LAP 04841 - Unbrecciated mare basalt
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Description: 

LAP 04841 and its paired masses, LAP 02205 , 02224, 02226, 02436 and 03632 are an unbrecciated mare basalt that in total weighs ~1930 g. These meteorites were discovered in the LaPaz Icefield, Antarctica in 2002, 2003, and 2004 and their recovery locations define a linear trend, which together with their textural, mineralogical, and petrologic similarities argue for pairing. They represent a unique basaltic composition not represented in the Apollo collections, and the first unbrecciated mare basaltic meteorite from Antarctica. Petrographically they are all medium to coarse-grained subophitic basalts, with a dominance of pyroxene, plagioclase and ilmenite. Each contains traces of olivine, spinel (chromite and ulvöspinel), troilite, silica, baddeleyite and metallic iron. They also contain heterogeneous melt veins and pockets whose composition is similar to the bulk composition of the rock.

Olivine is generally subhedral in shape although some grains have a skeletal habit with subhedral outlines. The olivine compositions range from Fo53 to Fo62 in the cores to Fo46 to Fo57 in the rims. The modal proportion of olivine in four LAP meteorites ranges from 1.1 to 3.6%. The pyroxene is either intersertile or enclosing plagioclase within all of the rocks. Pyroxene grains have strong chemical variation from pigeonite to ferroaugite. Plagioclase is a dominant component and ranges from 32 to 45 modal percent.  It occurs commonly as laths but in some cases has a blocky texture. Baddeleyite occurs in association with ulvöspinel, ilmenite and troilite, and is typically 20 to 40 μm in size.

Our thin section is beginning to lift at the edges where rock slice is separating from glass slide.

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Ma = Millions of years ago
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meteorite
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