DOCSLIB.ORG

Chondrules and Their Origins. Subject Index

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

359 1983chto.conf..359. SUBJECT INDEX Ablation spherules 21 formation 46, 50 as chondrule analogs 11, 22 internal isochrons 251, 256 composition 14, 15, 17, 18 iodine-xenon dating 256 formation 11-14, 19 matrix ages 257 grains 13, 14 metamorphic structure 47 iron 14 origin 50 magnetic properties 15 photomicrographs 47 matrix 13 potassium-argon dating 251 melting 19, 21, 22 texture 44 metals 19 ultrathin sections 47 mineralogy 19 Allende chondrules photomicrographs 13 ages 247-251,253,255-257 porphyritic 21 alteration 159 siderophiles 15-19 cavities 155-157, 159 texture 19 classification 207 thermal effects 12-14 composition 42, 93, 156, 157 volatiles 13, 14 EPMA 93 Aerodynamic spherules extraction temperature 254 as chondrule analogs 10, 12 formation 160 composition 12 iodine 254, 256, 257 formation 12 iodine-xenon 258 thermal effects 12 isochrons 254 Age dating techniques 257 isotopes 37, 39-42, 270 iodine-xenon 246, 247 mineralogy 93, 149-152, 154, 155, 158, 160 isochrons 257 mixing line 41 metamorphic processes 257 opaque inclusions 155, 159 potassium-argon 246, 247 photomicrographs 148, 150, 151, 154, 156, rubidium-strontium 246, 247 157 uranium-lead 246, 247 precursors 42 Ages of chondrules sample analysis 39 iodine-xenon 246, 247, 251-257 SEM studies 150, 151, 152, 154, 156, 157 potassium-argon 246, 247, 250, 251, 257, 258 texture 39, 41, 155 rubidium-strontium 246-250, 258 thermal history 255 uranium-lead 246-248, 258 xenon closure 254 Allegan Allende inclusions 145 bulk analysis of chondrules 48, 49 ages 255 chemistry 46 initial iodine 256· chondrule ages 251, 256, 257 iodine-xenon dating 255 chondrule oxygen isotope analysis 40 isochrons 255 chondrules 44, 47 isotope analysis 39 classification 46, 50 sample analysis 39 composition 46 texture 39 description 46 Allende matrix 145, 257 equilibration 44, 50 alteration 159 © Lunar and Planetary Institute • Provided by the NASA Astrophysics Data System 360 Chondrules and their Origins 1983chto.conf..359. composition 145, 146, 159 Barred olivine chondrules formation 145,147,159,160 ages 251 mineral composition 152, 153, 159 chondrule formation 126 photomicrographs 153 classification 95 SEM studies 152, 153 composition 95-97, 100, 113, 126, 129 Allende meteorite cooling rates 126 analysis of chondrules 38 INAA data 113 analysis of inclusions 38 lithophiles 96 bulk silicates 38 melting 125 CAI mixing line 38 microprobe data 113 chondrule formation 145 mineralogy 95, 97 chondrule intercrystalline pores 326 Na/ Al ratios 113 chondrule vesicles 322-325, 327 petrography 97 chondrule-matrix interface 152-154, 160 refractory elements 95, 97 chondrules see also Allende chondrules siderophiles 95, 96 composition 146, 159 spherules 125 electric discharge experiments 279 texture 95, 125, 126 evaporation experiments 181, 182 thermal history 126 fusion experiments 181, 182 Barwell meteorite inclusion ages 251, 255 chondrule ages 248, 250 inclusions seeAllende inclusions internal isochrons 248, 250 internal isochrons 247-251, 253, 256 potassium-argon dating 250 iodine-xenon dating 253, 256 uranium-lead dating 248 matrix see Allende matrix Beardsley meteorite melt bead composition 