Primitive Enstatite Achondrites
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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. -
Fe,Mg)S, the IRON-DOMINANT ANALOGUE of NININGERITE
1687 The Canadian Mineralogist Vol. 40, pp. 1687-1692 (2002) THE NEW MINERAL SPECIES KEILITE, (Fe,Mg)S, THE IRON-DOMINANT ANALOGUE OF NININGERITE MASAAKI SHIMIZU§ Department of Earth Sciences, Faculty of Science, Toyama University, 3190 Gofuku, Toyama 930-8555, Japan § HIDETO YOSHIDA Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan § JOSEPH A. MANDARINO 94 Moore Avenue, Toronto, Ontario M4T 1V3, and Earth Sciences Division, Royal Ontario Museum, 100 Queens’s Park, Toronto, Ontario M5S 2C6, Canada ABSTRACT Keilite, (Fe,Mg)S, is a new mineral species that occurs in several meteorites. The original description of niningerite by Keil & Snetsinger (1967) gave chemical analytical data for “niningerite” in six enstatite chondrites. In three of those six meteorites, namely Abee and Adhi-Kot type EH4 and Saint-Sauveur type EH5, the atomic ratio Fe:Mg has Fe > Mg. Thus this mineral actually represents the iron-dominant analogue of niningerite. By analogy with synthetic MgS and niningerite, keilite is cubic, with space group Fm3m, a 5.20 Å, V 140.6 Å3, Z = 4. Keilite and niningerite occur as grains up to several hundred m across. Because of the small grain-size, most of the usual physical properties could not be determined. Keilite is metallic and opaque; in reflected light, it is isotropic and gray. Point-count analyses of samples of the three meteorites by Keil (1968) gave the following amounts of keilite (in vol.%): Abee 11.2, Adhi-Kot 0.95 and Saint-Sauveur 3.4. -
Silicate-Sio Reaction in a Protoplanetary Disk Recorded by Oxygen Isotopes in Chondrules
Silicate-SiO reaction in a protoplanetary disk recorded by oxygen isotopes in chondrules Ryoji Tanaka1* & Eizo Nakamura1 1The Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University, Misasa, Tottori, 682-0193, Japan *Corresponding author: [email protected] The formation of planetesimals and planetary embryos during the earliest stages of the solar protoplanetary disk largely determined the composition and structure of the terrestrial planets. Within a few million years (Myr) after the birth of the solar system, chondrule formation and accretion of the parent bodies of differentiated achondrites and the terrestrial planets took place in the inner protoplanetary disk1,2. Here we show that, for chondrules in unequilibrated enstatite chondrites, high-precision Δ17O values (deviation of δ17O value from a terrestrial silicate fractionation line) vary significantly (ranging from -0.49 to +0.84‰) and fall on an array with a steep slope of 1.27 on a three oxygen isotope plot. This array can be explained by reaction between an olivine-rich chondrule melt and a SiO-rich gas derived from vaporized dust and nebular gas. Our study suggests that the majority of the building blocks of planetary embryos formed by successive silicate-gas interaction processes: silicate-H2O followed by silicate-SiO interactions under more oxidized and reduced conditions, respectively, within a few Myr after the formation of the solar system. Major precursor components of enstatite chondrites (EC), differentiated planetesimals, Mars, and the Earth are thought to have been formed at similar heliocentric distances3,4. The unequilibrated EC preserve records of nebular conditions in each component (chondrules, Ca- Al-rich inclusions [CAIs], Fe-Ni-metal, and matrix), each of which has not been heavily overprinted by post-accretionary thermal processes. -
March 21–25, 2016
