The Early Archean Apex Basalt, found in northwestern Western Australia, is the source for some of the world’s oldest fossils. It holds eleven different taxa of microbes in a bedded chert (SAO/NASA a). They are microfossils because they are only 10 to 20 micrometers long. They are mostly filaments formed from chains of single cells and resemble current cyanobacteria and blue-green algae (USRA).
The microfossils’ strong resemblance to the cyanobacteria of today supports the possibility that oxygen producing photosynthetic bacteria could have existed as early as approximately 3.465 billion years ago. Also, the number of different kinds of microfossils gives evidence of the morphological diversity of the bacteria (SOA/NASA a).
The microfossils have also been a source of debate as to whether or not the fossils are abiotic. Using recent technology, scientists have been trying to verify the fossils’ biogenicity. However, the results thus far have not been clear (SAO/NASA b).

Page by Laura Snyder