DOCSLIB.ORG

The Jurassic Meteorite Flux: a Record from Extraterrestrial Chrome-Spinels

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Jurassic Meteorite Flux: a Record from Extraterrestrial Chrome-Spinels THE JURASSIC METEORITE FLUX: A RECORD FROM EXTRATERRESTRIAL CHROME-SPINELS A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI‘I AT MĀNOA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN EARTH & PLANETARY SCIENCE December 2020 By Caroline E. Caplan Dissertation Committee: Gary R. Huss, Chairperson Kazu Nagashima Hope A. Ishii Greg Ravizza Schelte J. Bus Keywords: chrome-spinel, chromite, Jurassic, meteorites, oxygen isotopes To my ten-year-old self who wanted this for so long, you did it! ii ACKNOWLEDGMENTS Graduate school will forever be one of my favorite times in life. Through its ups and downs I have become more knowledgeable, confident, and have found true joy in science. I am especially thankful to my advisor, Gary Huss, without whom none of this work would have been possible. He has guided me through graduate school to grow as researcher, including giving me the opportunities to explore new avenues of my work. I would also like to thank my committee members: Kazu Nagashima for always answering my questions with patience, Hope Ishii for work and life guidance, Greg Ravizza for his excitement and new perspectives, and Bobby Bus for help with statistics and his endless curiosity. Thanks to Birger Schmitz who allowed me to work on such a special project and for the incredible opportunity to travel to Sweden, Russia, and Italy to obtain a better understanding of my samples and the area of work. I would also like to thank the HIGP and ERTH (GG) departments for fostering a productive and friendly environment. The faculty truly helped me learn and improve as a researcher and person, including Linda Martel, Julia Hammer, Eric Hellebrand, Ryan Ogliore, Jeff Taylor, Paul Lucey, Jeff Gillis-Davis, Patty Fryer, John Bradley, and Kenta Ohtaki. Graduate school was so enjoyable due to the friendships of other students (past and present), including Myriam Telus, Christine Jilly, Sarah Crites, Katie Robinson, Myriam Lemelin, Estelle Bonny, Erin Fitch, Elizabeth Shields, Laura Corley, Melissa Adams, Macey Sandford, Lingzhi Sun, Chiara Ferrari- Wong, Abbey Flom, Emily Costello, Colin Ferguson, Warren McKenzie, and Hannah Shelton. Special thanks to the graduate students who helped with defense and dissertation prep: Diamond Tachera, Brytne Okuhata, and Trista McKenzie. Finally, I would like to thank my family. Thank you to my parents, for letting me live my dreams and for giving me every opportunity to succeed. Thank you to my grandparents for their support, and especially my grandfather, Calhoun Howard, for being a scientific inspiration throughout my life. Thanks to my sister, Anna, for always being my biggest supporter and reminding me that I am intelligent and worthy of great things. And thank you to my husband, Andrew, for always being by my side throughout the hardest and happiest parts of graduate school. iii ABSTRACT This dissertation focuses on the classification of extraterrestrial chrome-spinels to determine meteorite types and fluxes during the Jurassic time period and the techniques needed to achieve such classifications. We know the relative abundances of meteorite types falling on Earth today, but we do not know what fell in the distant past. Abundances of the past are unknown because meteorites tend to only survive on Earth’s surface for a few tens of thousands of years due to the weathering environment of the Earth. Fortunately, chrome-spinels from disaggregated meteorites and micrometeorites can be preserved in limestone and retain their characteristic compositions. In many instances, the parent meteorite type of each grain can be determined by comparing their chemical compositions and oxygen isotope abundances to those of chrome-spinels from modern day meteorites. The goal of this dissertation is to classify chrome-spinel grains from the Jurassic period, determine the relative abundances of parent meteorite types, and compare these abundances to those of other time periods. This was achieved by ensuring we had a well-characterized database of chrome-spinel compositions from modern meteorites in order to reliably classify each remnant chrome-spinel. We also had to confirm that our chemistry and oxygen-isotope measurements of the Jurassic chrome-spinels were reliable. This was determined, in part, by taking new measurements of chrome-spinels from modern meteorites using the same electron and ion microprobes used for the remnant grains. It was also necessary to understand instrumental artifacts that may affect oxygen isotope abundances during ion probe measurements, such as the crystal orientation of chrome-spinel. We confidently classified the remnant chrome-spinels of the Jurassic using the compiled database, and compared the meteorite abundances to other time periods. However, it was difficult to determine the subgroup for a few of the ordinary-chondrite-like grains using chemistry and isotopes alone. In this event, (scanning) transmission