NEWS: Stromatolite Reef (Early Archaean) Australia

Stromatolite reef from the Early Archaean era of Australia
News from Nature - International weekly journal of science.
Abigail C. Allwood, Malcolm R. Walter, Balz S. Kamber, Craig P. Marshall and Ian W. Burch

"The 3,430-million-year-old Strelley Pool Chert (SPC) (Pilbara Craton, Australia) is a sedimentary rock formation containing laminated structures of probable biological origin (stromatolites). Determining the biogenicity of such ancient fossils is the subject of ongoing debate. However, many obstacles to interpretation of the fossils are overcome in the SPC because of the broad extent, excellent preservation and morphological variety of its stromatolitic outcrops—which provide comprehensive palaeontological information on a scale exceeding other rocks of such age. Here we present a multi-kilometre-scale palaeontological and palaeoenvironmental study of the SPC, in which we identify seven stromatolite morphotypes—many previously undiscovered—in different parts of a peritidal carbonate platform. We undertake the first morphotype-specific analysis of the structures within their palaeoenvironment and refute contemporary abiogenic hypotheses for their formation. Finally, we argue that the diversity, complexity and environmental associations of the stromatolites describe patterns that—in similar settings throughout Earth's history—reflect the presence of organisms."

Australian Centre for Astrobiology/Macquarie University Biotechnology Research Institute, and
Department of Earth and Planetary Sciences, Macquarie University, Herring Road, Sydney, New South Wales 2109, Australia
Department of Earth Sciences, Laurentian University, 933 Ramsey Lake Road, Sudbury, Ontario P3E 6B5, Canada
Vibrational Spectroscopy Facility, School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia

Received 9 September 2005 Accepted 29 March 2006

This is exciting news from a Paleontological standpoint! Stromatolie Fossils are, in many respects, "the most intriguing fossils that are our singular visual portal (except for phylogenetic determination of conserved nucleic acid sequences and molecular fossils) into deep time on earth, the emergence of life, and the eventual evolving of the beautiful life forms from Cambrian to modern time. A small piece of stromatolite encodes biological activity perhaps spanning thousands of years. In broad terms, stromatolites are fossil evidence of the prokaryotic life that remains today, as it has always been, the preponderance of biomass in the biosphere. For those that subscribe to the theory of the living earth, it is the prokaryotes that maintain the homeostasis of the earth, rendering the biosphere habitable for all other life. They maintain and recycle the atomic ingredients upon which proteins that "are" all life are made, including oxygen, nitrogen and carbon. We humans are, in simple terms, bags of water filled with proteins and prokaryotic bacteria (the bacteria in your body outnumber the cells in your body about 10 to 1). We humans have descended from organisms that adapted to living in a prokaryotic world, and we humans retain (conserved in evolutionary terms) in our mitochondria the cellular machinery to power our cells that we inherited (i.e., endosymbiosis) from the prokaryotes of deep time on earth," states one source from FossilMall.

"Stromatolites and their close cousins the thrombolites, are rock-like buildups of microbial mats that form in limestone- or dolostone-forming environments," this souce continues. "Together with oncoids (formerly called "algal biscuits" or "Girvanella"), they typically form by the baffling, trapping, and precipitation of particles by communities of microorganisms such as bacteria and algae. In some cases, they can form inorganically, when seawaters are oversaturated with chemical precipitates. Stromatolites are defined as laminated accretionary structures that have synoptic relief (i.e., they stick up above the seafloor). Stromatolite-building communities include the oldest known fossils, dating back some 3.5 billion years when the environments of Earth were too hostile to support life as we know it today. We can presume that the microbial communities consisted of complex consortia of species with diverse metabolic needs, and that competition for resources and differing motility among them created the intricate structures we observe in these ancient fossils."

Finally, "Excluding some exceedingly rare Precambrian fossils such as the Ediacaran fauna, stromatolites are
the only fossils encoding the first 7/8th of the history of life on earth. They encode the role that ancient microorganisms played in the evolution of life on earth and in shaping earth's environments. The fossil record of stromatolites is astonishingly extensive, spanning 4 billion years of geological history with the forming organisms possibly having occupied every conceivable environment that ever existed. Today, stromatolites are nearly extinct in marine environments, living a precarious existence in only a few localities worldwide. Modern stromatolites were first discovered in Shark Bay, Australia in 1956, and through out western Australia in both marine and non-marine environments. New stromatolite localities have continued to be discovered in various places such as the Bahamas, the Indian Ocean and Yellowstone National Park, to name but a few localities."

The work that will be undertaken on the Strelley Pool Chert wil give us an even broader glimpse into a bygone era, and provide more data concerning the presence of organisms within the stromatolite formation located there. I will keep you updated as this study is carried out. Best of luck to those involved with this!

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