Martian Xenon Components in Basaltic Shergottite Meteorites
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Implications for the Solar Protoplanetary Disk from Short-Lived Radionuclides
From Dust to Planetesimals: Implications for the Solar Protoplanetary Disk from Short-lived Radionuclides M. Wadhwa The Field Museum Y. Amelin Geological Survey of Canada A. M. Davis The University of Chicago G. W. Lugmair University of California at San Diego B. Meyer Clemson University M. Gounelle Muséum National d’Histoire Naturelle S. J. Desch Arizona State University ________________________________________________________________ Since the publication of the Protostars and Planets IV volume in 2000, there have been signifi- cant advances in our understanding of the potential sources and distributions of short-lived, now ex- tinct, radionuclides in the early Solar System. Based on recent data, there is definitive evidence for the presence of two new short-lived radionuclides (10Be and 36Cl) and a compelling case can be made for revising the estimates of the initial Solar System abundances of several others (e.g., 26Al, 60Fe and 182Hf). The presence of 10Be, which is produced only by spallation reactions, is either the result of irradiation within the solar nebula (a process that possibly also resulted in the production of some of the other short-lived radionuclides) or of trapping of Galactic Cosmic Rays in the protosolar mo- lecular cloud. On the other hand, the latest estimates for the initial Solar System abundance of 60Fe, which is produced only by stellar nucleosynthesis, indicate that this short-lived radionuclide (and possibly significant proportions of others with mean lives ≤10 My) was injected into the solar nebula from a nearby stellar source. As such, at least two distinct sources (e.g., irradiation and stellar nu- cleosynthesis) are required to account for the abundances of the short-lived radionuclides estimated to be present in the early Solar System. -
Shergotty Basalt, 5 Kg Seen to Fall Introduction the Shergotty Achondrite Fell on August 25, 1865 at 9:00 A.M
V. Shergotty basalt, 5 kg seen to fall Introduction The Shergotty achondrite fell on August 25, 1865 at 9:00 a.m. near a town called Shergahti in Bihar State, India after detonations were heard (Graham et al. 1985). Duke (1968) refers to several stones with fusion crusts, but this has not been confirmed. The main mass is at the Museum of the Geological Survey in Calcutta, India (figure V-1). In 1984, an international consortium was organized by J. C. Laul to study ~30 grams of Shergotty in detail (Laul 1986a, b). Shergottites (Shergotty, Zagami, EETA79001B, QUE94201, Los Angeles) are texturally and mineralogically similar to terrestrial diabases (although all of the plagioclase has been shocked to maskelynite), but quite distinct petrologically and chemically from the rest of the basaltic achondrites (Stolper et al. 1979). Stolper and McSween (1979) and others have noted that Shergotty crystallized under relatively oxidizing conditions. Figure V-1. Photograph of Shergotty meteorite The Shergotty meteorite has been severely shocked and showing fusion crust and borken surfaces. Two saw is considered the “type locality” for maskelynite (dense cuts are visible. Sample is about 25 cm across. Photo plagioclase glass). In fact, it has proven to be very kindly provided by Prof. N. Bhandari, Director, Physical Research Laboratory, Ahmedabad, India. difficult to date the original crystallization event of Figure V-2. Photograph of slab of Shergotty meteorite showing basaltic texture and alignment of pyroxene crystals. Note the inclusion of black glass in the center of this slab. This is figure 1 in Duke (1968). Photo courtesy of U. -
Physical Properties of Martian Meteorites: Porosity and Density Measurements
