Signatures for Ancient Life in Europe’s Largest Impact Structure

October 24, 2019


Crystals_H_Drake (002)

Photographer: Henrik Drake 
Summary Author: Henrik Drake 

Recent research has indicated novel findings of signatures for ancient life in Europe’s largest impact structure. The photo above shows calcite crystals from deep within the crater that formed some 37 million years ago, as shown by U-Pb dating. These crystals have carbon isotopic signatures that reveal microbial methanogenesis. Fractured rocks of impact craters have been thought to host deep microbial communities on Earth, and potentially other terrestrial planets, yet direct evidence has remained elusive.

At the scenic site of Siljan, in the heart of Sweden, an impressive impact structure of approximately 31 miles (50 km) in diameter formed almost 400 million years ago. Previous well-known drilling attempts for deep natural gas have been renewed and from these newly retrieved drill cores, a team of researchers found widespread evidence for deep ancient life. Deep beneath our feet life thrives in a vast but underexplored environment coined the deep biosphere. Our findings confirm that impact craters are favorable microbial habitats on Earth and perhaps beyond. Moreover, it’s suggested that colonization of these deep environments may have been sparked by meteorite impacts.