DOCSLIB.ORG

Studies on Oman Meteorites

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Studies on Oman Meteorites Inauguraldissertation der Philosophisch-naturwissenschaftlichen Fakultät der Universität Bern vorgelegt von Ali Faraj Ahmed Al-Kathiri von Oman Leiter der Arbeit: PD Dr. Edwin Gnos Dr. Beda Hofmann Institut für Geologie, Universität Bern Studies on Oman Meteorites Inauguraldissertation der Philosophisch-naturwissenschaftlichen Fakultät der Universität Bern vorgelegt von Ali Faraj Ahmed Al-Kathiri von Oman Leiter der Arbeit: PD Dr. Edwin Gnos Dr. Beda Hofmann Institut für Geologie, Universität Bern Von der Philosophisch-naturwissenschaftlichen Fakultät angenommen Der Dekan Bern, 9. Februar 2006 Prof. Dr. P. Messerli Acknowledgments I thank to the Swiss National Foundation for funding this project (grants 2100-064929 and 200020-107681) and the Ministry of Commerce and Industry of the Sultanate of Oman for assistance and permitting fieldwork in Oman. Special thanks to the following: All my family members and relatives for their patience and the love they gave me through the period of my study. His Highness Maqbool Bin Ali Sultan, Minister of Commerce and Industry, for his support and granting me a study leave to conduct my PhD thesis at the University of Bern. Drs. Beda Hofmann and Edwin Gnos for their direct supervision and their unlimited scientific and technical assistance. They are also thanked for their transfer of knowledge and experience through the period of my PhD study and during the meteorite search campaigns. Prof. Martin Engi for his scientific guiding and supervision. His is thanked for his care, hospitality and creating very friendly working atmosphere. Akram Al-Muraza, Khalid Al-Rawas, and Sami Al-Zubaidi and all my colleagues from the Ministry of Commerce and Industry, Salalah, for their logistic and administrative support during the project. Dr. Hilal Al-Azri, Directorate general of Minerals, Ministry of Commerce and Industry, Muscat, for his support in initiating the project, and permission to search for meteorite in Oman. Prof. Tjerk Peters for presenting the research proposal to the Ministry of Commerce and Industry to initiate a joint Omani-Swiss meteorite search project and his recommendation to include me as member of the search team. Dr. Timothy Jull, NSF lab, University of Arizona, for providing the 14C terrestrial ages of a large number of meteorites recovered during the joint Omani-Swiss meteorite search project including those used for the study of weathering of meteorites from Oman. Prof. Otto Eugster for his noble gas isotope measurements and his field support during one meteorite search campaign in Oman. Prof. Urs Krähenbühl for his chemical analyses on the iron meteorite Shisr 043 and the lunar meteorite SaU 169, and his field support during one meteorite search campaign in Oman. Dr. Kees Welten for his determination of the cosmic ray exposure age for the Shisr 043 iron meteorite. V Manuel Eggimann and Dr. Sylvio Lorenzetti for their assistance and joining us during various periods of meteorite search in Oman. Profs. Rainer Wieler and Ingo Leya, Dr. Salim Al-Busaidi, Ali Al-Rajihi, Mohamed Al-Batashi, Dr. Niklaus Waber, Mohamed Ishaq, Jürg Bühler, Lorenz Moser and Mark Hauser for joining us during some meteorite searching periods. Ulli Linden and Werner Zaugg for passing on their computing experience and helping whenever it is needed. Vreni Jakob and Jürg Megert for preparing petrographic thin sections of the meteorites recovered during our search program, and Ruth Mäder for analysis of water content in meteorites. Peter Vollenweider for making additional photographs of meteorites used in this study. Isabelle Jobin, Sarah Antenen, Barbara Grose and Brigitte Schneiter for always having been very helpful with any administrative work or question during my stay in Bern. Many thanks to all professors, assistants, post doctors, colleges and employees at the Institute of Geological Science and the Museum of Natural History at Bern for their hospitality and kind help. VI Abstract A large number of meteorites have been recovered during the joint Omani-Swiss meteorite search project (2001-2005). This made meteorites from Oman available to scientists around the world as well as to Omani researchers and students to perform scientific research on different aspects of the science of meteoritics. This PhD thesis consists of five independent sections prepared for publication in peer- reviewed journals, in which I am the first author in the first three papers and a co-author in the last two papers. During this PhD thesis most of the work was directed to study the terrestrial weathering of meteorites, starting in the field by measuring fragmentation, dispersion of fragments on the soil and taking soil samples to compare the effect of soil chemistry on the meteorites. At the