183 chondrule vesicles 320, 321 opaque inclusions 146, 147, 159 porosity of chondrules 319, 320 oxygen isotope analysis 38 Bishunpur petrography 146 matrix composition 165-167, 170, 171 porosity of chondrules 319 Bishunpur chondrules po~ium-argon dating 251 EPMA 93 rubidium-strontium dating 249 matrix composition 164-167, 170, 171 sample analysis 38, 184 matrix origin 170 SEM studies 147, 148, 149, 152 Bjurbole chondrules silicon isotope analysis 38 ages 249, 251, 253 spherule abundance 16 density 63, 79 uranium-lead dating 247, 248 EPMA 93 Analogs of chondrules 129 extraction temperature 254 in lunar samples 263-266 formation time 253 spherules 10, 122, 239 iodine composition 253, 254 Antarctic meteorites iodine-xenon chronometer 258 ALHA 76004 37 isochrons 254 ALHA 77015 215, 216, 217 isotopic features 29 ALHA 77278 215, 216, 217 NAA 92 ALHA 77299 213 petrology 92 Allan Hills meteorites 212, 213 trapped xenon 253, 254 Yamato 74191 93 Bjurbole meteorite age differences 257 © Lunar and Planetary Institute • Provided by the NASA Astrophysics Data System Subject Index 361 1983chto.conf..359. chondrules see Bjurbole chondrules refractory abundance 99 impact experiments 192 CO3 chondrite chondrules internal isochrons 249, 251, 253 chemistry 94 iodine-xenon dating 251, 253 EPMA 94 isotopes 73 isotopic dilution 94 potassium-argon dating 251 NAA 94 rubidium-strontium dating 249 petrography 94 Bovedy meteorite CV chondrite chondrules anorthositic inclusion 168, 169 composition 97, 99 Bremervorde meteorite lithophiles 97, 99 porosity of chondrules 319 CV chondrites silica-bearing chondrules 231 abundance of chondrules 89, 99 Brownfield meteorite alteration 146 cadmium isotopes 73 composition 89, 100, 115 Bruderheim meteorite refractory abundance 99 chondrule ages 256 CV3 chondrite chondrules internal isochrons 256 chemistry 94 iodine-xenon dating 256 EPMA 94 isotopes 73 isotopic dilution 94 C2 cbondrites NAA 94 isotopic fractionation 142 petrography 94 Murchison 223 CV3 meteorites oxygen isotopes 3 7 alteration 146 C3 chondrites opaque assemblages 146 isotopic fractionation 142 Campo del Cielo meteorite oxygen isotopes 37 FeO in inclusions 311 CAi's Cape York meteorite 160 variations 37 formation 176 mixing lines 41 isotopic closure 176 oxygen isotope composition 41 Carbonaceous chondrite chondrules CAT spheres 15 ages 251 formation 14 analysis 195-197 CI chondrites 16 bulk ratios 99 abundance of chondrules 89 chalcophiles 99 alteration 146 chemistry 94, 96, 97,208,209 composition 89 classification 90, 97, 196, 198-205, 207-209 spherule abundance 17 composition 88, 99, 100, 197-199, 201, CM chondrites 16 205-207 abundance of chondrules 89 discriminant analysis 202, 204, 205 alteration 146 EPMA 93,94 composition 89 factor analysis 201-204 CO chondrite chondrules formation 109 composition 97, 99 isotopes 94, 208 lithophiles 97, 99 isotopic anomalies 141, 142 CO chondrites isotopic dilution 94 abundance of chondrules 89, 99 matrix 109, 208 composition 89, 100, 115 metals 109 © Lunar and Planetary Institute • Provided by the NASA Astrophysics Data System 362 Chondrules and their Origins 1983chto.conf..359. mineralogy 196, 198-201, 205 iron concentration 72 multiple 208 matrix ages 257 NAA 94 petrogenetic properties 61 origin 38 potassium-argon