The Meteoritical Bulletin, No. 92, 2007 September

Abstract— In this edition of The Meteoritical Bulletin, 1394 recognized meteorites are reported, 27 from specific locations within Africa, 133 from Northwest Africa, 1227 from Antarctica (from ANSMET, PNRA, and PRIC expeditions), and 7 from Asia. The Meteoritical Bulletin announces the approval of four new names series by the Nomenclature Committee of the Meteoritical Society, two from Africa and one from Asia, including Al Haggounia, from Al Haggounia, Morocco, which is projected to be on the order of 3 metric tons of material related to enstatite chondrites and aubrites. Approved are two falls from Africa, Bassikounou (Mauritania) and Gashua (Nigeria). Approved from areas other than Antarctica are one lunar, two Martian, 32 other achondrites, three mesosiderites, two pallasites, one CM, two CK, one CR2, two CV3, one CR2, and four R chondrites. The Nomenclature Committee of the Meteoritical Society announces 48 newly approved relict meteorites from two new name series, Österplana and Gullhögen (both from Sweden)

New insights into the mineralogy and weathering of the Meridiani Planum meteorite, Mars

Meridiani Planum is the first officially recognized meteorite find on the surface of Mars. It was discovered at and named after the landing site of the Mars Exploration Rover Opportunity. Based on its composition, it was classified as a IAB complex iron meteorite. Mössbauer spectra obtained by Opportunity are dominated by kamacite (a-Fe-Ni) and exhibit a small contribution of ferric oxide. Several small features in the spectra have been neglected to date. To shed more light on these features, five iron meteorite specimens were investigated as analogs to Meridiani Planum with a laboratory Mössbauer setup. Measurements were performed on (1) their metallic bulk, (2) troilite (FeS) inclusions, (3) cohenite ((Fe,Ni,Co)3C) and schreibersite ((Fe,Ni)3P), and (4) corroded rims. In addition to these room-temperature measurements, a specimen from the Mundrabilla IAB-ungrouped meteorite was measured at Mars-equivalent temperatures. Based on these measurements, the features in Meridiani Planum spectra can be explained with the presence of small amounts of schreibersite and ⁄ or cohenite and iron oxides. The iron oxides can be attributed to a previously reported coating on Meridiani Planum. Their presence indicates weathering through the interaction of the meteorite with small amounts of water

Bounce Rock—A shergottite-like basalt encountered at Meridiani Planum, Mars

The Opportunity rover of the Mars Exploration Rover mission encountered an isolated rock fragment with textural, mineralogical, and chemical properties similar to basaltic shergottites. This finding was confirmed by all rover instruments, and a comprehensive study of these results is reported here. Spectra from the miniature thermal emission spectrometer and the Panoramic Camera reveal a pyroxene-rich mineralogy, which is also evident in Mössbauer spectra and in normative mineralogy derived from bulk chemistry measured by the alpha particle X-ray spectrometer. The correspondence of Bounce Rock’s chemical composition with the composition of certain basaltic shergottites, especially Elephant Moraine (EET) 79001 lithology B and Queen Alexandra Range (QUE) 94201, is very close, with only Cl, Fe, and Ti exhibiting deviations. Chemical analyses further demonstrate characteristics typical of Mars such as the Fe ⁄Mn ratio and P concentrations. Possible shock features support the idea that Bounce Rock was ejected from an impact crater, most likely in the Meridiani Planum region. Bopolu crater, 19.3 km in diameter, located 75 km to the southwest could be the source crater. To date, no other rocks of this composition have been encountered by any of the rovers on Mars. The finding of Bounce Rock by the Opportunity rover provides further direct evidence for an origin of basaltic shergottite meteorites from Mars.Additional co-authors: Thanasis ECONOMOU, Steven P. GOREVAN, Brian C. HAHN, Göstar KLINGELHÖFER, Timothy J. McCOY, Harry Y. McSWEEN Jr, Douglas W. MING, Richard V. MORRIS, Daniel S. RODIONOV, Steven W. SQUYRES, Heinrich WÄNKE, Shawn P. WRIGHT, Michael B. WYATT, Albert S. YE

Geochemical properties of rocks and soils in Gusev Crater, Mars: Results of the Alpha Particle X-Ray Spectrometer from Cumberland Ridge to Home Plate