Meteoritics & Planetary Science 42, Nr 12, 2043–2054 (2007) Abstract available online at http://meteoritics.org Physical properties of Martian meteorites: Porosity and density measurements Ian M. COULSON1, 2*, Martin BEECH3, and Wenshuang NIE3 1Solid Earth Studies Laboratory (SESL), Department of Geology, University of Regina, Regina, Saskatchewan S4S 0A2, Canada 2Institut für Geowissenschaften, Universität Tübingen, 72074 Tübingen, Germany 3Campion College, University of Regina, Regina, Saskatchewan S4S 0A2, Canada *Corresponding author. E-mail: [email protected] (Received 11 September 2006; revision accepted 06 June 2007) Abstract–Martian meteorites are fragments of the Martian crust. These samples represent igneous rocks, much like basalt. As such, many laboratory techniques designed for the study of Earth materials have been applied to these meteorites. Despite numerous studies of Martian meteorites, little data exists on their basic structural characteristics, such as porosity or density, information that is important in interpreting their origin, shock modification, and cosmic ray exposure history. Analysis of these meteorites provides both insight into the various lithologies present as well as the impact history of the planet’s surface. We present new data relating to the physical characteristics of twelve Martian meteorites. Porosity was determined via a combination of scanning electron microscope (SEM) imagery/image analysis and helium pycnometry, coupled with a modified Archimedean method for bulk density measurements. Our results show a range in porosity and density values and that porosity tends to increase toward the edge of the sample. Preliminary interpretation of the data demonstrates good agreement between porosity measured at 100× and 300× magnification for the shergottite group, while others exhibit more variability. -
A Perspective from Extinct Radionuclides on a Young Stellar Object: the Sun and Its Accretion Disk
Annu. Rev. Earth Planet. Sci. 2011. 39: 351-386 doi:10.1146/annurev-earth-040610-133428 Copyright © 2011 by Annual Reviews. All rights reserved UNCORRECTED PREPRINT A PERSPECTIVE FROM EXTINCT RADIONUCLIDES ON A YOUNG STELLAR OBJECT: THE SUN AND ITS ACCRETION DISK Nicolas Dauphas,1 Marc Chaussidon2 1Origins Laboratory, Department of the Geophysical Sciences and Enrico Fermi Institute, Chicago, Illinois 60637; email: [email protected] 2Centre de Recherches Pétrographiques et Géochimiques (CRPG)-Nancy Université-CNRS, UPR 2300, 54501 Vandoeuvre-lès-Nancy, France ■ Abstract Meteorites, which are remnants of solar system formation, provide a direct glimpse into the dynamics and evolution of a young stellar object (YSO), namely our Sun. Much of our knowledge about the astrophysical context of the birth of the Sun, the chronology of planetary growth from micrometer-sized dust to terrestrial planets, and the activity of the young Sun comes from the study of extinct 26 radionuclides such as Al (t1/2 = 0.717 Myr). Here we review how the signatures of extinct radionuclides (short-lived isotopes that were present when the solar system formed and that have now decayed below detection level) in planetary materials influence the current paradigm of solar system formation. Particular attention is given to tying meteorite measurements to remote astronomical observations of YSOs and modeling efforts. Some extinct radionuclides were inherited from the long-term chemical evolution of the Galaxy, others were injected into the solar system by a nearby supernova, and some were produced by particle irradiation from the T-Tauri Sun. The chronology inferred from extinct radionuclides reveals that dust agglomeration to form centimeter-sized particles in the inner part of the disk was very rapid (<50 kyr), planetesimal formation started early and spanned several million years, planetary embryos (possibly like Mars) were formed in a few million years, and terrestrial planets (like Earth) completed their growths several tens of million years after the birth of the Sun. -
Lecture 2: Radioactive Decay