dating 251 oxides 198-200, 204-206 rubidium-strontium dating 249 petrography 94, 96, 97,205 Chen meteorite precursors 42 chondrule ages 248 redox state 198-200, 204, 209 internal isochrons 248 siderophiles 99 uranium-lead dating 248 sorting 208 Chondrite meteorites texture 97, 196, 205 abundance of chondrules 89 Carbonaceous chondrites 5 brecciation 44-46 alteration 146, 147 classification 45, 89, 319 chondrules see Carbonaceous chondrite composition 45, 49, 50, 98 chondrules crystallinity 44-46 classification 89 equilibration 44-46,48-50 composition 89, 91 metamorphism 44-46 multiple chondrules 197 morphology 319 porosity 322, 328 porosity of chondrules 319 refractory-rich objects 91 recrystallization 44 spherule abundance 17 solidification 44 temperature of formation 4 Chondrule ages see Ages of chondrules volatiles 322 Chondrule analogs see Analogs of chondrules Chainpur chondrules Chondrule composition see Composition of ages 249,251,256,257 chondrules bulk composition 72 Chondrule formation see Formation of chalcophiles 103, 104, 110 chondrules classification 66 Chondrule origin see Origin of chondrules composition 71, 74-77, 83, 103, 104, 107, Chondrule precursors see Precursors of 112 chondrules EPMA 93 Chondrule properties see Properties of factor analysis 110 chondrules formation 110 Chondrule types see type names lithophiles 104, 110 Composition of chondrules 89, 110, 267 microcraters 266 agglutinate abundance 265 NAA 92 Al/ Ca ratio 98 petrology 92 alteration 296 physical properties 80-82 aluminum content 104 precursor material 110 Au/Ir 107 rim composition 164 Ca-Al inclusions 147, 299 siderophiles 103, 104, 110 Ca/ Al ratios 111, 112 texture 66, 92 chalcophiles 101 Chainpur meteorite chemistry 95-97, 101, 108, 114, 115, 165 cadmium isotopes 73 clinoenstatite 145, 147 chondrules see Chainpur chondrules Co enrichment 76, 77 internal isochrons 249, 251, 256 critobalite 55, 56, 240 iodine-xenon dating 256 © Lunar and Planetary Institute • Provided by the NASA Astrophysics Data System Subject Index 363 1983chto.conf..359. element abundance 61, 92, 96, 97, 101, 112, silica-bearing chondrules 231 116,271 Droplet chondrules EPMA 92,111,112 crystallization 219 enrichment 61 formation 166, 219 Eu anomalies 114 in Manych 166, 167 Fe-rich olivine 145, 147 mineral composition 167 FeO content 315 Na/Al ratios 166, 167 INAA 111,112 silicate liquids 166 in Sharps 315 texture 123 in Tieschitz 315 see also Melt droplet chondrules iron 72, 116 Dust aggregates isotopes 61, 64, 73, 114 chemistry 26 lithophiles 88, 96, 100, 101 formation 26, 35 metal 1, 6, 226, 227 isotopes 26, 29 minerals 296, 299 lead/uranium ratio 29 NAA 92 refractory elements 26 Na/Al 107 structure 26 Ni-Fe composition 76, 77 Dusty inclusions olivine 78, 83, 214, 226 chondrule analogs 122 opaque assemblages 147 chondrule formation 122-125, 127, 131, oxygen isotopes 37, 72, 243-245, 262, 269, 217 270,272,273 chondrule texture 125, 127 petrography 92, 95-97 composition 124, 126, 131 pyroxene 78,226,227 cooling rates 125-127, 129, 131, 217 rare earth elements 61, 74-77, 92, 114,271 dendrite widths 124, 125 relic minerals
Recommended publications
  • Disequilibrium Melting and Melt Migration Driven by Impacts: Implications for Rapid Planetesimal Core Formation

