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

• Authors: Tadeusz A. Przylibski , Katarzyna Łuszczek , Ryszard Kryza

Title variants

EN

A new ordinary chondrite L6, S1, W1: Northwest Africa 11779

• Languages of publication: PL

Abstracts

EN

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.

Keywords

EN

L6 chondrite; NWA chondrite; bulk chemistry; chemistry of minerals; meteorite; ordinary chondrite

Discipline

• GEOLOGY: GEOLOGY

• Publisher: Polskie Towarzystwo Meteorytowe
• Journal: Acta Societatis Metheoriticae Polonorum
• Year: 2019
• Volume: 10
• Pages: 121-139

Contributors

author

Tadeusz A. Przylibski

• Politechnika Wrocławska, Wydział Geoinżynierii, Górnictwa i Geologii, Zakład Geologii i Wód Mineralnych, Wybrzeże S. Wyspiańskiego 27, 50-370 Wrocław

author

Katarzyna Łuszczek

• Politechnika Wrocławska, Wydział Geoinżynierii, Górnictwa i Geologii, Zakład Geologii i Wód Mineralnych, Wybrzeże S. Wyspiańskiego 27, 50-370 Wrocław

author

Ryszard Kryza

• Uniwersytet Wrocławski, Wydział Nauk o Ziemi i Kształtowania Środowiska, Instytut Nauk Geologicznych, Zakład Mineralogii i Petrologii, ul. W. Cybulskiego 30, 50-205 Wrocław

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• Document Type: article