Geol. 655 Isotope Geochemistry Lecture 2 Spring 2005 RADIOACTIVE DECAY As we have seen, some combinations of protons and neutrons form nuclei that are only “metastable”. These ultimately transform to stable nuclei through the process called radioactive decay. Just as an atom can exist in any one of a number of excited states, so too can a nucleus have a set of discrete, quantized, excited nuclear states. The new nucleus produced by radioactive decay is often in one of these excited states. The behavior of nuclei in transforming to more stable states is somewhat similar to atomic transformation from excited to more stable states, but there are some important differences. First, energy level spacing is much greater; second, the time an unstable nucleus spends in an excited state can range from 10-14 sec to 1011 years, whereas atomic life times are usually about 10-8 sec; third, excited atoms emit photons, but excited nuclei may emit photons or particles of non-zero rest mass. Nuclear reactions must obey general physical laws, conservation of momentum, mass-energy, spin, etc. and conservation of nuclear particles. Nuclear decay takes place at a rate that follows the law of radioactive decay. There are two extremely interesting and important aspects of radioactive decay. First, the decay rate is dependent only on the energy state of the nuclide; it is independent of the history of the nucleus, and essentially independent of external influences such as temperature, pressure, etc. It is this property that makes radioactive decay so useful as a chronometer. Second, it is completely impossible to predict when a given nucleus will decay. -
Isotope Geochemistry
Isotope Geochemistry Chapter 5: Isotope Cosmochemistry Isotope Cosmochemistry 5.1 INTRODUCTION Meteorites are our primary source of in- formation about the early Solar System. Chemical, isotopic, and petrological fea- tures of meteorites reflect events that occurred in the first few tens of millions of years of Solar Sys- tem history. Obser- vations on meteor- ites, together with astronomical obser- vations on the birth of stars and the laws of physics, are the basis of our ideas on how the Solar Sys- tem, and the Earth, Figure 5.1. Photograph of the meteorite Allende, which fell in Mexico in 1969. formed. Circular/spherical features are chondrules. Irregular white patches are Meteorites can be CAI’s. divided into two broad groups: primitive meteorites and differentiated meteorites. The chondrites constitute the primitive group: most of their chemical, isotopic, and petrological features resulted from processes that occurred in the cloud of gas and dust that we refer to as the solar nebula. They are far more commonly observed to fall than differentiated meteorites*. All chondrites, however, have experienced at least some meta- morphism on “parent bodies”, the small planets (diameters ranging from a few km to a few hundred km) from which meteorites are derived by collisions. The differentiated meteorites, which include the achondrites, stony irons, and irons, were so extensively processed in parent bodies, by melting and brecciation, that information about nebular processes has largely been lost. On the other hand, the dif- ferentiated meteorites provide insights into the early stages of planet formation. We’ll provide only a brief overview here. More details of meteoritics (the study of meteorites) can be found in McSween and Huss (2010) and White (2013). -
The I-Xe Chronometer and the Early Solar System
Meteoritics & Planetary Science 41, Nr 1, 19–31 (2006) Abstract available online at http://meteoritics.org The I-Xe chronometer and the early solar system J. D. GILMOUR1*, O. V. PRAVDIVTSEVA2, A. BUSFIELD1, and C. M. HOHENBERG2 1School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK 2McDonnell Center for the Space Sciences and Physics Department, Washington University, CB 1105, One Brookings Drive, Saint Louis, Missouri 63130, USA *Corresponding author. E-mail: [email protected] (Received 31 January 2005; revision accepted 05 August 2005) Abstract–We review the development of the I-Xe technique and how its data are interpreted, and specify the best current practices. Individual mineral phases or components can yield interpretable trends in initial 129I/127I ratio, whereas whole-rock I-Xe ages are often hard to interpret because of the diversity of host phases, many of which are secondary. Varying standardizations in early work require caution; only samples calibrated against Shallowater enstatite or Bjurbˆle can contribute reliably to the emerging I-Xe chronology of the early solar system. Although sparse, data for which I-Xe and Mn-Cr can be compared suggest that the two systems are concordant among ordinary chondrite samples. We derive a new age for the closure of the Shallowater enstatite standard of 4563.3 ± 0.4 Myr from the relationship between the I-Xe and Pb-Pb systems. This yields absolute I-Xe ages and allows data from this and other systems to be tested by attempting to construct a common chronology of events in the early solar system. -