University of Bern sample preparations were done on a large number of meteorites and soil samples for chemical analysis and petrographic investigations. In addition, studies were also performed on rare and unique meteorites such as the KREEP-rich lunar meteorite SaU 169, the only iron meteorite so far found in Oman (Shisr 043) and the Martian meteorite SaU 094. Results from the weathering study showed that the chemical composition of the desert soil in the interior of Oman is very homogeneous and the influence of soil geochemistry on meteorite weathering can therefore be assumed to be nearly constant over the whole study area. The investigation of weathering-related parameters (fragmentation, dispersion of fragments on the soil, alteration mineralogy, color of powdered meteorites, bulk chemistry) as a function of 14C terrestrial ages showed an accumulation of Sr, Ba and H2O, and a loss of S with increasing terrestrial age. Fast iron metal oxidation is correlated with rapid rates of water absorption. The slower oxidation of troilite releases sulfate, allowing the steady precipitation of Ba and Sr sulfates over time. Cementation of pores with weathering products gradually decreases the weathering rate over time, however the rate of purely physical weathering will remain constant. Meteorite powders exhibit a color change as a function of weathering grade. Fresh unweathered meteorites have a dark grey color, with increasing amounts of weathered metal and troilite, the powder commonly grades to dusky brown, grayish brown, moderate brown, and finally light brown for strongly weathered meteorites. The local surface topography (hard/soft soil, depressions and small hills) also has a marked influence on the weathering of meteorites. The iron meteorite Shisr 043 is a single mass not paired with any of the other eight known iron meteorites from the Arabian Peninsula. Based on the mean kamacite bandwidth and the chemical composition of the meteorite it is classified as a medium octahedrite belonging to the chemical group IIIAB. Cosmic ray exposure data yielded an age of 290 ± 20 Ma, and a terrestrial age of <10,000 years. Sayh al Uhaymir 169 is the first known KREEP-rich lunar meteorite. The study on the regolith part of the lunar meteorite showed that it contains clasts of Ti-poor to Ti-rich basalts, gabbros to granulites, and regolith breccias, and that the regolith formed in two stages. The younger regolith additionally contains a highland gabbronorite clast with anorthite An96-97, forsteritic (Fo85) and fayalitic (Fo12) mineral clasts, and impact melt shards. Based on the regolith chemistry, the comparison of Fe-Ti-Th-K concentrations with remote sensing data from the lunar surface, the KREEP clast contained in the regolith, and the volcanic clast types and its TiO2 content, the regolith source area can be assigned to the vicinity of the Apollo 12 and 14 landing sites. In combination with data on the impact melt part of SaU 169 the complex history of the VII meteorite could be reconstructed registering impact events on the Moon at 3909 ± 13 Ma, ~2800 Ma, ~200 Ma, <340000 years, and a delivery to Earth <10000 years ago. Sayh al Uhaymir 094 is classified as a strongly-shocked melanocratic olivine-porphyric Martian rock belonging to the shergottite group with affinities to lherzolitic shergottites. Its model composition is very similar to the Dar al Gani 476/489/670/735/876 shergottites from the Libyan Desert. The meteorite is now recognized to be paired with SaU 005/008/051/060/090/120/125/130/131/150 making it the largest known strewnfield produced by a Martian meteorite. All meteorites found during this project were classified using optical methods and electron microprobe. These results are listed in the appendix 1. VIII Contents Page Acknowledgements V Abstract VII Contents IX Introduction 1 Meteorites 1 Meteorite searching in Oman 2 Aims of the project 3 Importance of meteorite finds during this project for Oman 3 Geology of the searched area 3 Meteorite finds 5 Soil samples 6 PhD thesis content 8 Section 1 8 Section 2 8 Section 3 9 Section 4 10 Section 5 10 Appendices 11 References 11 Section 1: Weathering of meteorites from Oman: Correlation of chemical 13 and mineralogical weathering proxies with 14C terrestrial ages and the influence of soil chemistry Abstract 13 Introduction 13 Geology of the interior Oman desert 14 Characterization of meteorite collection surfaces and climatic conditions 14 Samples and methods 15 Results 19 Effects of weathering measured in the field: Fragmentation, fragment 19 dispersion, aeolian abrasion Terrestrial ages of meteorites from Oman 20 Meteorite powder color and weathering grade 20 Mineralogy of weathering products 20 Chemistry of meteorite alteration 22 Correlation of weathering
Recommended publications
  • A New Sulfide Mineral (Mncr2s4) from the Social Circle IVA Iron Meteorite

