the terrestrial alteration of saharan shergottites dar al gani 476 and 489 a case study of weathering in a hot desert environment abstract rare earth element ree and other selected trace and minor element concentrations were determined in various phases of dar al gani 476 and 489 two basaltic shergottites recently found in the libyan sahara whereas merrillite and feldspathic glass compositions do not seem to have been altered since the fall of these meteorites olivine and pyroxenes commonly show light ree enrichments sometimes accompanied by ce anomalies that are attributed to terrestrial alteration sr and ba enrichments are also observed the calcium carbonate that resides in most cracks is essentially devoid of ree but a fine grained amorphous silicate material that fills some veins and pockets has striking light ree enrichments and elevated p sr and ba it is argued that this material likely to be impact melt as well as the notoriously light ree poor olivine and pyroxenes were preferentially affected by a crustal light ree rich contaminant caution is urged when using whole rock or even mineral separate compositional and isotopic data for hot desert meteorites

the petrology geochemistry and age of lunar regolith breccias miller range 090036 and 090070 insights into the crustal history of the moon meteorites ejected from the surface of the moon as a result of impact events are an important source of lunar material in addition to apollo and luna samples here we report bulk element composition mineral chemistry age and petrography of miller range mil 090036 and 090070 lunar meteorites mil 090036 and 090070 are both anorthositic regolith breccias consisting of mineral fragments and lithic clasts in a glassy matrix they are not paired and represent sampling of two distinct regions of the lunar crust that have protoliths similar to ferroan anorthosites 40ar 39ar chronology performed on two subsplits of mil 090070 33 a pale clast impact melt and a dark glassy melt component shows that the sample underwent two main degassing events one at 3 88 ga and another at 3 65 ga the cosmic ray exposure data obtained from mil 090070 are consistent with a short 8 9 ma exposure close to the lunar surface bulk rock feo tio2 and th concentrations in both samples were compared with 2 degree lunar prospector gamma ray spectrometer lp grs data sets to determine areas of the lunar surface where the regolith matches the abundances observed on the sample we find that mil 090036 bulk rock is compositionally most similar to regolith surrounding the procellarum kreep terrane whereas mil 090070 best matches regolith in the feldspathic highlands terrane on the lunar farside our results suggest that some areas of the lunar farside crust are composed of ferroan anorthosite and that the samples shed light on the evolution and impact bombardment history of the ancient lunar highlands

partition coefficients for calcic plagioclase implications for archean anorthosites by the use of a multiple aliquot technique combined with statistical calculations to overcome effects of alteration and contamination we have determined partition coefficients d s for rare earth elements rees between natural high ca plagioclase megacrysts and their basaltic matrices some of the basalts that we investigated are shown experimentally to crystallize only high ca plagioclase over approximately a 20 30 c temperature interval below the liquidus the ree d s agree well with experimentally determined values and predict equilibrium melts for archean anorthosites that agree well with coeval basaltic flows and dikes furthermore the d s appear to be valid for both tholeiitic and alkali basalts over a range of mg numbers 34 58 and ree concentrations la from 3 50 ppm similarly calculated d s for co sc cr rb sr cs ba hf ta and th also predict equilibrium melts for anorthosites that agree reasonably well with coeval basaltic flows and dikes the apparent values for co sc and ta seem good to better than 50 whereas the standard deviations for rb and th are equal to their means making the d s of questionable value the others are useful probably to within a factor of 2 experimental studies of the d for total fe as feot indicate a value of about 04 at an oxygen fugacity slightly below that of the qfm buffer a by product of the feot experiments was the experimental d s for mgo tio2 and k2o which could be compared with the d s from natural assemblages from the d s that were determined we suggest that plagioclase megacrysts in the bad vermilion lake anorthosite were in equilibrium with melts having the composition of tholeiitic basalts at an oxygen fugacity slightly below the qfm buffer the predicted melts have an feot content of about 13 k2o of about 15 tio2 of about 1 3 a chondrite normalized ree pattern that is nearly flat at 10 to 20 chondrites with a slight depletion of lrees other incompatible trace elements at 10 to 20 chondrites and cr and co at 0 01 to 0 1 chondrites this range of compositions is essentially identical to the tholeiitic flows and dikes in archean greenstone belts we therefore suggest that the moderately fe rich tholeiites that are hosts to plagioclase megacrysts in greenstone belts form the parental melts for megacrysts which make up the bad vermilion lake anorthositic complex and probably other similar archean anorthositic complexes

oxygen isotope studies of achondrites abstract oxygen isotope abundances provide a powerful tool for recognizing genetic relationships among meteorites among the differentiated achondrites three isotopic groups are recognized l snc mars 2 earth and moon and 3 hed howardites eucrites diogenites the hed group also contains the mesosiderites main group pallasites and silicates from iiiab irons the angrites may be marginally resolvable from the hed group within each of these groups internal geologic processes give rise to isotopic variations along a slope 1 2 fractionation line as is well known for terrestrial materials variations of 17o from one planet to another are inherited from the inhomogeneities in the solar nebula as illustrated by the isotopic compositions of chondrites and their constituents among the undifferentiated achondrites five isotopic groups are found 1 aubrites 2 winonaites and iab iiicd irons 3 brachinites 4 acapulcoites and lodranites and 5 ureilites the isotopic compositions of aubrites coincide with the earth and moon and also with the enstatite chondrites these bodies apparently were derived from a common reservoir the isotopic composition of which was established at the chondrule scale by nebular processes isotopic similarities between chondrites and achondrites are seen only for the following instances 1 enstatite chondrites and aubrites 2 h chondrites and he irons and 3 l or ll chondrites and iva irons the isotopic data also support the following genetic associations 1 winonaites and iab iiicd irons 2 acapulcoites and lodranites and 3 ureilites and dark inclusions of c3 chondrites an attempt to reconcile the whole planet isotopic compositions of earth mars and the eucrite parent body with mixing models of their chemical compositions failed it is not possible to satisfy both the chemical and isotopic compositions of the terrestrial planets using known primitive solar system components

lunar highland meteorites and the composition of the lunar crust abstract major minor and trace element data obtained by neutron activation techniques and by spark source mass spectrometry ssms on two lunar meteorites mac88104 and mac88105 are reported both mac samples were also analysed for their contents and isotopic compositions of rare gases additional ssms data were obtained on four lunar highland meteorites previously found in antarctica alha81005 y791197 y82192 and y86032 mac88104 and mac88105 are very similar in chemistry suggesting that they are pieces of a single fall event the bulk chemical composition of mac88104 5 is not very different from the other lunar highland meteorites highly aluminous with relatively low contents of ree and siderophile element concentrations slightly above 1 of a ci chondritic level however mafic element concentrations mg cr mn etc are slightly lower in mac88104 5 than in the other lunar highland meteorites the contents of solar rare gases in the two mac samples are low indicating only a small regolith contribution in agreement with rare petrographically identifiable regolith components the mac samples and also y82192 and y86032 are classified as fragmental breccias with negligible regolith components in contrast to alha81005 and y791197 which are regolith breccias with high solar wind derived rare gas contents there is no correlation among lunar meteorites between peak shock pressures and solar gas contents indicating that peak shock pressures of up to 25 gpa do not lead to gas loss a low 26al activity vogt et al 1990 and high contents of cosmogenic rare gases in mac88104 5 suggest a long exposure 400 000 years in the lunar sub surface k ar ages are in excess of 3 9 by lunar highland meteorites and compositionally similar granulitic rocks from the apollo 16 and 17 landing sites contain about 1 of a ci chondritic component according to siderophile and volatile element contents but independent of the amount of regolith components apparently the major fraction of meteoritic elements in these rocks was not provided by micrometeorites impacting the regolith the abundances of siderophile e g ir and volatile elements may therefore reflect the last spike of accretion of the moon after the formation of the anorthositic crust lunar meteorites of highland origin are chemically different from the bulk of the apollo 16 highland samples in having higher fe mg ratios and lower contents and less fractionated patterns of incompatible and siderophile elements since lunar highland meteorites are associated with at least three but probably four different fall events and since they are not derived from chemically exotic front side terranes they may represent a better sampling of the average chemical composition of the lunar crust than previous estimates based on returned lunar samples and remote sensing data a comparison between an average highland composition derived by taylor 1982 and an estimate based on lunar highland meteorites shows that the taylor composition contains higher concentrations and more fractionated incompatible elements mainly because of a substantial amount of kreep a trace element rich highly fractionated component from the front side of the moon not present at the sites from which the lunar meteorites come

a rock fragment related to the magnesian suite in lunar meteorite allan hills alha 81005 among the lunar samples that were returned by the apollo missions are many cumulate plutonic rocks with high mg molar mg mg fe in and abundances of kreep elements potassium rare earth elements phosphorus u th etc that imply kreep rich parental magmas these rocks collectively called the magnesian suite are nearly absent from sampling sites distant from imbrium basin ejecta including those of lunar highlands meteorites this absence has significant implications for the early differentiation of the moon and its distribution of heat producing elements k th u here we analyze a unique fragment of basalt with the mineralogy and mineral chemistry of a magnesian suite rock in the lunar highlands meteorite allan hills alh a81005 in thin section the fragment is 700 300 m and has a sub ophitic texture with olivine phenocrysts euhedral plagioclase grains an97 70 and interstitial pyroxenes its minerals are chemically equilibrated olivine has fe mn 70 consistent with a lunar origin and mg 80 which is consistent with rocks of the magnesian suite and far higher than in mare basalts it has a rich suite of minor minerals fluorapatite ilmenite zr armalcolite chromite troilite silica and fe metal ni 3 8 co 0 17 the metal is comparable to that in chondrite meteorites which suggests that the fragment is from an impact melt the fragment itself is not a piece of magnesian suite rock which are plutonic but its mineralogy and mineral chemistry suggest that its protolith which was melted by impact was related to the magnesian suite however the fragment s mineral chemistry and minor minerals are not identical to those of known magnesian suite rocks suggesting that the suite may be more varied than apparent in the apollo samples although alha81005 is from the lunar highlands and likely from the farside clast u need not have formed in the highlands it could have formed in an impact melt pool on the nearside and been transported by meteoroid impact lunar highlands meteorites should be searched for rock fragments related to the magnesian suite rocks but the fragments are rare and may have mineral compositions similar to some meteoritic impactor materials

elephant moraine 87521 the first lunar meteorite composed of predominantly mare material abstract the trace element chemistry and detailed petrography of brecciated antarctic meteorite eet87521 reveal that it is not as originally classified a eucrite its fe mn ratio and bulk co content are far higher than expected for a eucrite an affiliation with the snc meteorites appears almost equally improbable on the basis of far lower ga al and na ca ratios in eet87521 only one known type of extraterrestrial material resembles eet87521 in all important respects for which constraints exist very low ti vlt lunar mare basalts even compared to vlt basalts eet87521 is enriched in ree however other varieties of high alumina low ti mare basalt are known that contain ree at even higher concentrations than eet87521 several clasts in eet87521 preserve clear vestiges of coarse grained igneous possibly orthocumulate textures mineralogically these coarse grained clasts are diverse e g olivine ranges from fo15 in one to fo67in another one clast with an anomalously fine grained texture is anor thositic and contains exceptionally mg rich pyroxene and na poor plagioclase along with the only feni metal in the thin section this clast is probably an impact melt breccia from the lunar highlands its feni metals have compositions typical of metals incorporated into lunar soils and polymict breccias as debris from metal rich meteorites however the low ni and ir contents of our bulk rock analysis imply that the proportion of impact projectile matter in our chip sample is probably small the moderate degree of lithologic diversity among the lithic clasts and the bulk composition in general indicate that eet87521 is dominated by a single rock type vlt mare basalt the fundamental distinction between mare and nonmare lunar materials has traditionally been based primarily on ti content and secondarily on such characteristics as ca al ratio and ree pattern however eet87521 recent studies of apollo 12 and apollo 14 rocks and the many apparent vlt basalts reported earlier as clasts in lunar highlands meteorites all tend to indicate that the dichotomy of lunar magmatism into distinct nonmare and mare styles may have been less abrupt than commonly envisaged

