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SOCORRO

Stony

TIPO:

CLASSE:

CLAN:

GRUPO:

SUB-GRUPO:

TIPO PET.:

EST. CHOQUE:

INTERPERISMO:

PAÍS:

ANO:

DESCRIÇÃO:

ACHONDRITE

MARTIAN

SCN

SHERGOTTITE

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BRAZIL - PE

2019

Martian Shergottite

PETROGRAFIA:

(C. Agee, UNM) The two major phases in this meteorite are clinopyroxene and maskelynite. Ubiquitous minor phases are merrillite/apatite, titanomagnetite, ilmenite and silica. The clinopyroxene has a modal abundance of approximately 60%, with significant core to rim zoning observed in backscattered electron images indicating an igneous crystallization trend with Mg-rich sub-calcic augite cores, mantled by intermediate pigeonite, and rimmed with ferropigeonite. Clinopyroxene average grain size is approximately 500-1000 μm. Maskelynite has modal abundance of approximately 30%, most grains are subophitic with maximum length ~1 mm. Merrillite laths are up to 1 mm in length. There are numerous domains of fine-grained intergrowths or quench crystals presumably formed during a shock event.

GEOQUÍMICA:

(C. Agee, UNM) Clinopyroxene Fs57.3±21.4Wo19.5±7.5, core to rim range Fs29.0Wo30.6 (sub-calcic augite) – Fs83.5Wo11.7 (ferropigeonite), Fe/Mn=36±5, n=34; maskelynite An47.0±7.7Ab50.8±6.0Or2.2±1.8, n=11; fusion crust (20 μm defocused electron beam) SiO2=47.5±0.7, TiO2=0.96±0.04, Al2O3=11.9±0.3, MgO=4.1±0.1, FeO=18.9±0.3, MnO=0.44±0.03, CaO=9.8±0.1, Na2O=2.3±0.1 (all wt%), titanomagnetite FeO=52.8±1.2, Fe2O3=19.2±1.4, TiO2=24.2±1.1, Al2O3=1.9±0.6±0.4, (all wt%), n=3; Oxygen isotopes (K. Ziegler, UNM): 5 acid-washed fragments analyzed by laser

CLASSIFICAÇÃO:

Evolved martian basalt, clinopyroxene compositional zoning trends are similar to QUE 94201.

CLASSIFICADORES:

C. Agee

HISTÓRIA:

Physical characteristics: The remaining MNRJ sample measures 36.2 × 25.1 × 14.4 mm and weighs 24.4 g. It is an end-piece of a larger stone with a distinct angular edge and shows dark-brown fusion crust. The cut surface exhibits a slightly brownish-gray interior. Microscopically, the meteorite is quite fresh, with metal phase preserved.

Todas as informações que não possuírem fonte especifica, foram extraídas do Meteoritical Bulletin Database.

Todas as imagens possuem direitos autorais.

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