    A New Sulfide Mineral (Mncr2s4) from the Social Circle IVA Iron Meteorite

    American Mineralogist, Volume 101, pages 1217–1221, 2016 Joegoldsteinite: A new sulfide mineral (MnCr2S4) from the Social Circle IVA iron meteorite Junko Isa1,*, Chi Ma2,*, and Alan E. Rubin1,3 1Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, California 90095, U.S.A. 2Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, U.S.A. 3Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, U.S.A. Abstract Joegoldsteinite, a new sulfide mineral of end-member formula MnCr2S4, was discovered in the 2+ Social Circle IVA iron meteorite. It is a thiospinel, the Mn analog of daubréelite (Fe Cr2S4), and a new member of the linnaeite group. Tiny grains of joegoldsteinite were also identified in the Indarch EH4 enstatite chondrite. The chemical composition of the Social Circle sample determined by electron microprobe is (wt%) S 44.3, Cr 36.2, Mn 15.8, Fe 4.5, Ni 0.09, Cu 0.08, total 101.0, giving rise to an empirical formula of (Mn0.82Fe0.23)Cr1.99S3.95. The crystal structure, determined by electron backscattered diffraction, is aFd 3m spinel-type structure with a = 10.11 Å, V = 1033.4 Å3, and Z = 8. Keywords: Joegoldsteinite, MnCr2S4, new sulfide mineral, thiospinel, Social Circle IVA iron meteorite, Indarch EH4 enstatite chondrite Introduction new mineral by the International Mineralogical Association (IMA 2015-049) in August 2015. It was named in honor of Thiospinels have a general formula of AB2X4 where A is a divalent metal, B is a trivalent metal, and X is a –2 anion, Joseph (Joe) I.
  • Antarctic Guide to Martian Weathering

