Lee, M. and Chatzitheodoridis, E. (2016) Replacement of glass in the Nakhla meteorite by berthierine: implications for understanding the origins of aluminium-rich phyllosilicates on Mars. Meteoritics and Planetary Science, 51(9), pp. 1643-1653. (doi: 10.1111/maps.12687)
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Abstract
A scanning and transmission electron microscope study of aluminosilicate glasses within melt inclusions from the Martian meteorite Nakhla shows that they have been replaced by berthierine, an aluminum-iron serpentine mineral. This alteration reaction was mediated by liquid water that gained access to the glasses along fractures within enclosing augite and olivine grains. Water/rock ratios were low, and the aqueous solutions were circumneutral and reducing. They introduced magnesium and iron that were sourced from the dissolution of olivine, and exported alkalis. Berthierine was identified using X-ray microanalysis and electron diffraction. It is restricted in its occurrence to parts of the melt inclusions that were formerly glass, thus showing that under the ambient physico-chemical conditions, the mobility of aluminum and silicon were low. This discovery of serpentine adds to the suite of postmagmatic hydrous silicates in Nakhla that include saponite and opal-A. Such a variety of secondary silicates indicates that during aqueous alteration compositionally distinct microenvironments developed on sub-millimeter length scales. The scarcity of berthierine in Nakhla is consistent with results from orbital remote sensing of the Martian crust showing very low abundances of aluminum-rich phyllosilicates.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Lee, Professor Martin |
| Authors: | Lee, M., and Chatzitheodoridis, E. |
| College/School: | College of Science and Engineering > School of Geographical and Earth Sciences |
| Journal Name: | Meteoritics and Planetary Science |
| Publisher: | Wiley |
| ISSN: | 1086-9379 |
| ISSN (Online): | 1945-5100 |
| Published Online: | 20 July 2016 |
| Copyright Holders: | Copyright © 2016 The Authors |
| First Published: | First published in Meteoritics and Planetary Science 51(9):1643-1653 |
| Publisher Policy: | Reproduced under a Creative Commons License |
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