Archeaen Paleontology as an Analog for Possible Martian Life

Abstract

Record ID: 230

Award(s): Excellence in Research Mentoring

Program Affiliation: University Honors Program

Student Major: Geology

Project Advisor: Andrea Corpolongo

Abstract: Archean paleontology seeks to locate evidence of life in 2.5 to 4 billion-year-old rock. Documenting the morphology and fossilization of microfossil-bearing facies sheds insight into the search for extraterrestrial life. Carbonate rocks located around the rim of Jezero crater, a 3.5 billion-year-old lake on Mars, resemble fossiliferous deposits of Earth's Archean era. Microbialites, which are formations similar to what could be found on Mars, are any rocks formed through microbial processes. Though carbonate microbialites tend not to preserve individual microfossils, they display structures created by the bacterial colonies that formed them. Orbital imaging and spectroscopy of Jezero crater shows evidence of carbonates near ancient deltaic channels and erosional features. However promising the Martian landscape is, research must be done on Earth to establish what features definitively indicate a rock is of biological origin. We use 3D models derived from the serial imaging of Archean age microbialites from the Gamohaan formation in South Africa to establish overall colonial morphology. Raman spectroscopy is also used to observe signatures indicative of organic life. We show that ancient microorganisms formed complex, web-like structures within the texture of the rock, forming recognizable "peak" or "circus-tent" structures. Fossilized organic material can also be reliably detected through Raman spectroscopy due to its characteristic spectrum. The Perseverance rover performs Raman spectroscopy on Mars, allowing comparison with positive controls from Earth. This methodology may one day allow the discovery and study of potential extraterrestrial life in carbonates far from Earth's surface.