    Disequilibrium Melting and Melt Migration Driven by Impacts: Implications for Rapid Planetesimal Core Formation

    Available online at www.sciencedirect.com Geochimica et Cosmochimica Acta 100 (2013) 41–59 www.elsevier.com/locate/gca Disequilibrium melting and melt migration driven by impacts: Implications for rapid planetesimal core formation Andrew G. Tomkins ⇑, Roberto F. Weinberg, Bruce F. Schaefer 1, Andrew Langendam School of Geosciences, P.O. Box 28E, Monash University, Melbourne, Victoria 3800, Australia Received 20 January 2012; accepted in revised form 24 September 2012; available online 12 October 2012 Abstract The e182W ages of magmatic iron meteorites are largely within error of the oldest solar system particles, apparently requir- ing a mechanism for segregation of metals to the cores of planetesimals within 1.5 million years of initial condensation. Cur- rently favoured models involve equilibrium melting and gravitational segregation in a static, quiescent environment, which requires very high early heat production in small bodies via decay of short-lived radionuclides. However, the rapid accretion needed to do this implies a violent early accretionary history, raising the question of whether attainment of equilibrium is a valid assumption. Since our use of the Hf–W isotopic system is predicated on achievement of chemical equilibrium during core formation, our understanding of the timing of this key early solar system process is dependent on our knowledge of the seg- regation mechanism. Here, we investigate impact-related textures and microstructures in chondritic meteorites, and show that impact-generated deformation promoted separation of liquid FeNi into enlarged sulfide-depleted accumulations, and that this happened under conditions of thermochemical disequilibrium. These observations imply that similar enlarged metal accumu- lations developed as the earliest planetesimals grew by rapid collisional accretion.
  • Chondrule Sizes, We Have Compiled and Provide Commentary on Available Chondrule Dimension Literature Data

    Chondrule Sizes, We Have Compiled and Provide Commentary on Available Chondrule Dimension Literature Data

    Invited review Chondrule size and related physical properties: a compilation and evaluation of current data across all meteorite groups. Jon M. Friedricha,b,*, Michael K. Weisbergb,c,d, Denton S. Ebelb,d,e, Alison E. Biltzf, Bernadette M. Corbettf, Ivan V. Iotzovf, Wajiha S. Khanf, Matthew D. Wolmanf a Department of Chemistry, Fordham University, Bronx, NY 10458 USA b Department of Earth and Planetary Sciences, American Museum of Natural History, New York, NY 10024 USA c Department of Physical Sciences, Kingsborough College of the City University of New York, Brooklyn, NY 11235, USA d Graduate Center of the City University of New York, 365 5th Ave, New York, NY 10016 USA e Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964 USA f Fordham College at Rose Hill, Fordham University, Bronx, NY 10458 USA In press in Chemie der Erde – Geochemistry 21 August 2014 *Corresponding Author. Tel: +718 817 4446; fax: +718 817 4432. E-mail address: [email protected] 2 ABSTRACT The examination of the physical properties of chondrules has generally received less emphasis than other properties of meteorites such as their mineralogy, petrology, and chemical and isotopic compositions. Among the various physical properties of chondrules, chondrule size is especially important for the classification of chondrites into chemical groups, since each chemical group possesses a distinct size-frequency distribution of chondrules. Knowledge of the physical properties of chondrules is also vital for the development of astrophysical models for chondrule formation, and for understanding how to utilize asteroidal resources in space exploration. To examine our current knowledge of chondrule sizes, we have compiled and provide commentary on available chondrule dimension literature data.
  • Constraining the Source Regions of Lunar Meteorites Using Orbital Geochemical Data

    Constraining the Source Regions of Lunar Meteorites Using Orbital Geochemical Data

    Meteoritics & Planetary Science 50, Nr 2, 214–228 (2015) doi: 10.1111/maps.12412 Constraining the source regions of lunar meteorites using orbital geochemical data A. CALZADA-DIAZ1,2*, K. H. JOY3, I. A. CRAWFORD1,2, and T. A. NORDHEIM2,4 1Department of Earth and Planetary Sciences, Birkbeck College, London WC1E 7HX, UK 2Centre for Planetary Sciences UCL/Birkbeck, London WC1E 6BT, UK 3School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL, UK 4Mullard Space Science Laboratory, University College London, Dorking RH5 6NT, UK *Corresponding author. E-mail: [email protected] (Received 30 July 2014; revision accepted 06 November 2014) Abstract–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.
  • Petrogenesis of Acapulcoites and Lodranites: a Shock-Melting Model

