Elephant Moraine 79001
Elephant Moraine 79001, also known as EETA 79001, is a Martian meteorite. It was found in Elephant Moraine, in the Antarctic during the 1979–1980 collecting season.
The meteorite is classified as a
Discovery
EETA 79001 was discovered at the Elephant Moraine, near Reckling Peak, Victoria Land, Antarctica. It was especially significant due to the fact that it had glass inclusions that were found to contain rare
Macroscopic descriptions
The meteorite is made up of two distinct lithologies, designated as lithology A and lithology B. Lithology B is an igneous melt, almost certainly originating deep in the Martian crust. Lithology A has some uncertainty associated with it, but appears to be made up of shocked, impact melt from the collision that caused the ejection of EETA 79001.[6]
The meteorite is a nearly completely crystalline rock, with a composition typical of volcanic lava crystallized from molten silicate. The sample closely resembles that of basalts collected from Earth and the Moon.[2] Close examination of this sample shows glassy feldspar, which can be shown to have formed under unique conditions, common with impact shock. This glass retains its original structure, showing evidence for no flow having occurred. This process is likely caused due to intense shock waves, such as a large meteoric impact.[2]
Mineralogical descriptions
The main mass of the meteorite is a shocked pyroxene.[7] Large pyroxene grains range up to 3.5 mm. A few large olivines also occur, as large as 2.5 mm.[7]
The less abundant lithology, lithology B, resembles fine grained
Dark glass appears throughout, connected with thin veinlits. This glass is of melted origin.[2]
Importance
Martian meteors
EETA 79001 has been shown to originate from the Martian interior, so holds great importance because of the clues it can provide about the composition and evolution of Mars. It was the first sample that provided conclusive evidence of an origin from Mars.[8] The idea of meteorites ejected from other planets was at first not popular with scientists, as they believed such an impact would completely melt the ejected debris, EETA 79001 showed that while some portion is likely melted from impact, original rock crystals can survive the process.[2] This meteorite is one of only 99 known meteorites discovered on Earth, of Martian origin.[5] Martian meteorites were critical in our early understanding of a planet that is both a close neighbor and physically very similar to Earth. Before lander missions, the only physical samples to be analyzed were meteorites ejected from Mars, and impacting on Earth.
Debunked evidence for life on Mars
Carbonate found in EETA 79001 was used as a crucial piece of evidence for potential early life on Mars. It was argued that the most likely formation of the carbonate was in liquid water by
See also
References
- Wikidata Q105670571.
- ^ Wikidata Q105653329.
- ^ Wikidata Q59093587.
- ^ Wikidata Q105653393.
- ^ a b Meteoritical Bulletin Database
- Wikidata Q105653347.
- ^ a b c Reid, Arch (August 1980). "Elephant Moraine A79001 Petrographic Description". Antarctic Meteorite Newsletter. 3 (3).
- ^ Infobase Publishing.