Geochemical diversity of rocks and soils has been discovered by the Alpha Particle X-Ray Spectrometer (APXS) during Spirit’s journey over Husband Hill and down into the Inner Basin from sol 470 to 1368. The APXS continues to operate nominally with no changes in calibration or spectral degradation over the course of the mission. Germanium has been added to the Spirit APXS data set with the confirmation that it occurs at elevated levels in many rocks and soils around Home Plate. Twelve new rock classes and two new soil classes have been identified at the Spirit landing site since sol 470 on the basis of the diversity in APXS geochemistry. The new rock classes are Irvine (alkaline basalt), Independence (low Fe outcrop), Descartes (outcrop similar to Independence with higher Fe and Mn), Algonquin (mafic-ultramafic igneous sequence), Barnhill (volcaniclastic sediments enriched in Zn, Cl, and Ge), Fuzzy Smith (high Si and Ti rock), Elizabeth Mahon (high Si, Ni, and Zn outcrop and rock), Halley (hematite-rich outcrop and rock), Montalva (high K, hematite-rich rock), Everett (high Mg, magnetite-rich rock), Good Question (high Si, low Mn rock), and Torquas (high K, Zn, and Ni magnetite-rich rock). New soil classes are Gertrude Weise (very high Si soil) and Eileen Dean (high Mg, magnetite-rich soil). Aqueous processes have played a major role in the formation and alteration of rocks and soils on Husband Hill and in the Inner Basin

Nickel on Mars: Constraints on meteoritic material at the surface

Impact craters and the discovery of meteorites on Mars indicate clearly that there is meteoritic material at the Martian surface. The Alpha Particle X-ray Spectrometers (APXS) on board the Mars Exploration Rovers measure the elemental chemistry of Martian samples, enabling an assessment of the magnitude of the meteoritic contribution. Nickel, an element that is greatly enhanced in meteoritic material relative to samples of the Martian crust, is directly detected by the APXS and is observed to be geochemically mobile at the Martian surface. Correlations between nickel and other measured elements are used to constrain the quantity of meteoritic material present in Martian soil and sedimentary rock samples. Results indicate that analyzed soils samples and certain sedimentary rocks contain an average of 1% to 3% contamination from meteoritic debris

The Meteoritical Bulletin, No. 86, 2002 July

Meteoritical Bulletin No. 86 lists information for 1154 newly classified meteorites, comprising 661 from Antarctica, 218 from Africa, 207 from Asia (203 of which are from Oman), 62 from North America, 3 from South America, and 3 from Europe. Information is provided for 5 alls (El Idrissia, Undulung, Dashoguz, El Tigre, and Yafa). Noteworthy specimens include 7 martian meteorites (Dhofar 378, Grove Mountais 99027, Northwest Africa 856, 1068, and 1110, and Sayh al Uhaymir 060 and 090); 4 lunar meteorites (Dhofar 301, 302, 303, and 489); 9 new iron meteorites; a mesosiderite (Northwest Africa 1242); an ungrouped stony-iron meteorite (Dar al Gani 962); and a wide variety of other interesting stony meteorites, including CH, CK, CM, CR, CV, R, enstatite, unequilibrated ordinary, and ungrouped chondrites, primitive achondrites, howardite-eucrite-diogenite (HED) achondrites, and ureilites.The Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Composition, petrology, and chondrule-matrix complementarity of the recently discovered Jbilet Winselwan CM2 chondrite

Jbilet Winselwan (JW) is a recently found CM2 chondrite breccia containing two lithologies. A study of 508 chondrules provides the first statistically reliable size distribution for CM chondrite chondrules, which is about log normal with a mean chondrule size of 149 mu m (lithology I) and 141 mu m (lithology II). Chondrules are surrounded by fine-grained rims. Apparent chondrule diameters and their apparent rim thicknesses are positively correlated with slopes of 0.12 (lithology II) and 0.18 (lithology I), the latter typical of CM chondrites. The CM chondrites are generally primitive and parts of JW experienced only mild aqueous alteration. Bulk JW element ratios are solar (=CI chondritic), e.g., Si/Mg (1.12), Fe/Mg (1.80-1.83), Ti/Al (0.053), and about solar for Ca/Al. The 26 chemically studied chondrules have subchondritic Si/Mg (0.88) and Fe/Mg ratios (0.21). Matrix and the fine-grained chondrule rims on the other hand have superchondritic Si/Mg ratios with means of 1.34 and 1.41, respectively. The Fe/Mg ratios are also superchondritic, with means of 2.41 (matrix) and 2.61 (fine-grained rims). The refractory element ratios in chondrules are superchondritic (Ti/Al: 0.106; Ca/Al: 1.64), and subchondritic in the JW matrix (Ti/Al: 0.031; Ca/Al: 0.71) and in the fine-grained rims (Ti/Al: 0.023; Ca/Al: 0.68). These complementary element ratios require formation of chondrules and matrix/rims from the same reservoir in order to obtain a chondritic bulk composition. Most chondrules are mineralogically zoned, with olivine in the core and low-Ca pyroxene in the rim; hence, CM chondrules were open systems, exchanging material with the surrounding gas

