Nanoscale Biosignatures Reveal Diverse Microbial Life in 3.7-Ga Rocks from Greenland
G3 Co-Evolution of Earth and Life from the Archean to the Proterozoic 📅 Add to Calendar✉ Corresponding: Zhongqiang Chen
Carbonaceous matter (CM) in the 3.7 Ga Isua Supracrustal Belt represents a crucial target for early life investigations, yet its biological origin remains debated. Using nanoscale secondary ion mass spectrometry (NanoSIMS) and Raman spectroscopy, we identify three CM types. Type A (~5%), matrix-hosted and of low-temperature, exhibits strong 12C, 12C14N, and 32S signals, with light δ¹³C (avg. -40.6‰). Type B (~85%), of high-temperature and lacking N-S, shows higher δ¹³C (avg. -27.6‰). Type C (~10%), of high-temperature, has extremely light δ¹³C. These results demonstrate diverse microbial origins for Isua CM, establish a new biosignature classification framework for high-grade metamorphic terranes, and has direct applications in the study of meteorites and Mars samples.
Affiliations
- State Key Laboratory of Geomicrobiology and Environmental Changes, China University of
- Geosciences (Wuhan), Wuhan, China
- Natural History Museum of Denmark, Copenhagen, Denmark
- Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China