Nakhlites areigneous rocks that are rich inaugite and were formed frombasalticmagma about 1.3 billion years ago. They containaugite andolivinecrystals. Their crystallization ages, compared to a crater count chronology of different regions on Mars, suggest the nakhlites formed on the large volcanic construct of eitherTharsis,Elysium, orSyrtis Major Planum.[1]
A 2017 study dated them to at least four different eruptions from 1416 ± 7 Ma to 1322 ± 10 Ma.[2] 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.[1]
A 6.5 km diameter crater at29°40′26″N130°47′56″E / 29.674°N 130.799°E /29.674; 130.799 in the volcanic plains to the northwest ofElysium 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.[2]
^Imae N., Okazaki R., Kojima H. and Nagao K. (2002a) The first Nakhlite from Antarctica (abs#1483). Lunar Planet. Sci. XXXIII. Lunar Planetary Institute, Houston
^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
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