Serpines et protéases à sérine dans la réponse immunitaire de la drosophile

Les Arthropodes se défendent contre les agressions microbiennes par un ensemble de réactions très efficaces, comprenant l'activation de cascades protéolytiques aboutissant à la coagulation, à la mélanisation et à la synthèse de peptides antimicrobiens. Ces cascades protéolytiques font intervenir des protéases à sérine et sont régulées par des serpines, qui sont des inhibiteurs de protéases à sérine. L'équipe au sein de laquelle j'ai effectué ma thèse étudie le rôle de serpines et de protéases à sérine dans la réponse immunitaire de la drosophile.La première cascade protéolytique mise en évidence dans l'immunité de la drosophile mène à l'activation de la voie Toll, qui contrôle l'expression de nombreux gènes dont les peptides antimicrobiens. Spaetzle, le ligand du récepteur Toll, est présent sous la forme d'un précurseur dans l'hémolymphe des drosophiles. Son activation lors des infections par les bactéries à Gram positif et par les champignons requiert une maturation protéolytique. Cette coupure est contrôlée par la serpine Necrotic, dont l'absence se traduit par l'activation de Toll en absence d'infection et le développement d'un phénotype de nécrose et de létalité des adultes quelques jours après leur émergence.Nous avons réalisé un crible génétique suppresseur de ce phénotype et identifié la première protéase à sérine (Perséphone) impliquée dans l'activation immunitaire de Spaetzle. L'analyse des mutants perséphone a révélé que, de façon tout à fait surprenante, les bactéries à Gram positif et les champignons activent deux cascades protéolytiques distinctes aboutissant à la coupure de Spaetzle.La serpine Necrotic possède dans sa région N-terminale une extension atypique riche en glutamine. Nous avons pu montrer que cette extension est coupée au cours de l'activation de la voie Toll. L'analyse de cette coupure a révélé une complexité et une relation inattendues entre les cascades protéolytiques activées respectivement par les bactéries à Gram positif et par les champignons. Une autre cascade protéolytique activée au cours de la réponse immunitaire des insectes mène à la coupure et à l'activation de l'enzyme de la mélanisation : la Phénoloxydase (PO). Nous avons isolé les premiers mutants de la cascade protéolytique aboutissant à l'activation de cette enzyme chez la drosophile.La première mutation affecte une serpine (la Serpine27A). Les mutants pour cette serpine présentent une activation constitutive de la PO en absence de stimulus immun. L'étude de la Serpine27A a révélé que l'activation de la PO nécessite une synthèse protéique préalable et qu'elle est sous le contrôle de la voie Toll.La deuxième mutation affecte une protéase à sérine, PAE1 (Prophenoloxidase Activating Enzyme 1) Les mutants PAE1 ne présentent aucune activation de la PO lors d'une infection. Leur étude nous a permis de montrer que l'activation de l'enzyme dépend d'une cascade protéolytique, ce qui n'était que supposé auparavant.Arthropods defend themselves against microbial aggression with an efficient battery of reactions, including activation of proteolytic cascades leading to coagulation, melanization and the production of antimicrobial peptides. These proteolytic cascades use serine proteases and they are regulated by serine protease inhibitors, such as the serpins. During my thesis, I studied the role of serpins and proteases in the Drosophila immune response.first proteolytic cascade found to be involved in the Drosophila immune response leads to activation of the Toll pathway, which controls the expression of numerous genes including those for the antimicrobial peptides. Spaetzle, the Toll ligand, is present as a precursor in Drosophila haemolymph. This precursor is proteolytically cleaved during Gram-positive bacterial or fungal infections, under the control of the serpin, Necrotic. Absence of Necrotic leads to constitutive activation of the Toll pathway and the development of a phenotype consisting of necrosis and adult mortality a few days after emergence. During a genetic suppressor screen using the Necrotic phenotype, Persephone, the first serine protease to be directly implicated in the immune activation of Spaetzle, was identified. Unexpectedly, the analysis of psh mutants revealed that two distinct proteolytic cascades can trigger immune activation of Spaetzle, dependant on either Gram-positive bacterial or fungal infection. In its N-terminal region, the serpin Necrotic has an atypically glutamine-rich extension. I was able to show that this section is removed during activation of the Toll pathway. A further analysis of this event revealed an unexpected level of complexity in relation with the proteolytic cascades activated by infections of Gram-positive bacteria or fungi.Another proteolytic cascade stimulated during the insect immune response leads to cleavage and activation of phenoloxidase (PO), the central enzyme of melanization. I isolated the first mutants involved in the proteolytic cascade controlling activation of PO in Drosophila.The first of these mutants, which displays a constitutive activation of PO, affects the Serpin27A gene. The study of Serpin27A revealed that protein production under the control of the Toll pathway must be underway before PO can be activated. The second mutant identified was in the gene encoding the serine protease Prophenoloxidase Activating Enzyme 1 (PAE1). This mutant has lost the capacity to activate PO during infections. The work carried out on PAE1 mutants allowed me to demonstrate that activation of PO in Drosophila depends on a proteolytic cascade.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Refractory element fractionation in the Allende meteorite: Implications for solar nebula condensation and the chondritic composition of planetary bodies