FORTY-SEVENTH LUNAR AND PLANETARY SCIENCE CONFERENCE PROGRAM OF TECHNICAL SESSIONS MARCH 21–25, 2016 The Woodlands Waterway Marriott Hotel and Convention Center The Woodlands, Texas INSTITUTIONAL SUPPORT Universities Space Research Association Lunar and Planetary Institute National Aeronautics and Space Administration CONFERENCE CO-CHAIRS Stephen Mackwell, Lunar and Planetary Institute Eileen Stansbery, NASA Johnson Space Center PROGRAM COMMITTEE CHAIRS David Draper, NASA Johnson Space Center Walter Kiefer, Lunar and Planetary Institute PROGRAM COMMITTEE P. Doug Archer, NASA Johnson Space Center Nicolas LeCorvec, Lunar and Planetary Institute Katherine Bermingham, University of Maryland Yo Matsubara, Smithsonian Institute Janice Bishop, SETI and NASA Ames Research Center Francis McCubbin, NASA Johnson Space Center Jeremy Boyce, University of California, Los Angeles Andrew Needham, Carnegie Institution of Washington Lisa Danielson, NASA Johnson Space Center Lan-Anh Nguyen, NASA Johnson Space Center Deepak Dhingra, University of Idaho Paul Niles, NASA Johnson Space Center Stephen Elardo, Carnegie Institution of Washington Dorothy Oehler, NASA Johnson Space Center Marc Fries, NASA Johnson Space Center D. Alex Patthoff, Jet Propulsion Laboratory Cyrena Goodrich, Lunar and Planetary Institute Elizabeth Rampe, Aerodyne Industries, Jacobs JETS at John Gruener, NASA Johnson Space Center NASA Johnson Space Center Justin Hagerty, U.S. Geological Survey Carol Raymond, Jet Propulsion Laboratory Lindsay Hays, Jet Propulsion Laboratory Paul Schenk, -
Aluminium-Mg Systematics of Winonaites and Differentiation of the Iab-Winonaite Parent Body
77th Annual Meteoritical Society Meeting (2014) 5155.pdf ALUMINIUM-MG SYSTEMATICS OF WINONAITES AND DIFFERENTIATION OF THE IAB-WINONAITE PARENT BODY. Y. Hidaka1, V. Debaille1 and G. Hublet1. 1Laboratoire G-Time, Université Libre de Bruxelles, Brussels, Belgium. Introduction: Primitive achondrites such as winonaites are important materials to investigate the early differentiation processes of asteroids. Winonaites are considered to originate from the same parent body than IAB non-magmatic iron meteorites [1]. Short-lived radionuclide chronometers are useful to understand the first few million years of the solar system history. The Al-Mg system is one of the most established short- lived systematics that provides a very good time resolution. Previous Hf-W isotopic studies have revealed that IAB- winonaite parent body had accreted ~1 Ma after CAI formation [2] and its magmatic activity ceased ~4 Ma later [3]. However, there is no other chronological data of winonaites from other short-lived radionuclide systems, in particular from fully lithophile systematics, as W is siderophile. Therefore, we consider here additional Al-Mg chronological data of winonaites to investigate the early evolutionary history of the silicate portion of their parent body. Results and Discussion: We have investigated two winonaite meteorites NWA 725 and Y-8005, with a present focus on the first one. NWA 725 is officially classified as an acapulcoite, but oxygen isotopic data of this meteorite indicated that NWA 725 and paired meteorites are actually winonaites [4, 5]. NWA 725 has been reported as chondrule-bearing, the least metamorphosed primitive achondrite [6]. The evolutionary models of IAB-winonaite parent body [1, 2] indicated that this parent body should preserve intact, chondritic areas during partial melting and silicate-metal segregation processes. -
Sulfides in Enstate Chondrites
