances and the amount of tio2 in stoichiometric ilmenite and use it as a constraint in our model we validate our methodology with lunar soil spectra of known composition our results show that the integrated wac uvvis nir data and the uvvis nir data overestimate ilmenite abundances by 8 80 wt and 7 97 wt respectively when a fixed maximum of 20 wt ilmenite is used when the maximum stoichiometrically possible ilmenite content is used as a constraint the integrated wac uvvis nir data give slightly more accurate ilmenite abundance estimation 2 87 wt than when using only uvvis nir data 3 04 wt we find ilmenite concentrations of 0 11 wt in mare australe and 0 6 wt in mare ingenii region ilmenite abundances between 4 and 7 wt are exposed in mare australe whereas ilmenite abundances between 7 and 11 wt are found on the walls of 0 6 11 8 km diameter craters within mare australe

near infrared optical constants of naturally occurring olivine and synthetic pyroxene as a function of mineral composition 1 radiative transfer theory will assist in determining olivine and pyroxene proportions and compositions from the surface of a planetary body composed of intimately mixed minerals in order to use radiative transfer techniques the model requires the optical constants of olivine and pyroxene optical constants are parameters that describe the degree light absorbed k and refracted n in a medium here we only parameterize k in the near infrared from 0 6 to 2 5 m of natural olivine as a function of forsterite number and synthetic pyroxene with respect to wollastonite and ferrosilite number in contrast to previous work this study is an improvement on previous work because we have a diverse and larger sample size leading to robust optical parameters additionally we characterize each k spectrum with the modified gaussian model mgm mgm is a physically realistic model of near infrared absorptions due to electronic transitions in each spectrum we model each absorption and continuum with gaussians and an inverse of a linear function respectively we find that our fitting routine characterizes the olivine and pyroxene k spectra in a robust and consistent manner then we use regression analysis to characterize each parameter of the gaussians and the continuum as a function of mineral composition the developed optical parameters from this work will allow calculations of mineral proportions and compositions on planetary surfaces with use of data from missions such as dawn messenger selene and chandrayaan 1

famennian upper devonian stromatolite reefs at shatang guilin guangxi south china stromatolites occurred in many reef complexes throughout the phanerozoic and microbial communities played an important role in both ancient and modem stromatolite reefs famennian upper devonian limestone outcrops at shatang northwest of guilin south china contain stromatolite reefs calcimicrobes and algae are also abundant in the reef limestones highlighting the importance of microbial communities in initial reef formation after the frasnian famennian biotic crisis in some cases the shatang stromatolites are connected to form a rigid framework showing a significant ability for construction of biohermal reefs and in other cases they occur as isolated structures the cores of stromatolite reefs were formed by massive limestone containing columnar and dichotomous branching stromatolites calcimicrobes and algae e g solenopora parachaetetes garwoodia and problematic forms are also common some of the calcimicrobes formed stromatolites and other calcimicrobes played a role in sediment stabilization and were more common in biostromal thickets shatang stromatolitic reefs grew on a shoal deposit composed of sand and pebble sized bioclasts field observation and facies analysis suggest that shatang stromatolitic reefs formed platform margin facies which together with previously described renalcis epiphyton reefs renalcis reefs ooid shoals brachiopod shell shoals and nautiloid shoals rimmed the northwest part of the guilin carbonate platform the fossil microbial algal communities together with a complex of sedimentary features allow reconstruction of the depositional history of the environment based on comparison with coeval reefs in the guilin area and the previously developed regional tectonic history a model is proposed describing the sedimentary history of famennian reefs in guilin interpretation of the shatang stromatolites as disaster biota is equivocal as other factors may also have influenced the abundance and type of microbialites in shallow platform margin reef settings in the late devonian c 2004 elsevier b v all rights reserved

apparently homogenous reef limestones built by high frequency cycles upper jurassic sw germany abstract central european upper jurassic sponge microbial reefs are commonly regarded as compact massive and homogenous facies bodies a continuous study of borehole cores from sw germany clearly shows a very systematic architecture of these reefs built by sedimentary cycles of various hierarchical levels altogether five orders of cycles can be distinguished decimeter scale microcycles building meter scale mesocycles which in turn are stacked to form several meter thick macrocycles these high frequency cycles in turn are parts of basin wide medium scale and large scale cycles reported in a previous paper this paper documents the high frequency micro meso and macrocycles microcycles 0 1 0 8 m thick usually have a sharp erosional base covered by reworked sponges shells and intraclasts interpreted as storm events these bioclastic layers are colonised by a succession of thrombolitic and stromatolitic microbialites successive microcycles form distinct stacks that record gradually increasing and decreasing depositional energy thus defining mesocycles 0 5 4 m thick several mesocycles construct macrocycles 3 25 m the cycle stacking patterns were analysed by means of facies proportion diagrams the dominant microscale cyclicity records changes in water agitation possibly caused by fluctuating storm wave base the sponge microbial mounds could probably build up just to average storm wave base within the cycles of larger hierarchical levels the successive smaller scale cycles show systematic trends in their symmetry and in thickness this may be caused by variations in the ratio of accomodation space and associated energy level to carbonate production external reef geometries progradation aggradation retrogradation condensation can be related to internal cycle stacking patterns to approximate the duration of the high frequency cycles two different approaches were used firstly the duration of cycles was determined with the help of published chronostratigraphic time scales secondly cycle duration was estimated using published microbial reef growth rates both approximations result in ca 0 4 ma for the medium scale cycles and 0 1 ma for the macrocycles both are regionally correlatable thus appear to be allocyclic in nature and probably are milankovitch driven in contrast the microcycles are only locally correlatable and thus indicate an autocyclic storm induced nature this study poses the question if not more of the apparently homogenous reef bodies of other settings and geological ages may possibly also show internal high frequency cycles

