Answer Monday

Last week on Fossil Friday, I presented you with a fossil—and very little information about said fossil. I told you it was found in modern day Nevada, and hails from the Miocene. But beyond that, you were on your own. Was it a piece of dino-poo? A strange and warty blowfish? An early gambling chip?

 No, it was a stromatolite! From the UCMP:

“The oldest stromatolites date to the Early Archaean, and they became abundant by the end of the Archaean. In the Proterozoic, stromatolites were widespread on earth, and were ecologically important as the first reefs. By the close of the Proterozoic, the abundance of stromatolites decreased markedly, though cyanobacteria continued to leave a fossil record, such as Langiella and Kidstoniella known from the Lower Devonian Rhynie chert.

The cyanobacteria have also been tremendously important in shaping the course of evolution and ecological change throughout earth's history. The oxygen atmosphere that we depend on was generated by numerous cyanobacteria photosynthesizing during the Archaean and Proterozoic Era. Before that time, the atmosphere had a very different chemistry, unsuitable for life as we know it today.”

Thanks to those who played this week. Stay tuned for more fossil fun this Friday!