Investigating Microbial Trace-fossils and Abiotic Alteration in Hydrovolcanic Tuffs of the Fort Rock Volcanic Field, Oregon

Microbial ichnofossils in volcanic rocks provide a significant record of subsurface microbes and potentially extraterrestrial biosignatures. Here, the textures, mineralogy, and geochemistry of two continental basaltic hydrovolcanic deposits - Reed Rocks and Black Hills - in the Fort Rock Volcanic Field (FRVF) are investigated. Methods include petrographic microscopy, micro and powder X-ray diffraction, SEM/BSE/EDF imaging, energy dispersive spectroscopy, stable isotopes, and X-ray fluorescence. Petrographic analysis revealed granular and tubular textures with biogenic morphologies that include terminal enlargements, septate divisions, branching forms, spiral filaments, and ovoid bodies resembling endolithic microborings described in ocean basalts. They display evidence of behaviour and a geologic context expressing their relative age and syngenicity. Differences in abiotic alteration and the abundance/morphotype assemblage of putative microborings between the sites indicate that water/rock ratio, fluid composition and flux, temperature and secondary phase formation are influences on microboring formation. This study is the first report of reputed endolithic microborings in basalts erupted in a continental lacustrine setting.

Name thesis:degree_name

M.Sc. Earth Sciences

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Faculty of Mathematics and Science

Department dc:contributor.department

Department of Earth Sciences

Grantor

Brock University

Year dc:date.issued

2016

Author dc:creator

• Nikitczuk, Matthew Peter Casimir

• basaltic glass
• endolithic microborings
• palagonite
• Fort Rock Volcanic Field
• hydrovolcanism

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/10464/7997

OAI identifier oai:identifier

oai:brocku.scholaris.ca:10464/7997