Distribution and Origin of Lithium-Enriched Formation Waters in Alberta

The initial report of lithium-enriched formation waters in Alberta was made during the early 1990s, when a well database of nearly 130,000 analyses of formation waters was investigated for the government in the search for elements of potential economic interest. Deep aquifers were identified as a source of metals with economic potential with lithium abundances of up to 140 mg/L in Devonian carbonate formation waters. However, only statistical results and minimal data were actually included at that time. In an effort to make those data available for the public, a digital data file was put together in 2010 containing lithium abundances in groundwater including formation waters. This digital data file has facilitated the recent mineral exploration boom for lithium in the province at a time when the world demand has been rapidly increasing. In early 2017, this dataset was made available through the Alberta’s Interactive Map (AIMM) which has been updated since then as more data become available. Currently, AIMM’s lithium dataset comprises lithium abundances data in formation waters captured from various government and industry publications, comprising a total of 1,683 records, of which 172 have concentrations over 50 mg/L. Most of the anomalous data (>50 mg/L) and highest concentrations occur within Devonian carbonates in south-central and west-central Alberta. Fewer analyses display anomalous values in Cambrian, Triassic, Carboniferous-Mississippian, Jurassic and Cretaceous units. Devonian formation waters of the Swan Hills, Leduc and Nisku formations are those with the most significant lithium values.  

A recent research study on the geochemical characteristics of lithium-enriched oilfield brines within Devonian carbonates of the southwestern Alberta Basin shows the presence of at least two brines with distinct chemistry and thus distinct evolutionary histories. Lithium-enriched brines of the Swan Hills Formation are thought to have formed by the dissolution of halite and mixing with Li-enriched basement-derived fluids. Lithium-enriched brines of the Nisku and Leduc formations are thought to have formed by preferential dissolution of lithium-enriched late-stage evaporite minerals, likely from the middle Devonian Prairie Evaporite, into evapoconcentrated late Devonian seawater.