a ferroan region of the lunar highlands as recorded in meteorites mac88104 and mac88105 macalpine hills 88104 and 88105 mac88104 5 are paired meteorites of noritic anorthosite composition from the lunar highlands mac88105 is a breccia composed mainly of melt breccia clasts in a fine grained fragmental and partly glassy matrix the most abundant melt lithologies are feldspathic and are similar in composition to the bulk meteorite other melt lithologies include feldspathic melt rocks mafic melt breccias and a rare melt breccia relatively enriched in incompatible trace elements subordinate lithic clasts are granulitic breccias and ferroan relatively low mg mg fe igneous lithologies including troctolitic anorthosite anorthositic norite gabbronorite and anorthosite igneous clasts having mafic mineral compositions more magnesian than fo55 and en60 were not observed rare fragments of glass spheres and shards as well as glass clasts indicate that the meteorite was derived from an immature regolith the bulk composition of mac88105 is characterized by a molar mg mg fe ratio of 0 62 at the extreme low end of the range for meteorites from the lunar highlands its low concentrations of incompatible trace elements and feldspathic bulk composition 29 al2o3 suggest that it like the other lunar meteorites formed at a site far removed from the areas sampled by the apollo missions similarities in mineral compositions among the different lithologies of the breccia melt breccia clasts granulitic breccias igneous fragments and the distribution of mineral fragments suggest that most components of the meteorite were derived from a crustal section dominated by material with a noritic anorthosite composition and an affinity to the ferroan suite of plutonic rocks the mafic melt breccias have roughly peritectic melt compositions similar to many low k fra mauro melt breccias in the apollo collection but much more ferroan and represent a source material distinct from the noritic anorthosite moderate ce anomalies both positive and negative occur in some separated clasts and to a lesser extent in some small chips dominated by matrix but not in powder prepared from 20 g of bulk meteorite these anomalies are almost certainly terrestrial weathering effects one granulitic breccia clast is rich in siderophile elements as a result of a large amount of fe ni metal the auir ratio of the clast 0 64 ci normalized is distinctly different from that of metal rich impact melts from apollo 16 3 ci normalized the compositional range observed among the nonmare lunar meteorites alha81005 y791197 y82192 3 y86032 and mac88104 5 is equivalent to that observed among representative samples of 1 mm fines from apollo 16 thus compositional data provide little constraint on the number of impacts required to eject these meteorites from the moon

the perils of partition difficulties in retrieving magma compositions from chemically equilibrated basaltic meteorites abstract the chemical compositions of magmas can be derived from the compositions of their equilibrium minerals through mineral magma partition coefficients this method cannot be applied safely to basaltic rocks either solidified lavas or cumulates which have chemically equilibrated or partially equilibrated at subsolidus temperatures i e in the absence of magma applying mineral melt partition coefficients to mineral compositions from such rocks will typically yield magma compositions that are strongly fractionated and unreasonably enriched in incompatible elements e g rees in the absence of magma incompatible elements must go somewhere they are forced into minerals e g pyroxenes plagioclase at abundance levels far beyond those established during normal mineral magma equilibria further using mineral magma partition coefficients with such rocks may suggest that different minerals equilibrated with different magmas and the fractionation sequence of those melts i e enrichment in incompatible elements may not be consistent with independent constraints on the order of crystallization subsolidus equilibration is a reasonable cause for incompatibleelement enriched minerals in some eucrites diogenites and martian meteorites and offers a simple alternative to petrogenetic schemes involving highly fractionated magmas or magma infiltration metasomatism

feldspathic lunar meteorites pecora escarpment 02007 and dhofar 489 contamination of the surface of the lunar highlands by post basin impacts abstract pca pecora escarpment 02007 and dhofar 489 are both meteorites from the feldspathic highlands of the moon pca 02007 is a feldspathic breccia consisting of lithified regolith from the lunar surface it has concentrations of both incompatible and siderophile elements that are at the high end of the ranges for feldspathic lunar meteorites dhofar 489 is a feldspathic breccia composed mainly of impact melted material from an unknown depth beneath the regolith concentrations of incompatible and siderophile elements are the lowest among brecciated lunar meteorites among 19 known feldspathic lunar meteorites all of which presumably originate from random locations in the highlands concentrations of incompatible elements like sm and th tend to increase with those of siderophile elements like ir feldspathic meteorites with high concentrations of both suites of elements are usually regolith breccias iridium derives mainly from micrometeorites that accumulate in the regolith with duration of surface exposure micrometeorites have low concentrations of incompatible elements however so the correlation must reflect a three component system we postulate that the correlation between sm and ir occurs because the surface of the feldspathic highlands terrane has become increasingly contaminated with time in sm rich material from the procellarum kreep terrane that has been redistributed across the lunar surface by impacts of moderate sized post basin impacts the most sm rich regolith breccias among feldspathic lunar meteorites are about 3 enriched compared to the most sm poor breccias but this level of enrichment requires only a few percent sm rich material typical of the procellarum kreep terrane the meteorite data suggest that nowhere in the feldspathic highlands are the concentrations of k rare earths and th measured by the lunar prospector mission at the surface representative of the underlying bedrock all surfaces covered by old regolith as opposed to fresh ejecta are at least slightly contaminated dhofar 489 is one of 15 paired lunar meteorite stones from oman total mass of meteorite 1037 g on the basis of its unusually high mg fe ratio the meteorite is likely to have originated from northern feldspathic highlands

paired lunar meteorites mac88104 and mac88105 a new fan of lunar petrology abstract new lunar meteorite mac88104 5 represents an exciting new opportunity to study a potentially unsampled region of the moon we have analyzed six thin sections by electron microprobe and three bulk samples by instrumental neutron activation ina in order to determine the chemical characteristics of this new lunar sample lunar meteorite macs 8104 5 is dominated by lithologies of the ferroan anorthosite fan suite and contains abundant granulitized highland clasts devitrified glass beads of impact origin and two small clasts which appear to be of basaltic origin one of these asaltic clasts clast e in mac88105 84 is probably mesostasis material whereas the second larger clast clast g may be similar to the very low ti vlt or low ti high alumina mare basalts impact melt clasts mac88105 69 and 72 have major and trace element compositions similar to the bulk meteorite there is little evidence of any lkfm low k fra mauro or low k kreep contribution to this meteorite as mac88104 5 and other brecciated lunar meteorites are fe rich and poor in the incompatible elements relative to apollo 16 regolith and feldspathic breccias while the exact site of origin for the lunar meteorites cannot be pinpointed it is evident that they were derived from a relatively kreep free ferroan anorthosite terrain

evidence of chemical heterogeneity within lunar anorthosite parental magmas abstract lunar anorthosites are known for displaying a limited range of plagioclase an content an 94 to 98 here we demonstrate that plagioclase trace element variations from apollo ferroan anorthosites fan samples collected by the apollo 15 and 16 missions display more significant chemical heterogeneity e g chondrite normalized la sm 0 33 5 42 than previously reported we report mineral plagioclase pyroxene and olivine major and trace element abundances for a suite of apollo fan samples in addition to anorthositic clasts within apollo 16 regolith breccias this suite of data extends the compositional range currently reported for apollo anorthosites and for anorthositic clasts previously found within lunar meteorites petrological classifications of the regolith breccia clasts e g anorthosite versus noritic anorthosites cannot always be accurately assessed due to the limited size

propagation and maintenance mechanism of the tc submonthly wave pattern and tc feedback in the western north pacific abstractpropagation and maintenance mechanisms of the tropical cyclone submonthly wave pattern in the western north pacific are explored the wave pattern exhibited an equivalent barotropic structure with maximum vorticity and kinetic energy in the lower troposphere and propagated northwestward in the philippine sea in the intraseasonal oscillation iso westerly phase and north northeastward near the east asian coast in the easterly phase the mean flow advection played a dominant role in the propagation in both phases barotropic energy conversion is the dominant process in maintaining the kinetic energy of the pattern the wave pattern tended to occur in the confluent zone between the monsoon trough and the anticyclonic ridge where the kinetic energy could be efficiently extracted from the westerly mean flow associated with the monsoon trough the individual circulation circuit embedded in the pattern was oriented northeast southwest east west to have optimal growth and propagation during the iso wes

kreep cumulates in the western lunar highlands ion and electron microprobe study of alkali suite anorthosites and norites from apollo 12 and 14 alkali suite anorthosites and norites are the second most common plutonic rock association in the western lunar highlands after the magnesian suite but their origin poses an enigma for most petrologic models of lunar crustal evolution some models suggest that the alkali and magnesian suites formed from distinct unrelated parental magmas whereas other models propose that both suites formed from the same parental magma the contrast in major element chemistry of the cumulus phases in each suite is difficult to reconcile with their similar incompatible element chemistry we present herein a detailed ion microprobe sims and electron microprobe study of seven alkali suite rocks our data show that most alkali suite anorthosites preserve major and trace element characteristics acquired during their formation as igneous cumulate rocks and that these characteristics can be used to reconstruct the parental magma composition the data indicate that cumulates of the alkali suite crystallized from magmas with rare earth element ree contents approximately 0 6 2 0xhigh k kreep and small but consistently positive eu anomalies eu eu super approximately 2 relative to kreep snyder and others 1995a have proposed that the alkali suite parental magma is similar to apollo 15 pristine kreep basalt our model suggests that the major element composition of cumulus plagioclase in most alkali suite rocks is too sodic for the calculated crystal line of descent of pristine kreep basalt and that assimilation of pre existing calcic anorthosite is required this conclusion is supported by the ree patterns of the alkali suite parental magma determined here we propose that alkali suite anorthosites formed as flotation cumulates in kreepy plutons that may have formed norites as complementary bottom cumulates the alkali flotation cumulates reflect fractional crystallization of their parental pluton local equilibrium crystallization assimilation of plagioclase rich roof rock and episodic magma mixing during convective overturn of the crystallizing magma bodies texturally pristine alkali anorthosites exhibit petrographic characteristics that are consistent with their origin as cumulates in a kreepy pluton including abundant modal plagioclase post cumulus pyroxenes both augite and pigeonite that generally lack exsolution lamellae and that have equilibration temperatures of 950 1100 degrees c relict igneous textures and in some cases igneous lamination the lack of cumulus mafic phases in rocks that should be pyroxene saturated suggests separation of the plagioclase by flotation not sinking assimilation of plagioclase from older anorthositic highlands crust is indicated by the high eu contents of the cumulates and by the positive eu anomalies in their calculated parental melts relative to high k kreep mixing of the evolved alkali suite parental magma with primitive melt occurred episodically as shown by reverse zoning profiles in some cumulus plagioclase injection of this primitive hot magma into the crystallizing pluton may have induced convective overturn of the magma chamber

some things we can infer about the moon from the composition of the apollo 16 regolith randy l korotev department of earth and planetary sciences and mcdonnell center for the space sciences washington university st louis missouri 63130 usa author s e mail address rlk levee wustl edu received 1996 september 16 accepted in revised form 1997 may 12 abstract characteristics of the regolith of cayley plains as sampled at the apollo 16 lunar landing site arereviewed and new compositional data are presented for samples of 1 mm fines soils and 1 2 mm rego lith particles as a means of determining which of the many primary igneous and secondary crystalline brec cias lithoiogic components that have been identified in the soil are volumetrically important and providing anestimate of their relative abundances more than 3 x 106 combinations of components representing nearly everylithology that has been observed in the apollo 16 regolith were systematically tested to determine which com binations best account for the composition of the soils conclusions drawn from the modeling include the fol lowing at the site mature soil from the cayley plains consists of 64 5 2 7 components representing prebasin materials anorthosites feldspathic breccias and a small amount 2 6 1 5 of total soil ofnonmare mafic plutonic rocks mostly gabbronorites on average these components are highly feldspathic with average concentrations of 31 32 a1203 and 2 3 feo and a molar mg mg fe ratio of 0 68 theremaining 36 of the regolith is syn and postbasin material 28 8 2 4 mafic impact melt breccias mimbs i e lkfm and vha basalts created at the time of basin formation 6 0 1 4 mare derived material impact and volcanic glass crystalline basalt with an average tio2 concentration of 2 4 and 1 postbasin meteoritic material the mimbs are the principal 80 90 carrier of incompatible traceelements rare earths th etc and the carrier of about one half of the siderophile elements and elementsassociated with mafic mineral phases fe mg mn cr sc most 71 of the fe in the present regolithderives from syn and postbasin sources mimbs mare derived material and meteorites thus althoughthe bulk composition of the apollo 16 regolith is nominally that of noritic anorthosite the noritic part themimbs and the anorthositic part the prebasin components are largely unrelated there is compositionalevidence that 3 4 of the soil is th rich material such as that occurring at the apollo 14 site and one frag ment of this type was found among the small regolith particles studied here if regolith such as that repre sented by the apollo 16 ancient regolith breccias was a protolith of the present regolith such regolith cannotexceed 71 of the present regolith the rest must be material added or redistributed since closure of theancient regolith breccias the postclosure material includes the mare derived material and the apollo 14 like component compositions of all mature surface soils from apollo 16 even those collected 4 km apart on the cayleyplains are very similar which is in stark contrast to the wide compositional range of the lithologies of whichthe soil is composed this uniformity indicates that the ratio of mimbs to feldspathic prebasin componentsis not highly variable in the megaregolith over distances of a few kilometers that there are no large sub surface concentrations of pure mafic impact melt breccia and that the intimate mixing is inherent to thecayley plains at a gross scale thus the mixing ofmafic impact melt breccias and feldspathic prebasin com ponents must have occurred during formation and deposition of the cayley plains such uniformity could nothave been achieved by small postdeposition impacts into a stratified megaregolith using this conclusion asone constraint and the known distribution of th on the lunar surface as another and the assumption that the im brium impact is primarily responsible for formation of the cayley plains arguments are presented that theapollo 16 mimbs derive from the imbrium region and consequently that one fourth of the apollo 16 regolithis primary imbrium ejecta in the form of mafic impact melt breccias

