Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso

Mount McRae Shale

  • Nicholas Arndt
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_1029-3


The Mount McRae Shale is a 2.5-Ga-old unit of mudstone, siltstone, chert, iron formation, and dolomite in the Hamersley basin of the Pilbara craton, Western Australia. It is characterized by a high concentration of organic carbon (∼2–8 wt%), abundant disseminated pyrite (∼1 to ∼10 wt% S in the bulk rocks), and pyrite nodules (∼1–10 cm radius). Analysis of S and Fe isotopic compositions of carbonaceous pyritic shale recovered in the NASA-sponsored Astrobiology Drilling Program revealed variations in isotopic compositions that have been linked to changes in the composition of the ocean and the atmosphere and to fluctuations and a temporary rises of atmospheric oxygen that preceded the Great Oxygenation Event (GOE) at 2.32 Ga.

See Also


Organic Carbon Isotopic Composition Temporary Rise Bioorganic Chemistry Atmospheric Oxygen 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Maison des GéosciencesLGCA, Université J. FourierSt-Martin d’HèresFrance