Leachates formed carbonates in ALH84001 and on early Mars

Melwani Daswani, M.; Grady, M. M.; Schwenzer, S. P. and Wright, I. P. (2013). Leachates formed carbonates in ALH84001 and on early Mars. In: European Planetary Science Congress (EPSC) 2013, 8-13 Sep 2013, London, UK.

URL: http://www.epsc2013.eu/

Abstract

Evidence abounds for liquid water existing on Mars prior to the late heavy bombardment (LHB) ~ 3.9 Ga ago and physicochemically interacting with rocks to form distinct geomorphological landforms and mineralogical alteration products (e.g. [3, 4, 8, 14]). ALH84001, the oldest (~4.5–4.1 Ga [11, 13]) known martian meteorite, contains secondary carbonate minerals formed on Mars ~3.9–4.0 Ga ago [5], roughly contemporaneous to the LHB. Recent isotopic evidence supports their formation at low temperature (~18 °C [9]) and also by fluids derived from aqueous weathering in the Noachian/Phyllosian, due to the elevated ⁸⁷Sr/⁸⁶Sr ratios in the carbonates and bulk rock of ALH84001 [1].