geochemistry and 40ar 39ar geochronology of impact melt clasts in feldspathic lunar meteorites implications for lunar bombardment history we studied 42 impact melt clasts from lunar feldspathic regolith breccias macalpine hills mac 88105 queen alexandra range que 93069 dar al gani dag 262 and dag 400 for texture chemical composition and or chronology although the textures are similar to the impactmelt clasts identified in mafic apollo and luna samples the meteorite clasts are chemically distinct from them having lower fe ti k and p thus representing previously unsampled impacts the 40ar 39ar ages on 31 of the impact melts the first ages on impact melt samples from outside the region of the apollo and luna sampling sites range from 4 to 2 5 ga we interpret these samples to have been created in at least six and possibly nine or more different impact events one inferred impact event may be consistent with the apollo impact melt rock age cluster at 3 9 ga but the meteorite impact melt clasts with this age are different in chemistry from the apollo samples suggesting that the mechanism responsible for the 3 9 ga peak in lunar impact melt clast ages is a lunar wide phenomenon no meteorite impact melts have ages more than 1 older than 4 0 ga this observation is consistent with but does not require a lunar cataclysm

determination of planetary basalt parentage a simple technique using the electron microprobe many basaltic meteorites are being discovered in old and new meteorite suites including those from cold deserts e g antarctica and hot desert environments it is important to establish the specific planetary body source proven techniques for establishing planetary parentage include stable isotopic signatures especially oxygen certain elemental ratios in bulk samples and certain elemental ratios in specific minerals some of these techniques are expensive require considerable sample preparation and are adversely affected by weathering processes on the parent body or on earth we have been seeking key major and minor elemental ratios in pyroxene olivine and feldspar that can be measured by the electron microprobe on standard thin sections these ratios may be preserved in unweathered portions of mineral grains and thus see through weathering processes in addition if the sample is too small to provide a representative bulk composition it may still have key information recorded in individual minerals we have found that some of the most useful chemical parameters are fe mn atomic in olivine or pyroxene and the percent anorthite an in plagioclase solid solutions a plot of fe mn in pyroxene and or olivine verses an defines compositional fields that are significantly different for earth mars moon 4 vesta and the angrite parent body this method may be especially powerful when combined with oxygen isotope data

interannual variability of the intraseasonal oscillation and its impact on the summertime wave patterns and tropical cyclones over the western north pacific abstractin this study intraseasonal oscillations isos and submonthly wave patterns were separated into maximal variance maxv and minimal variance minv years on the basis of iso variance from july to october the mean state 850 hpa streamfunction for submonthly cases indicated that in the minv years tropical cyclones tcs formed near areas southeast of those in the maxv years isos propagated northward in the maxv years whereas a weaker westward propagating tendency was observed in the minv years track analysis of the centers of the submonthly cyclonic anomalies suggested that the background flow dictated the propagation routes of the easterly cyclonic anomalies in the maxv years however the propagation routes of the westerly cyclonic anomalies were barely affected by the background flow further analysis of the iso mean flow patterns showed that in the maxv years the propagation routes of the westerly cyclonic anomalies were more likely controlled by the anomalous easterly flow generated by

the magma ocean concept and lunar evolution the model of lunar evolution in which the anorthositic plagioclase rich oldest crust of the moon is formed over a period of 300 myr or less by crystallization as it floats on a global ocean of magma tens or hundreds of km thick is examined in a review of petrological and theoretical studies consideration is given to the classification of lunar rocks the evidence for primordial deep global differentiation constraints on the depth of the molten zone the effects of pressure on mineral stability relationships mainly liquid vs mainly magmifer ocean models and the evidence for multiple ancient differentiation episodes a synthesis of the model of primordial differentiation and its aftereffects is presented and the generalization of the model to the earth and to mars mercury venus and the asteroids is discussed

northwestward propagation of the intraseasonal oscillation in the western north pacific during the boreal summer structure and mechanism abstract the convection of the intraseasonal timescale in the western north pacific during the boreal summer tends to propagate northwestward in the philippine sea to near 20 n and then continues propagating westward the formation of enhanced convection in the western north pacific is a result of the merging of a convective system moving eastward along the equator and a westward propagating low level convergence anomaly which is located to the east of a vortex in the subtropics a positive feedback between the anomalous circulation and convection leads to a rapid enhancement of the system the strengthened southwesterly associated with the vortex enhances evaporation over the oceans e g the eastern indian ocean the bay of bengal and the south china sea and transports moisture northeastward the moisture converges at the northwestern corner of the convection and results in a potentially unstable atmosphere the result is the northwestward propagation of the coupled circulation convection system in

ion and electron microprobe study of troctolites norite and anorthosites from apollo 14 evidence for urkreep assimilation during petrogenesis of apollo 14 mg suite rocks abstract most of the moon s highland crust formed during the period 4 65 4 45 ga ago from a vast magma ocean up to 800 km deep hess and parmentier 1995 this early lunar crust comprises fe rich anorthosites with calcic plagioclase compositions subsequent evolution of the highland crust was dominated by troctolites anorthosites and norites of the mg suite this plutonic series is characterized by calcic plagioclase and mafic minerals with high mg 100 mg mg fe these rocks evidently formed by partial melting of ultramafic rocks of the lunar mantle but their bulk rock incompatible element characteristics are too enriched to represent such a primitive source previous studies have suggested that this enrichment in incompatible trace elements is the result of metasomatism of the crust by fluids rich in ree and p the products of this suggested metasomatic event are ree rich phosphates typically whitlockite deposited interstitially alternatively the incompatible element rich nature of these plutonic rocks may represent a characteristic of their parent magma acquired prior to crystallization of the plutons in an effort to distinguish the origin of this important lunar rock series we have analyzed the ree content of primary cumulus phases in ten mg suite cumulates using sims along with their major and minor element compositions by electron microprobe analysis nine of these samples have high mg s consistent with their formation from the most primitive parent melts of the mg suite the data presented here show that mg suite troctolites and anorthosites preserve major and trace element characteristics acquired during their formation as igneous cumulate rocks and that these characteristics can be used to reconstruct related aspects of the parent magma composition our data show that primitive cumulates of the mg suite crystallized from magmas with ree contents similar to high k kreep in both concentration and relative abundance the highly enriched nature of this parent magma contrasts with its primitive major element characteristics as pointed out by previous workers this enigma is best explained by the mixing of residual magma ocean urkreep melts with ultramagnesian komatiitic partial melts from the deep lunar interior the data do not support earlier models that invoke crustal metasomatism to enrich the mg suite cumulates after formation or models which call for a superkreep parent for the troctolites and anorthosites

geochemistry and petrology of lunar meteorite queen alexandra range 94281 a mixed mare and highland regolith breccia with special emphasis on very low titanium mafic components queen alexandra range que 94281 a lunar meteorite recently discovered in antarctica is a glassy matrix clast rich regolith breccia containing a mixture of mafic volcanic glass and gabbroic constituents and a diverse set of highland constituents in thin section the clast assemblage is dominated by coarse mineral debris from a shallow intrusive or hypabyssal setting or from deep within a thick mare flow abundant coarse grained pyroxene clasts have fine scale exsolution lamellae and compositions similar to pyroxenes of known lunar very low ti vlt basalts and other lunar meteorites of basaltic composition pyroxene compositions follow fe enrichment extending to hedenbergite which is associated with fayalite and cristobalite indicating slow cooling we refer to the protolith of the crystalline vlt component as vlt gabbro fragments of pyroclastic glasses that have high fe and low ti concentrations similar to the pyroclastic green glasses known from apollo samples are common lithic clasts include abundant subrounded glassy to cryptocrystalline aluminous 17 30 wt al2o3 kreep poor melt breccias of highland origin and a variety of other feldspathic impactites on the basis of composition of our subsamples que 94281 consists of 54 wt mafic or mare components and 46 wt feldspathic or highland components the bulk composition of que 94281 is similar to that of yamato y 793274 but que 94281 has slightly greater concentrations of some siderophile elements and slightly lower concentrations of those elements contributed mainly by mafic constituents differences in siderophile element concentrations are consistent with longer surface exposure of que 94281 minor differences in trace element variations of subsamples of the two meteorites suggest subtle differences in the composition of their highland constituents nonetheless the overall similarity of compositions supports the possibility that they were ejected from the same source region on the moon the crystalline vlt component of que 94281 differs from those known from apollo 17 and luna 24 vlt lithologies and from that of basaltic breccia elephant moraine eet 87521 the vlt gabbro component and the ferroan vlt volcanic glasses in que 94281 have compositions that may be petrogenetically related by derivation from a common picritic parent composition represented by an ultramafic glass found in que 94281

cogenetic rock fragments from a lunar soil evidence of a ferroan noritic anorthosite pluton on the moon abstract the impact that produced north ray crater apollo 16 landing site exhumed rocks that include relatively mafic members of the lunar ferroan anorthositic suite bulk and mineral compositions indicate that a majority of 2 4 mm lithic fragments from sample 67513 including impact breccias and monomict igneous rocks are related to a common noritic anorthosite precursor compositions and geochemical trends of these lithic fragments and of related samples collected along the rim of north ray crater suggest that these rocks derived from a single igneous body this body developed as an orthocumulate from a mixture of cumulus plagioclase and mafic intercumulus melt after the plagioclase had separated from any cogenetic mafic minerals and had become concentrated into a crystal mush 70 wt plagioclase 30 wt intercumulus melt we present a model for the crystallization of the igneous system wherein system is defined as cumulus plagioclase and intercumulus melt the initial accumulation of plagioclase is analogous to the formation of thick anorthosites of the terrestrial stillwater complex however a second stage of formation is indicated involving migration of the cumulus plagioclase intercumulus melt system to a higher crustal level analogous to the emplacement of terrestrial massif anorthosites compositional variations of the lithic fragments from sample 67513 are consistent with dominantly equilibrium crystallization of intercumulus melt the highly calcic nature of orthocumulus pyroxene and plagioclase suggests some reaction between the intercumulus melt and cumulus plagioclase perhaps facilitated by some recrystallization of cumulus plagioclase bulk compositions and mineral assemblages of individual rock fragments also require that most of the mafic minerals formed in close contact with cumulus plagioclase not as separate layers the distribution of compositions and by inference modes has a narrow peak at anorthosite and a broader larger peak at noritic anorthosite characteristics of the samples and their geochemical trends imply an origin in a system that was large relative to the unknown size of the impact that produced the brecccas of ferroan noritic anorthosite composition that were excavated later by the formation of north ray crater and they appear to be consistent with an origin of the suite within a perched plagioclase cumulate if the moon s crust formed by accumulation of plagioclase in a magma ocean ferroan noritic anorthosite formed as an orthocumulate is an alternative to extensive adcumulus formation of ferroan anorthosite 90 vol plagioclase this provides a relatively mafic ferroan anorthositic component 15 vol mafics which is required by mass balance models of compositions of polymict lunar crustal materials the inferred bulk composition of the system of cumulus plagioclase and intercumulus melt is similar to that of ferroan regolith breccia macalpine hills 88104 5 a lunar highland meteorite and may represent a common and widespread component of the moon s early highland crust