electron microscope techniques were implemented to study the silicate inclusions within these chrome-spinels to help determine their parent meteorite type. Overall, this work supports the use of chemistry, oxygen isotopes, and inclusions to classify remnant chrome-spinels and demonstrates that meteorite populations from the past are different than today. iv TABLE OF CONTENTS ACKNOWLEDGMENTS ........................................................................................................... iii ABSTRACT .................................................................................................................................. iv LIST OF TABLES ...................................................................................................................... vii LIST OF FIGURES ..................................................................................................................... ix CHAPTER1. INTRODUCTION ................................................................................................. 1 1.1 Background ................................................................................................................................................... 2 1.2 Jurassic Grains ............................................................................................................................................. 3 1.3 Classifications ............................................................................................................................................... 4 1.4 Technical Advancements ......................................................................................................................... 6 1.5 Dissertation Outline ................................................................................................................................... 7 CHAPTER 2. REMNANT EXTRATERRESTRIAL CHROME-SPINELS REVEAL METEORITE ABUNDANCES OF THE JURASSIC............................................................... 8 2.1 Abstract........................................................................................................................................................... 8 2.2 Introduction .................................................................................................................................................. 9 2.3 Methods ....................................................................................................................................................... 10 2.3.1 Collection and Preparation ............................................................................................................................ 10 2.3.2 Analysis .................................................................................................................................................................. 12 2.3.3 Classification Schemes ..................................................................................................................................... 24 2.4 Results .......................................................................................................................................................... 29 2.4.1 Chemical Compositions ................................................................................................................................... 29 2.4.2 Oxygen Isotopic Compositions..................................................................................................................... 31 2.4.3 Classification ........................................................................................................................................................ 34 2.5 Discussion ................................................................................................................................................... 41 2.5.1 Classification Limitations ............................................................................................................................... 41 2.5.2 Jurassic Grains ..................................................................................................................................................... 50 2.5.3 Time period comparisons .............................................................................................................................. 51 2.5.4 Jurassic Relative Abundances....................................................................................................................... 62 2.6 Conclusions ...............................................................................................................................................
Load more

Recommended publications
  • New Major and Trace Element Data from Acapulcoite-Lodranite Clan
