Signatures of the post-hydration heating of highly aqueously altered CM carbonaceous chondrites and implications for interpreting asteroid sample returns

Backscatter electron microscope images of a meteorite

This paper is available as an Open Access article via the journal.

This research paper continues the work of Paula Lindgren, who I worked with earlier when looking at a suite of meteorites. In this paper, a single carbonaceous chondrite meteorite was heated in the laboratory to simulate the heating that took place during the life of a meteorite. A sample was studied using a series of different techniques, including scanning electron microscopy, Raman spectroscopy, infra-red spectroscopy, oxygen isotopic analysis and X-ray diffraction. It was then heated to 400 °C and 800 °C and studied again. We found that the minerals, isotopes and organic matter all changed with heating. Sometimes 400 °C was enough to make a change, sometimes no change was observed until 800 °C.

Changing Raman spectropscopy measurements from unheated (blue), 400 °C (yellow) and 800 °C (red) samples of the same meteorite

These changes can be used to work out the thermal history of meteorites collected on Earth, and even for asteroids sampled in space!