The Bonnie Claire volcano-sedimentary Li–B deposit

Bonnie Claire is an example of the emerging “claystone-hosted” or “volcano-sedimentary” lithium-boron deposit type. They form in extensional tectonic settings and are closely associated with felsic volcanism. They are hosted in closed arid basins, and form when volcanic glass alters to lithium-rich smectite and illite. Lithium grades range from 1000 ppm to 6000 ppm, and can be up to 5B tonnes in size, with mine lives projected to span several generations.

Most of these deposits have been discovered in last decade, with projected industrial demand fueling market and academic interest. By virtue of their scale, we believe that these deposits could become the cornerstone of N American lithium production, and a broader understanding of their formation is clearly warranted.

Bonnie Claire is the second largest example of this deposit type identified so far. The deposit seems to have formed from rhyolitic tuffs that erupted from the nearby Timber Mountain Complex and accumulated into an active, transcurrent pull-apart basin within the Walker Lane Trend.

While it displays many typical volcano-sedimentary characteristics, this combination of structure, basin dynamics, sedimentation and volcanism with lithium and boron mineralization is unique. Understanding those relationships will be integral to its eventual development and broaden our understanding of this emerging deposit type.