influences of urban fabric on pyroclastic density currents at pompeii italy 1 flow direction and deposition 1 to assess ways in which the products of explosive eruptions interact with human settlements we performed volcanological and rock magnetic analyses on the deposits of the a d 79 eruption at the pompeii excavations italy during this eruption the roman town of pompeii was covered by 2 5 m of fallout pumice and then partially destroyed by pyroclastic density currents pdcs anisotropy of magnetic susceptibility measurements performed on the fine matrix of the deposits allowed the quantification of the variations in flow direction and emplacement mechanisms of the parental pdcs that entered the town these results integrated with volcanological field investigations revealed that the presence of buildings still protruding through the fallout deposits strongly affected the distribution and accumulation of the erupted products all of the pdcs that entered the town even the most dilute ones were density stratified currents in which interaction with the urban fabric occurred in the lower part of the current the degree of interaction varied mainly as a function of obstacle height and density stratification within the current for examples the lower part of the eu4pf current left deposits up to 3 m thick and was able to interact with 2 to 4 m high obstacles however a decrease in thickness and grain size of the deposits across the town indicates that even though the upper portion of the current was able to decouple from the lower portion enabling it to flow over the town it was not able to fully restore the sediment supply to the lower portion in order to maintain the deposition observed upon entry into the town

reversed spatial asymmetries between el nino and la nina and their linkage to decadal enso modulation in cmip3 models abstractthis study examines preindustrial simulations from coupled model intercomparison project phase 3 cmip3 models to show that a tendency exists for el nino sea surface temperature anomalies to be located farther eastward than la nina anomalies during strong el nino southern oscillation enso events but farther westward than la nina anomalies during weak enso events such reversed spatial asymmetries are shown to force a slow change in the tropical pacific ocean mean state that in return modulates enso amplitude cmip3 models that produce strong reversed asymmetries experience cyclic modulations of enso intensity in which strong and weak events occur during opposite phases of a decadal variability mode associated with the residual effects of the reversed asymmetries it is concluded that the reversed spatial asymmetries enable an enso tropical pacific mean state interaction mechanism that gives rise to a decadal modulation of enso intensity and that at least three cmip3 models realistically simu

hydrodynamic and suspended sediment transport controls on river mouth morphology 1 river mouths building into standing bodies of water have strikingly varied growth habits this presents a compelling pattern formation problem that is also of great practical relevance for subsurface prediction and managing coastal wetlands here we present a generalized 2 5 dimensional potential vorticity pv theory that explains sedimentation patterns of a sediment laden stationary jet by coupling an understanding of vorticity with suspended sediment concentration fields we explore the physical meaning of this new sediment pv definition and its impact on outflow depositional patterns by analyzing data from a shallow wall bounded plane jet experiment and by discussing new theoretical insights a key result is that lateral advection and diffusion of suspended sediment are directly proportional to jet vorticity a feature that reveals the mechanistic process that forms elongated channels by focused levee deposition the new pv theory constitutes a more generalized mathematical framework that expands the rouse theory for the equilibrium of suspended sediment

chemcam passive reflectance spectroscopy of surface materials at the curiosity landing site mars the spectrometers on the mars science laboratory msl chemcam instrument were used in passive mode to record visible near infrared 400 840 nm radiance from the martian surface using the onboard chemcam calibration targets housing as a reflectance standard we developed methods to collect calibrate and reduce radiance observations to relative reflectance such measurements accurately reproduce the known reflectance spectra of other calibration targets on the rover and represent the highest spatial resolution 0 65 mrad and spectral sampling 1 nm visible near infrared reflectance spectra from a landed platform on mars relative reflectance spectra of surface rocks and soils match those from orbital observations and multispectral data from the msl mastcam camera preliminary analyses of the band depths spectral slopes and reflectance ratios of the more than 2000 spectra taken during the first year of msl operations demonstrate at least six spectral classes of materials distinguished by variations in ferrous and ferric components initial comparisons of chemcam spectra to laboratory spectra of minerals and mars analog materials demonstrate similarities with palagonitic soils and indications of orthopyroxene in some dark rocks magnesium rich raised ridges tend to exhibit distinct near infrared slopes the ferric absorption downturn typically found for martian materials at 600 nm is greatly subdued in brushed rocks and drill tailings consistent with their more ferrous nature calcium sulfate veins exhibit the highest relative reflectances observed but are still relatively red owing to the effects of residual dust such dust is overall less prominent on rocks sampled within the blast zone immediately surrounding the landing site these samples were likely affected by the landing thrusters which partially removed the ubiquitous dust coatings increased dust coatings on the calibration targets during the first year of the mission were documented by the chemcam passive measurements as well ongoing efforts to model and correct for this dust component should improve calibration of the relative reflectance spectra this will be useful as additional measurements are acquired during the rover s future examinations of hematite sulfate and phyllosilicate bearing materials near the base of mt sharp that are spectrally active in the 400 840 nm region