Sulfides in Enstatite Chondrites: Indicators of Impact History Kristyn Hill1,2, Emma Bullock2, Cari Corrigan2, and Timothy McCoy2 1Lock Haven University of Pennsylvania, Lock Haven, PA 17745, USA 2National Museum of Natural History, Department of Mineral Sciences, Washington D.C. 20013, USA Introductton Results Discussion Enstatite chondrites are a class of meteorites. They are Determining the history of the parent body of a referred to as chondrites because of the spherical Impact Melt, Slowly Cooled chondritic meteorite often includes distinguishing whether chondrules found in the matrix of the meteorites. Enstatite aa bb cc d d or not the meteorite was impact melted, and the cooling chondrites are the most highly reduced meteorites and rate. contain iron-nickel metal and sulfide bearing minerals. The Impact melts are distinguishable by the texture of the matrix is made up of silicates, enstatite in particular. There metal and sulfide assemblages. A meteorite that was are usually no oxides found, which supports the idea that impact melted will contain a texture of euhedral to these formed in very oxygen poor environments. The subhedral silicates, like enstatite, protruding into the metal enstatite chondrites in this study are type 3, meaning they or sulfides (figure 2). Some textures will look shattered are unmetamorphosed and not affected by fluids. (figure 2b). Meteorites that contain the mineral keilite are Studying enstatite chondrites will help us determine the PCA 91125 ALHA 77156 PCA 91444 PCA 91085 also an indicator of impact melts (figure 3). Keilite only evolution of their parent bodies which formed at the occurs in enstatite chondrite impact-melt rocks that cooled beginning of our solar system. -
'San Juan', a New Mass of the Campo Del Cielo Meteorite Shower
‘San Juan’, a new mass of the Campo del Cielo meteorite shower Marcela Eliana SAAVEDRA1, María Eugenia VARELA1, Andrew J. CAMPBELL 2 and Dan TOPA 3 1Instituto de Ciencias Astronómicas de la Tierra y del Espacio (ICATE)-CONICET, San Juan, Argentina. 2Deptartment of the Geophysical Sciences, University of Chicago, , Chicago, USA. 3Central Research Laboratories, Natural History Museum, , Vienna, Austria. Email: [email protected] Editor: Diego A. Kietzmann Recibido: 19 de marzo de 2021 Aceptado: 15 de junio de 2021 Disponible online: 15 de junio de 2021 ABSTRACT Petrographic and chemical (major, minor and trace element) studies of silicate inclusions and metal from the San Juan A and B samples revealed that they are new masses belonging to the Campo del Cielo IAB iron meteorite shower. These masses must have being transported from the large strewn field in the Chaco and Santiago del Estero Provinces to the surroundings of San Juan city, where they have being recover in the year 2000. The sizes of the two masses of San Juan, collected 770 km SW from Santiago del Estero, is in agreement with the previously suggested anthropic hypothesis for the transport of Campo del Cielo. Keywords: IAB iron meteorites, Campo del Cielo meteorite, San Juan meteorite. RESUMEN San Juan, una nueva masa de la lluvia de meteoritos de Campo del Cielo Estudios petrográficos y químicos (elementos mayores, menores y trazas) de inclusiones de silicatos y de metal de las muestras A y B de San Juan, reveló que son nuevas masas que pertenecen a la lluvia de meteoritos de Campo del Cielo. -
A New Primitive Achondrite from Northwest Africa
A New Primitive Achondrite from Northwest Africa Kseniya K. Androsova* University of Calgary, Calgary, AB, Canada [email protected] and Alan R. Hildebrand University of Calgary, Calgary, AB, Canada Summary The winonaite and acapulcoite/lodranite meteorites constitute small groups of primitive achondrites that have experienced thermal metamorphism sometimes accompanied by varying degrees of partial melting. Petrographic and elemental abundance studies [optical microscope observations and electron microprobe analysis] have been conducted on several meteorites recovered in Northwest Africa (NWA). One meteorite has fine-grained, granulitic texture, abundant, evenly distributed metal and troilite grains, and highly reduced mineral compositions [Olivine (Fa6.0±0.4), low-Ca pyroxene (Fs7.5±0.4, Wo1.3±0.2), high-Ca pyroxene (Fs3.2±0.2, Wo45.8±0.7)]. Based on these criteria it appears that the data are consistent with the sample