    Antarctic Guide to Martian Weathering

    PSRD: Antarctic Guide to Martian Weathering http://www.psrd.hawaii.edu/April05/DryValleysSoils.html posted April 13, 2005 Antarctic Guide to Martian Weathering --- Soils in the Antarctic Dry Valleys contain traces of silicate alteration products and secondary salts much like those found in Martian meteorites. Written by Linda M. V. Martel Hawai'i Institute of Geophysics and Planetology Field sites in the Antarctic Dry Valleys serve as useful (and relatively nearby) analogs to the surface of Mars for several reasons that have been known since the Viking Lander experiments. The environmental similarities include: low mean temperatures; strong, desiccating winds; lack of rain; sparse snowfall; sublimation; diurnal freeze-thaw cycles; low humidity; high solar radiation; and the presence of salts in the soils. A team of planetary scientists have recently reexamined earlier work on cold Antarctic desert soils to better understand the Martian near-surface environment and weathering processes. The ongoing studies by Susan Wentworth (ERC/ESCG at Johnson Space Center), Everett Gibson and David McKay (Johnson Space Center), and Michael Velbel (Michigan State University) include Martian meteorites, most of which contain traces of aqueous weathering products. They report that these meteorite weathering features, which are of Martian origin, are remarkably similar in composition, nature, and abundance to those found in the Antarctic Dry Valleys soils, suggesting the weathering processes are also similar. Reference: S. J. Wentworth, Gibson, E. K., Velbel, M. A., and McKay, D. S. (2005) Antarctic Dry Valleys and indigenous weathering in Mars meteorites: implications for water and life on Mars. Icarus, v. 174, p. 382-395. Insights from Polar Desert Soils 1 of 6 PSRD: Antarctic Guide to Martian Weathering http://www.psrd.hawaii.edu/April05/DryValleysSoils.html The photograph on the left is a general scene of the environment of Wright Valley, Antarctica.
  • Meteorites from the Lut Desert (Iran)

    Meteorites from the Lut Desert (Iran)

    Meteorites from the Lut Desert (Iran) Hamed Pourkhorsandi, Jérôme Gattacceca, Pierre Rochette, Massimo d’Orazio, Hojat Kamali, Roberto Avillez, Sonia Letichevsky, Morteza Djamali, Hassan Mirnejad, Vinciane Debaille, et al. To cite this version: Hamed Pourkhorsandi, Jérôme Gattacceca, Pierre Rochette, Massimo d’Orazio, Hojat Kamali, et al.. Meteorites from the Lut Desert (Iran). Meteoritics and Planetary Science, Wiley, 2019, 54 (8), pp.1737-1763. 10.1111/maps.13311. hal-02144596 HAL Id: hal-02144596 https://hal-amu.archives-ouvertes.fr/hal-02144596 Submitted on 31 May 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Distributed under a Creative Commons Attribution - NonCommercial - ShareAlike| 4.0 International License doi: 10.1111/maps.13311 Meteorites from the Lut Desert (Iran) Hamed POURKHORSANDI 1,2*,Jerome^ GATTACCECA 1, Pierre ROCHETTE 1, Massimo D’ORAZIO3, Hojat KAMALI4, Roberto de AVILLEZ5, Sonia LETICHEVSKY5, Morteza DJAMALI6, Hassan MIRNEJAD7, Vinciane DEBAILLE2, and A. J. Timothy JULL8 1Aix Marseille Universite, CNRS, IRD, Coll France, INRA, CEREGE, Aix-en-Provence, France 2Laboratoire G-Time, Universite Libre de Bruxelles, CP 160/02, 50, Av. F.D. Roosevelt, 1050 Brussels, Belgium 3Dipartimento di Scienze della Terra, Universita di Pisa, Via S.
  • Phosphorus and Sulfur Cosmochemistry: Implications for the Origins of Life

    Phosphorus and Sulfur Cosmochemistry: Implications for the Origins of Life

    Phosphorus and Sulfur Cosmochemistry: Implications for the Origins of Life Item Type text; Electronic Dissertation Authors Pasek, Matthew Adam Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 07/10/2021 06:16:37 Link to Item http://hdl.handle.net/10150/194288 PHOSPHORUS AND SULFUR COSMOCHEMISTRY: IMPLICATIONS FOR THE ORIGINS OF LIFE by Matthew Adam Pasek ________________________ A Dissertation Submitted to the Faculty of the DEPARTMENT OF PLANETARY SCIENCE In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College UNIVERSITY OF ARIZONA 2 0 0 6 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Dissertation Committee, we certify that we have read the dissertation prepared by Matthew Adam Pasek entitled Phosphorus and Sulfur Cosmochemistry: Implications for the Origins of Life and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy _______________________________________________________________________ Date: 04/11/2006 Dante Lauretta _______________________________________________________________________ Date: 04/11/2006 Timothy Swindle _______________________________________________________________________ Date: 04/11/2006
  • Wednesday, March 22, 2017 [W453] MARTIAN METEORITE MADNESS: MIXING on a VARIETY of SCALES 1:30 P.M