    Petrogenesis of Acapulcoites and Lodranites: a Shock-Melting Model

    Geochimica et Cosmochimica Acta 71 (2007) 2383–2401 www.elsevier.com/locate/gca Petrogenesis of acapulcoites and lodranites: A shock-melting model Alan E. Rubin * Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, USA Received 31 May 2006; accepted in revised form 20 February 2007; available online 23 February 2007 Abstract Acapulcoites are modeled as having formed by shock melting CR-like carbonaceous chondrite precursors; the degree of melting of some acapulcoites was low enough to allow the preservation of 3–6 vol % relict chondrules. Shock effects in aca- pulcoites include veins of metallic Fe–Ni and troilite, polycrystalline kamacite, fine-grained metal–troilite assemblages, metal- lic Cu, and irregularly shaped troilite grains within metallic Fe–Ni. While at elevated temperatures, acapulcoites experienced appreciable reduction. Because graphite is present in some acapulcoites and lodranites, it seems likely that carbon was the principal reducing agent. Reduction is responsible for the low contents of olivine Fa (4–14 mol %) and low-Ca pyroxene Fs (3–13 mol %) in the acapulcoites, the observation that, in more than two-thirds of the acapulcoites, the Fa value is lower than the Fs value (in contrast to the case for equilibrated ordinary chondrites), the low FeO/MnO ratios in acapulcoite olivine (16–18, compared to 32–38 in equilibrated H chondrites), the relatively high modal orthopyroxene/olivine ratios (e.g., 1.7 in Monument Draw compared to 0.74 in H chondrites), and reverse zoning in some mafic silicate grains. Lodranites formed in a similar manner to acapulcoites but suffered more extensive heating, loss of plagioclase, and loss of an Fe–Ni–S melt.
  • Lost Lake by Robert Verish

    Lost Lake by Robert Verish

    Meteorite-Times Magazine Contents by Editor Like Sign Up to see what your friends like. Featured Monthly Articles Accretion Desk by Martin Horejsi Jim’s Fragments by Jim Tobin Meteorite Market Trends by Michael Blood Bob’s Findings by Robert Verish IMCA Insights by The IMCA Team Micro Visions by John Kashuba Galactic Lore by Mike Gilmer Meteorite Calendar by Anne Black Meteorite of the Month by Michael Johnson Tektite of the Month by Editor Terms Of Use Materials contained in and linked to from this website do not necessarily reflect the views or opinions of The Meteorite Exchange, Inc., nor those of any person connected therewith. In no event shall The Meteorite Exchange, Inc. be responsible for, nor liable for, exposure to any such material in any form by any person or persons, whether written, graphic, audio or otherwise, presented on this or by any other website, web page or other cyber location linked to from this website. The Meteorite Exchange, Inc. does not endorse, edit nor hold any copyright interest in any material found on any website, web page or other cyber location linked to from this website. The Meteorite Exchange, Inc. shall not be held liable for any misinformation by any author, dealer and or seller. In no event will The Meteorite Exchange, Inc. be liable for any damages, including any loss of profits, lost savings, or any other commercial damage, including but not limited to special, consequential, or other damages arising out of this service. © Copyright 2002–2010 The Meteorite Exchange, Inc. All rights reserved. No reproduction of copyrighted material is allowed by any means without prior written permission of the copyright owner.
  • The Mineralogical Magazine Journal

    The Mineralogical Magazine Journal

    THE MINERALOGICAL MAGAZINE AND JOURNAL OF THE MINERALOGICAL SOCIETY. 1~o. 40. OCTOBER 1889. Vol. VIII. On the Meteorites which have been found iu the Desert of Atacama and its neighbourhood. By L. FLETCHER, M.A., F.R.S., Keeper of Minerals in the British Museum. (With a Map of the District, Plate X.) [Read March 12th and May 7th, ]889.J 1. THE immediate object of the present paper is to place on record J- the history and characters of several Atacama meteorites of which no description has yet been published; but incidentally it is con- venient at the same time to consider the relationship of these masses to others from the same region, which either have been already described, or at least are stated to be preserved in one or more of the known Meteo. rite-Collections. 2. The term " Desert of Atacama " is generally applied to that part of western South America which lies between the towns of Copiapo and Cobija, about 330 miles distant from each other, and which extends island as far as the Indian hamlet of Antofagasta, about 180 miles from 224 L. FLETCHER ON THE METEORITES OF ATACAMA. the coast. The Atacama meteorites preserved in the Collections have been found at several places widely separated throughout the Desert. 3. A critical examination of the descriptive literature, and a compari- son of the manuscript and printed meteorite-lists, which have been placed at my service, lead to the conclusion that all the meteoritic frag- ments from Atacama now preserved in the known Collections belong to one or other of at most thirteen meteorites, which, for reasons given below, are referred to in this paper under the following names :-- 1.
  • The Weston Meteorite (1807) – Impact Sites in Fairfield County, Connecticut