mineralogy provenance and diagenesis of a potassic basaltic sandstone on mars chemin x ray diffraction of the windjana sample kimberley area gale crater the windjana drill sample a sandstone of the dillinger member kimberley formation gale crater mars was analyzed by chemin x ray diffraction xrd in the msl curiosity rover from rietveld refinements of its xrd pattern windjana contains the following sanidine 21 weight or95 augite 20 magnetite 12 pigeonite olivine plagioclase amorphous and smectitic material 25 and percent levels of others including ilmenite fluorapatite and bassanite from mass balance on the alpha proton x ray spectrometer apxs chemical analysis the amorphous material is fe rich with nearly no other cations like ferrihydrite the windjana sample shows little alteration and was likely cemented by its magnetite and ferrihydrite from chemcam laser induced breakdown spectrometer libs chemical analyses windjana is representative of the dillinger and mount remarkable members of the kimberley formation libs data suggest that the kimberley sediments include at least three chemical components the most k rich targets have 5 6 k2o 1 8 times that of windjana implying a sediment component with 40 sanidine e g a trachyte a second component is rich in mafic minerals with little feldspar like a shergottite a third component is richer in plagioclase and in na2o and is likely to be basaltic the k rich sediment component is consistent with apxs and chemcam observations of k rich rocks elsewhere in gale crater the source of this sediment component was likely volcanic the presence of sediment from many igneous sources in concert with curiosity s identifications of other igneous materials e g mugearite implies that the northern rim of gale crater exposes a diverse igneous complex at least as diverse as that found in similar age terranes on earth

petrogenetic linkages among martian basalts implications based on trace element chemistry of olivine the shergottites exhibit a range of major and trace element compositions crystallization ages and initial sr nd hf and pb isotopic compositions to constrain the physical mechanisms by which shergottites obtain their compositional characteristics we examined the major and trace element record preserved in olivine in the more primitive shergottites based on such characteristics as the mg v zoning calculated dni co the olivine in y 980459 are most likely phenocrysts many of these same characteristics indicate that the olivines in other shergottites are not in equilibrium with the adjacent melt however in most cases they are not xenocrystic but additions of olivine from the same basaltic system elephant moraine eet a79001 may be an exception with the olivine data suggesting that it is xenocrystic in this case the olivine crystallized from a reduced and lreedepleted melt and was incorporated into an oxidized and enriched basalt vanadium and cao in olivine appear to record the appearance of spinel and pyroxene on the liquidus of most of the shergottites most of the olivine shergottites represent basalts produced by melting of reduced iw to iw 1 depleted mantle sources olivine data indicate that many of the primary melts derived from this source had similar ni co and mn shergottites such as northwest africa nwa 1110 1068 and perhaps roberts massif rbt 04261 that appear to be derived from more enriched sources have distinctly different olivine in the case of nwa 1110 1068 the olivine data suggests that the enriched component was added to system prior to olivine crystallization

contributions of gamma ray spectrometry to terrestrial impact crater studies the example of serra da cangalha northeastern brazil 1 several geophysical methods have been used for decades for the identification and exploration of impact craters most of them are based on seismic potential fields and electrical data focusing on exploration of anomalies caused by changes in physical properties or by structures associated with the formation of the crater gamma ray spectrometry is usually not mentioned among the geophysical methods employed in crater studies although it is known that impact cratering processes cause a number of physical chemical changes in the country rocks these changes include the remobilization of hydrothermal fluids which directly modify the composition of target rocks and subsidiarily of soils related to these rocks therefore the distribution of radioactive elementsk th and uhas the potential to map such modifications we present the analysis of gamma ray signatures at the serra da cangalha impact structure located in northeastern brazil using methods for enhancingkanomalies and also the overall gamma ray signatures these results provide valuable information on the distinct zones within the crater and might contribute to the understanding of hydrothermal enrichment processes produced as a result of the impact event