    Wednesday, March 22, 2017 [W453] MARTIAN METEORITE MADNESS: MIXING on a VARIETY of SCALES 1:30 P.M

    Lunar and Planetary Science XLVIII (2017) sess453.pdf Wednesday, March 22, 2017 [W453] MARTIAN METEORITE MADNESS: MIXING ON A VARIETY OF SCALES 1:30 p.m. Waterway Ballroom 5 Chairs: Arya Udry Geoffrey Howarth 1:30 p.m. Nielsen S. G. * Magna T. Mezger K. The Vanadium Isotopic Composition of Mars and Evidence for Solar System Heterogeneity During Planetary Accretion [#1225] Vanadium isotope composition of Mars distinct from Earth and chondrites. 1:45 p.m. Tait K. T. * Day J. M. D. Highly Siderophile Element and Os-Sr Isotope Systematics of Shergotittes [#3025] The shergottite meteorites represent geochemically diverse, broadly basaltic, and magmatically-derived rocks from Mars. New samples were processed and analyzed. 2:00 p.m. Armytage R. M. G. * Debaille V. Brandon A. D. Agee C. B. The Neodymium and Hafnium Isotopic Composition of NWA 7034, and Constraints on the Enriched End-Member for Shergottites [#1065] Couple Sm-Nd and Lu-Hf isotopic systematics in NWA 7034 suggest that such a crust is not the enriched end-member for shergottites. 2:15 p.m. Howarth G. H. * Udry A. Nickel in Olivine and Constraining Mantle Reservoirs for Shergottite Meteorites [#1375] Ni enrichment in olivine from enriched versus depleted shergottites provide evidence for constraining mantle reservoirs on Mars. 2:30 p.m. Jean M. M. * Taylor L. A. Exploring Martian Mantle Heterogeneity: Multiple SNC Reservoirs Revealed [#1666] The objective of the present study is to assess how many mixing components can be recognized, and address ongoing debates within the martian isotope community. 2:45 p.m. Udry A. * Day J.
  • Petrography, Mineralogy, and Geochemistry of Lunar Meteorite Sayh Al Uhaymir 300

    Petrography, Mineralogy, and Geochemistry of Lunar Meteorite Sayh Al Uhaymir 300

    Meteoritics & Planetary Science 43, Nr 8, 1363–1381 (2008) Abstract available online at http://meteoritics.org Petrography, mineralogy, and geochemistry of lunar meteorite Sayh al Uhaymir 300 Weibiao HSU1*, Aicheng ZHANG1, Rainer BARTOSCHEWITZ2 , Yunbin GUAN3, Takayuki USHIKUBO3, Urs KRÄHENBÜHL4, Rainer NIEDERGESAESS5, Rudolf PEPELNIK5, Ulrich REUS5, Thomas KURTZ6, and Paul KURTZ6 1Laboratory for Astrochemistry and Planetary Sciences, Lunar and Planetary Science Center, Purple Mountain Observatory, 2 West Beijing Road, Nanjing, 210008, China 2Bartoschewitz Meteorite Lab, Lehmweg 53, D-38518 Gifhorn, Germany 3Department of Geological Sciences, Arizona State University, Tempe, Arizona 85287, USA 4Abteilung für Chemie und Biochemie, Universität Bern, Freiestr. 3, CH-3012 Bern, Switzerland 5GKSS Forschungszentrum GmbH, Institut für Küstenforschung, Max-Planck-Strasse, D-21502 Geesthacht, Germany 6Henckellweg 25, D-30459 Hannover, Germany *Corresponding author. E-mail: [email protected] (Received 24 May 2007; revision accepted 19 March 2008) Abstract–We report here the petrography, mineralogy, and geochemistry of lunar meteorite Sayh al Uhaymir 300 (SaU 300). SaU 300 is dominated by a 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 (Al2O3 21.6 wt% and FeO 8.16 wt%) are very similar to those of two basalt-bearing feldspathic 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.
  • METEORITES NEWLY FOUND in RUSSIA References

