: 1.3-Billion-Years-Old Martian Meteorite had Limited Exposure To Water
Using neutron and X-ray tomography, a team of planetary researchers from Lund University and elsewhere examined a section of Miller Range (MIL) 03346, a nakhlite meteorite from Miller Range in Antarctica.
A polished section of the Martian meteorite Miller Range (MIL) 03346: (A) photograph of the interior of MIL 03346,230; note the yellow tint in the left region of the sample, marked by dotted lines; mineral grains in the yellow-tinted region are heavily affected by aqueous alteration; (B) BSE image of the same section as in (A); light gray olivine grains, marked with arrows, are situated in the altered areas; the white boxes show locations for detailed images in (C) to (F); (C) BSE image of the upper left olivine grain, marked with a box in (B); iddingsite veins are cutting through a fractured olivine grain; augite grains and a fine-grained mesostasis (dark gray) containing titanomagnetite (bright, skeletal grains) are also shown in the figure; (D) photograph of the upper left olivine grain, same as in (C); iddingsite veins have a dark red color; (E) BSE image showing details of the upper right olivine grain; the grain is fractured and crosscut by iddingsite veins that are predominantly oriented east to west in the image; (F) photograph of the same grain as in (E), where the dark red iddingsite veins have been outlined. Image credit: Martell et al., doi: 10.1126/sciadv.abn3044.
Nakhlites are a group of igneous Martian meteorites that are rich in minerals called pyroxene and olivine.
One of the most important findings in these meteorites is evidence of preterrestrial, Martian-aqueous alteration to olivine grains.
All nakhlites found to date are thought to derive from the same volcanic system, on the basis of their similar petrology, geochemistry, and ejection age of 11 million years.
The nakhlites were deposited in at least four magmatic events with crystallization ages that range from 1. 42 to 1. 32 billion years ago.
Suggested sources are the large volcanic terrains of the Northern Plains and Tharsis, Elysium Amazonis volcanic plains and Syrtis Major.
“Since water is central to the question of whether life ever existed on Mars, we wanted to investigate how much of the MIL 03346 nakhlite meteorite reacted with water when it was still part of the Mars bedrock,” said Josefin Martell, a doctoral student at Lund University.
To answer the question whether there was a major hydrothermal system that is generally conducive for life to take place, Martell and his colleagues used neutron tomography and X-ray imaging.
Xray tomography is a popular method for inspecting an object without damaging them. Because neutrons are sensitive to hydrogen, neutron tomography was developed.
This means that if a mineral contains hydrogen, it is possible to study it in three dimensions and see where in the meteorite the hydrogen is locat