International Journal of Astrobiology

Table of Contents - 2006 - Volume 5, Issue 04  


The ~3.4 billion-year-old Strelley Pool Sandstone: a new window into early life on Earth

David Wacey a1, Nicola McLoughlin a1, Owen R. Green a1, John Parnell a2, Crispin A. Stoakes a3 and Martin D. Brasier a1
a1 Department of Earth Sciences, University of Oxford, Parks Road, Oxford OX1 3PR, UK e-mail: davidwa@earth.ox.ac.uk
a2 Department of Geology and Petroleum Geology, University of Aberdeen, Aberdeen AB24 3UE, UK
a3 C.A. Stoakes and Associates Pty Ltd, 3185 Victoria Road, Hovea, WA 6071, Australia

Article author query
wacey d   [PubMed][Google Scholar] 
mcloughlin n   [PubMed][Google Scholar] 
r. green o   [PubMed][Google Scholar] 
parnell j   [PubMed][Google Scholar] 
stoakes ca   [PubMed][Google Scholar] 
brasier md   [PubMed][Google Scholar] 

Abstract

The recognition and understanding of the early fossil record on Earth is vital to the success of missions searching for life on other planets. Despite this, the evidence for life on Earth before ~3.0 Ga remains controversial. The discovery of new windows of preservation in the rock record more than 3.0 Ga would therefore be helpful to enhance our understanding of the context for the earliest life on Earth. Here we report one such discovery, a ~3.4 Ga sandstone at the base of the Strelley Pool Formation from the Pilbara of Western Australia, in which micrometre-sized tubular structures preserve putative evidence of biogenicity. Detailed geological mapping and petrography reveals the depositional and early diagenetic history of the host sandstone. We demonstrate that the depositional environment was conducive to life and that sandstone clasts containing putative biological structures can be protected from later metamorphic events, preserving earlier biological signals. We conclude from this that sandstones have an exciting taphonomic potential both on early Earth and beyond.

(Received June 28 2006)
(Accepted August 28 2006)


Key Words: Archaean; early life; microtubes; Pilbara; sandstone; Strelley Pool Formation; taphonomy.