geology and age of the late archean keivy alkaline province northeastern baltic shield abstract the keivy alkaline province kola peninsula consists of six peralkaline granite bodies alkaline syenogranite dikes and two nepheline syenite intrusions emplaced between the tonalite trondhjemite granodiorite basement and the supracrustal keivy terrane u pb zircon ages for the keivy alkaline province range from 2613 to 2682 ma and for the spatially associated gabbro anorthosite complexes from 2659 to 2668 ma the keivy alkaline granitoids are geochemically different from other late archean alkaline rocks inferred to have been emplaced in subduction zone settings the keivy alkaline province may represent the earliest example of magmatism associated with continental rifting and the involvement of a mantle plume with oceanic island basalt like characteristics

chronology chemistry and origin of trachytes from hualalai volcano hawaii 1 hualalai volcano is unique among hawaiian volcanoes in that it possesses a relatively high proportion of evolved trachytic lavas that were erupted at the beginning of the alkalic postshield phase of volcanism these evolved lavas yield insights into magma sources magma supply rates and the evolution of the subvolcanic magmatic plumbing system at this time trachyte lavas are exposed at the puu waawaa pumice dome and puu anahulu flow as blocks in maars on the south flank of the volcano and as flows in water wells drilled on the west flank of hualalai new 40ar 39ar dates show that the puu waawaa and puu anahulu complex is 114 ka a block from the waha pele maar is 103 ka and water well trachytes range from 107 to 92 ka in age indicating a range for trachyte volcanism of 20 ka nd and pb isotopic compositions overlap with younger alkalic basalts from hualalai but are distinct from hualalai tholeiitic basalts and pacific mid ocean ridge basalts linking the trachytes to alkalic parental magmas that underwent extensive crystallization to yield trachytic residual magmas both sr and o isotopic ratios are higher in the trachytes than in hualalai alkalic lavas which is best explained by reaction with or assimilation of altered hualalai shield basalts at shallow depth major trace element and isotopic variations between trachytes are consistent with their evolution by fractional crystallization from a puu anahulu parent the short time gap between the end of tholeiitic volcanism 133 ka and the onset of trachytic alkalic volcanism and the lack of deep origin xenoliths place the magma reservoir within which the trachytes evolved rapidly at shallow 7 km depth whereas mauna kea and kohala volcanoes produced small volumes of highly evolved lavas as magma supply rates dwindled through the postshield stage postshield magma intrusion rates at hualalai were lowest during trachyte formation and increased through a more recent period of alkalic basalt eruptions subtle rare earth element and radiogenic isotopic distinctions between trachytes from the three localities indicate that the roof of the shallow magma reservoir may have been irregular allowing some trachytes to evolve independently from others

alkalic parental magmas for chassignites detailed analysis of cumulate and melt inclusion assemblages in the chassignites provide important constraints on the nature of the melt trapped as inclusions in cumulus olivine and by extension parental magma compositions the pressures of crystallization and magmatic volatile contents these mineral assemblages show strong similarities to the experimental fractionation assemblages that produce the sodic silica saturated alkalic lavas on earth e g ascension island azores the nandewar volcano of australia the experimental assemblages were produced from silica saturated hawaiite at pressures above 4 3 kbar with dissolved water contents above 0 5 wt such pressures are consistent with ti al ratios of the melt inclusion pyroxenes in the chassigny meteorite pyroxene compositions suggest early high crystallization temperatures and thus relatively low initial water and f contents feldspars indicate that melt evolution proceeded to rhyolite compositions both within the interstices of the cumulate olivine and within the melt inclusions even though rhyolitic glass is only found within olivine hosted polyphase melt inclusions the observed rhyolite glass is compositionally similar to the alkali rich rhyolite of ascension island which is produced experimentally by crystallization of hawaiite it is proposed that the melt trapped in cumulus olivine of the chassigny dunite was similar to a terrestrial silica saturated hawaiite while that trapped in olivine of the northwest africa nwa 2727 dunite was less evolved perhaps mildly alkalic basalt melts similar to terrestrial intra plate tholeiite could be parental to the cumulus minerals and evolve upon crystallization at pressures above 4 3 kbar and water contents above 0 4 wt to mildly alkalic basalt silica saturated hawaiite and alkali rich rhyolite the melt inclusion assemblages are inconsistent with either crystallization of a low al high fe basalt or low pressure crystallization of a terrestrial like tholeiite

