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

Definition

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

Keywords

Organic Carbon Isotopic Composition Temporary Rise Bioorganic Chemistry Atmospheric Oxygen 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

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