being a winonaite. The overall textural resemblance of this meteorite to NWA 1463 and /or NWA 725 (somewhat anomalous) winonaites (both having multiple relict chondrules) may suggest that this meteorite is paired with one or both. Although, until its oxygen isotope composition is obtained the classification of this meteorite as a winonaite (vs. as an acapulcoite) remains uncertain, its primitive achondritic nature is quite evident. Introduction The winonaite meteorites represent a class of rare primitive achondrites (together with the acapulcoite/lodranite association) that have sometimes undergone partial melting but generally have chondritic mineralogy and composition. Winonaites can be characterized by fine- to medium-grained, mostly granulitic textures, highly reduced mineral compositions, and unique oxygen isotope signatures (Benedix et al., 1998). Although most of the winonaites lack chondrules, several have been reported to have regions containing relict chondrules. -
Siderophile Elements and Molybdenum, Tungsten, And
ABSTRACT Title of Dissertation: SIDEROPHILE ELEMENTS AND MOLYBDENUM, TUNGSTEN, AND OSMIUM ISOTOPES AS TRACERS OF PLANETARY GENETICS AND DIFFERENTIATION: IMPLICATIONS FOR THE IAB IRON METEORITE COMPLEX Emily Anne Worsham, Doctor of Philosophy, 2016 Dissertation directed by: Professor Richard Walker, Department of Geology Isotopic and trace element abundance data for iron meteorites and chondrites are presented in order to investigate the nature of genetic relations between and among meteorite groups. Nebular and planetary diversity and processes, such as differentiation, can be better understood through study of IAB complex iron meteorites. This is a large group of chemically and texturally similar meteorites that likely represent metals with a thermal history unlike most other iron meteorite groups, which sample the cores of differentiated planetesimals. The IAB complex contains a number of chemical subgroups. Trace element determination and modeling, Re/Os isotopic systematics, nucleosynthetic Mo isotopic data, and 182Hf-182W geochronology are used to determine the crystallization history, genetics, and relative metal-silicate segregation ages of the IAB iron meteorite complex. Highly siderophile element abundances in IAB complex meteorites demonstrate that diverse crystallization mechanisms are represented in the IAB complex. Relative abundances of volatile siderophile elements also suggest late condensation of some IAB precursor materials. Improvements in the procedures for the separation, purification, and high- precision analysis of Mo have led to a ~2 fold increase in the precision of 97Mo/96Mo isotope ratio measurements, compared to previously published methods. Cosmic ray exposure-corrected Mo isotopic compositions of IAB complex irons indicate that at least three parent bodies are represented in the complex. The Hf-W metal-silicate segregation model ages of IAB complex subgroups suggests that at least four metal segregation events occurred among the various IAB parent bodies. -
UNIVERSITY of CALIFORNIA, SAN DIEGO Primitive and Differentiated
UNIVERSITY OF CALIFORNIA, SAN DIEGO Primitive and differentiated achondrite meteorites and partial melting in the early Solar System A Thesis submitted in partial satisfaction of the requirements for the degree Master of Science in Earth Sciences By Christopher Andrew Corder Committee in charge: Professor James M. D. Day, Chair Professor Geoffrey W. Cook Professor David R. Stegman 2015 © Christopher Andrew Corder, 2015 All rights reserved. The Thesis of Christopher Corder is approved and it is acceptable in quality and form for publication on microfilm and electronically: Chair University of California, San Diego 2015 iii Dedication This manuscript would be far from complete without thanking those who helped set