Basaltic shergottite
A basaltic shergottite is a Martian lava rock made mainly of pyroxene and shocked plagioclase.
A basaltic shergottite is a Martian meteorite made mainly of pyroxene, both pigeonite and augite, with plagioclase that has usually been converted to maskelynite glass by shock. It resembles a basalt or fine-grained gabbro and is named after Shergotty, which fell in India in 1865.
Other well-known basaltic shergottites include Zagami, which fell in Nigeria in 1962, and Los Angeles, found in California in 1999. Most crystallised a few hundred million years ago, much more recently than most meteorites, which helped show they came from a large planet still volcanically active in its later history. Gas trapped in shock melt within the Antarctic shergottite EETA79001 matches the Martian atmosphere measured by the Viking landers.
Shergottites are subdivided into basaltic, olivine-phyric and poikilitic types according to texture and mineralogy. Basaltic examples often show pyroxenes aligned in one direction, suggesting the crystals settled or flowed in the magma before it solidified.
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