DNA sequencing, microbial indicators, and the discovery of buried kimberlites

Abstract

Population growth and technological advancements are placing growing demand on mineral resources. New and innovative exploration technologies that improve detection of deeply buried mineralization and host rocks are required to meet these demands. Here we used diamondiferous kimberlite ore bodies as a test case and show that DNA amplicon sequencing of soil microbial communities resolves anomalies in microbial community composition and structure that reflect the surface expression of kimberlites buried under 10 s of meters of overburden. Indicator species derived from laboratory amendment experiments were employed in an exploration survey in which the species distributions effectively delineated the surface expression of buried kimberlites. Additional indicator species derived directly from field observations improved the blind discovery of kimberlites buried beneath similar overburden types. Application of DNA sequence-based analyses of soil microbial communities to mineral deposit exploration provides a powerful illustration of how genomics technologies can be leveraged in the discovery of critical new resources.

Microbial indicators and detection of Cu-sulfide ore mineralization

“…DNA extraction and QA/QC DNA extraction and quantification was performed as described in: (Simister et al, 2023).…”

“…Gene amplification and DNA amplicon sequencing were performed as described in: (Simister et al, 2023).…”

“…This is forcing mineral exploration efforts to increasingly focus on concealed targets (Winterburn et al, 2020), requiring development of tools that detect unexposed mineralization. Whereas biological approaches to exploration have received minimal attention and uptake in the past, emerging DNA sequencing technologies offer new opportunities to harness the power of genomics across the resource sector with strong potential to improve mineral resource discovery (Simister et al, 2023).…”

“…Mineral deposits in the subsurface likely represent an acute example of this, whereby ore minerals and constituent elements can be elevated orders of magnitude above background concentrations (Kelley et al, 2006). As such, microbial community compositions likely reflect variability in the mineralogical composition of soils based on their proximity to, and interaction with, buried ore minerals (Simister et al, 2023). Furthermore, given the sensitivity of microorganisms to their surroundings, anomalies in microbial community compositions may develop, even if differences in physicochemical properties of the host soils are not resolvable through geochemical analyses.…”

“…Microbial community fingerprinting effectively delineates lithologically controlled mineralization, but capacity for resolving disseminated and structural ores remains untested. For example, diamondiferous kimberlites concealed by glacial till can be detected through soil microbial community anomalies that develop over kimberlite pipes, even where geochemical signals have been glacially dispersed (Simister et al, 2023). It remains unknown, however, whether this phenomenon is more broadly extensible, and if other ore types can be detected through similar applications of DNA sequencing.…”