Impact fracturing and aqueous alteration of the CM carbonaceous chondrites

Lindgren, P., Lee, M.R. and Simpson, S.S.L. (2014) Impact fracturing and aqueous alteration of the CM carbonaceous chondrites. In: 45th Lunar and Planetary Science Conference, The Woodlands, TX USA, 17-21 March 2014,

Abstract

Aqueous alteration of the CM carbonaceous chondrites has produced a suite of secondary minerals, and differences between meteorites in their abundance defines a progressive alteration sequence [e.g. 1, 2]. The means by which this water gained access to the original anhydrous constituents of the meteorites is the subject of considerable debate. Studies of rock texture, mineralogy and bulk chemical composition have concluded that solutions were generated by the melting of water ice in situ, and remained essentially static as a consequence very low intergranular permeabilities [e.g. 3, 4]. By contrast, results of oxygen isotope work and modelling have suggested that the fluids moved considerable distances within the parent body [5, 6]. Given the intergranular permeability of the CMs, an extensive fracture network would be required to support such flow. Clues to how the two very different models for aqueous alteration of the CMs can be reconciled have been recently provided by Rubin [7]. He recognised a good correlation between the magnitude of impact-induced compaction of CM meteorites and their degree of aqueous processing, with the more highly deformed meteorites being more altered. Here we have asked whether compaction was accompanied by the development of fracture networks that could have provided the conduits for aqueous solutions that mediated all or some of the alteration.

• Item Type: Conference Proceedings
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Lee, Professor Martin and Lindgren, Dr Paula
• Authors: Lindgren, P., Lee, M.R., and Simpson, S.S.L.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Copyright Holders: Copyright © 2014 The Authors
• Publisher Policy: Reproduced with the permission of the publisher