the flux of meteorites to the earth and weathering in hot desert ordinary chondrite finds abstract the abundance of ferric iron produced by weathering in ordinary chondrites collected from hot desert regions is related to their terrestrial age enabling a variety of processes involved in meteorite weathering to be deduced fe0 fe2 fe3 content was measured quantitatively by 57fe mossbauer spectroscopy it is observed that meteorites from different regions are oxidised at different rates we also propose the tentative hypothesis that one source of scatter in total oxidation versus terrestrial age for a region is climatic change a mechanism to explain the variable response to climatic conditions involves the high initial porosity of samples being reduced as ferric oxides and other alteration products are produced reliable recovery data from a meteorite accumulation site roosevelt county new mexico usa and a quantitative measure of weathering and terrestrial age permit an estimate of the flux of meteorites to the earth s surface having established a decay constant for meteorites and accounting for the area of searches and pairing we estimate an accumulation rate of 159 falls of mass greater than 20 g per 106 km2 per yr this calculation is distinct from but in broad agreement with previous estimates from camera observations suggesting that the accumulation rate of meteorite falls to the earth s surface has remained essentially unchanged over the last 50 000 years at between 59 and 159 falls of mass exceeding 20 g per 106 km2 per yr the error for both methods is approximately a factor of 2

lunar granulites and their precursor anorthositic norites of the early lunar crust lunar granulites are breccias with metamorphic textures they are not pristine having been contaminated with meteoritic siderophiles nonetheless they constitute an abundant class of highlands rocks that are important because they are ancient and kreep free they may represent our best samples of the early lunar crust the granulites can be divided into ferroan and magnesian groups and each group can be subdivided on the basis of mineral composition and ree concentrations textural and compositional data show that some of the granulites especially 67215 and 67415 may be derived from distinct anorthositic norite precursors while some other granulites 79215 78155 are clearly polymict even the polymict granulites probably had anorthositic norites as their dominant precursors and not anorthosites norites or troctolites the granulites have compositions similar to those of the two lunar meteorites one of which yamato 791197 is ferroan the other alha81005 magnesian these meteorites are soil breccias from an unknown location distant from the apollo landing sites and contain anorthositic norites as abundant clasts compositions of granulites and lunar meteorites more closely resemble the average composition of lunar highlands as determined by remote sensing than do those of any other returned lunar samples the predominance of plutonic anorthositic norite precursors in material having the composition typical of highlands suggests that plutonic anorthositic norites were more abundant in the early lunar crust than is implied by their scarcity among pristine rocks from apollo missions

relationship between summertime intraseasonal oscillations and submonthly wave patterns under meridional periodic fluctuations abstractin this study submonthly wave patterns under the periodically fluctuating japan south china sea jscs pattern were separated into intraseasonal oscillation iso westerly and easterly phases the composite results showed that the wave patterns in the westerly jscs high and low phases were more effectively organized and situated in a more intense monsoon trough than their counterparts in the easterly phase tropical cyclones tcs tended to occur over cyclonic systems of the wave patterns where minimal vertical shear axes were also located more tcs formed in the westerly jscs phases near areas where maximal moisture convergence was located taiwan experienced heavier rainfall during the westerly jscs phases because the iso enhanced the monsoon troughs for the cyclonic system of the wave pattern to develop near taiwan in the westerly jscs high phase additionally in the westerly jscs low phase a stronger southeasterly mean flow generated by the iso steered the wave pattern and tcs farther west

rare earth element variations resulting from inversion of pigeonite and subsolidus reequilibration in lunar ferroan anorthosites we present results of a secondary ion mass spectrometry study of the rare earth elements rees in the minerals of two samples of lunar ferroan anorthosite and the results are applicable to studies of rees in all igneous rocks no matter what their planet of origin our pyroxene analyses are used to determine solid solid ree distribution coefficients d cree in low ca pyroxene cree in augite in orthopyroxene augite pairs derived by inversion of pigeonite our data and predictions from crystal chemical considerations indicate that as primary pigeonite inverts to orthopyroxene plus augite and subsolidus reequilibration proceeds the solid solid ds for orthopyroxene augite pairs progressively decrease for all rees the decrease is greatest for the lrees the ree pattern of solid solid ds for inversion derived pyroxene pairs is close to a straight line for sm lu and turns upward for rees lighter than sm the shape of this pattern is predicted by the shapes of the ree patterns for the individual minerals equilibrium liquids calculated for one sample from the compositions of primary phases using measured or experimentally determined solid liquid ds have chondrite normalized ree patterns that are very slightly enriched in lrees the plagioclase equilibrium liquid is overall less rich in rees than pyroxene equilibrium liquids and the discrepancy probably arises because the calculated plagioclase equilibrium liquid represents a liquid earlier in the fractionation sequence than the pyroxene equilibrium liquids equilibrium liquids calculated from the compositions of inversion derived pyroxenes or orthopyroxene derived by reaction of olivine are lree depleted in some cases substantially in comparison with equilibrium liquids calculated from the compositions of primary phases these discrepancies arise because the inversion derived and reaction derived pyroxenes did not crystallize directly from liquid and the use of solid liquid ds is inappropriate the lree depletion of the calculated liquids is a relic of formation of these phases from primary lree depleted minerals thus if one attempts to calculate the compositions of equilibrium liquids from pyroxene compositions it is important to establish that the pyroxenes are primary in addition our data suggest that experimental studies have underestimated solid liquid ds for rees in pigeonite and that ree contents of liquids calculated using these ds are overestimates our results have implications for sm nd age studies our work shows that if pigeonite inversion and or subsolidus reequilibration between augite and orthopyroxene occurred significantly after crystallization and if pyroxene separates isolated for sm nd studies do not have the bulk composition of the primary pyroxenes then the sm nd isochron age and end will be in error

petrologic province maps of the lunar highlands derived from orbital geochemical data orbital and sample geochemical data from the lunar highlands are combined in variation diagrams to determine a the coincidence between the two data sets and b the geologic validity of extrapolating observed diagrammatic relations to an image format we examined three variation diagrams mg 100 mg mg fe molar versus th ti c ratio normalized to chondrites al versus mg th ti c and fe versus th ti c for the orbital data within each diagram we establish a petrologic classification based on the data s clustering or coincidence with sample compositions or both the spatial distributions of each diagram s classes are shown as petrologic units on color coded classification maps the mg th ti c diagram which is similar to the mg sm ti c diagram that has been used in sample studies is inferior to the al mg th ti c diagram in discriminating kreep from mg suite rock types the orbital geochemical spectrometers analyzed the regolith in which mg varies much less than al although the fe th ti c diagram shows a diverse distribution of orbital data similar to that shown by the al mg th ti c diagram it is unable to discriminate adequately between kreep and mg suite rock types the fe th ti c diagram is nonetheless very useful because of its greater areal coverage orbital and soil sample compositions of the four highland landing sites correspond in both the al mg th ti c and the fe th ti c data the diagrams show some units of virtually pure anorthosite and norite most units show the effects of mixing of pristine rock types in the regolith one unit which dominates the eastern limb and farside highlands has a composition so mafic that with the chosen end members it requires a 30 mare basalt component we interpret this to mean that the highlands experienced a significantly greater amount of mare volcanism before the end of heavy bombardment than has been previously suggested the average global composition of the highlands under the apollo groundtracks is that of anorthositic gabbro an average that has significant implications for the role of near global plagioclase fractionation in lunar crustal genesis our analysis has shown that the simultaneous use of orbital and sample geochemical data in variation diagrams can 1 bridge the mechanical gap between orbital and sample studies by relating orbital data to sample petrology 2 present the results of several elemental databases as one map for rapid geologic analysis and 3 display quantitative mixing relations of different crustal materials in a spatial format this technique will be valuable for petrologic interpretation of the global geochemical data to be received from the future lunar geosciences orbiter mission

trace element distributions within ordinary chondrite chondrules implications for chondrule formation conditions and precursors the concentrations of thirty six lithophile elements in the major silicate phases of chondrules have been determined by ion microprobe two types of porphyritic chondrule olivines normal and incompatible rich have been identified the incompatible rich olivines which have forsterite contents that are greater than fo98 appear to have formed under highly reducing conditions the olivine and low ca pyroxene grains in porphyritic chondrules have relatively unfractionated l chondrite normalized ree abundances compared to expectations from equilibrium distribution coefficients this is consistent with porphyritic chondrules having formed at cooling rates of the order of 1000 c h or faster the alkali metal na k rb and cs to al ratios in chondrule glasses vary by two orders of magnitude the lower values possibly being the result of volatile loss from chondrules no correlation was found between alkali metal depletions in chondrule glasses and enrichments in the surrounding rims but any such correlation may have been destroyed by the diffusive redistribution of these elements in rims that is likely to occur even under mild metamorphic conditions the refractory lithophiles with the exception of mg are all highly incompatible in silicate melts and are as a result concentrated in the chondrule glasses the refractory lithophiles in the glass are in most cases unfractionated from one another suggesting that neither vapor phase nor crystal liquid fractionation played a major role in the formation of chondrules or their precursors based largely on the observation that the refractory lithophiles are concentrated in the chondrule glasses it is suggested that previously reported correlations between these elements in bulk chondrule analyses are due to chondrules themselves as opposed to refractory condensates having been their own immediate precursors a simple monte carlo simulation using the compositions of the major chondrule silicate phases reported here supports this hypothesis it is argued that the upper limit of about one observed in the atomic na al ratios of chondule glasses is not due to an albitic precursor but simply reflects that for na to be incorporated into the structure of the melt it must take part in the coupled substitution naalo2 sio2

petrography mineralogy and geochemistry of lunar meteorite sayh al uhaymir 300 we report here the petrography mineralogy and geochemistry of lunar meteorite sayh al uhaymir 300 sau 300 sau 300 is dominated by it fine grained crystalline matrix surrounding mineral fragments plagioclase pyroxene olivine and ilmenite and lithic clasts mainly feldspathic to noritic mare basalt and kreepy rocks are absent glass melt veins and impact melts are present indicating that the rock has been subjected to a second impact event feni metal and troilite grains were observed in the matrix major element concentrations of sau 300 al 2 o 3 21 6 wt and feo s 16 wt are very similar to those of two basalt bearing feldspathic rei regolith breccias calcalong creek and yamato y 983885 however the rare earth element ree abundances and pattern of sau 300 resemble the patterns of feldspathic highlands meteorites e g queen alexandra range que 93069 and dar al gani dag 400 and the average lunar highlands crust it has a relatively lree enriched 7 to 10 x ci pattern with a positive eu anomaly similar to 11 x ci values of fe mn ratios of olivine pyroxene and the bulk sample are essentially consistent with l lunar origin sau 300 also contains high siderophile abundances with a chondritic ni ir ratio sau 300 has experienced moderate terrestrial weathering as its bulk sr concentration is elevated compared to other lunar meteorites and apollo and luna samples mineral chemistry and trace clement abundances of sau 300 fall within the ranges of lunar feldspathic meteorites and fan rocks sau 300 is a feldspathic impact melt breccia predominantly composed of feldspathic highlands rocks with a small amount of mafic component with a bulk mg of 0 67 it is the most mafic of the feldspathic meteorites and represents a lunar surface composition distinct from any other known lunar meteorites oil the basis of its low th concentration 0 46 ppm and its lack of kreepy and mare basaltic components the source region of sau 300 could have been within a highland terrain a great distance from the imbrium impact basin probably on the far side of the moon