a large spectral survey of small lunar craters implications for the composition of the lunar mantle a global spectral survey of 4506 immature craters with diameters 1 km was carried out using near ir data from the kaguya spectral profiler to characterize the composition of the lunar megaregolith on the basis of band minima and radiative transfer mixing models small crater spectra fall into three groups 1 mare basalts with strong absorptions at relatively long wavelengths indicating high ratios of high to low ca pyroxene 2 norites containing about 50 plagioclase and with pyroxene assemblages dominated by low ca pyroxene that occur within the south pole aitken basin spa near apollo 14 and other locations near imbrium basin and three major cryptomaria deposits and 3 noritic anorthosites occurring within the feldspathic highlands terrane containing about 20 wt pyroxene with a pyroxene assemblage containing exclusively very low ca pyroxene very few pure anorthosites are present in this survey and there are no occurrences of pyroxene poor olivine rich assemblages models of the composition of basin ejecta incorporate large amounts of mantle material and the spectral results require that that the sampled mantle is orthopyroxenite basin depth diameter ratios used in the models required to match the measured composition are consistent with prior estimates for the largest basins the composition found in the spa and imbrium regions are consistent with mafic impact melt breccias or basaltic impact melts of basin origin for spa we model this composition and find it requires an extremely low impact angle while this is consistent with prior work on an oblique impact for the spa event a more robust solution invokes the production of norite in impact melt seas

sedimentary evolution of a coral microbialites and debris rich upper jurassic reef upper tithonian eastern sardinia italy abstract this work investigates a portion of a poorly documented upper tithonian reef lower mt bardia reef lbr developed along the northern platform margin of the eastern sardinia platform esp the lbr was probably one of the most southerly reefs of the northern tethys margin and this study provides the first comprehensive description of facies and internal structure giving insights for the depositional setting detailed compositional and facies analyses of lbr have been carried out in three quarries located in the orosei gulf eastern sardinia the main reef components are represented by carbonate bioclastic debris microbialites and microencrusters and reef building organisms mainly corals and stromatoporoids these components combine in various proportions forming several facies and facies associations ten reef facies rf grouped into three main facies associations have been identified within the studied reef portion the distribution and arrangement of facies reveal a sedimentary evolution evolving from a microframework dominated reef to a carbonate debris dominated one with the internal reef architecture evolving from massive to patchy to coarsely stratified and roughly bedded the reef components and facies indicate that the investigated portion of the lbr corresponds to a shallow back reef zone characterized by well lit and generally low energy hydrodynamic conditions possibly developed in back position with respect to a higher energy zone that was closer to the edge of the platform in this depositional context the arrival of large amounts of debris and the evolving internal architecture are interpreted as the result of the infilling process of the back reef zone due to the progradation of a sand apron during a long term regional regressive phase

deconvolution of lunar olivine reflectance spectra implications for remote compositional assessment lunar olivines typically contain inclusions of cr spinel chromite that influence their measured optical properties these altered optical properties complicate modeled predictions of olivine composition from reflectance spectra approaches developed for inclusion free terrestrial olivine spectra must be modified to be applied to chromite bearing lunar olivine spectra we present a revised approach for predicting the compositions of chromite bearing lunar olivines using the modified gaussian model mgm the results of this revised approach for chromite bearing lunar olivines are consistent with previous results for terrestrial olivine reflectance spectra and successfully predict the olivine s composition these results are an important step in compositional assessment of remotely sensed olivine spectra and are essential to ongoing investigations of that topic our results are based on a limited set of available lunar olivine separates and would be strengthened by the inclusion of additional compositions

copernicus crater central peak lunar mountain of unique composition olivine is identified as the major mafic mineral in a central peak of copernicus crater information on the mineral assemblages of such unsampled lunar surface material is provided by near infrared reflectance spectra 0 7 to 2 5 micrometers obtained with earth based telescopes the composition of the deep seated material comprising the copernicus central peak is unique among measured areas other lunar terra areas and the wall of copernicus exhibit spectral characteristics of mineral assemblages comparable to the feldspathic breccias returned by the apollo missions with low calcium orthopyroxene being the major mafic mineral