Biogenic Origin for Earth's Oldest Putative Microfossils

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Geology

DOI:https://doi.org/10.1130/G25683A.1· OSTI ID:980041

De Gregorio, B; Sharp, T; Flynn, G; Wirick, S; Hervig, R

Carbonaceous microbe-like features preserved within a local chert unit of the 3.5 Ga old Apex Basalt in Western Australia may represent some of the oldest evidence of life on Earth. However, the biogenicity of these putative microfossils has been called into question, primarily because the sample collection locality is a black, carbon-rich, brecciated chert dike representing an Archean submarine hydrothermal spring, suggesting a formation via an abiotic organic synthesis mechanism. Here we describe the macromolecular hydrocarbon structure, carbon bonding, functional group chemistry, and biotic element abundance of carbonaceous matter associated with these filamentous features. These characteristics are similar to those of biogenic kerogen from the ca. 1.9 Ga old Gunflint Formation. Although an abiotic origin cannot be entirely ruled out, it is unlikely that known abiotic synthesis mechanisms could recreate both the structural and compositional complexity of this ancient carbonaceous matter. Thus, we find that a biogenic origin for this material is more likely, implying that the Apex microbe-like features represent authentic biogenic organic matter.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 980041
• Report Number(s): BNL--92959-2010-JA
• Journal Information: Geology, Journal Name: Geology Journal Issue: 7 Vol. 37; ISSN 0091-7613; ISSN GLGYBA
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
BASALT
BONDING
CARBON
CHEMISTRY
CHERT
ELEMENT ABUNDANCE
FUNCTIONALS
GEOLOGIC STRUCTURES
HYDROCARBONS
KEROGEN
LOCALITY
MATERIALS
MATTER
ORGANIC MATTER
ORIGIN
SUBMARINES
SYNTHESIS
UNITS
WESTERN AUSTRALIA
national synchrotron light source