Bitter Springs Formation

The Bitter Springs Formation, also called the Bitter Springs Group, is a Precambrian fossil locality in the Amadeus Basin of the Northern Territory and Western Australia, preserving stromatolites and microorganisms in chert. It dates to the Tonian period of the Proterozoic, roughly 896 to 767 million years ago, and divides into three formations, the Gillen, Loves Creek and Johnnys Creek Formations, its silica-rich chert exceptionally preserving delicate microfossil structures. It has yielded well-preserved cyanobacteria microfossils and several stromatolite species, notably Linella avis and Inzeria intia, along with debated evidence of preserved eukaryotic green algae; its distinctive silicifying mode of preservation ceased later in the Neoproterozoic with the rise of silicifying organisms.