the origin and evolution of the peace vallis fan system that drains to the curiosity landing area gale crater mars the landing site for the curiosity rover is located at the distal end of the peace vallis fan in gale crater peace vallis fan covers 80 km2 and is fed by a 730 km2 catchment which drains an upland plains area through a 15 km wide gap in the crater rim valley incision into accumulated debris delivered sediment through a relatively low density valley network to a main stem channel to the fan an estimated total fan volume of 0 9 km3 matches the calculated volume of removal due to valley incision 0 8 km3 and indicates a mean thickness of 9 m the fan profile is weakly concave up with a mean slope of 1 5 for the lower portion numerous inverted channels outcrop on the western surface of the fan but on the eastern portion such channels are rare suggesting a change in process from distributary channel domination on the west to sheet flow on the eastern portion of the fan runoff discharge watershed area to produce the fan is estimated to be more than 600 m perhaps as much as 6000 m indicating a hydrologic cycle that likely lasted at least thousands of years atmospheric precipitation possibly snow not seepage produced the runoff based on topographic data peace vallis fan likely onlapped bradbury rise and spilled into a topographic low to the east of the rise this argues that the light toned fractured terrain within this topographic low corresponds to the distal deposits of peace vallis fan and in such a setting lacustrine deposits are expected

akaganeite β feooh precipitation in inland acid sulfate soils of south western new south wales nsw australia abstract the prevalence of sulphidic sediments in inland wetlands has been only recently recognized in many parts of the world including australia the exposure of sulphidic sediments in these wetlands due to natural and human induced drying events has resulted in the oxidation of iron sulfide minerals the formation of secondary iron minerals characteristic of acid sulfate soils and the release of highly acidic solutions the objective of this study was to determine the mineralogy and morphology of sediments collected from the oxidized surface horizon 0 5 cm of an inland acid sulfate soil located in south western new south wales nsw australia random powder x ray diffraction xrd transmission electron microscopy tem and scanning transmission electron microscopy combined with energy dispersive x ray spectroscopy stem eds techniques were used to characterize the minerals present in these sediments akaganeite was identified as the major mineral phase in the sediments k jarosite was also determined in small amounts in some sediments the xrd patterns of sequentially washed e pure water 0 01 m hcl 0 01 m edta sediment samples showed all akaganeite peaks the rietveld refinement of these patterns also revealed a predominance of akaganeite the chemical analyses of the original and washed sediments using stem eds clearly showed the presence of akaganeite as a pure mineral phase with an average fe cl mole ratio of 6 7 and a structural formula of fe 8 o 8 oh 6 8 cl 1 2 these findings show that the extreme saline acidic solutions ph 2 ec 216 ds m at the bottle bend lagoon provide ideal conditions for the crystallization of this rarely forming mineral

constraints on abundance composition and nature of x ray amorphous components of soils and rocks at gale crater mars x ray diffraction patterns of the three samples analyzed by curiosity s chemistry and mineralogy chemin instrument during the first year of the mars science laboratory mission the rocknest sand and the john klein and cumberland drill fines both extracted from the sheepbed mudstone show evidence for a significant amorphous component of unclear origin we developed a mass balance calculation program that determines the range of possible chemical compositions of the crystalline and amorphous components of these samples within the uncertainties of mineral abundances derived from chemin data in turn the chemistry constrains the minimum abundance of amorphous component required to have realistic compositions all oxides 0 wt 21 22 wt for rocknest and 15 20 wt for cumberland in good agreement with estimates derived from the diffraction patterns 27 and 31 wt respectively despite obvious differences between the rocknest sand and the sheepbed mudstone the amorphous components of the two sites are chemically very similar having comparable concentrations of sio2 tio2 al2o3 cr2o3 feot cao na2o k2o and p2o5 mgo tends to be lower in rocknest although it may also be comparable between the two samples depending on the exact composition of the smectite in sheepbed the only unambiguous difference is the so3 content which is always higher in rocknest the observed similarity suggests that the two amorphous components share a common origin or formation process the individual phases possibly present within the amorphous components include volcanic or impact glass hisingerite or silica ferrihydrite amorphous sulfates or adsorbed so42 and nanophase ferric oxides

