UBC Theses and Dissertations
Microorganisms as sensors for concealed mineral deposits ; application and development of microbiological mineral exploration in the Northwest Territories and British Columbia, Canada Iulianella Phillips, Bianca P.
Mineral exploration is becoming more challenging in that undiscovered deposits are likely concealed beneath thick cover sequences. Current, through-cover, geochemical methodologies often provide inconsistent results and have poorly developed anomalies that may go undetected. The development of innovative exploration strategies and robust techniques to see through cover is thus imperative to future discovery success. Profiling of microbial communities that populate the soils above mineral deposits provide a solution for geologists exploring in covered terrains. Microorganisms are well equipped to detect geochemical gradients as they are highly sensitive to subtle differences in the chemical and physical properties of their surroundings. High-throughput DNA sequencing technology and big-data analysis techniques have now advanced to the point that high-resolution information on microbial community composition and structure is readily accessible. My results have demonstrated the viability of microbial fingerprinting to directly identify the surface projection of buried kimberlites and porphyry copper deposits. Lab incubations and case studies from the Northwest Territories and south-central British Columbia were used to test the efficacy of microbial community profiling in deposit-scale exploration. Resulting 16S sequencing-derived datasets were integrated with chemistry, mineralogy, surface and sub-surface geology. My analyses show statistically significant microbial community shifts, correlated with the presence of porphyry copper mineralization and kimberlites, with a distinct community response at the species level directly over known deposits. The diversity of soil bacteria at kimberlites is also depressed in the same regions where microbial community profiles were anomalous. The observed relationship between microbial communities and buried mineralization demonstrates the power of microbial fingerprinting as a tool to accurately delineate putative ore deposits in covered terrain. The integration of microbial community information with soil chemistry and landscape development coupled with geology and geophysics appreciably improves the drill / no-drill decision process and has proven to be far more accurate than traditional surficial exploration methods, alone. There is high potential for application as a field-based technique as microbial databases for kimberlites and porphyry deposits are refined, and as sequencing technology is progressively developed into portable platforms.
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