    52nd Lunar and Planetary Science Conference 2021 (LPI Contrib. No. 2548) 1307.pdf New Major and Trace Element Data from Acapulcoite-Lodranite Clan Meteorites: Evidence for Melt-Rock Reaction Events and Early Collisional Fragmentation of the Parent Body Michael P. Lucas1, Nick Dygert1, Nathaniel R. Miller2, and Harry Y. McSween1, 1Department of Earth & Planetary Sciences, University of Tennessee, Knoxville, [email protected], 2Department of Geological Sciences, Univer- sity of Texas at Austin. Introduction: New major and trace element data illumi- patterns exhibit negative Eu anomalies. REE patterns are nate the magmatic and thermal evolution of the acapul- generally consistent among the three groups, however coite-lodranite parent body (ALPB). We observe major comparison of calculated equilibrium melts for acapulco- and trace element disequilibrium in the acapulcoite and ite and transitional cpx and opx demonstrates disequilib- transitional groups that provide evidence for melt infil- rium partitioning in those samples, especially for light- tration and melt-rock reaction processes. In lodranites, REEs in cpx. In contrast, lodranites are in apparent trace which represent sources of the infiltrating melts, we ob- element equilibrium (Fig 1b). They are depleted in serve rapid cooling from high temperatures (hereafter REE+Y relative to acapulcoite-transitional samples in temps), consistent with collisional fragmentation of the cpx (Fig. 1a), and display consistent REE abundances parent body during differentiation. except NWA 5488, which
    [Show full text]
  • Hf–W Thermochronometry: II. Accretion and Thermal History of the Acapulcoite–Lodranite Parent Body
    Earth and Planetary Science Letters 284 (2009) 168–178 Contents lists available at ScienceDirect Earth and Planetary Science Letters journal homepage: www.elsevier.com/locate/epsl Hf–W thermochronometry: II. Accretion and thermal history of the acapulcoite–lodranite parent body Mathieu Touboul a,⁎, Thorsten Kleine a, Bernard Bourdon a, James A. Van Orman b, Colin Maden a, Jutta Zipfel c a Institute of Isotope Geochemistry and Mineral Resources, ETH Zurich, Clausiusstrasse 25, 8092 Zurich, Switzerland b Department of Geological Sciences, Case Western Reserve University, Cleveland, OH, USA c Forschungsinstitut und Naturmuseum Senckenberg, Frankfurt am Main, Germany article info abstract Article history: Acapulcoites and lodranites are highly metamorphosed to partially molten meteorites with mineral and bulk Received 11 November 2008 compositions similar to those of ordinary chondrites. These properties place the acapulcoites and lodranites Received in revised form 8 April 2009 between the unmelted chondrites and the differentiated meteorites and as such acapulcoites–lodranites are Accepted 9 April 2009 of special interest for understanding the initial stages of asteroid differentiation as well as the role of 26Al Available online 3 June 2009 heating in the thermal history of asteroids. To constrain the accretion timescale and thermal history of the Editor: R.W. Carlson acapulcoite–lodranite parent body, and to compare these results to the thermal histories of other meteorite parent bodies, the Hf–W system was applied to several acapulcoites and lodranites. Acapulcoites Dhofar 125 Keywords: – Δ chronology and NWA 2775 and lodranite NWA 2627 have indistinguishable Hf W ages of tCAI =5.2±0.9 Ma and Δ isochron tCAI =5.7±1.0 Ma, corresponding to absolute ages of 4563.1±0.8 Ma and 4562.6±0.9 Ma.
    [Show full text]
  • Linking the Chassigny Meteorite and the Martian Surface Rock Backstay: Insights Into Igneous Crustal Differentiation Processes on Mars
    Meteoritics & Planetary Science 44, Nr 6, 853–869 (2009) Abstract available online at http://meteoritics.org Linking the Chassigny meteorite and the Martian surface rock Backstay: Insights into igneous crustal differentiation processes on Mars Hanna NEKVASIL*, Francis M. MCCUBBIN, Andrea HARRINGTON, Stephen ELARDO, and Donald H. LINDSLEY Department of Geosciences, Stony Brook University, Stony Brook, New York 11794–2100, USA *Corresponding author. E-mail: [email protected] (Received 05 August 2008; revision accepted 18 March 2009) Abstract–In order to use igneous surface lithologies to constrain Martian mantle characteristics, secondary processes that lead to compositional modification of primary mantle melts must be considered. Crystal fractionation of a mantle-derived magma at the base of the crust followed by separation and ascent of residual liquids to the surface is common in continental hotspot regions on Earth. The possibility that this process also takes place on Mars was investigated by experimentally determining whether a surface rock, specifically the hawaiite Backstay analyzed by the MER Spirit could produce a known cumulate lithology with a deep origin (namely the assemblages of the Chassigny meteorite) if trapped at the base of the Martian crust. Both the major cumulus and melt inclusion mineral assemblages of the Chassigny meteorite were produced experimentally by a liquid of Backstay composition within the pressure range 9.3 to 6.8 kbar with bulk water contents between 1.5 and 2.6 wt%. Experiments at 4.3 and 2.8 kbar did not produce the requisite assemblages. This agreement suggests that just as on Earth, Martian mantle-derived melts may rise to the surface or remain trapped at the base of the crust, fractionate, and lose their residual liquids.
    [Show full text]
  • 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.
