Bedrock Base Map Location 1
These layered domes are fossil stromatolites, sedimentary structures formed from ancient microbial life (most likely cyanobacteria) which produced an adhesive substance that would cement sediment to form “microbial mats”. These microorganisms are thought to have used sunlight to carry out oxygen-producing photosynthesis. This oxygen eventually accumulated in the Earth’s atmosphere, dramatically transforming Earth into the oxygen-rich world we know today.
Bedrock southwest of Marquette, Michigan | Paleoproterozoic | 2.1 to 2.2 billion years old