Uncovering and understanding the chemical and fossil record of ancient life is crucial to understanding how life arose, evolved, and distributed itself across Earth. Potential signs of ancient life, however, are often challenging to establish as definitively biological and require multiple lines of evidence. Hydrothermal silica deposits may preserve some of the most ancient evidence of life on Earth, and such deposits are also suggested to exist on the surface of Mars. Here we use micron-scale elemental mapping by secondary ion mass spectrometry to explore for trace elements that are preferentially sequestered by microbial life and subsequently preserved in hydrothermal deposits. The spatial distributions and concentrations of trace elements associated with life in such hydrothermal silica deposits may have a novel application as a biosignature in constraining ancient life on Earth as well as the search for evidence of past life on Mars. We find that active microbial mats and recent siliceous sinter deposits from an alkaline hot spring in Yellowstone National Park appear to sequester and preserve Ga, Fe, and perhaps Mn through early diagenesis as indicators of the presence of life during formation.
Bibliographical noteFunding Information:
The Ohio Space Grant Consortium, Geological Society of America, Paleontological Society, Sigma Xi, the University of Cincinnati Graduate Student Governance Association, and the University of Minnesota provided funding for travel and sample analyses. The American Philosophical Society, NASA Astrobiology Institute, and the University of Cincinnati provided funding for sample collection and field work in Yellowstone National Park.
© Mary Ann Liebert, Inc., publishers 2020.
- Trace element
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't
- Research Support, U.S. Gov't, Non-P.H.S.