    [Show full text]
  • Olivine-Dominated Asteroids and Meteorites: Distinguishing Nebular and Igneous Histories
    Meteoritics & Planetary Science 42, Nr 2, 155–170 (2007) Abstract available online at http://meteoritics.org Olivine-dominated asteroids and meteorites: Distinguishing nebular and igneous histories Jessica M. SUNSHINE1*, Schelte J. BUS2, Catherine M. CORRIGAN3, Timothy J. MCCOY4, and Thomas H. BURBINE5 1Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA 2University of Hawai‘i, Institute for Astronomy, Hilo, Hawai‘i 96720, USA 3Johns Hopkins University, Applied Physics Laboratory, Laurel, Maryland 20723–6099, USA 4Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560–0119, USA 5Department of Astronomy, Mount Holyoke College, South Hadley, Massachusetts 01075, USA *Corresponding author. E-mail: [email protected] (Received 14 February 2006; revision accepted 19 November 2006) Abstract–Melting models indicate that the composition and abundance of olivine systematically co-vary and are therefore excellent petrologic indicators. However, heliocentric distance, and thus surface temperature, has a significant effect on the spectra of olivine-rich asteroids. We show that composition and temperature complexly interact spectrally, and must be simultaneously taken into account in order to infer olivine composition accurately. We find that most (7/9) of the olivine- dominated asteroids are magnesian and thus likely sampled mantles differentiated from ordinary chondrite sources (e.g., pallasites). However, two other olivine-rich asteroids (289 Nenetta and 246 Asporina) are found to be more ferroan. Melting models show that partial melting cannot produce olivine-rich residues that are more ferroan than the chondrite precursor from which they formed. Thus, even moderately ferroan olivine must have non-ordinary chondrite origins, and therefore likely originate from oxidized R chondrites or melts thereof, which reflect variations in nebular composition within the asteroid belt.
    [Show full text]
  • 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.
    [Show full text]
  • Problems of Planetology, Cosmochemistry and Meteoritica Alexeev V.A., Ustinova G.K
    Problems of Planetology… Problems of Planetology, Cosmochemistry and Meteoritica Alexeev V.A., Ustinova G.K. Meteoritic evidence radionuclides before the meteorite fall onto the Earth. The investigation of radionuclides with different T1/2 in the on peculiarities of the contemporary solar cycles chondrites with various dates of fall, which have various V.I. Vernadsky Institute of Geochemistry and Analytical Chemistry extension and inclination of orbits, provides us with such RAS, Moscow long sequences of homogeneous data on variation of the Abstract. The meteorite data on monitoring of the intensity and GCR intensity and integral gradients (E >100 MeV) in the gradient of the galactic cosmic rays (GCR) in the heliosphere 3D heliosphere [Lavrukhina,Ustinova,1990]. The long during 5 solar cycles are used for the correlative analysis with the sequences of homogeneous data on the GCR intensity in variations of the solar activity (SA), strength of the interplanetary magnetic field (IMF) and tilt angle of the heliospheric current the stratosphere [Stozhkov et al., 2009] are used for sheet (HCS). The dependence of the GCR modulation depth in the evaluation of the gradients. Nowadays, such a sequence of 11-year solar cycles on the character of the solar magnetic field certain homogeneous data on the GCR intensity and (SMF) inversions in the heliosphere at the change of the 22-year gradients in the inner heliosphere covers ~5 solar cycles magnetic cycles is revealed. (see figure 1) [Alexeev, Ustinova, 2006]. This smoothes, Key words: galactic cosmic rays, solar modulation, solar cycles, to a considerable extent, both the temporal and spatial inversion of magnetic field, solar dynamo, climate.
    [Show full text]
  • 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.