106. Distinct 238 U/ 235 U Ratios and REE Patterns in Plutonic And
Available online at www.sciencedirect.com ScienceDirect Geochimica et Cosmochimica Acta 213 (2017) 593–617 www.elsevier.com/locate/gca Distinct 238U/235U ratios and REE patterns in plutonic and volcanic angrites: Geochronologic implications and evidence for U isotope fractionation during magmatic processes Franc¸ois L.H. Tissot a,b,⇑, Nicolas Dauphas a, Timothy L. Grove b a Origins Laboratory, Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, 5734 South Ellis Avenue, Chicago, IL, USA b Department of the Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA Received 28 December 2016; accepted in revised form 28 June 2017; Available online 8 July 2017 Abstract Angrites are differentiated meteorites that formed between 4 and 11 Myr after Solar System formation, when several short- lived nuclides (e.g., 26Al-26Mg, 53Mn-53Cr, 182Hf-182W) were still alive. As such, angrites are prime anchors to tie the relative chronology inferred from these short-lived radionuclides to the absolute Pb-Pb clock. The discovery of variable U isotopic composition (at the sub-permil level) calls for a revision of Pb-Pb ages calculated using an ‘‘assumed” constant 238U/235U ratio (i.e., Pb-Pb ages published before 2009–2010). In this paper, we report high-precision U isotope measurement for six angrite samples (NWA 4590, NWA 4801, NWA 6291, Angra dos Reis, D’Orbigny, and Sahara 99555) using multi- collector inductively coupled plasma mass-spectrometry and the IRMM-3636 U double-spike. The age corrections range from À0.17 to À1.20 Myr depending on the samples. -
Extra-Terrestrial Igneous Granites and Related Rocks: a Review of Their Occurrence and Petrogenesis
This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier’s archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Author's personal copy Lithos 153 (2012) 3–24 Contents lists available at SciVerse ScienceDirect Lithos journal homepage: www.elsevier.com/locate/lithos Extra-terrestrial igneous granites and related rocks: A review of their occurrence and petrogenesis Bernard Bonin ⁎ UMR8148 ‘IDES’, CNRS, Département des Sciences de la Terre, Université de Paris-Sud, F-91405 ORSAY CEDEX, France article info abstract Article history: The telluric planets and the asteroid belt display the same internal structure with a metallic inner core and a Received 4 November 2011 silicate outer shell. Experimental data and petrological evidence in silicate systems show that granite can be Accepted 4 April 2012 produced by extreme igneous differentiation through various types of igneous processes. Available online 14 April 2012 On Moon, 4.4–3.9 Ga granite clasts display dry mineral assemblages. They correspond to at least 8 discrete intru- sive events. Large K/Ca enrichment and low REE abundances in granite relative to KREEP are consistent with sil- Keywords: icate liquid immiscibility, a process observed in melt inclusions within olivine of lunar basalts and in lunar Planetary granites fi A-type meteorites. -
List G - Meteorites - Alphabetical List
LIST G - METEORITES - ALPHABETICAL LIST Specific name Group name Specific name Group name Abee Meteorite EH chondrites EETA 79001 Elephant Moraine Meteorites Acapulco Meteorite acapulcoite and shergottite acapulcoite stony meteorites Efremovka Meteorite CV chondrites Acfer Meteorites meteorites EH chondrites enstatite chondrites achondrites stony meteorites EL chondrites enstatite chondrites ALH 84001 Allan Hills Meteorites and Elephant Moraine meteorites achondrites Meteorites ALHA 77005 Allan Hills Meteorites and enstatite chondrites chondrites shergottite eucrite achondrites ALHA 77307 Allan Hills Meteorites and Fayetteville Meteorite H chondrites CO chondrites Frontier Mountain meteorites ALHA 81005 Allan Hills Meteorites and Meteorites achondrites Gibeon Meteorite octahedrite Allan Hills Meteorites meteorites GRA 95209 Graves Nunataks Meteorites Allende Meteorite CV chondrites and lodranite angrite achondrites Graves Nunataks meteorites Ashmore Meteorite H chondrites Meteorites Asuka Meteorites meteorites H chondrites ordinary chondrites ataxite iron meteorites Hammadah al Hamra meteorites aubrite achondrites Meteorites Barwell Meteorite L chondrites Haveroe Meteorite ureilite Baszkowka Meteorite L chondrites Haviland Meteorite H chondrites Belgica Meteorites meteorites HED meteorites achondrites Bencubbin Meteorite chondrites Hedjaz Meteorite L chondrites Bishunpur Meteorite LL chondrites Henbury Meteorite octahedrite Bjurbole Meteorite L chondrites hexahedrite iron meteorites Brenham Meteorite pallasite HL chondrites ordinary chondrites -
