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Procesy wielokrotnego brekcjonowania deformacyjnego i powstawania stopów impaktowych w chondrytach na przykładzie meteorytów z kolekcji Jacka Siemiątkowskiego

Krzesińska A., Siemiątkowski J.

Przegląd Geologiczny

2011

Vol. 59, nr 8

576-588

Chondrites NWA-869 (L3.9-6 S2), Tsarev (L5 S5), Ghubara (L5 S4), Zag (H3-6 S3) from the Jacek Siemiatkowski Collection show evidence of multiple brecciation. Petrographic and microprobe analyses of thin sections allowed to identify and distinguish syn- and postaccretion impact and thermal transformations which took place on the chondrite parent bodies. The studied meteorites contain clasts of chemically equilibrated and unequilibrated rocks as well as many unusual achondritic-like clasts. The latter are cognate impact-melt rocks. All the clasts provide records of complex metamorphic and deformational histories of the parent bodies. Chondrites displayed numerous metamorphic transformations and deformations caused by many shock or shock-related processes under conditions ranging from impact-related shearing to HP shock-induced shattering and melting. These processes led to the formation of quenched impact melts, metal veins and nodules, darkened clasts and locally cataclasis.

Mineralogy and petrology of two ordinary chondrites and their correlation with other meteorites

Owocki K., Pilski A.

Mineralogia

2009

Vol. 40, iss. 1/4

107--116

Two ordinary chondrites are compared and classified using transmitted and reflected light microscopy and electron microprobe analyses. Both meteorites were confiscated by the Polish Customs Service at the border with Belarus. The first meteorite (called in this paper Terespol-1) is a L/LL6 chondrite, its classification being supported by the equilibrated compositions of olivine and orthopyroxene and the presence of large recrystallized feldspars (< 150 μm). The specimen examined experienced weak shock metamorphism (S3) and moderate weathering (although metal in the inner part of the meteorite seems to be unaffected by oxidization). The other meteorite (called in this paper Terespol-2) is a LL6 chondrite which experienced weak shock metamorphism (S3) and is unaffected by weathering. The Terespol-2 meteorite shares its classification with the Dhofar 1401 chondrite but the lack of data prevents further correlation. Both meteorites have been correlated with known findings from the Meteoritical Bulletin database and an attempt is made to identify their place of origin (fall event). Results indicate that Terespol-1 is most closely related to the Dhofar 1316 chondrite and we suggest that both meteorites at least came from the same parent body.