    [Show full text]
  • 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,
    [Show full text]
  • Color Study of Asteroid Families Within the MOVIS Catalog David Morate1,2, Javier Licandro1,2, Marcel Popescu1,2,3, and Julia De León1,2
    A&A 617, A72 (2018) Astronomy https://doi.org/10.1051/0004-6361/201832780 & © ESO 2018 Astrophysics Color study of asteroid families within the MOVIS catalog David Morate1,2, Javier Licandro1,2, Marcel Popescu1,2,3, and Julia de León1,2 1 Instituto de Astrofísica de Canarias (IAC), C/Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain e-mail: [email protected] 2 Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain 3 Astronomical Institute of the Romanian Academy, 5 Cu¸titulde Argint, 040557 Bucharest, Romania Received 6 February 2018 / Accepted 13 March 2018 ABSTRACT The aim of this work is to study the compositional diversity of asteroid families based on their near-infrared colors, using the data within the MOVIS catalog. As of 2017, this catalog presents data for 53 436 asteroids observed in at least two near-infrared filters (Y, J, H, or Ks). Among these asteroids, we find information for 6299 belonging to collisional families with both Y J and J Ks colors defined. The work presented here complements the data from SDSS and NEOWISE, and allows a detailed description− of− the overall composition of asteroid families. We derived a near-infrared parameter, the ML∗, that allows us to distinguish between four generic compositions: two different primitive groups (P1 and P2), a rocky population, and basaltic asteroids. We conducted statistical tests comparing the families in the MOVIS catalog with the theoretical distributions derived from our ML∗ in order to classify them according to the above-mentioned groups. We also studied the background populations in order to check how similar they are to their associated families.
    [Show full text]
  • Did a Comet Deliver the Chelyabinsk Meteorite?
    EPSC Abstracts Vol. 11, EPSC2017-2, 2017 European Planetary Science Congress 2017 EEuropeaPn PlanetarSy Science CCongress c Author(s) 2017 Did a Comet Deliver the Chelyabinsk Meteorite? O.G. Gladysheva Ioffe Physical-Technical Institute of RAS, St.Petersburg, Russa, ([email protected] / Fax: +7(812)2971017) Abstract source of the appearance of such a gradient can be only the direct bombardment of the crystal by SCR An explosion of a celestial body occurred on the iron nuclei with energy of 1-100 MeV [6]. fifteenth of February, 2013, near Chelyabinsk Interacting with the surface of the meteorite, protons (Russia). The explosive energy was determined as and helium GCR nuclei form isotopes, some ~500 kt of TNT, on the basis of which the mass of radioactive, which are allocated to a specific location the bolide was estimated at ~107 kg, and its diameter by depth in the body of the meteorite. A measurement of the composition of radionuclides at ~19 m [1]. Fragments of the meteorite, such as 22 26 54 60 LL5/S4-WO type ordinary chondrite [2] with a total Na, Al, Mn and Co in 12 fragments of the mass only of ~2·103 kg, fell to the earth’s surface [3]. Chelyabinsk meteorite, and a comparison of the Here, we will demonstrate that the deficit of the results with model calculations of the formation of celestial body’s mass can be explained by the arrival these isotopes in meteorites according to depth, of the Chelyabinsk chondrite on Earth by a showed that 4 fragments of the meteorite were significantly more massive but fragile ice-bearing located in a layer 30 cm deep, 3 fragments at a depth celestial body.
    [Show full text]
  • 3D Ichnofabrics in Shale Gas Reservoirs
    3D ICHNOFABRICS IN SHALE GAS RESERVOIRS By @ Małgorzata Bednarz A thesis submitted to the School of Graduate Studies in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Earth Sciences Memorial University of Newfoundland October 2014 St. John’s Newfoundland Abstract This PhD research project uses three-dimensional ichnology to address issues of shale- hydrocarbon reservoir quality and provides new tools for ichnofabric analysis and ichnotaxonomic considerations. The study presents deterministic (devoid of conceptual simplifications and interpretations) visualizations of the true spatial geometry of the aff. Chondrites, aff. Phycosiphon and Nereites trace fossils and models the three-dimensional arrangements of the burrow components. The volumetric reconstructions of the real geometry of the trace fossils allowed for their comparison with the previously established visualizations and for reconsideration of pre-existing palaeobiological models. To date three-dimensional understanding of the majority of trace fossils is presented as conceptual drawings available only on two-dimensional media. Such reconstructions are extrapolated mainly from observations of cross sections of burrows from core and outcrop and do not allow for realistic volumetric quantification and full elucidation of complex trace fossil geometries in the context of the host-sediment. The new methodology based on precise serial grinding and volume-visualization presented herein addresses this gap in ichnological knowledge, and is especially useful for examination of the ichnofabric contained in mudstones and muddy siltstones where the application or non-destructive methods of 3D reconstructions as CT scanning or MRI is impossible owing to the rock petrological characteristics (e.g., low burrow-matrix density difference).
    [Show full text]