Summary:
The Prairie Project is located on the northeastern flank of the Williston Basin. The Williston Basin is an elliptically shaped, 560 km diameter intracratonic sedimentary basin on the western shelf of the North American craton centered in North Dakota (Kent and Christopher, 1994).
The target interval of this Project is porous carbonate rocks of the Upper Devonian (Frasnian) Duperow Formation, Saskatchewan Group (Gerhard et al., 1982; Kent and Christopher, 1994). Upper Devonian sediments were laid down in a northwest to southeast elongated Elk Point Basin that extended broadly from northwestern Alberta, through Saskatchewan, and across into North Dakota and Montana (Dunn, 1975).
The lithology consists of layered limestone, dolomite, and evaporites. Repeated shallowing-up or "briningup" successions occur within each member consisting of marine limestone and dolomite at the base and passing gradually upwards into dominantly restricted evaporitic intervals of anhydrite and halite (Dunn, 1975). Carbonates (particularly dolomite) form laterally continuous units or aquifers of higher reservoir quality, whereas evaporites form intervals of poor reservoir quality and may contribute as vertical permeability baffles or aquitards. Dolomite occurrence and thickness decreases upwards within the Duperow Formation and generally increases in thickness northeastward at the Project.
The Duperow Formation correlates westward with the Leduc Formation, a prominent series of reefs in the open-marine Alberta Basin. Middle and Late Devonian sedimentation was characterized by cyclic carbonates and evaporites. Cyclic ordering of strata from shelf carbonates to restricted supratidal carbonates and evaporites, are identified as shallowing-upward or "brining-upward" parasequences and these cyclic intervals are recognized throughout the entire Devonian stratigraphic column in the Elk Point Basin of southern Saskatchewan (Kent and Christopher, 1994). The Duperow Formation was deposited as a shallow-marine, carbonate inner platform to supratidal sabkha or tidal flat (Cen and Salad Hersi, 2006).
The deposit type being explored by Arizona Lithium is a lithium-bearing brine hosted by the Duperow Formation. Other lithium-rich brine deposits within oilfields include the brines within the Smackover Formation of the Gulf Coast and the Leduc Formation in Alberta (Kesler et al., 2012; Bowell et al., 2020).
Lithium brines are defined as accumulations of saline groundwater enriched in dissolved lithium (Bradley, et al., 2017) within arid climates. Lithium brines are located within closed sedimentary basins with a close association with evaporite deposits resulting from trapped evaporatively concentrated seawater (Bradley et al., 2013). Lithium brines are hosted within one or more aquifers, which have had sufficient time to concentrate a brine (Bradley et al., 2017).
Historical and newly acquired brine analysis data indicates that the Property is located within an area of extremely elevated TDS brine above 300,000 mg/L and with lithium concentrations of up to 258 mg/L within the Duperow Formation. Newly acquired geochemical data has allowed Arizona Lithium to characterize lithium content of the Duperow Formation within much of the Property. Lithium results from wells located across the Property and beyond indicate that lithium concentrations are elevated and laterally continuous across the Property.
The northern limit of elevated lithium concentrations in the Duperow Formation occurs beyond the northern limits of the Property. Elevated lithium trends extend through the Property and south into North Dakota. Lithium values indicate low lithium concentrations from R18W2 and beyond to the west.
Dimensions
Across the Project, the top of the Duperow Formation varies in depth from 1,700 m true vertical depth (TVD) the northeast to 2,500 m TVD in the southwest. Structure elevation maps between the top of the Duperow (Seward member) and the bottom of the Duperow Formation (top of Souris River Formation) were prepared in the resource area. Between 548 wells (top Souris River Formation) and 570 wells (top Duperow Formation) were used in the interpolation of each surface. Based on the high quality of the wireline logs and the nature of the high correlation of the Duperow, the dimensions of the Mineral Resource are well constrained.
Based on the geologic setting, regional hydraulic head mapping, and regional geochemical characterizations, the Duperow Aquifer is judged to be hydraulically continuous within, and far beyond, the Arizona Lithium resource area. The historical, and recently measured lithium concentrations in the Duperow Formation, also suggest that lithium concentrations are continuous across the Resource Area.