magmatic evolution of lunar highland rocks estimated from trace elements in plagioclase a new bulk silicate moon model with sub chondritic ti ba sr ba and sr al ratios abstract the compositions of host magmas of ferroan anorthosites fan host magmas were estimated from secondary ion mass spectrometry analyses of plagioclase in lunar highland rocks the evolution of the magmas was investigated by considering phase relations based on the melts algorithm and by re examining partition coefficients for trace elements between plagioclase and melts data little affected by post magmatic processes were selected by using plagioclase with relatively primitive sc and co contents the fan host magma contained 90 174 ppm sr 40 119 ppm ba and 0 5 1 3 tio2 and had sub chondritic sr ba and ti ba ratios it is difficult to account for the formation of fan host magma on the basis of magma evolution processes of previously proposed bulk silicate moon models with chondritic ratios for refractory elements at global scale therefore the source of the fan host magma must have had primordial sub chondritic sr ba and ti ba ratios the fan host magmas were consistent in refractory elements with the estimated host mafic magma for feldspathic crust based on lunar meteorites and some very low ti mare rocks from lunar meteorites here we propose an alternative bulk silicate moon model the cbsm model which is enriched in crustal components of proto bodies relative to the present whole earth moon system

pyroxene as a recorder of cumulate formational processes in asteroids moon mars earth reading the record with the ion microprobe igneous cumulate rocks provide an important record of planetary magmatism but there are pitfalls in their interpretation cumulus minerals may react with the trapped melt and other cumulus phases during sub solidus reactions thus losing a direct record of their igneous history one of the best approaches for estimating the melt compositions parental to the cumulates is to analyze the cores of cumulus phases for elements with slow diffusion rates e g ree in pyroxene because these most reliably retain a record of the mineralmelt partitioning we have conducted sims studies of pyroxenes from a variety of planetary cumulates including lunar norites martian orthopyroxenites asteroidal orthopyroxenites diogenites asteroidal pyroxene plagioclase cumulates cumulate eucrites and terrestrial orthopyroxenites and norites stillwater complex montana we emphasized the ree la ce nd sm eu dy er yb along with sr y and zr in these investigations our studies yielded the several conclusions i lunar mg suite norites crystallized from highly evolved kreepy melts that were emplaced into the lunar anorthositic crust one viable model suggests remobilization of kreep lithologies that formed late in the crystallization of the lunar magma ocean 2 orthopyroxenites from asteroid 4 vesta diogenites likely formed as cumulates from melts derived from depleted mantle which had previously experienced eucritic basalt removal the calculated parental melts show a limited range of major element compositions but an exceedingly large range of trace element variation that is difficult to explain by any simple crystallization or melting models 3 the diogenites of 4 vesta are cumulates from melts derived from many depleted mantle reservoirs that either formed numerous orthopyroxene plutons later mixed by impact brecciation or commingled by magma mixing to form a limited number of differentiated plutons we base this conclusion on a comparative investigation of a well studied terrestrial orthopyroxenite sequence bronzitite zone of the stillwater complex an important lesson to be learned from these studies in comparative planetology is that if simple petrogenetic models do not work for well studied terrestrial occurrences there is little reason to believe that they will work for planetary environments where we have little geologic control on sampling

constraining the source regions of lunar meteorites using orbital geochemical data lunar meteorites provide important new samples of the moon remote from regions visited by the apollo and luna sample return missions petrologic and geochemical analysis of these meteorites combined with orbital remote sensing measurements have enabled additional discoveries about the composition and age of the lunar surface on a global scale however the interpretation of these samples is limited by the fact that we do not know the source region of any individual lunar meteorite here we investigate the link between meteorite and source region on the moon using the lunar prospector gamma ray spectrometer remote sensing data set for the elements fe ti and th the approach has been validated using apollo and luna bulk regolith samples and we have applied it to 48 meteorites excluding paired stones our approach is able broadly to differentiate the best compositional matches as potential regions of origin for the various classes of lunar meteorites basaltic and intermediate fe regolith breccia meteorites are found to have the best constrained potential launch sites with some impact breccias and pristine mare basalts also having reasonably well defined potential source regions launch areas for highland feldspathic meteorites are much less well constrained and the addition of another element such as mg will probably be required to identify potential source regions for these

iso modulating effects on the east asian summer monsoon circulation patterns associated with southern taiwan s monsoon rainfall abstractin this study the circulation patterns of the summer monsoon associated with monsoon rainfall in southern taiwan were analyzed and two types of monsoon patterns were defined the first type was characterized by a broad low pressure area extending northeastward from a low pressure center near southern china to southern japan strong southwesterly flows were observed over the southern flank of the monsoon trough the second type of monsoon pattern was characterized by a strong westward extending anticyclone in the area north of taiwan including central china south korea and japan and a weaker east west elongated monsoon trough south of taiwan driving the easterly flow to southern taiwan the modulating effect of intraseasonal oscillations isos on these monsoon flow patterns indicates that as isos propagate northwestward toward southern china they create favorable conditions for developing and strengthening southwesterly flows and convection however because of the latitudinal limit of nor

an interdisciplinary study of weathering effects in ordinary chondrites from the acfer region algeria weathering effects on meteorite finds from the acfer region were studied by various analytical techniques and in dependence on the depth of sampling in thin sections of weathered meteorites weathering effects usually decrease from the outside to the interior of the meteorite the results of evolved gas analysis indicate that variation in weathering between surface and core is not significant in respect to the formation of fe oxyhydroxides the secondary alteration effects in the noble gases are distributed unevenly throughout the specimens as seen in the nonsystematic differences observed for the heavy noble gases chemical analyses show significant enrichment of ba and sr in the outer parts of the weathered samples due to element contamination through aqueous solution iron ni and co are partly flushed from the system as the metal oxidation proceeds oxygen isotopes show increases in d180 and d17o with increasing terrestrial age for a set of h3 chondrites the degree of weathering determined from the water content was correlated with terrestrial ages and is discussed with respect to possible weathering mechanisms

characterization of multiple lithologies within the lunar feldspathic regolith breccia meteorite northeast africa 001 lunar meteorite northeast africa nea 001 is a feldspathic regolith breccia this study presents the results of electron microprobe and la icp ms analyses of a section of nea 001 we identify a range of lunar lithologies including feldspathic impact melt ferroan noritic anorthosite and magnesian feldspathic clasts and several very low titanium vlt basalt clasts the largest of these basalt clasts has a rare earth element ree pattern with light ree lree depletion and a positive euanomaly this clast also exhibits low incompatible trace element ite concentrations e g 0 1 ppm th 0 5 ppm sm indicating that it has originated from a parent melt that did not assimilate kreep material positive eu anomalies and such low ite concentrations are uncharacteristic of most basalts returned by the apollo and luna missions and basaltic lunar meteorite samples we suggest that these features are consistent with the vlt clasts crystallizing from a parent melt which was derived from early mantle cumulates that formed prior to the separation of plagioclase in the lunar magma ocean as has previously been proposed for some other lunar vlt basalts feldspathic impact melts within the sample are found to be more mafic than estimations for the composition of the upper feldspathic lunar crust suggesting that they may have melted and incorporated material from the lower lunar crust possibly in large basin forming events the generally feldspathic nature of the impact melt clasts lack of a kreep component and the compositions of the basaltic clasts leads us to suggest that the meteorite has been sourced from the outer feldspathic highlands terrane fht o probably on the lunar farside and within about 1000 km of sources of both low ti and vlt basalts the latter possibly existing as cryptomaria deposits

northwest africa 032 product of lunar volcanism mineralogy major element compositions of minerals and elemental and oxygen isotopic compositions of the whole rock attest to a lunar origin of the meteorite northwest africa 032 nwa 032 an unbrecciated basalt found in october 1999 the rock consists predominantly of olivine pyroxene and chromite phenocrysts set in a crystalline groundmass of feldspar pyroxene ilmenite troilite and trace metal whole rock shock veins comprise a minor but ubiquitous portion of the rock undulatory to mosaic extinction in olivine and pyroxene phenocrysts and micro faults in groundmass and phenocrysts also are attributed to shock several geochemical signatures taken together indicate unambiguously that nwa 032 originated from the moon the most diagnostic criteria include whole rock oxygen isotopic composition and ratios of fe mn in the whole rock olivine and pyroxene a lunar origin is documented further by the presence of fe metal troilite and ilmenite zoning to extremely fe rich compositions in pyroxene the ferrous oxidation state of all fe in pyroxene and the rare earth element pattern with a well defined negative europium anomaly this rock is similar in major element chemistry to basalts from apollo 12 and 15 but is enriched in light rare earth elements and has an unusually high th sm ratio some apollo 14 basalts yield a closer match to nwa 032 in rare earth element patterns but have higher concentrations of al2o3 ar ar step release results are complex but yield a whole rock age of ca 2 8 ga suggesting that nwa 032 was extruded at 2 8 ga or earlier this rock may be the youngest sample of mare basalt collected to date noble gas concentrations combined with previously collected radionuclide data indicate that the meteorite exposure history is distinct from currently recognized lunar meteorites in short the geochemical and petrographic features of nwa 032 are not matched by apollo or luna samples nor by previously identified lunar meteorites indicating that it originates from a previously unsampled mare deposit detailed assessment of petrographic features olivine zoning and thermodynamic modelling indicate a relatively simple cooling and crystallization history for nwa 032 chromite spinel olivine and pyroxene crystallized as phenocrysts while the magma cooled no faster than 2 c hr based on the polyhedral morphology of olivine comparison of olivine size with crystal growth rates and preserved fe mg diffusion profiles in olivine phenocrysts suggest that olivine was immersed in the melt for no more than 40 days plumose textures in groundmass pyroxene feldspar and ilmenite and fe rich rims on the phenocrysts formed during rapid crystallization cooling rates 20 to 60 c hr after eruption

orthopyroxene as a recorder of lunar crust evolution an ion microprobe investigation of mg suite norites the lunar mg suite which includes dunites troctolites and norites could make up 20 30 of the moon s crust down to a depth of 60 km the remainder is largely anorthositic this report focuses on norites because we have found that the chemical characteristics of orthopyroxene are effective recorders of their parental melt compositions many of the samples representing the mg suite are small and unrepresentative in addition they are cumulates and thus are difficult to study by whole rock techniques therefore we decided to study these rocks by sims techniques to analyze a suite of trace elements in orthopyroxene the 12 norite samples were selected from a recent compilation by warren who attempted to select the best candidate samples from the standpoint of their pristine character our present database includes greater than 300 superior electromagnetic pulse emp analyses and greater than 50 scanning ion mass spectroscopy sims analyses for 8 rare earth elements ree zr y and sr the mg s for the parental melts calculated from mg s in orthopyroxene show that most melts have mg s in the range of 0 36 0 60 this compares with a range of mg s for lunar volcanic picritic glass beads of 0 4 0 68 therefore although the cumulate whole rock compositions of the mg suite can be extremely magnesian the calculated parental melts are not anomalously high in mg a chemical characteristic of the mg suite norites that is more difficult to explain is the high kreep content of the calculated parental melts the ree contents for the calculated norite parental melts have ree that match or exceed the high k kreep component of warren therefore mixing of a kreep component and a picritic melt cannot by itself explain the high estimated ree contents of the melts parental to norites advanced crystallization following kreep incorporation especially of plagiclase may also be required

kreepy lunar meteorite dhofar 287a a new lunar mare basalt dhofar 287 dho 287 is a new lunar meteorite found in oman on january 14 2001 the main portion of this meteorite dho 287a consists of a mare basalt while a smaller portion of breccia dho 287b is attached on the side dho 287a is only the fourth crystalline mare basalt meteorite found on earth to date and is the subject of the present study the basalt consists mainly of phenocrysts of olivine and pyroxene set in a finer grained matrix which is composed of elongated pyroxene and plagioclase crystals radiating from a common nucleii the majority of olivine and pyroxene grains are zoned from core to rim in terms of fe and mg accessory minerals include ilmenite chromite ulvaspinel troilite and feni metal chromite is invariably mantled by ulvaspinel this rock is unusually rich in late stage mesostasis composed largely of fayalite si k ba rich glass fluorapatite and whitlockite in texture and mineralogy dho 287a is a low ti mare basalt with similarities to apollo 12 a 12 and apollo 15 a 15 basalts however all plagioclase is now present as maskelynite and its composition is atypical for known low ti mare basalts the fe to mn ratios of olivine and pyroxene the presence of feni metal and the bulk rock oxygen isotopic ratios along with several other petrological features are evidence for the lunar origin for this meteorite whole rock composition further confirms the similarity of dho 287a with a 12 and a 15 sam ples but requires possible kreep assimilation to account for its rare earth element ree contents cooling rate estimates based on fo zonation in olivine yield values of 0 2 0 8 c hr for the lava typical for the center of a 10 20 m thick flow the recalculated major element concentrations after removing 10 15 modal olivine are comparable to typical a 15 mare basalts crystallization mod eling of the recalculated dho 287a bulk composition yields a reasonable fit between predicted and observed mineral abundances and compositions

