Alcheringa Archaean Stromatolites

Description: Stromatolites are remnants of the most ancient of colonial organisms. Stromatolites are fossils that are the result of the work of simple blue-green “algae” or Cyanophytes, which lived in chains or mats covered in a jellylike substance. By taking in carbon dioxide as a food source, the precipitate limy deposits on the jelly that builds up in layers. Thus these organisms build up stony supports for their colonies. These mound like structures can be anywhere from several centimeters to several meters in height. The production of oxygen is thought to have led to the “rusting of the seas” which brought about deposition of extensive iron deposits such as the Mesabi Range. Hematite is an iron mineral, and is one of the components of this banded structure (dark bands). Stromatolites have persisted to the modern day in such places as Shark Bay, Australia where they continue their billions of years old lifestyle. Western Australia is home to a number of types of stromatolites, with Alcheringa narrina being the oldest. The fabric of this stromatolte is indicative of composition by a microorganism with coarse filaments or perhaps filament bundles similar to those of the cyanophyte Rivularia. The deep charcoal color is most pleasing, as is the fine polish of the display side.