interpretation of neovolcanic versus palaeovolcanic sand grains an example from miocene deep marine sandstone of the topanga group southern california despite abundant data on volcaniclastic sand stone the compositional spatial and temporal distribution of volcanic detritus within the sedimentary record is poorly documented one of the most intricate tasks in optical analysis of sand stone containing volcanic particles is to distinguish grains derived by erosion of ancient volcanic rocks i e palaeovolcanic noncoeval grains from grains generated by active volcanism subaqueous and or subaerial during sedimentation neovolcanic coeval grains deep marine volcaniclastic sandstones of the middle topanga group of southern california are interstratified with 3000 m thick volcanic deposits both subaqueous and subaerial lava and pyroclastic rocks ranging from basalt andesite to dacite these rocks overlie quartzofeldspathic sandstones petrofacies 1 of the lower topanga group derived from deep erosion of a mesozoic magmatic arc changes in sandstone composition in the middle topanga group provide an example of the influence of coeval volcanism on deep marine sedimentation volcaniclastic strata were deposited in deep marine portions of a turbidite complex volcaniclastic apron built onto a succession of intrabasinal lava flows and on the steep flanks of subaerially emplaced lava flows and pyroclastic rocks distinctive petrofacies 2 5 directly overlying basalt and basaltic andesite lava flows petrofacies 2 is a pure volcanolithic sandstone including vitric microlitic and lathwork volcanic grains and neovolcanic crystals plagioclase pyroxene and olivine the abundance of quenched glass palagonite fragments suggests a subaqueous neovolcanic provenance whereas sandstones including andesite and minor basalt grains suggest subaerial neovolcanic provenance this petrofacies probably was deposited during syneruptive periods testifying to provenance from both intrabasinal and extrabasinal volcanic events deposited during intereruptive periods impure volcanolithic petrofacies 3 includes both neovolcanic 85 and older detritus derived from plutonic metamorphic and palaeovolcanic rocks during post eruptive periods the overlying quartzofeldspathic petrofacies 4 and 5 testify to progressive decrease of neovolcanic detritus 48 14 and increase of plutonic metamorphic and palaeovolcanic detritus the upper topanga group calabasas formation conformably overlying the middle unit has dominantly plutoniclastic sandstone petrofacies 6 neovolcanic detritus is drastically reduced 4 whereas palaeovolcanic detritus is similar to percentages of the lower topanga group petrofacies 1 the middle topanga group sandstones are vertically organized into four

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

sulfur bearing phases detected by evolved gas analysis of the rocknest aeolian deposit gale crater mars the sample analysis at mars sam instrument suite detected so2 h2s ocs and cs2 from 450 to 800 c during evolved gas analysis ega of materials from the rocknest aeolian deposit in gale crater mars this was the first detection of evolved sulfur species from a martian surface sample during in situ ega so2 3 22 mol is consistent with the thermal decomposition of fe sulfates or ca sulfites or evolution desorption from sulfur bearing amorphous phases reactions between reduced sulfur phases such as sulfides and evolved o2 or h2o in the sam oven are another candidate so2 source h2s 41 109 nmol is consistent with interactions of h2o h2 and or hcl with reduced sulfur phases and or so2 in the sam oven ocs 1 5 nmol and cs2 0 2 1 nmol are likely derived from reactions between carbon bearing compounds and reduced sulfur sulfates and sulfites indicate some aqueous interactions although not necessarily at the rocknest site fe sulfates imply interaction with acid solutions whereas ca sulfites can form from acidic to near neutral solutions sulfides in the rocknest materials suggest input from materials originally deposited in a reducing environment or from detrital sulfides from an igneous source the presence of sulfides also suggests that the materials have not been extensively altered by oxidative aqueous weathering the possibility of both reduced and oxidized sulfur compounds in the deposit indicates a nonequilibrium assemblage understanding the sulfur mineralogy in rocknest materials which exhibit chemical similarities to basaltic fines analyzed elsewhere on mars can provide insight in to the origin and alteration history of martian surface materials

evidence for indigenous nitrogen in sedimentary and aeolian deposits from the curiosity rover investigations at gale crater mars the sample analysis at mars sam investigation on the mars science laboratory msl curiosity rover has detected oxidized nitrogen bearing compounds during pyrolysis of scooped aeolian sediments and drilled sedimentary deposits within gale crater total n concentrations ranged from 20 to 250 nmol n per sample after subtraction of known n sources in sam our results support the equivalent of 110 300 ppm of nitrate in the rocknest rn aeolian samples and 70 260 and 330 1 100 ppm nitrate in john klein jk and cumberland cb mudstone deposits respectively discovery of indigenous martian nitrogen in mars surface materials has important implications for habitability and specifically for the potential evolution of a nitrogen cycle at some point in martian history the detection of nitrate in both wind drifted fines rn and in mudstone jk cb is likely a result of n2 fixation to nitrate generated by thermal shock from impact or volcanic plume lightning on ancient mars fixed nitrogen could have facilitated the development of a primitive nitrogen cycle on the surface of ancient mars potentially providing a biochemically accessible source of nitrogen