    The Weston Meteorite (1807) – Impact Sites in Fairfield County, Connecticut

    Lunar and Planetary Science XXXIX (2008) 2163.pdf THE WESTON METEORITE (1807) – IMPACT SITES IN FAIRFIELD COUNTY, CONNECTICUT. D. T. King, Jr.1 and L. W. Petruny2, 1Geology Office, Auburn University, Auburn, AL 36849 [[email protected]], 2Astra-Terra Research, Auburn, AL 36831-3323 [[email protected]]. Introduction: Ernst Chladni’s 1794 book laying within the town of Weston as constituted in 1807, out the arguments that meteorites came from outer hence the name). This primary site is located about space, not volcanoes or storm clouds, marks the theo- 500 m north of a road intersection at the historic 1715 retical origin of the modern science of meteoritics. Burton House. The largest fragment (~ 16 kg) was Criticisms of Chladni’s assertions began to fall away excavated from a shallow (~ 60 cm) pit at this site. At after the witnessed and well-documented meteoritic that time, the property owner was William Prince [3]. falls at Wold Cottage, Yorkshire, England (1795), and This area is today in a heavily wooded, upscale hous- l’Aigle, Normandy, France (1803). On December 14, ing subdivision with a vigilant neighborhood watch. 1807, a widely witnessed meteorite fall over Weston, Fairfield County, Connecticut, brought the new sci- ence of meteoritics to the United States. Recovered, documented, and chemically analyzed by Yale Univer- sity professors Benjamin Silliman and James Kingsley, the Weston meteorite became the first such scientifi- cally verified meteorite fall in the New World. Frag- ments collected by Silliman and Kingsley were the first catalogued objects in the Yale meteorite collec- tion, the oldest such collection in the United States.
  • Pyrrhotite and Pentlandite in Ll3 to Ll6 Chondrites: Determining Compositional and Microstructural Indicators of Formation Conditions

    Pyrrhotite and Pentlandite in Ll3 to Ll6 Chondrites: Determining Compositional and Microstructural Indicators of Formation Conditions

    49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083) 2621.pdf PYRRHOTITE AND PENTLANDITE IN LL3 TO LL6 CHONDRITES: DETERMINING COMPOSITIONAL AND MICROSTRUCTURAL INDICATORS OF FORMATION CONDITIONS. D. L. Schrader1 and T. J. Zega2, 1Center for Meteorite Studies, School of Earth and Space Exploration, Arizona State Uni- versity, Tempe, AZ 85287-1404, USA ([email protected]), 2Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721, USA ([email protected]). Introduction: The compositions, textures, and electron microscope (FIB-SEM) at UAz and the JEOL crystal structures of sulfides can be used to constrain JXA-8530F Hyperprobe EPMA at Arizona State Uni- oxygen fugacity, aqueous, thermal, and cooling history versity (ASU). The FIB-SEM was also used to extract [e.g., 1–5]. The most abundant sulfides in extraterres- ~10 × 5 µm sections transecting the pyrrhotite- trial samples are the pyrrhotite group [(Fe,Ni,Co,Cr)1– pentlandite interfaces within sulfide grains from each xS], which can occur with pentlandite [(Fe,Ni,Co,Cr)9– meteorite, which were thinned to electron transparency xS8]. The pyrrhotite group sulfides are largely non- (<100 nm) using methods of [14]. FIB sections were stoichiometric and have a range of compositions then analyzed using the 200 keV aberration-corrected (0<x<0.125) and distinct crystal structures (polytypes). Hitachi HF5000 scanning transmission electron micro- The stoichiometric end members are 2C (troilite; FeS, scope (TEM) at UAz. hexagonal) and 4C (Fe7S8, monoclinic) pyrrhotite. There are also non-integral NC-pyrrhotites with inter- mediate compositions with 0<x<0.125 (all hexagonal); which includes the integral 5C (Fe9S10), 6C (Fe11S12), and 11C (Fe10S11) pyrrhotites [e.g., 6–8].
  • Meteorite Wis91600: a New Sample Related to a D- Or T-Type Asteroid

