Characterizing the potential of wind-blown lithium sediments: A case study from Devonian evaporites of the Western Canada Sedimentary Basin

Abstract Elevated lithium (Li) within the formational waters of deep sedimentary basins continues to garner attention as a widespread addition to global Li resources. However, the nature of Li emplacement remains understudied. Here we document elevated Li in Devonian evaporites of the Western Canada Sedimentary Basin and reconstruct the processes that led to their enrichment. Our results show bulk Li concentrations ranging from 49.4 ppm to 284 ppm. Contrary to previous speculation that Li is hosted within evaporitic minerals, our findings indicate that it is instead within aggregate grains of clay-sized particles composed of micas and clay minerals. The Li-bearing grains range from subangular to rounded, displaying a bimodal distribution with particle fractions of either medium- to coarse-grained silt or very fine sand. The individual particles average 304 ppm Li and attain concentrations as high as 394 ppm. Previous work has shown that Li was weathered from Precambrian basement and transported into the basin via fluvial discharge; however, no attempt has been made to characterize the distribution of these sediments by wind-borne processes. Thin sections reveal that these aggregate grains are widespread and that they dominantly occur in supratidal sediments, waning in abundance into lower intertidal deposits. Based on the particle distribution and several other lines of evidence, we suggest that these Li-rich detritals were deposited by wind-borne processes, and the results herein are the first to characterize the potential of wind-blown Li sediments. Given the extent of enrichment in these evaporites, we propose that aeolian processes play an important yet underappreciated role in transporting and accumulating Li-rich sediments. As alternative Li resources continue emerging, these findings highlight the potential of wind transport and provide a predictive framework for the paleogeographic distribution of Li-rich strata and their associations with Li-enriched brines.