Any sedimentary rocks that formed before life appeared ... They found that carbon in the apatite had the same low C-13 ratio as biological carbon today -- a ratio that could only have come from ...

"Our study focuses on chemical sedimentary rocks found in the ... that the carbon isotopic composition of these rocks is indicative of a biological origin, but rather suggesting abiotic ...

“The approximately 3.5-billion-year-old stromatolites in sedimentary rocks of Western Australia are currently regarded as the oldest evidence of life on Earth, and pushing the record further back in ...

During biological weathering ... Rock particles can be transported by rivers and form sedimentary rocks. 1 Sediment transport Sediment transport is the first all of the processes by which the ...

I am a chemical sedimentologist: I study how and why chemical sediments form and lithify, with the goal of better understanding how chemical sedimentary rocks (e.g., carbonates, chert, iron formations ...