quasi periodic behavior of the pacific japan pattern affecting propagation routes of summertime wave patterns and the associated tropical cyclone tracks over the western north pacific abstractthis study introduces a modified pacific japan pj index that exhibits a substantial periodicity of 5 16 days in the east asian summer monsoon region the quasi periodic fluctuations of the pj index can indicate changes in the large scale circulation systems in the pj high phase the wave pattern propagates northwestward from the western north pacific tropics to an area near northern luzon and is then forced to move westward because of a stationary anomalous high pressure system over southern japan the tropical cyclones tcs associated with the anomalous low pressure systems tend to follow a straight moving propagation route through the northern south china sea the anomalous cyclonic flow causes heavy rainfall in eastern taiwan however in the pj low phase the wave pattern and tcs follow a recurving propagation route toward higher latitudes the circulation pattern typically brings heavy rainfall to northern taiwan in the pj low phase therefore wave patterns under the influence of the qu

petrogenesis of lunar highlands meteorites dhofar 025 dhofar 081 dar al gani 262 and dar al gani 400 the petrogenesis of four lunar highlands meteorites dhofar 025 dho 025 dhofar 081 dho 081 dar al gani 262 dag 262 and dar al gani 400 dag 400 were studied for dho 025 measured oxygen isotopic values and fe mn ratios for mafic minerals provide corroboratory evidence that it originated on the moon similarly fe mn ratios in the mafic minerals of dho 081 indicate lunar origin lithologies in dho 025 and dho 081 include lithic clasts granulites and mineral fragments a large number of lithic clasts have plagioclase an and coexisting mafic mineral mg that plot within the gap separating ferroan anorthosite suite fan and high magnesium suite hms rocks this is consistent with whole rock ti sm ratios for dho 025 dho 081 and dag 262 which are also intermediate compared to fan and hms lithologies although ion microprobe analyses performed on dho 025 dho 081 dag 262 and dag 400 clasts and minerals show far stronger fan affinities than whole rock data suggest most clasts indicate admixture of 12 hms component based on geochemical modeling in addition coexisting plagioclase pyroxene ree concentration ratios in several clasts were compared to experimentally determined plagioclase pyroxene ree distribution coefficient ratios two dho 025 clasts have concordant plagioclase pyroxene profiles indicating that equilibrium between these minerals has been sustained despite shock metamorphism one clast has an intermediate fan hms composition these lunar meteorites appear to represent a type of highland terrain that differs substantially from the kreep signatured impact breccias that dominate the lunar database from remote sensing data it is inferred that the lunar far side appears to have appropriate geochemical signatures and lithologies to be the source regions for these rocks although the near side cannot be completely excluded as a possibility if these rocks are indeed from the far side their geochemical characteristics may have far reaching implications for our current scientific understanding of the moon

compositional variation in apollo 16 impact melt breccias and inferences for the geology and bombardment history of the central highlands of the moon abstract high precision data for the concentrations of a number of lithophile and siderophile elements were obtained on multiple subsamples from 109 impact melt rocks and breccias mostly crystalline from the apollo 16 site compositions of nearly all apollo 16 melt rocks fall on one of two trends of increasing sm concentration with increasing sc concentration the eastern trend lower sm sc mg fe and sm yb ratios consists of compositional groups 3 and 4 of previous classification schemes these melt rocks are feldspathic poor in incompatible and siderophile elements and appear to have provenance in the descartes formation to the east of the site the western trend higher sm sc mg fe and sm yb ratios consists of compositional groups 1 and 2 these relatively mafic kreep bearing breccias are a major component 35 of the cayley plains west of the site and are unusual compared to otherwise similar melt breccias from other sites in having high concentrations of fe ni metal 1 2 the metal is the carrier of the low ir au 0 3 chondritic siderophile element signature that is characteristic of the apollo 16 site four compositionally distinct groups 1m 1f 2db and 2nr of western trend melt breccias occur that are each represented by at least six samples compositional group 1 of previous classification schemes the poikilitic or lkfm melt breccias can be subdivided into two groups group 1m represented by six samples including 60315 is characterized by lower al2o3 concentrations higher mgo and alkali concentrations and higher mg fe and cr sc ratios than group 1f represented by fifteen samples including 65015 group 1m also has siderophile element concentrations averaging about twice those of group 1f and ir au and ir ni ratios that are even lower than those of other western trend melt rocks ir au 0 24 0 03 ci normalized at the mafic extreme of group 2 vha melt breccias the melt lithology occurring as clasts in feldspathic fragmental breccias from north ray crater group 2nr is compositionally distinct from the melt lithology of dimict breccias from the cayley plains group 2db in having higher concentrations of sc cr and heavy rare earth elements and lower concentrations of siderophile elements the distinct siderophile element signature high absolute abundances low ir au ratio suggest that the four groups of mafic melt breccia are all somehow related ratios of some lithophile elements also suggest that they are more closely related to each other than they are to melt breccias from other apollo sites however none of the breccia compositions can be related to any of the others by any simple process of igneous fractionation or mixing involving common lunar materials thus the origin of the four groups of mafic melt breccia is enigmatic if they were produced in only one or two impacts then a mechanism exists for generating regimes of impact melt breccia in a single impact that are substantially different from each other in composition for various reasons including the problem of delivering large volumes of four different types of melt to the apollo 16 site it is unlikely that any of these breccias were produced in basin forming impacts if they were produced in as many as four crater forming impacts then the unusual siderophile element signature is difficult to explain possible explanations are 1 1 the four groups of melt breccia all contain metal from a single earlier impact 2 2 they were each formed by related metal rich meteoroids or 3 3 some common postimpact process has resulted in metal of similar composition in each of four melt pools within a compositional group most intrasample and intersample variation in lithophile element concentrations is caused by differences among samples in the proportion of a component of normative anorthosite or noritic anorthosite in most cases this compositional variation probably reflects variation in clast abundance for group 2db and probably 2nr differences in abundance of a component of ferroan anorthosite estimated al2o3 32 accounts for the compositional variation for groups 1m and 1f the anorthositic component is more mafic estimated al2o3 26 some group 2 samples may be related by a troctolitic component of varying abundance

formation of lunar highlands anorthosites abstract the lunar magma ocean lmo model was proposed after the discovery of anorthosite in apollo 11 samples however the chemical and isotopic compositions of lunar anorthosites are not fully consistent with its lmo origin we have analyzed major and trace elements in anorthositic clasts from ten lunar feldspathic meteorites which are related to the solidification of the lmo the plagioclase rare earth element ree abundances and patterns are not correlated with the mg of coexisting mafic minerals in anorthosites implying that mafic minerals and plagioclase may not be in chemical equilibrium consistent with their textural differences the ree abundances in plagioclase range approximately fortyfold which cannot be produced by fractional crystallization of a single magma combining plagioclase trace element data from apollo and meteoritic anorthosites we propose that plagioclases derived from the lmo floated to the surface to form the primordial crust which then may have been metasomatized by incompatible element rich kreep potassium rare earth element phosphorus melts and mantle derived partial melts the lunar anorthosites may represent this metasomatized crust rather than solely a derivative from the lmo furthermore silicate melts similar to the metasomatic agents may also have melted the crust to form the mg suite rocks this hypothesis is consistent with overlapping ranges of age and initial end between lunar anorthosites and mg suite rocks these events are consistent with an overturn event of the cumulate mantle very early after primordial crust formation to produce the partial melts that metasomatized the crust

chemical alteration and ree mobilization in meteorites from hot and cold deserts the effects of terrestrial weathering on ree mobilization are evaluated for a variety of uncommon meteorites found in antarctica and in hot deserts the meteorites analyzed include 7 non cumulate eucrites 10 shergottites 3 nakhlites 2 lunar meteorites 4 angrites 10 acapulcoites 1 winonaite and 1 brachinite in situ concentration measurements of lanthanides and selected other minor and trace elements were made on individual grains by secondary ion mass spectrometry sims in antarctic meteorites oxidation converts ce 3 to ce 4 which is less soluble than the trivalent ree resulting in ce anomalies the mineral most affected is low ca pyroxene however not all grains of a given mineral are and distinct analyses of a single grain can even yield ree patterns with and without ce anomalies the effect is most pronounced for antarctic eucrites in which ce anomalies are observed not only in individual minerals but also in whole rock samples although ce anomalies are observed in meteorites from hot deserts as well the most characteristic signs of chemical alteration in this environment are a lree enrichment with a typical crustal signature as well as sr ba and u contaminations these can modify the whole rock ree patterns and disturb the isotope systematics used to date these objects the lree contamination is highly heterogeneous affecting some grains and not others of a given mineral mainly olivine and low ca pyroxene the two minerals with the lowest ree concentrations the major conduit for ree movement is through shock induced cracks and defects and the highest levels of contamination are found in altered material filling such veins and cracks meteorites that experienced low shock levels and those that are highly recrystallized are the least altered copyright 2003 elsevier ltd

mac88105 a regolith breccia from the lunar highlands mineralogical petrological and geochemical studies abstract the new large lunar meteorite mac88105 is a dense breccia with lithic and mineral clasts and fragments set into a welded matrix it is a regolith breccia which shows some recrystallization and evidence for a late shock event during which anorthositic glass veins were formed shock effects most probably due to the impact ejection from the moon are present throughout the sample and require a shock pressure of about 25 30 gpa in agreement with observations made on other lunar meteorites some components of mac88105 have been subjected to a shock pressure of about 40 45 gpa as evident from melt pockets in a clast the population of lithic clasts in mac88105 is similar to other lunar highland breccias vitric breccias are more abundant than granulitic breccias and plutonic rock fragments the presence of devitrified glass spheres and shards supports a regolith origin most common are metameltbreccias consisting of abundant anorthitic plagioclase clasts and a dense fine grained matrix some fine grained hornfelsic to granulitic metabreccias are also present lithic clast compositions are predominantly anorthositic noritic or noritic anorthositic and anorthositic troctolitic spinel bearing rocks are present but do not belong to the spinel troctolite group a spinel bearing clast in mac88105 consists of anorthite pigeonite spinel and indicates a different heritage possibly similar to spinel cataclasites described from apollo 17 the pyroxenes in mac88105 have somewhat unusual compositions orthopyroxenes and augites appear to be rare most lithologies breccias and igneous rocks contain solely pigeonite we have found one igneous mafic rock a gabbro which has a low mg number and is possibly of mare origin a metal grain of a composition similar to metal in h chondrites supports the interpretation of mac88105 as a regolith breccia the bulk composition of mac88105 is similar to the other lunar highland meteorites the ree contents are slightly higher than for the other anorthositic meteorites with a smaller positive eu anomaly this is in agreement with a possible kreep contribution possibly introduced from glasses macs 8105 is a mixture of rocks with a predominant contribution from the anorthosite suite and small admixtures from other rock types mare basalt mg suite which becomes obvious in plots of molar mg or sm content vs the ti sm ratio the siderophile element abundances in mac88105 are similar to other highland meteorites and show the characteristic co excess and a au ir ratio similar to the other anorthositic meteorites and lower than the hyperchondritic ratio in apollo 16 rocks thus support the notion that the lunar meteorites are a more representative sample of the lunar highlands than the apollo samples the chemistry and mineralogy of mac88105 is different from that of the other lunar meteorites and suggests a different source which is supported by cosmic ray and noble gas data at this time it seems likely that about four individual impact events have been responsible for delivering the seven highland meteorites mac88105 and other lunar meteorites are important as they are probably random samples from the lunar surface and may thus be more representative than the apollo and luna rocks which come from only a small area of the moon