The Kaidun Meteorite: Clasts of Alkaline-Rich Fractionated Materials
Meteoritics & Planetary Science 38, Nr 5, 725–737 (2003) Abstract available online at http://meteoritics.org The Kaidun meteorite: Clasts of alkaline-rich fractionated materials Andrei V. IVANOV, 1* Nataliya N. KONONKOVA, 1 S. Vincent YANG, 2 and Michael E. ZOLENSKY 3 1Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow 117975, Russia 2Lockheed Engineering and Science Company, Houston, Texas 77258, USA 3SN2, NASA Johnson Space Center, Houston, Texas 77058, USA *Corresponding author. E-mail: [email protected] (Received 9 April 2002; revision accepted 11 November 2002) Abstract–Clasts of alkaline (the second find in meteorites) and subalkaline rocks were found in the Kaidun meteorite. One of them (#d4A) is a large crystal of albite with inclusions of fluorapatite, arfvedsonite, aenigmatite, and wilkinsonite. The two latter minerals were previously unknown in meteorites. Another clast (#d[3–5]D) has a melt crystallization texture of mainly feldspar (oligoclase) composition and contains relict grains of both high-Ca and low-Ca pyroxene and fluorapatite. The mineralogical characteristics of these clasts suggest a genetic relationship and an origin from the same parent body. The textural and mineralogical characteristics of the clasts indicate origin by extensive igneous differentiation. Such processes most likely took place in a rather large differentiated body. The material of clast #d(3–5)D is similar in some mineralogical respects to basaltic shergottites. INTRODUCTION and nature of this enigmatic meteorite lies in studying its different components. In this paper, we describe the results of The Kaidun meteorite is an extremely unusual our investigation of two clasts, #d(3–5)D and #d4A, that show heterogeneous breccia. -
Ejection of Martian Meteorites
Meteoritics & Planetary Science 40, Nr 9/10, 1393–1411 (2005) Abstract available online at http://meteoritics.org Ejection of Martian meteorites Jˆrg FRITZ1*, Natalia ARTEMIEVA2, and Ansgar GRESHAKE1 1Institut f¸r Mineralogie, Museum f¸r Naturkunde, Humboldt-Universit‰t zu Berlin, Invalidenstrasse 43, 10115 Berlin, Germany 2Institute for Dynamics of Geospheres, Russian Academy of Science, Leninsky Prospect 38, Building 1, Moscow 119334, Russia *Corresponding author. E-mail: [email protected] (Received 29 March 2005; revision accepted 11 April 2005) Abstract–We investigated the transfer of meteorites from Mars to Earth with a combined mineralogical and numerical approach. We used quantitative shock pressure barometry and thermodynamic calculations of post-shock temperatures to constrain the pressure/temperature conditions for the ejection of Martian meteorites. The results show that shock pressures allowing the ejection of Martian meteorites range from 5 to 55 GPa, with corresponding post-shock temperature elevations of 10 to about 1000 °C. With respect to shock pressures and post-shock temperatures, an ejection of potentially viable organisms in Martian surface rocks seems possible. A calculation of the cooling time in space for the most highly shocked Martian meteorite Allan Hills (ALH) 77005 was performed and yielded a best-fit for a post-shock temperature of 1000 °C and a meteoroid size of 0.4 to 0.6 m. The final burial depths of the sub-volcanic to volcanic Martian rocks as indicated by textures and mineral compositions of meteorites are in good agreement with the postulated size of the potential source region for Martian meteorites during the impact of a small projectile (200 m), as defined by numerical modeling (Artemieva and Ivanov 2004).