geochemical diversity in first rocks examined by the curiosity rover in gale crater evidence for and significance of an alkali and volatile rich igneous source the first four rocks examined by the mars science laboratory alpha particle x ray spectrometer indicate that curiosity landed in a lithologically diverse region of mars these rocks collectively dubbed the bradbury assemblage were studied along an eastward traverse sols 46 102 compositions range from na and al rich mugearite jake matijevic to fe mg and zn rich alkali rich basalt hawaiite bathurst inlet and span nearly the entire range in feo and mno of the data sets from previous martian missions and martian meteorites the bradbury assemblage is also enriched in k and moderately volatile metals zn and ge these elements do not correlate with cl or s suggesting that they are associated with the rocks themselves and not with salt rich coatings three out of the four bradbury rocks plot along a line in elemental variation diagrams suggesting mixing between al rich and fe rich components chemcam analyses give insight to their degree of chemical heterogeneity and grain size variations in trace elements detected by chemcam suggest chemical weathering li and concentration in mineral phases e g rb and sr in feldspars we interpret the bradbury assemblage to be broadly volcanic and or volcaniclastic derived either from near the gale crater rim and transported by the peace vallis fan network or from a local volcanic source within gale crater high fe and fe mn in et then likely reflect secondary precipitation of fe 3 oxides as a cement or rind the k rich signature of the bradbury assemblage if igneous in origin may have formed by small degrees of partial melting of metasomatized mantle

mineralogy of a mudstone at yellowknife bay gale crater mars sedimentary rocks at yellowknife bay gale crater on mars include mudstone sampled by the curiosity rover the samples john klein and cumberland contain detrital basaltic minerals calcium sulfates iron oxide or hydroxides iron sulfides amorphous material and trioctahedral smectites the john klein smectite has basal spacing of similar to 10 angstroms indicating little interlayer hydration the cumberland smectite has basal spacing at both similar to 13 2 and similar to 10 angstroms the larger spacing suggests a partially chloritized interlayer or interlayer magnesium or calcium facilitating h2o retention basaltic minerals in the mudstone are similar to those in nearby eolian deposits however the mudstone has far less fe forsterite possibly lost with formation of smectite plus magnetite late noachian early hesperian or younger age indicates that clay mineral formation on mars extended beyond noachian time

geochemical properties of rocks and soils in gusev crater mars results of the alpha particle x ray spectrometer from cumberland ridge to home plate 1 geochemical diversity of rocks and soils has been discovered by the alpha particle x ray spectrometer apxs during spirit s journey over husband hill and down into the inner basin from sol 470 to 1368 the apxs continues to operate nominally with no changes in calibration or spectral degradation over the course of the mission germanium has been added to the spirit apxs data set with the confirmation that it occurs at elevated levels in many rocks and soils around home plate twelve new rock classes and two new soil classes have been identified at the spirit landing site since sol 470 on the basis of the diversity in apxs geochemistry the new rock classes are irvine alkaline basalt independence low fe outcrop descartes outcrop similar to independence with higher fe and mn algonquin mafic ultramafic igneous sequence barnhill volcaniclastic sediments enriched in zn cl and ge fuzzy smith high si and ti rock elizabeth mahon high si ni and zn outcrop and rock halley hematite rich outcrop and rock montalva high k hematite rich rock everett high mg magnetite rich rock good question high si low mn rock and torquas high k zn and ni magnetite rich rock new soil classes are gertrude weise very high si soil and eileen dean high mg magnetite rich soil aqueous processes have played a major role in the formation and alteration of rocks and soils on husband hill and in the inner basin

ancient plutonic processes on mars inferred from the detection of possible anorthositic terrains the formation of the silicate mineral anorthosite is thought to require magmatic processes that are not expected on mars because of its predominately mafic terrains localized spectral detections by the mars reconnaissance orbiter are consistent with anorthosite suggestive of ancient intrusive igneous processes similar to those active on earth