doi:

DOI: 10.3724/SP.J.1084.2013.00329

Chinese Journal of Polar Research (极地研究) 2013/25:4 PP.329-341

PETROLOGY AND MINERALOGY OF LUNAR METEORITE MIL 090070 FROM ANTARCTICA


Abstract:
MIL 090070, a new lunar meteorite found in 2009, is a lunar highland anorthosite. It has a typical breccia texture that consists mainly of lithic, mineral and glassy clasts in a fine-grained matrix. Its lithic clasts include anorthositic polymicts, anorthosite, gabbro, gabbroic norite, gabbroic troctolite, gabbroic anorthosite and olivine-gabbro. Mineral clasts include augite, pigeonite, plagioclase, spinel, quartz and ilmenite. The glassy clasts are anorthositic. Its shapes are usually thin plate-like and bending plate-like with numerous fractures. The mineral assemblage is mostly plagioclase (86 vol%, An92-99), olivine (6 vol%, Fo53-89), pyroxene (7 vol%, En25-83Fs7-43Wo2-45), spinel, ilmenite and silica. In addition, the pyroxene has two kinds of augite (En25-63Fs7-43 Wo6-45) and pigeonite (En55-83 Fs13-41 Wo2-5). The Mn to Fe values of olivine and pyroxene plot mostly in the area of rocks with a lunar-origin, which is far from those of Earth, Mars, Venus and main-belt asteroids. MIL 090070 experienced many shock events and is cemented by shock-induced glassy breccias. Therefore, the mineral composition and grain size of the lithic clasts has changed gradually and the lithic clast types became more varied and complicate during the shock events. Examination of the petrology of MIL 090070, including clast types and textural features, will improve understanding of the process of lunar regolith formation.

Key words:lunar meteorite, MIL 090070, highland anorthosite, lunar regolith

ReleaseDate:2014-07-21 16:59:36



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