    Meteorite Wis91600: a New Sample Related to a D- Or T-Type Asteroid

    Lunar and Planetary Science XXXVI (2005) 1564.pdf METEORITE WIS91600: A NEW SAMPLE RELATED TO A D- OR T-TYPE ASTEROID. T. Hiroi1, E. Tonui2, C. M. Pieters1, M. E. Zolensky3, Y. Ueda4, M. Miyamoto4, and S. Sasaki4,5, 1Dept. of Geological Sci., Brown University, Providence, RI 02912 ([email protected]), 2Dept. of Earth and Space Sci., University of California Los Angeles, 595 Charles Young Drive East, Los Angeles, CA 90095-1567, 3SN2, NASA Johnson Space Center, Houston, TX 77058, 4Dept. of Earth and Planetary Sci., University of Tokyo, Hongo, Tokyo 113- 0033, Japan, 5National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan. Introduction: Since the Tagish Lake meteorite On the other hand, WIS91600 shows a very similar fell in January 2000, the assumed one-of-the-kind 3-µm feature to a T/D-type asteroid 308 Polyxo, if one meteorite has become the hottest issue among a peculiar data point of Polyxo at 3.5 µm can be disre- diversity of scientists. Meanwhile, as the physical garded and its VNIR spectrum shows a near-perfect origin of the meteorite in our solar system, D or T match with the average T/D asteroid spectrum as asteroids have been suggested by Hiroi et al. [1, 2] shown in Fig. 1. The VNIR spectrum, especially its based on comparison of their visible-near-infrared continuum slope, is believed to be strongly affected by (VNIR) reflectance spectra. While it is probably still the amount of carbon and other opaque phase, while true that the Tagish Lake meteorite is possibly the first the 3-µm band feature shows characteristics of the recovered sample from a D or T asteroid as a meteorite component hydrous minerals.
  • Chelyabinsk Airburst, Damage Assessment, Meteorite Recovery and Characterization

    Chelyabinsk Airburst, Damage Assessment, Meteorite Recovery and Characterization

    O. P. Popova, et al., Chelyabinsk Airburst, Damage Assessment, Meteorite Recovery and Characterization. Science 342 (2013). Chelyabinsk Airburst, Damage Assessment, Meteorite Recovery, and Characterization Olga P. Popova1, Peter Jenniskens2,3,*, Vacheslav Emel'yanenko4, Anna Kartashova4, Eugeny Biryukov5, Sergey Khaibrakhmanov6, Valery Shuvalov1, Yurij Rybnov1, Alexandr Dudorov6, Victor I. Grokhovsky7, Dmitry D. Badyukov8, Qing-Zhu Yin9, Peter S. Gural2, Jim Albers2, Mikael Granvik10, Läslo G. Evers11,12, Jacob Kuiper11, Vladimir Kharlamov1, Andrey Solovyov13, Yuri S. Rusakov14, Stanislav Korotkiy15, Ilya Serdyuk16, Alexander V. Korochantsev8, Michail Yu. Larionov7, Dmitry Glazachev1, Alexander E. Mayer6, Galen Gisler17, Sergei V. Gladkovsky18, Josh Wimpenny9, Matthew E. Sanborn9, Akane Yamakawa9, Kenneth L. Verosub9, Douglas J. Rowland19, Sarah Roeske9, Nicholas W. Botto9, Jon M. Friedrich20,21, Michael E. Zolensky22, Loan Le23,22, Daniel Ross23,22, Karen Ziegler24, Tomoki Nakamura25, Insu Ahn25, Jong Ik Lee26, Qin Zhou27, 28, Xian-Hua Li28, Qiu-Li Li28, Yu Liu28, Guo-Qiang Tang28, Takahiro Hiroi29, Derek Sears3, Ilya A. Weinstein7, Alexander S. Vokhmintsev7, Alexei V. Ishchenko7, Phillipe Schmitt-Kopplin30,31, Norbert Hertkorn30, Keisuke Nagao32, Makiko K. Haba32, Mutsumi Komatsu33, and Takashi Mikouchi34 (The Chelyabinsk Airburst Consortium). 1Institute for Dynamics of Geospheres of the Russian Academy of Sciences, Leninsky Prospect 38, Building 1, Moscow, 119334, Russia. 2SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043, USA. 3NASA Ames Research Center, Moffett Field, Mail Stop 245-1, CA 94035, USA. 4Institute of Astronomy of the Russian Academy of Sciences, Pyatnitskaya 48, Moscow, 119017, Russia. 5Department of Theoretical Mechanics, South Ural State University, Lenin Avenue 76, Chelyabinsk, 454080, Russia. 6Chelyabinsk State University, Bratyev Kashirinyh Street 129, Chelyabinsk, 454001, Russia.
  • N Arieuican%Mllsellm