International audienceChondritic meteorites represent primitive undifferentiated solar system material that is compositionally similar to the nonvolatile fraction of the Sun. The mineralogy and texture of chondritic meteorites is complex, however, because they are mixtures of several components that formed under different conditions in the solar nebula and were further processed on their parent bodies: chondrules, a volatile rich, fine-grained matrix, including a variety of mineral and lithic clasts, metal, sulfides, and Ca, Al-rich inclusions (CAI). The bulk chemistry of a single aliquot of a chondritic meteorite consequently depends on the size and distribution of its constituents. Here, we investigate the effect of sample heterogeneity on the major and trace element composition of the CV chondrite Allende using a single 30 g slice, which is 22.5 cm(2) in dimension and 4 mm thick. Thirty-nine equally sized pieces with an average sample weight of ca. 0.6 g (corresponding to a cube with an edge length of 5 to 6 mm) were powdered and aliquots of 0.12 g and 0.02-0.03 g were analyzed by XRF for major and ICP-MS for trace elements. One sample contained a large CAI, another sample was dominated by a dark inclusion (DI). Excluding these two samples, the concentrations of the major elements Mg, Si and Fe are constant within analytical uncertainty at the millimeter-centimeter scale (S.D. 0.9, 1.3 and 2.6%, respectively). Non-refractory minor and trace elements are similarly constant, including geochemically very different elements such as Mn, Cr, Ni, Co, P, Zn and Pb. This reflects a uniform mixture of the various host phases of these elements during accretion, and excludes elemental redistribution above a millimeter-scale by aqueous alteration and/or thermal metamorphism on the parent body. The refractory elements Al, Ca, Ti etc. are more variable (S. D. 17, 10 and 9%, respectively), which is mainly the result of different proportions of millimeter-size CAI, many of them with strongly fractionated group II rare earth element patterns, i.e., variable enrichment of the more volatile refractory elements (Ta, U, Nb, Sr, Tm, Nd) over the strongly refractory elements (Lu, Zr, Hf). Admixture of group II CAI can also account for the sub-chondritic Nb/Ta and Zr/Nb ratios in CV chondrites. The total average of all 37 samples has a clear group II-type rare earth element pattern. If this fractionated refractory element pattern is representative of the Allende parent body, this observation suggests that bulk planetary bodies, possibly including the Earth-forming planetary embryos, may have refractory element patterns that are fractionated relative to those of CI chondrites

The Meteoritical Bulletin No. 92, 2007 September

In this edition of The Meteoritical Bulletin, 1394 recognized meteorites are reported, 27 from specific locations within Africa, 133 from Northwest Africa, 1227 from Antarctica (from ANSMET, PNRA, and PRIC expeditions), and 7 from Asia. The Meteoritical Bulletin announces the approval of four new names series by the Nomenclature Committee of the Meteoritical Society, two from Africa and one from Asia, including Al Haggounia, from A1 Haggounia, Morocco, which is projected to be on the order of 3 metric tons of material related to enstatite chondrites and aubrites. Approved are two falls from Africa, Bassikounou (Mauritania) and Gashua (Nigeria). Approved from areas other than Antarctica are one lunar, two Martian, 32 other achondrites, three mesosiderites, two pallasites, one CM, two CK, one CR2, two CV3, one CR2, and four R chondrites. The Nomenclature Committee of the Meteoritical Society announces 48 newly approved relict meteorites from two new name series, Österplana and Gullhögen (both from Sweden)