the stage for the many hours of work it documents, and those thank-yous would be far from complete without recognizing my parents and their unwavering support throughout years of study. I know I was the one in the lab, but I never would have made it there, or to my defense, or through any of the long days and nights if it weren’t for you both. Thank you, so much. I’d love to thank my entire family, especially Stephen. You’re a brother Stephen, and you encourage me more than you know. Whenever it seemed like research was going nowhere, you were there to remind me why science is always a worthwhile endeavor. Even more importantly you remind me, by example, that there are exceptional people in this world. Many thanks are due to the lab group I worked with and other smart folks at SIO. First of all, thank you James for trusting this intriguing suite of meteorites to my care. -
Buseckite, (Fe,Zn,Mn)S, a New Mineral from the Zakłodzie Meteorite
American Mineralogist, Volume 97, pages 1226–1233, 2012 Buseckite, (Fe,Zn,Mn)S, a new mineral from the Zakłodzie meteorite CHI MA,* JOHN R. BECKETT, AND GEORGE R. ROSSMAN Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, U.S.A. ABSTRACT Buseckite (IMA 2011-070), (Fe,Zn,Mn)S, is the Fe-dominant analog of wurtzite, a new member of the wurtzite group discovered in Zakłodzie, and an ungrouped enstatite-rich achondrite. The type material occurs as single-crystal grains (4–20 µm in size) in contact with two or more of enstatite, plagioclase, troilite, tridymite, quartz, and sinoite. Low-Ni iron, martensitic iron, schreibersite, keilite, cristobalite, and graphite, which are also present in the type sample, are not observed to be in contact with buseckite. Buseckite is black under diffuse illumination and nearly opaque grayish brown in transmitted light. The mean chemical composition of buseckite, as determined by electron micro- probe analysis of the type material, is (wt%) S 35.84, Fe 28.68, Zn 23.54, Mn 10.04, Mg 1.18, sum 99.28, leading to an empirical formula calculated on the basis of 2 atoms of (Fe0.46Zn0.32Mn0.16Mg0.04 )∑0.99S1.01. Electron backscatter diffraction patterns of buseckite are a good match to that of synthetic 3 (Zn0.558Fe0.442)S with the P63mc structure, showing a = 3.8357, c = 6.3002 Å, V = 80.27 Å , and Z = 2. Buseckite is likely derived from the breakdown of high-temperature pyrrhotite to form troilite and buseckite following the solidification of sulfide-rich liquids produced during impact melting of an enstatite-rich rock. -
Bartoschewitz - Catalogue of Meteorites
BARTOSCHEWITZ - CATALOGUE OF METEORITES *FALL TOTAL BC- BC - NAME COUNTRY FIND WEIGHT TYPE No. SPECIMEN WEIGHT (kg) (gms) 1.1 CHONDRITES - ORDINARY OLIVINE BRONZITE CHONDRITES ACFER 005 Algeria March 1989 0,115 H 3.9/4 613.1 cut endpiece 32,70 ACFER 006 Algeria March 1989 0,561 H 3.9/4 614.1 slice 1,30 ACFER 011 Algeria 1989 3,8 H 5 399.1 cut fragm. 3,00 ACFER 020 Algeria 1989 0,708 H 5 401.1 cut fragm. 2,50 ACFER 028 Algeria 1989 3,13 H 3.8 844.1 part slice 1,70 ACFER 050 Algeria 1989 1,394 H 5-6 443.1 complete slice 105,00 ACFER 084 Algeria Apr. 16, 1990 6,3 H 5 618.1 cut corner piece 12,60 ACFER 089 Algeria 1990 0,682 H 5 437.1 complete slice 62,00 ACFER 098 Algeria 1990 5,5 H 5 615.1 cut fragment 29,20 ACFER 222 Algeria 1991 0,334 H 5-6 536.1 cut fragm. with crust 2,50 ACFER 284 Algeria 1991 0,12 H 5 474.1 slice 11,00 ACHILLES USA, Kansas 1924 recogn. 1950 16 H 5 314.1 slice 3,40 ACME USA, New Mexico 1947 75 H 5 303.1 slice 10,80 AGEN France *Sept. 5, 1815 30 H 5 208.1 fragm. with crust 54,40 ALAMOGORDO USA, New Mexico 1938 13,6 H 5 2.1 fragment 0,80 ALLEGAN USA *July 10, 1899 35 H 5 276.0 5 small fragments 1,52 ALLEGAN USA *July 10, 1899 35 H 5 276.1 5 small fragments 1,50 ALLEGAN USA *July 10, 1899 35 H 5 276.2 chondrules 0,02 ALLEN USA, Texas 1923 recogn.