Preferences help
enabled [disable] Abstract
Number of results
2019 | 10 | 121-139
Article title

Nowy chondryt zwyczajny L6, S1, W1: Northwest Africa 11779

Title variants
A new ordinary chondrite L6, S1, W1: Northwest Africa 11779
Languages of publication
Based on petrological, mineralogical and geochemical research authors classified new meteorite Northwest Africa 11779 as the ordinary chondrite L6, S1, W1. Chemical composition of olivine crystals (Fa 24.9 mol.%) and of pyroxene crystals (Fs 19.4 mol.%) proved that this meteorite belongs to L chondrites. However, bulk chemical composition of NWA 11779 is not typical for L chondrites. Nevertheless, all analyzed elements (except Mo, Sn and Nb) are in abundances reported for L chondrites, some of elements have concentration closed to average abundances for L chondrites. The content of chosen, characteristic lithophile, siderophile and chalkophile elements in NWA 11779 chondrite is in most cases in accord with its typical abundance in L chondrites. Presence of poorly defined chondrules, secondary feldspar crystals larger than 50 µm in size, absence of glass within chondrules, coarse recrystallized matrix (with olivine crystals of 0.5 mm in diameter and pyroxene crystals of 0.3 mm in diameter) as well as carbon content below 0.2 wt% proved that studied meteorite belongs to the petrologic type 6. The only difference from characteristic features of petrologic type 6 in case of NWA 11779 chondrite is presence of ca. 10% of monoclinic Ca-poor pyroxenes. Undulatory extinction by olivine and absence of other shock features in this chondrite allow to determine the shock level as S1. Weathering grade of NWA 11779 was identified as W1 based on weathering of only FeNi alloy grains. The outer part of metallic grains as well as contact zones of FeNi and FeS are changed due to weathering. Between 10 and 20% of FeNi alloy grains are oxidized to iron oxides and hydroxides. These secondary products of weathering replace outer zone of FeNi grains and fill the small cracks, creating a few thin veins.
Physical description
  • Politechnika Wrocławska, Wydział Geoinżynierii, Górnictwa i Geologii, Zakład Geologii i Wód Mineralnych, Wybrzeże S. Wyspiańskiego 27, 50-370 Wrocław
  • Politechnika Wrocławska, Wydział Geoinżynierii, Górnictwa i Geologii, Zakład Geologii i Wód Mineralnych, Wybrzeże S. Wyspiańskiego 27, 50-370 Wrocław
  • Uniwersytet Wrocławski, Wydział Nauk o Ziemi i Kształtowania Środowiska, Instytut Nauk Geologicznych, Zakład Mineralogii i Petrologii, ul. W. Cybulskiego 30, 50-205 Wrocław
  • Bus S.J., Binzel R.P., 2002, Phase II of the Small Main-Belt Asteroid Spectroscopic Survey. A Feature-Based Taxonomy, Icarus, 158, s. 146–177.
  • Grady M.M., Pratesi G., Cecchi V.M., 2014, Atlas of meteorites, Cambridge University Press, UK.
  • Hutchison R., 2006, Meteorites. A Petrologic, Chemical and Isotopic Synthesis, Cambridge University Press, Cambridge, UK.
  • Koblitz J., 2010, MetBase®, ver. 7.3, Meteorite Data Retrieval Software, Ritterhude, Germany.
  • McSween H.Y., Huss G.R., 2010, Cosmochemistry, Cambrigde Univeristy Press, Cambrigde.
  • Nesvorný D., Vokrouhlický D., Morbidelli A., Bottke W. F., 2009, Asteroidal source of L chondrite meteorites, Icarus, 200, s. 698–701.
  • de Pater I., Lissauer J.J., 2010, Planetary Science, Second edition, Cambridge University Press, Cambridge, 646 str.
  • Stöffler D., Keil K., Scott E.R.D., 1991, Shock metamorphism of ordinary chondrites, Geochimica et Cosmochimica Acta, 55, s. 3845–3867.
  • Van Schmus W.R., Wood J.A., 1967, A chemical-petrologic classification for the chondritic meteorites, Geochimica et Cosmochimica Acta, 31, s. 747–765.
  • Wlotzka F., 1993, A weathering scale for the ordinary chondrites, Meteoritics, 28, s. 460.
Document Type
Publication order reference
YADDA identifier
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.