    METEORITES NEWLY FOUND in RUSSIA References

    melting crust beneath a thin oxide rind, it is reasonable to suggest that the meteorite fell within a century ago. The other five smaller fragments found at the fall site are METEORITES NEWLY FOUND IN RUSSIA no larger than 7 cm. All of them are also covered by carbonate and iron oxide crusts. The fragments are flattened, ungeometrical, and their sharp uneven edges make them look like chips. Sergei V. Kolisnichenko The identified phases of the meteorite are taenite (30.6 wt.% Ni), kamacite (7.95 wt.% collector, Verkhnyaya Sanarka , Urals, Russia Ni) , and inclusions of troilite and schreibersite (microprobe analyses were conduc- [email protected] ted at the Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, analyst N.N. Kononkova). The Suzemka is the first meteorite found in Bryansk oblast. ussia's collection of meteorites received two newly found meteorites in Uakit . The Uakit meteorite was found in summer 2016 on the stream terrace of 2017, which are registered in the international Meteoritical Bulletin Mukhtunnyiy Creek, a left-hand tributary of the Uakit River, 4 km west of the village R Database as the Suzemka (Meteoritical Bulletin, 2017 ) and Uakit of Uakit, Evenkiyskiy district, Buryatia (found at 55° 29'47.50'' N, 113°33'47.98''E). 1 (Meteoritical Bulletin, 2017 ) iron meteorites. The meteorite was found by a group of small diggers (O.Yu. Korshunov and others) 2 at a gold deposit. Suzemka . The Suzemka meteorite was found in Bryansk oblast (territory) near the town of Suzemka on July 18, 2015 (at 52°20.25'N, 34°3.24'E).
  • Aqueous Alteration in Martian Meteorites: Comparing Mineral Relations in Igneous-Rock Weathering of Martian Meteorites and in the Sedimentary Cycle of Mars

    Aqueous Alteration in Martian Meteorites: Comparing Mineral Relations in Igneous-Rock Weathering of Martian Meteorites and in the Sedimentary Cycle of Mars

    AQUEOUS ALTERATION IN MARTIAN METEORITES: COMPARING MINERAL RELATIONS IN IGNEOUS-ROCK WEATHERING OF MARTIAN METEORITES AND IN THE SEDIMENTARY CYCLE OF MARS MICHAEL A. VELBEL Department of Geological Sciences, 206 Natural Science Building, Michigan State University, East Lansing, Michigan 48824-1115 USA e-mail: [email protected] ABSTRACT: Many of the minerals observed or inferred to occur in the sediments and sedimentary rocks of Mars, from a variety of Mars-mission spacecraft data, also occur in Martian meteorites. Even Martian meteorites recovered after some exposure to terrestrial weathering can preserve preterrestrial evaporite minerals and useful information about aqueous alteration on Mars, but the textures and textural contexts of such minerals must be examined carefully to distinguish preterrestrial evaporite minerals from occurrences of similar minerals redistributed or formed by terrestrial processes. Textural analysis using terrestrial microscopy provides strong and compelling evidence for preterrestrial aqueous alteration products in a numberof Martian meteorites. Occurrences of corroded primary rock-forming minerals and alteration products in meteorites from Mars cover a range of ages of mineral–water interaction, from ca. 3.9 Ga (approximately mid-Noachian), through one or more episodes after ca. 1.3 Ga (approximately mid–late Amazonian), through the last half billion years (late Amazonian alteration in young shergottites), to quite recent. These occurrences record broadly similar aqueous corrosion processes and formation of soluble weathering products over a broad range of times in the paleoenvironmental history of the surface of Mars. Many of the same minerals (smectite-group clay minerals, Ca-sulfates, Mg-sulfates, and the K-Fe–sulfate jarosite) have been identified both in the Martian meteorites and from remote sensing of the Martian surface.
  • THE REGOLITH PORTION of the LUNAR METEORITE SAYH AL UHAYMIR 169 A. Al-Kathiri1, 2, E. Gnos1 and B. A. Hofmann3 1Institut Für Ge

