Geoscience
Lithium in Manitoba
 Lithium-bearing pegmatiteLithium-bearing brinesLithium, the lightest metallic element, has physical and chemical properties uniquely suited to a wide range of applications including pharmaceuticals, glass and ceramics, and aerospace technologies. More recently, the manufacture of lithium batteries for use in personal electronic devices and electric or electric-hybrid vehicles has brought about substantial increases in demand. The major worldwide sources of lithium production are salt lake brines (e.g., Salar de Atacama, Chile) and granitic pegmatites (e.g., Greenbushes mine, Australia). In Manitoba, spodumene pegmatite in the world-class Tanco deposit, located in the Bird River greenstone belt of the Archean Superior province, historically represented an important lithium ore. The Manitoba Geological Survey is committed to improving the understanding of lithium resources in the province. Magmatic deposits (pegmatite) in the Archean Superior province and Paleoproterozoic Trans-Hudson orogen are currently being evaluated as sources of lithium. The Williston Basin overlies the Precambrian basement in southwestern Manitoba and contains several stacked saline aquifers, as well as thick evaporite deposits, that may host lithium brines or salts but have yet to be systematically evaluated for their potential.
Lithium-bearing pegmatiteGranitic pegmatite contains the largest known resources of lithium in Manitoba. The most prolific region is the Winnipeg River–Cat Lake pegmatite field, which hosts the world-class Tanco lithium-cesium-tantalum deposit, along with numerous other pegmatites that collectively define this large field.Elsewhere in the Archean Superior province, lithium-bearing pegmatite occurs at Red Sucker Lake, Gods Lake, Cross Lake, Red Cross Lake and McLaughlin Lake, and at Wekusko Lake in the Paleoproterozoic Trans Hudson orogen (Figure 1), indicating widespread potential for this deposit type. Spodumene, petalite and lepidolite are the most common lithium-bearing minerals in this type of deposit.
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Figure 1: Geological map of Manitoba showing the locations of lithium-bearing pegmatite fields. |
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Suggested referencesBannatyne, B.B. 1985: Industrial minerals in rare-element pegmatites of Manitoba; Manitoba Energy and Mines; Mineral Resources Division, Economic Geology Report 84-1, 96 p. Benn, D., Linnen, R.L. and Martins, T. 2018: Geology and bedrock mapping of the Wekusko Lake pegmatite field (northeastern block), central Manitoba (part of NTS 63J13); in Report of Activities 2018, Manitoba Growth, Enterprise and Trade, Manitoba Geological Survey, p. 79–88. Černý, P., Trueman, D.L., Ziehlke, D.V., Goad, B.E. and Paul, B.J. 1981: The Cat Lake-Winnipeg River and the Wekusko Lake pegmatite fields, Manitoba; Manitoba Energy and Mines, Mineral Resources Division, Economic Geology Report ER80-1, 216 p. plus 5 maps. |
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Lithium-bearing brinesThe Phanerozoic Williston Basin in southwestern Manitoba has a complex groundwater system with multiple aquifers and a wide range of salinities. The basin's regional aquifers are characterized by an eastward and upward flow of deep saline groundwater. Lithium concentrations within these brines vary throughout the basin and various aquifers. Despite limited lithium data being available for groundwater in Manitoba, regional extrapolation within the basin suggests elevated lithium concentrations may exist in deep aquifers. (Nicolas, 2017a)Located on the eastern edge of the sedimentary basin where the subsurface formation transition to a vast outcrop belt, a hydrologic divide separates fresh and saline groundwater in southern Manitoba (Figures 2 and 3; Nicolas, 2017b). Fresh water occurs in shallow aquifers to the east of the divide, whereas brines occur in deeper aquifers west of the divide. Brine sourcesManitoba has a number of brine sources:
Oilfield brinesManitoba's oil and gas operations produce large quantities of saline water (mostly brine) which contain a wide range of trace elements, including lithium. Following extraction of oil and gas at the battery site, saline wastewater is injected back into the oil reservoir or deep aquifers. Lithium extraction from this wastewater may represent an economic opportunity, which could utilize existing infrastructure to extend the life of marginal oil wells.Deep brinesDeep saline water occur through the Phanerozoic strata in southwestern Manitoba. These waters are the same as those associated with oilfield waste water with the exception that they are untapped and have never been produced. Devonian and Ordovician-aged strata, which have been identified as the most prospective intervals for lithium-rich brines, currently do not have oil production in Manitoba, and therefore no current means of evaluating their prospectivity directly.Brine springsDozens of brine springs occur along the western shores of Lake Winnipegosis. These springs are the surface expressions of a mixture of original basin brines and glacial melt water pushed into the basin during Pleistocene glaciation (Grasby and Betcher, 2002). These waters are thought to have low lithium concentrations due to water mixing. Historically, these springs produced small amounts of salt using an evaporation process for local use.Salt solution-derived brinesThe basin is surrounded by several lithium-bearing pegmatites that would have contributed lithium to the basin through weathering processes resulting in potential enrichment in the salts of the Prairie Evaporite. This formation is a thick salt-bearing formation (including potash) that may contain lithium-bearing salt minerals that can be extracted by salt solution operations. There is currently no data available on the lithium prospectivity of the Prairie Evaporite. The Prairie Evaporite salt is currently being solution mined near Virden, Manitoba to produce sodium chlorate. |
 Figure 2: Geological map of southern Manitoba showing distribution of rock units, oil fields, brine springs and the hydrologic divide.
Figure 3: West to east cross-section through southern Manitoba showing generalized groundwater salinity distribution and flow in Phanerozoic rock units. |
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Lithium concentrationsThe hydrogeochemistry of the saltwater is variable, depending on the source formation and location within the basin, which is itself related to the generative mechanism for these brines, whether it is by evaporitic concentration or halite dissolution. The concentration of lithium in Manitoba's groundwater is variable, with values from brines in the oil wells ranging from 0.258 to 7.32 ppm; values from freshwater to brackish water wells ranging from 0.01 ppb to 0.3 ppm; and values from shallow saline waters to brines in monitoring wells ranging from 0.488 to 3.84 ppm (Nicolas, 2017a, b). Despite the small number of results from deep brines, lithium concentrations in Manitoba's groundwater are low, with overall higher concentrations in the deep Jurassic and Paleozoic brines of southwestern Manitoba's oil region. Shallower brines and saline waters measured from the groundwater monitoring wells have slightly lower values for lithium, compared with the brines derived from deep oil wells (Nicolas, 2017a, b). Freshwater-dominated Cambro-Ordovician aquifers along the eastern erosional edge of the Williston Basin have extremely low lithium concentrations (Ferguson et al., 2005; Nicolas, 2017a).Given the limited availability of lithium data in Manitoba groundwater, preliminary studies indicate that the best targets would be from the oilfield and deep brines. Saltwater production and disposal from oil wells is a constant issue for the petroleum industry and is one of the dominant reasons for marginal well abandonment. The mineral potential of these brines may serve as an excellent economic opportunity for the operators to improve their profits and extend the life of marginal oil wells. Drilling to deeper horizons below the currently producing oil horizons is required to test their potential. Both the water-producing oil wells and deep target tests would have the benefit of taking advantage of the array of infrastructure already in place for oil operations. Suggested referencesGrasby, S.E. and Betcher, R.N. 2002: Regional hydrogeochemistry of the carbonate rock aquifer, southern Manitoba; Canadian Journal of Earth Sciences, v. 39, p. 1053–1063.Ferguson, G., Betcher, R.N. and Grasby, S.E. 2005: Water chemistry of the Winnipeg Formation in Manitoba; Geological Survey of Canada, Open File 4933, 37 p. Nicolas, M.P.B. 2017a: Preliminary investigation of the potential for lithium in groundwater in sedimentary rocks in southwestern Manitoba; in Report of Activities 2017, Manitoba Growth, Enterprise and Trade, Manitoba Geological Survey, p. 183–190. Nicolas, M.P.B. 2017b: Lithium in groundwater in sedimentary rocks, southwestern Manitoba; Manitoba Growth, Enterprise and Trade, Manitoba Geological Survey, Manitoba Mining and Minerals Convention 2017, Winnipeg, Manitoba, November 15–16, poster presentation.
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