a concise compilation of petrologic information on possibly pristine nonmare moon rocks ansrn q cr to facilitate systematic study of the surviving compositionally pristine endogenously igneous rocks of the ancient lunar crust a compilation has been generated of all likely samples along with key information on the petrologic characteristics and chemistry of each sample the compilation includes 260 samples besides information related to the likelihood of each sample being truly pristine i e mainly its texture and siderophile element abundances information is compiled on mineral content listing major phases present as well as basic information on mineral compositions on size expressed as mass and on whether a reasonably comprehensive chemical analysis has been published the compilation also classifies the samples into seven categories of confidence in the pristine composition of the samples reflecting an estimation of the relative likelihood that each arguably pristine sample is in fact pristine for many purposes it is crucial to avoid inclusion of polymict rocks in a data base on petrologic diagrams such as a plot of average mg mg 100 x molar mg mg fe in a low ca mafic silicate vs average an content in plagioclase rocks in the top three categories of the confidence in pristine character appear distinctly bimodal in composition with roughly half belonging to a ferroan suite characterized by high an despite relatively low mg when samples of low to moderate pristine character are included the bimodality appears less distinct sample mass can also be important with a data base restricted to samples more massive than i g there is a clear distinction in feldspar content and bulk density between ferroan and nonferroan mgsuite rocks such that only the ferroan suite rocks are likely to have formed as flotation cumulates with a data base including smaller samples the same basic pattern is seen but only in a blurred form as the two rock types show considerable overlap in their modal feldspar contents

impact of interannually varying background circulation on summertime wave patterns and tropical cyclone tracks in the western north pacific this study analyzed summertime wave patterns in the western north pacific by separating them into those during el nino en and la nina ln years for 1979 2015 the background flow revealed that in the en years the subtropical high was weaker and the east asian summer monsoon trough was deeper and extended farther southeastward the composite results indicated that in the en years tropical cyclone tc tracks were more solid and stably associated with wave pattern propagation routes because the circulation anomalies were significantly stronger however in the ln years when the wave patterns were weak under the shorter and less organized monsoon trough due to the enhanced subtropical high the tc tracks and cyclonic anomalies were irregular and sporadic further background flow analyses indicated that the en circulation favored the development of the monsoon trough and east west expansion and contraction of the subtropical ridge whereas the stronger subtropical ridge dominated most western north pacific areas in the ln years therefore the monsoon trough was weaker in the ln years and induced recurving tcs to take more scattered routes near taiwan and china s east coast therefore taiwan experienced more rainfall during recurving tc periods in the ln years than in the en years for the straight moving tcs passing through taiwan rainfall was concentrated over southern taiwan in the en years but more evenly distributed in the ln years thus background flow changes strongly affect wave patterns and tcs

lunar highland meteorite dhofar 026 and apollo sample 15418 two strongly shocked partially melted granulitic breccias studies of lunar meteorite dhofar 026 and comparison to apollo sample 15418 indicate that dhofar 026 is a strongly shocked granulitic breccia or a fragmental breccia consisting almost entirely of granulitic breccia clasts that experienced considerable post shock heating probably as a result of diffusion of heat into the rock from an external hotter source the shock converted plagioclase to maskelynite indicating that the shock pressure was between 30 and 45 gpa the post shock heating raised the rock s temperature to about 1200 c as a result the maskelynite devitrified and extensive partial melting took place the melting was concentrated in pyroxene rich areas all pyroxene melted as the rock cooled the partial melts crystallized with fine grained subophitic poikilitic textures sample 15418 is a strongly shocked granulitic breccia that had a similar history but evidence for this history is better preserved than in dhofar 026 the fact that dhofar 026 was previously interpreted as an impact melt breccia underscores the importance of detailed petrographic study in interpretation of lunar rocks that have complex textures the name impact melt has in past studies been applied only to rocks in which the melt fraction formed by shock induced total fusion recently however this name has also been applied to rocks containing melt formed by heating of the rocks by conductive heat transfer assuming that impact is the ultimate source of the heat we urge that the name impact melt be restricted to rocks in which the bulk of the melt formed by shock induced fusion to avoid confusion engendered by applying the same name to rocks melted by different processes

lunar regolith breccia dhofar 287b a record of lunar volcanism dhofar 287 dho 287 a recently found lunar meteorite consists in large part 95 of low ti mare basalt dho 287a and a minor attached portion 5 of regolith breccia dho 287b the present study is directed mainly at the breccia portion of this meteorite this breccia consists of a variety of lithic clasts and mineral fragments set in a fine grained matrix and minor impact melt the majority of clasts and minerals appear to have been mainly derived from the low ti basalt suite similar to that of dho 287a very low ti vlt basalts are a minor lithology of the breccia these are significantly lower in mg and slightly higher in ti compared to luna 24 and apollo 17 vlt basalts picritic glasses constitute another minor component of the breccia and are compositionally similar to apollo 15 green glasses dho 287b also contains abundant fragments of mg rich pyroxene and anorthite rich plagioclase grains that are absent in the lithic clasts such fragments appear to have been derived from a coarse grained mg rich na poor lithology a kreep component is apparent in chemistry but no highlands lithologies were identified the dho 287 basaltic lithologies cannot be explained by near surface fractionation of a single parental magma instead magma compositions are represented by a picritic glass a low ti na poor glass and a low ti na enriched source similar to the dho 287a parental melt compositional differences among parent melts could reflect inhomogeneity of the lunar mantle alternatively the low ti na poor and dho 287a parent melts could be of hybrid compositions resulting from assimilation of kreep by picritic magma thus the dho 287b breccia contains lithologies from multiple magmatic eruptions which differed in composition formational conditions and cooling histories based on this study the dho 287 is inferred to have been ejected from a region located distal to highlands terrains possibly from the western limb of the lunar nearside dominated by mare basalts and kreep rich lithologies

the granulitic impactite suite impact melts and metamorphic breccias of the early lunar crust abstract an important and poorly understood group of rocks found in the ancient lunar highlands is called feldspathic granulitic impactites rocks of the granulite suite occur at most of the apollo highlands sites as hand samples rake samples clasts in breccias and soil fragments most lunar granulites contain 70 80 modal plagioclase but they can range from anorthosite to troctolite and norite previous studies have led to different interpretations for the thermal history of these rocks including formation as igneous plutons long duration metamorphism at high temperatures and short duration metamorphism at low temperatures this paper reports on a study of 24 polished thin sections of lunar granulites from the apollo 15 16 and 17 missions we identify three different textural types of granulitic breccias poikilitic granoblastic and poikilitic granoblastic breccias these breccias have similar equilibration temperatures 1100 50 c as well as common compositions crystal size distributions in two granoblastic breccias reveal that ostwald ripening took place during metamorphism solid state grain growth and diffusion calculations indicate relatively rapid cooling during metamorphism 0 5 to 50 c year and thermal modeling shows that they cooled at relatively shallow depths 200 m in contrast we conclude that the poikilitic rocks formed by impact melting whereas the poikilitic granoblastic rocks were metamorphosed and may have partially melted these results indicate formation of lunar granulites in relatively small craters 30 90 km in diameter physically associated with the impact melt breccia pile and possibly from fine grained fragmental precursor lithologies

the meteoritical bulletin no 84 2000 august meteoritical bulletin no 84 lists information for 1341 newly classified meteorites comprising 842 from antarctica 341 from africa 66 from australia 48 from asia including 42 from the arabian peninsula 38 from north america 4 from europe and 2 from south america information is provided for 11 recent falls bilanga devri khera djoumine guangmingshan kitchener kobe leighlinbridge sabrum songyuan tagish lake and vissannapeta 4 martian meteorites dar al gani 670 735 dhofar 019 los angeles and sayh al uhaymir 005 008 3 lunar meteorites northwest africa 032 dhofar 025 and 026 an ungrouped enstatite rich meteorite zaklodzie 11 iron meteorites and a wide variety of other interesting stony meteorites including ck cm co cr cv r enstatite and unequilibrated ordinary chondrites primitive achondrites hed achondrites ureilites and aubrites

lunar ferroan anorthosite petrogenesis clues from trace element distributions in fan subgroups the rare earth elements ree and selected other trace elements were measured in plagioclase and pyroxene from nine samples of the lunar ferroan anorthosite fan suite of rocks samples were selected from each of four fan subgroups previously defined by james et al 1989 plagioclase compositions are homogeneous within each sample but high and low ca pyroxenes from lithic clasts typically have different ree abundances from their counterparts in the surrounding granulated matrices measured plagioclase low ca pyroxene concentration ratios for the ree have steeper patterns than experimentally determined plagioclase low ca pyroxene partition coefficients in most samples textural and trace element evidence suggest that although subsolidus equilibration may be responsible for some of the discrepancy plagioclase compositions in most samples have been largely unaffected by intermineral redistribution of the ree the ree systematics of plagioclase from the four subgroups are broadly consistent with their derivation through crystallization from a single evolving magma however samples from some of the subgroups exhibit a decoupling of plagioclase and pyroxene compositions that probably reflects the complexities inherent in crystallization from a large scale magmatic system for example two anorthosites with very magnesian mafic minerals have highly evolved trace element compositions major element compositions in plagioclase also do not reflect the evolutionary sequence recorded by their ree compositions finally a noritic anorthosite breccia with relatively ferroan mafic minerals contains several clasts with high and variable ree and other trace element abundances although plagioclase ree compositions are consistent with their derivation from a magma with a kreepy trace element signature very shallow ree patterns in the pyroxenes suggest the addition of a component enriched in the light ree

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

iso modulation on the submonthly wave pattern and recurving tropical cyclones in the tropical western north pacific abstract this study demonstrates the multiscale nature from synoptic to intraseasonal time scales of the atmospheric flow in the tropical western north pacific the multiscale features include intraseasonal oscillations iso northwestward propagating submonthly wave patterns and recurving tropical cyclones tcs in the iso westerly phase the wave pattern was better organized and the tcs were clustered near the cyclonic circulation of the wave pattern during the genesis development and propagation on the other hand the wave pattern and tcs were weak and poorly organized in the iso easterly phase the distinct characteristics between the westerly and easterly phases could be attributed to the iso modulation on the monsoon trough and the subtropical anticyclonic ridge the iso in the westerly phase provided a favorable background e g enhanced monsoon trough and moisture confluent zone for the wave tc pattern development while the iso in the easterly phase provided a less favorable environment

evolution of the lunar crust sims study of plagioclase from ferroan anorthosites abstract the lunar crust down to a depth of 65 km is composed of older 4 5 ga ferroan anorthosites and younger 4 43 4 17 ga mg suite lithologies which include dunites troctolites and norites the anorthosites are generally inferred to represent floating cumulates in a lunar magma ocean possible depth 800 km moon s radius 1 738 km the cumulates that are inferred to be located near the base of the magma ocean are dominantly olivine and pyroxene the last dregs of the magma ocean are enriched in incompatible elements and have been named kreep k rare earth elements p kreep formed in this manner is probably concentrated near the crust mantle boundary at 70 km depth we are attempting to characterize melts parental to ferroan anorthosites and mg suite norites by analyzing rees la ce nd sm eu dy er yb and ba sr and y in their cumulus plagioclase if the cumulus grains have not been compromised by postcrystallization effects and if we know the relevant mineral melt partition coefficients ds we can invert the trace element data for plagioclase to parental melt compositions melts parental to ferroan anorthosites are estimated to contain ree at concentrations ten to fifty times chondrites melts parental to the earlier crystallizing anorthosites lower ree have virtually no eu anomaly while melts parental to later crystallizing anorthosites higher ree have small negative eu anomalies this is qualitatively consistent with the fractionation of eu relative to other ree by crystallization of plagioclase with large positive eu anomalies melts parental to the mg suite have much higher total ree and very large negative eu anomalies the characteristics of mg suite norite parental magmas may have been derived by the assimilation of kreep near the crust mantle boundary by mg rich basaltic melts formed deeper in the cumulate pile or near the contact between the lower cumulate horizons of the magma ocean and primitive unprocessed lunar mantle 800 km