    THE REGOLITH PORTION of the LUNAR METEORITE SAYH AL UHAYMIR 169 A. Al-Kathiri1, 2, E. Gnos1 and B. A. Hofmann3 1Institut Für Ge

    69th Annual Meteoritical Society Meeting (2006) 5098.pdf THE REGOLITH PORTION OF THE LUNAR METEORITE SAYH AL UHAYMIR 169 A. Al-Kathiri1, 2, E. Gnos1 and B. A. Hofmann3 1Institut für Geologie, Universität Bern, Baltzerstrasse 1, CH- 3012 Bern, Switzerland 2Directorate General of Commerce and Industry, Ministry of Commerce and Industry, Salalah, Sultanate of Oman. 3Naturhistorisches Museum der Burgergemeinde Bern, Bernastrasse 15, CH-3005 Bern, Switzerland. Introduction: SaU 169 is a complete, light gray- greenish stone (70 x 43 x 40 mm) with a mass of 206.45 g found in the Sultanate of Oman in January 2002. The rock consists of two contrasting lithologies. Approximately 87 vol% consists of a holocrystalline, fine-grained poikilitic polymict KREEP-rich im- pact melt breccia, the other 13 vol% are shock-lithified regolith [1]. Discussion: The regolith shows two formation stages and contains the following clasts: Ti-poor to Ti-rich basalts, gab- bros to granulites, and regolith breccias. The younger regolith additionally contains a highland gabbronorite clast with anorthite (An96-97), forsteritic (Fo85) and fayalitic (Fo12) mineral clasts, and impact melt glass shards. The average regolith bulk chemical composition and its REE content lie between the soil and regolith breccias of Apollo 12 and 14 , with more affinity with Apollo 14 [2,3,4]. The largest KREEP breccia clast in the regolith is identi- cal in its chemical composition and total REE content to the ITE- rich high-K KREEP rocks of the Apollo 14 landing site, pointing to a similar source. The regolith shows characteristic lunar ratios of Fe/Mn (74-80) and K/U (535-1682).
  • A New Meteoric Iron from Piedade Do Bagre, Minas Geraes, Brazil

    A New Meteoric Iron from Piedade Do Bagre, Minas Geraes, Brazil

    271 A new meteoric iron from Piedade do Bagre, Minas Geraes, Brazil. (With Plates XI and XII.) By L. J. SPENCER, M.A., Sc.D., F.R.S. With a chemical analysis by M. It. HEY, B.A., B.Se. Mineral Department, British Museum of Natural History. [Read June 3, 1930.] MASS of iron weighing 130 lb., stated to have been found in A 1922 near the village of Piedade do Bagre in Minas Geraes, Brazil, and believed to be meteoric, was submitted by Mr. N. Medawar in January 1929 to the Mineral Department of the British Museum for examination. The following description of the mass fully confirms the supposition of its meteoric origin. Unfortunately, only scanty details are available of the circumstances of the finding of the mass. All the information that Mr. Medawar was able to supply is given in the following short note written by Mr. R. J. Bohrer, with a rough sketch-map of the locality. Meteorito encontrado no ponto mareado +. Vendido por intermedio do Snr. Padre Jos6 Alves de Curvello a Rodolpho J. Bohrer. Encontrado em 1922 por um situante cujo nome n~o se conhece. Vendido a Snr. Medawar em Margo de 1927. Mr. Medawar's translation of this is : Meteorite found at the point marked +. Sold by the intermediary of Mr. Padre Jos6 Alves of Curvello to Rodolpho J. Bohrer. Found in 1922 by a local native whose name not known. Sold to Mr. Medawar in March of 1927. The spot marked is about 16 km. (10 miles) SW. of the village of Piedade do Bagre in Minas Geraes.
  • Appendix a Recovery of Ejecta Material from Confirmed, Probable

