Tissint Martian Meteorite

Tissint is the fifth witnessed Martian meteorite fall.  It is a Shergottite.  Many pieces totaling over 7 kg fell east of Tata, Morocco about 2 AM, July 18, 2011.  The stones have a shiny black fusion crust which is glossier over olivine macrocrysts.  Olivine macrocrysts and microphenocrysts are held in a finer groundmass of pyroxene, plagioclase (shocked to maskelynite) and other minerals.  Small melt pockets and thin veins of black glass are present. 

Larger olivine crystals are surrounded by a finer groundmass of pyroxene, plagioclase and other minerals. Field of view is 6.2 mm wide. Thin section in cross-polarized light.

Olivine crystals with cracks and small inclusions. Field of view is 3 mm wide. Thin section in cross-polarized light.

Olivine crystals with planar fractures in three orientations. Field of view is 2 mm wide. Thin section in cross-polarized light.

Olivine with inclusion and radiating cracks. Field of view is 0.37 mm wide. Thin section in cross-polarized light.

Olivine with inclusion and radiating cracks. Field of view is 0.37 mm wide. Thin section in incident light.

Black glass shock vein through meteorite groundmass. White grains are maskelynite. Field of view is 3 mm wide. Thin section in plane transmitted light.

Black glass shock vein through meteorite groundmass. White grains are maskelynite. Field of view is 3 mm wide. Thin section in plane transmitted light.

Black glass shock vein through meteorite groundmass and through a few mineral grains. Field of view is 3 mm wide. Thin section in cross-polarized light.

Black glass shock vein through a few mineral grains. Field of view is 1.2 mm wide. Thin section in cross-polarized light.

Section through a melt pocket. White is a void. It is surrounded by swirled brown and black melt glass. Field of view is 3 mm wide. Thin section in plane transmitted light.

Swirled brown and black glass in a melt pocket. The round white area is a void. Field of view is 1.2 mm wide. Thin section in plane transmitted light.

Glass with bubbles swirled and frozen in a melt pocket. The glass in Tissint contains Martian atmosphere. At lower right, minute crystals grew on the wall of the pocket in the short time the melt was cooling. Field of view is 0.3 mm wide. Thin section in plane transmitted light.


About the Author

John Kashuba
John is a natural history enthusiast living in Oregon.
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