    N Arieuican%Mllsellm

    n ARieuican%Mllsellm PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK 24, N.Y. NUMBER 2I63 DECEMBER I9, I963 The Pallasites BY BRIAN MASON' INTRODUCTION The pallasites are a comparatively rare type of meteorite, but are remarkable in several respects. Historically, it was a pallasite for which an extraterrestrial origin was first postulated because of its unique compositional and structural features. The Krasnoyarsk pallasite was discovered in 1749 about 150 miles south of Krasnoyarsk, and seen by P. S. Pallas in 1772, who recognized these unique features and arranged for its removal to the Academy of Sciences in St. Petersburg. Chladni (1794) examined it and concluded it must have come from beyond the earth, at a time when the scientific community did not accept the reality of stones falling from the sky. Compositionally, the combination of olivine and nickel-iron in subequal amounts clearly distinguishes the pallasites from all other groups of meteorites, and the remarkable juxtaposition of a comparatively light silicate mineral and heavy metal poses a nice problem of origin. Several theories of the internal structure of the earth have postulated the presence of a pallasitic layer to account for the geophysical data. No apology is therefore required for an attempt to provide a comprehensive account of this remarkable group of meteorites. Some 40 pallasites are known, of which only two, Marjalahti and Zaisho, were seen to fall (table 1). Of these, some may be portions of a single meteorite. It has been suggested that the pallasite found in Indian mounds at Anderson, Ohio, may be fragments of the Brenham meteorite, I Chairman, Department of Mineralogy, the American Museum of Natural History.
  • The Origin and History of Ordinary Chondrites: a Study by Iron Isotope Measurements of Metal Grains from Ordinary Chondrites

    The Origin and History of Ordinary Chondrites: a Study by Iron Isotope Measurements of Metal Grains from Ordinary Chondrites

    Available online at www.sciencedirect.com Geochimica et Cosmochimica Acta 72 (2008) 4440–4456 www.elsevier.com/locate/gca The origin and history of ordinary chondrites: A study by iron isotope measurements of metal grains from ordinary chondrites K.J. Theis a,*, R. Burgess a, I.C. Lyon a, D.W. Sears b a School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK b Arkansas Center for Space and Planetary Science and Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA Received 15 August 2007; accepted in revised form 30 May 2008; available online 14 June 2008 Abstract Chondrules and chondrites provide unique insights into early solar system origin and history, and iron plays a critical role in defining the properties of these objects. In order to understand the processes that formed chondrules and chondrites, and introduced isotopic fractionation of iron isotopes, we measured stable iron isotope ratios 56Fe/54Fe and 57Fe/54Fe in metal grains separated from 18 ordinary chondrites, of classes H, L and LL, ranging from petrographic types 3–6 using multi-col- lector inductively coupled plasma mass spectrometry. The d56Fe values range from À0.06 ± 0.01 to +0.30 ± 0.04& and d57Fe values are À0.09 ± 0.02 to +0.55 ± 0.05& (relative to IRMM-014 iron isotope standard). Where comparisons are possible, these data are in good agreement with published data. We found no systematic difference between falls and finds, suggesting that terrestrial weathering effects are not important in controlling the isotopic fractionations in our samples.