    Appendix a Recovery of Ejecta Material from Confirmed, Probable

    Appendix A Recovery of Ejecta Material from Confirmed, Probable, or Possible Distal Ejecta Layers A.1 Introduction In this appendix we discuss the methods that we have used to recover and study ejecta found in various types of sediment and rock. The processes used to recover ejecta material vary with the degree of lithification. We thus discuss sample processing for unconsolidated, semiconsolidated, and consolidated material separately. The type of sediment or rock is also important as, for example, carbonate sediment or rock is processed differently from siliciclastic sediment or rock. The methods used to take and process samples will also vary according to the objectives of the study and the background of the investigator. We summarize below the methods that we have found useful in our studies of distal impact ejecta layers for those who are just beginning such studies. One of the authors (BPG) was trained as a marine geologist and the other (BMS) as a hard rock geologist. Our approaches to processing and studying impact ejecta differ accordingly. The methods used to recover ejecta from unconsolidated sediments have been successfully employed by BPG for more than 40 years. A.2 Taking and Handling Samples A.2.1 Introduction The size, number, and type of samples will depend on the objective of the study and nature of the sediment/rock, but there a few guidelines that should be followed regardless of the objective or rock type. All outcrops, especially those near industrialized areas or transportation routes (e.g., highways, train tracks) need to be cleaned off (i.e., the surface layer removed) prior to sampling.
  • Heating Experiments of Maskelynite in Zagami, Elephant Moraine A79001 and Allan Hills 77005: Implications for the Effect of Shock Heating

    Heating Experiments of Maskelynite in Zagami, Elephant Moraine A79001 and Allan Hills 77005: Implications for the Effect of Shock Heating

    51st Lunar and Planetary Science Conference (2020) 1803.pdf HEATING EXPERIMENTS OF MASKELYNITE IN ZAGAMI, ELEPHANT MORAINE A79001 AND ALLAN HILLS 77005: IMPLICATIONS FOR THE EFFECT OF SHOCK HEATING. R. Shikina1,2 and T. Mikouchi1,2, 1Department of Earth and Planet. Science, The University of Tokyo, Hongo, Tokyo 113-0033, Japan ([email protected]), 2The University Museum, The University of Tokyo, Hongo, Tokyo 113-0033, Japan. Introduction: Plagioclase is one of the important along the cracks and at edges of the original grains. constituents of extraterrestrial materials and is sensi- Although maskelynites appear to have a smooth sur- tive to the shock metamorphism. Maskelynite is under- face through optical microscopy, the recrystallized stood as a diaplectic plagioclase glass that has been plagioclase shows a dirty devitrified texture. Electron transformed from plagioclase in solid-state transfor- microprobe analysis (shown in Fig. 2) revealed that Na mation by strong impact and is commonly found in and K are reduced, but Ca is enriched in the recrystal- Martian meteorites [1]. Maskelynite is known to be lized plagioclase of the samples showing partial recrys- easily converted to crystalline plagioclase by reheating tallization (900 °C for 8 and 24 hours and 1000 °C for and the degree of recrystallization depends upon shock 1 hour). In the maskelynite grains heated at 900 °C for pressure [2]. Such plagioclase recrystallizations is 168 hours, small glass regions enriched in Na and K found in meteorites. For example, the lunar meteorite are present (Na2O: ~6.5 wt%, K2O: ~2.5 wt%), sug- Y-793169 shows a recrystallized polycrystalline plagi- gesting that Na and K concentrate in areas where re- oclase texture by a reheating event after the formation crystallization did not start yet.