lunar meteorite queen alexandra range 94281 glass compositions and other evidence for launch pairing with yamato 793274 abstract lunar meteorite queen alexandra range 94281 is remarkably similar to yamato 793274 pairing in the conventional earth entry sense is difficult to reconcile with the 2500 km separation between the find locations for these two samples nonetheless both of these regolith breccias are dominated by very low ti vlt mare basalt the pyroxenes of which feature exsolution lamellae on a remarkably coarse scale typical lamella width 0 5 1 m by mare standards the pyroxenes also show similar compositional variations e g fe vs ti trends which confirm parentage from vlt mare basalt plots using al2o3 or feo as a tracer of the highland component indicate indistinguishable internal mare highland geochemical mixing trends the same two distinctive glass types dominate the mare glass populations of both breccias glass type yq1 features 0 37 0 63 wt tio2 10 17 wt mgo and 9 11 wt al2o3 glass type yq2 features higher tio2 0 99 1 22 wt which is inversely correlated with mgo 12 6 13 8 wt and nearly constant 8 8 wt al2o3 all of these similarities suggest that y 793274 and que 94281 are a launch pair which we designate yq most of these similarities also extend to another mare breccia meteorite elephant moraine 87521 however the eet 87521 mare basalt is unusually v poor 88 g g whereas the yq mare component contains 166 g g queen alexandra range 94281 features a variety of textural domains discrete patches of dark matrix material appear to represent clods of mature regolith that have been mixed with a coarser relatively immature material interior to a frothy fusion crust are areas of massive glass that probably formed as a splash coating on que 94281 when it was still on the moon the coarse yq and eet 87521 pyroxene exsolution features imply relatively slow cooling in either a very shallow sill or an unusually thick ponded lava and or later annealing within a cryptomare mare pyroclastic glasses including the two yq varieties are systematically mgo rich compared to crystalline mare basalts this disparity may be a consequence of limited survival of graphite the main fuel for explosive volcanism during formation of the mare source regions as magma ocean cumulates graphite 2 2 g cm3 survived preferentially in regions that avoided extensive early melting and thus remained mgo rich an apparent bimodality in the tio2 contents of mare volcanics especially the pyroclastic glasses also seems a plausible consequence of petrogenesis by remelting of magma ocean cumulates cumulates deposited after the magma ocean evolved to ilmenite saturation had vastly higher tio2 contents than cumulates deposited shortly before the yq regolith s subequal proportions of mare and highland matter are consistent with derivation from a terrain close to a mare highland boundary however a similar mixture might also develop through vertical mixing in a cryptomare or a region of thin mare coverage thus unfortunately the yq bulk composition is not a very useful clue to the identity of the source crater

petrology chemistry and isotopic compositions of the lunar highland regolith breccia dar al gani 262 lunar meteorite dar al gani 262 dg 262 found in the libyan part of the sahara is a mature anorthositic regolith breccia with highland affinities the origin from the moon is undoubtedly indicated by its bulk chemical composition radionuclide concentrations noble gas n and o isotopic compositions and petrographic features dar al gani 262 is a typical anorthositic highland breccia similar in mineralogy and chemical composition to queen alexandra range que 93069 about 52 vol of the studied thin sections of dar al gani 262 consist of fine grained 100 m constituents and 48 vol is mineral and lithic clasts and impact melt veins the most abundant clast types are feldspathic fine grained to microporphyritic crystalline melt breccias 50 2 vol includes recrystallized melt breccias whereas mafic crystalline melt breccias are extremely rare 1 4 vol granulitic lithologies are 12 8 vol intragranularly recrystallized anorthosites and cataclastic anorthosites are 8 8 and 8 2 vol respectively and devitrified glasses are 2 7 vol impact melt veins 5 5 vol of the whole thin sections cutting across the entire thin section were probably formed subsequent to the lithification process of the bulk rock at pressures below 20 gpa because the bulk rock never experienced a higher peak shock pressure mafic crystalline melt breccias are very rare in dar al gani 262 and are similar in abundance to those in que 93069 the extremely low abundance of mafic components and the bulk composition may constrain possible areas of the moon from which the breccia was derived the source area of dar al gani 262 must be a highland terrain lacking significant mafic impact melts or mare components on the basis of radionuclide activities an irradiation position of dg 262 on the moon at a depth of 55 85 g cm3and a maximum transit time to earth 0 15 ma is suggested dar al gani 262 contains high concentrations of solar wind implanted noble gases the isotopic abundance ratio 40ar 36ar 3 is characteristic of lunar soils the terrestrial weathering of dg 262 is reflected by the occurrence of fractures filled with calcite and by high concentrations of ca ba cs br and as there is also a large amount of terrestrial c and some n in the sample which was released at low temperatures during stepped heating high concentrations of ni co and ir indicate a significant meteoritic component in the lunar surface regolith from which dg 262 was derived

mechanisms of meridional teleconnection observed between a summer monsoon system and a subtropical anticyclone part i the pacific japan pattern abstract summertime atmospheric circulation over the midlatitude western north pacific wnp is influenced by anomalous convective activity near the philippines this meridional teleconnection observed in monthly anomalies and known as the pacific japan pj pattern is characterized by zonally elongated cyclonic and anticyclonic anomalies around the enhanced convection center and to its northeast respectively in the lower troposphere with an apparent poleward phase tilt with height the authors idealized two layer linear model whose basic state consists of a zonal subtropical jet and a pair of a monsoon system and a subtropical anticyclone can simulate a pj like response against diabatic heating located between the pair each of the observed and simulated patterns can gain energy through barotropic and baroclinic conversions from the zonally varying baroclinic mean flow in an efficiency comparable with that of energy generation due to the anomalous diabatic heating indicating a characteristic of

mineral chemistry and the petrogenesis of eucrites ii cumulate eucrites abstract we carried out an ion microprobe study of rees and other selected trace and minor element concentrations in orthopyroxene augite lamellae and plagioclase of two cumulate eucrites moama and moore county in order to reevaluate the relationships between cumulate and noncumulate eucrites and among cumulate eucrites pyroxene and plagioclase in these two meteorites are more homogeneous in major minor and trace elements than in noncumulate eucrites and trace and minor element concentrations in moore county are higher than in moama although subsolidus equilibration erased and original igneous zoning it did not affect the ree patterns of these minerals both pigeonite and plagioclase of moama and moore county have higher lree hree ratios than those phases in noncumulate eucrites this indicates that cumulate eucrites derived from melts with fractionated ree patterns and thus are not related to noncumulate eucrites in addition the inconsistency between degrees of fractional crystallization deduced from major and trace elements and the differences of lree hree ratios recorded in pigeonite and plagioclase also suggest that moama and moore county did not form in the same fractional crystallization sequence this study confirms earlier observations and conclusions of ma and schmitt 1979 and poses problems for prevalent models

the macalpine hills lunar meteorite and implications of the lunar meteorites collectively for the composition and origin of the moon the mac88104 mac88105 meteorite is a lunar highlands regolith breccia even more anorthositic than previously available samples of highlands regolith clasts studied include two unusual pristine rocks one a 2 5 mm slightly granulitic clast rated as probably pristine contains extraordinarily fe rich fo40 olivine the other a 5 mm clast with clear vestiges of a poikilitic cumulate texture has silicate compositions that extend the range of the mg suite in the direction of the high mg end of the ferroan anorthositic suite the pyroxene of the latter clast is relatively ca rich and poorly equilibrated by lunar cumulate standards suggesting that it may have formed in an uncommonly shallow intrusion the four lunar highlands meteorites are all regolith breccias or in one case a marginal type between regolith breccia and ordinary polymict breccia and they probably represent three to four separate lunar source craters the proportion of regolith breccias is higher among lunar highlands meteorites than among rock samples from the classic highlands site apollo 16 9 regolith breccias for the majorelement composition of the crust the highlands meteorites confirm that the two low th central nearside sites luna 20 and especially apollo 16 are approximately representative the consistently high al2o3 composition indicated for the upper crust supports the magmasphere hypothesis for the trace element composition of the crust the highlands meteorites indicate that the central nearside apollo and luna sites are in several respects grossly unrepresentative concentrations of siderophile elements are far lower in highlands meteoritic regolith breccias than in their central nearside counterparts the high overall siderophile levels and hyperchondritic niir and auir ratios characteristic of highlands materials from apollo 16 and apollo 14 are evidently idiosyncracies of the central nearside concentrations of incompatible elements including k th and u are far lower in the highlands meteorites than in regolith samples from the central nearside this trend implies that certain lower limits on the bulk moon content of u and associated refractory lithophile elements should be relaxed models of lunar origin implying large enrichments of refractory lithophile elements are not favored by the new constraints from these meteorites

northwestward propagating wave patterns over the tropical western north pacific during summer abstract the possible relationship between northwestward propagating wave disturbances and tropical cyclones over the tropical western north pacific during summer is studied using data assimilated by the navy s global model during may september 1989 91 a multiple set canonical correlation mcc analysis is applied to the 850 hpa meridional v component over a core domain covering the western pacific the analysis seeks the maximal geometrically averaged correlation between 12 consecutive twice daily fields two mcc components with a 90 phase difference and comparable variances that combine to nearly one third of the total variance describe the northwestward propagating pattern with a period near 8 9 days upstream of this steady northwestward propagating pattern there is a weaker westward propagation along 5 n that may be traced back to 170 e the surface pressure cell advancing east of the philippines is consistent with low level winds for a circulation in gradient wind balance it has a zonal wave

clinopyroxene ree distribution coefficients for shergottites the ree content of the shergotty melt abstract ree distribution coefficients were measured between synthetic pyroxenes and melts similar in composition to the inferred shergotty intercumulus liquid by in situ analysis with the electron microprobe using samples doped to per cent concentration levels these coefficients exhibit a strong positive correlation with pyroxene wollastonite content recommended values for augites similar in composition to the shergotty cumulus augite cores wo32en48 are d la 0 023 d ce 0 039 d nd 0 10 d sm 0 17 d eu 0 16 d gd 0 20 d yb 0 29 and d lu 0 30 recommended values for pigeonites similar in composition to the shergotty cumulus pigeonite cores wo12en58 are d la 0 002 d ce 0 004 d nd 0 019 d sm 0 031 d yb 0 13 and d lu 0 13 these values resemble distribution coefficients measured for terrestrial basalts of higher mg fe than the shergotty melt rather than those of more evolved siliceous rocks of similar mg fe to the shergotty melt thus it appears that mg fe is considerably less important than other factors in determining distribution coefficient values for pyroxenes ree abundances were computed for the shergotty intercumulus melt using distribution coefficients measured for the natural phase compositions these computed abundances display lree depletion such lree depleted abundance patterns cannot be generated by simple partial melting of a mafic mineral assemblage having the lree enriched patterns required for a two stage sm nd evolution history this result implies that either 1 the melting process was complex e g continuous melting 2 the source region had a more complex history than that of the simple 2 stage model or 3 shergotty does not satisfy the closed system assumption of the calculation and has suffered post magmatic lree enrichment

low frequency earthquakes observed in close vicinity of repeating earthquakes in the brittle upper crust of hakodate hokkaido northern japan we conducted a detailed investigation of an earthquake cluster distributed from the lower crust to the upper crust beneath hakodate hokkaido which included both low frequency earthquakes lfes a

ion microprobe investigation of plagioclase and orthopyroxene from lunar mg suite norites implications for calculating parental melt ree concentrations and for assessing postcrystallization ree redistribution the lunar mg suite which includes dunites troctolites and norites makes up to 20 30 of the moon s crust down to a depth of 60 km the remainder is largely anorthosite this report focuses on norites which consist mostly of orthopyroxene and plagioclase because we have found that both phases are effective recorders of their parental melt compositions in an earlier report we analyzed orthopyroxene from twelve samples three from apollo 14 two from a 15 and seven from a 17 by sims for eight ree la ce nd sm eu dy er yb inversion of these data to estimated melt compositions yielded extremely high ree concentrations similar to kreep in this study we report sims ree data for plagioclase from these same twelve samples the major objective of this study is to estimate parental ree concentrations from both orthopyroxene and plagioclase data to see if both data inversions produce concordant melt compositions and thus better constrain the composition of melts parental to mg suite norites the estimated ree concentrations from both phases show some evidence of slight postcrystallization ree redistribution comparison of the observed ratio of ree for pyroxene plagioclase to the ratio of the ds for pyroxene plagioclase is consistent with ree redistribution which involves lree diffusing from pyroxene into plagioclase and hree diffusing from plagioclase into pyroxene however apparently these postcrystallization exchanges have not seriously affected our ability to estimate melt ree concentrations the estimated melt ree concentrations using both plagioclase and orthopyroxene are similar to high k kreep especially for melts parental to a 15 norites this study provides support for mineral trace element inversion estimates for parental melts even though these lunar crustal lithologies experienced high temperature annealing apparently the cores of plagioclase and pyroxene continue to carry a record of their igneous crystallization history