Nakhlites are a group of Martian meteorites, named after the first one, Nakhla meteorite.
Nakhlites are igneous rocks that are rich in augite and were formed from basaltic magma about 1.3 billion years ago. They contain augite and olivine crystals. Their crystallization ages, compared to a crater count chronology of different regions on Mars, suggest the nakhlites formed on the large volcanic construct of either Tharsis, Elysium, or Syrtis Major Planum.Treiman, A.H., "The nakhlite meteorites: Augite-rich igneous rocks from Mars" - (PDF) Chemie der Erde 65, p. 203-270, (2005). URL accessed July 30, 2011.
History A 2017 study dated them to at least four different eruptions from 1416 ± 7 Ma to 1322 ± 10 Ma. It has been shown that the nakhlites were suffused with liquid water around 620 million years ago and that they were ejected from Mars around 10.75 million years ago by an asteroid impact. They fell to Earth within the last 10,000 years.
Possible source crater in Elysium A 6.5 km diameter crater at in the volcanic plains to the northwest of Elysium Mons has been identified as a possible source. Based on the crater dimensions, the inferred growth rate of the source volcano during that interval is 0.4–0.7 m per Ma, far slower than would be expected for a terrestrial volcano, and implying that Martian volcanism had slowed greatly by that point in history.
Samples
The following samples of nakhlites are known.
Nakhla meteorite (about 40 samples, total estimated weight ), vicinity of Nakhla, Abu Hommos district, Alexandria Governorate, Egypt, 1911 Governador Valadares meteorite"Mineralogy of nakhlite Martian meteorites: Implications for their relative burial depths ", Mikouchi, T.; McKay, Gordon; Miyamoto, M., 2006, NASA Technical Reports Server Lafayette meteorite, 800g, before 1931 "Lafayette - 800 grams Nakhlite", Martian Meteorite Compendium, C. Mayer, 2012 NWA817, 104g, Morocco, 2000 NWA 817 – 104 grams Nakhlite NWA998, 456g, Morocco, 2001 NWA 998 – 456 grams Nakhlite Y000593 (Yamato 593), NASA.govImae N., Okazaki R., Kojima H. and Nagao K. (2002a) The first Nakhlite from Antarctica (abs#1483). Lunar Planet. Sci. XXXIII. Lunar Planetary Institute, Houston Y000749, Imae N., Ikeda Y., Shinoda K., Kojima H. and Iwata N. (2002c) Two Nakhlites from Antarctica: Y000593 and Y000749 (abs). Antarctic Meteorites XXVII, 45-47. Nat. Inst. Polar Res., Tokyo Y000802, 22g MIL 03346 Miller Range, Antarctica MIL 090030, MIL 090032, and MIL 090136, Miller Range, Antarctica
See also Glossary of meteoritics Clinopyroxenite - the geological rock classification of Nakhlites
External links
Aerolite Meteorites (Martian meteorites)
References