Oldest Archean Fossils

Description: I was fortunately able to acquire a few examples of the currently oldest-known fossils from the early time of life on earth: microbial mats from the Dresser Formation of Western Australia. These specimens are some 50 MILLION YEARS Older than the Strelly Pool Stromatolites (see my other listings) also found in Western Australia. These structures were the response of microbial mats to sedimentary dynamics through processes that do not involve a production of minerals within the organic matrix as do stromatolites. Formation of such mats arise from primary shaping by physical sediment dynamics (e.g erosion, deposition, latency) followed by mineralization of the organic material. For example erosional stress by water currents passing over the mat triggers biostabilization in order to prevent burial. When a mat is exposed to sediment deposition, the matt’s filaments orient themselves perpendicularly to the surface, reaching into the water above causing turbulence known as baffling. This induces the fallout of sediment which are then incorporated into the mat’s structure. While the mats themselves are formed by these primary processes, the secondary process of rapid in situ mineralization is what preserves them. Comparison of the structures seen within the deposits of the Dresser Formation with those of later and even extant microbial mats have led the authors of the paper referenced below that they are indeed biogenic in nature. Perhaps when Man has made it to the surface of Mars similar type structures will be found.

Reference: Astrobiology, Vol 13 No 12, 2013, pp 1103-1124