Manitoba

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Mineral Commodities in Manitoba

Diamond Potential in Manitoba

The first diamond-bearing kimberlite in Canada was discovered in 1991 in the Northwest Territories, and the first diamond mine, Ekati, went into production by 1998. Canada produced 10.6 million carats of rough diamonds at a value of $1.9 billion (USD) in 2013, making it the fifth largest producer in the world and the third largest producer by value. Today, Canada has seven producing and past-producing diamond mines and many projects at various stages of exploration or development.

Primary diamond deposits are typically hosted by kimberlite or lamproite intrusions and volcanogenic rocks, although calcalkaline lamprophyre has recently been documented as an unconventional host for diamonds. These mantle-derived magmatic rocks act to transport the diamonds from deep in the mantle to the surface of the Earth. The relatively thick and cool lithospheric roots of Archean cratons create conditions amenable to diamond stability and typically underlie regions with the greatest potential for diamond deposits. Manitoba is underlain by extensive areas of Archean crust, namely the Superior, Hearne and Sask cratons, and there are documented occurrences of kimberlite in each of these cratons in adjacent jurisdictions. Although there are examples of mantle derived rocks sourced from the diamond stability field, kimberlite has yet to be documented, and Manitoba remains underexplored for diamonds.

The Manitoba Geological Survey has made significant progress in understanding the types and distribution of drift cover across Manitoba, and continues to engage in surficial geology and ice flow studies to support diamond exploration efforts. The results of this work are available at www.manitoba.ca/iem/geo/surficial/

Figure 1: Known occurrences of kimberlite and diamondiferous lamprophyre in Canada, shown in relation to Precambrian cratonic blocks. The crustal architecture of Manitoba is fundamentally similar to diamond-bearing regions throughout Canada, with known kimberlites west, east, and north of the province. Modified after Kjarsgaard (2007).

 

CARBONATITE OCCURRENCES

These carbonatite intrusions are not known to be related to kimberlites (see Figure 2). However, because they indicate crustal-scale ascent of small volumes of mantle-derived magma, the carbonatite occurrences may be spatially associated with kimberlite.

Figure 2: Carbonatite occurrences

 

LAMPROPHYRE OCCURRENCES

Considered in the context of favourable Kimberlite Indicator Minerals (KIM) results in surficial sediments, lamprophyre dikes of the Oxford–Knee Lake region may have potential for unconventional diamond deposits (e.g., diamondiferous lamprophyres of the Wawa and Abitibi subprovinces). Extrusive or resedimented equivalents of ultramafic lamprophyre composition were recently identified at Knee Lake, and contain possibly diatreme-related accretionary lapilli (Anderson, 2016).

 

SHOULDERBLADE DIATREME

Shoulderblade Island is a circular feature approximately 2 km in diameter dominated by carbonate breccias. It was interpreted by McCabe (1988) and Bezys and Bamburak (1994) as a diatreme. Although an association with mantle-derived magmatism has not been established at Shoulderblade, isolated centres of phreatomagmatic eruption may nonetheless indicate deep-seated structures necessary for kimberlite ascent.

 

KIMBERLITE INDICATOR MINERALS

Sampling of surficial sediments in parts of Manitoba has revealed a wide range of KIM suites, with promising results in the Hudson Bay Lowlands and the northern Superior province. Among the indicator minerals are garnets of G10 composition (low Ca, high Cr; potentially derived from diamond-forming mantle regions), which were found in several till samples from the northern Superior province and from areas of Mesozoic bedrock in the south. KIM sampling programs are currently underway in several parts of the province.

More detailed information, including public domain KIM data and an integrated anomaly map designed for kimberlite exploration, is available at www.manitoba.ca/iem/geo/kimdata

 

MANITOBA EXPLORATION AND MINING ADVANTAGES

  • Diverse, dynamic $59 billion economy — one of Canada’s strongest and most stable

  • Flexible transportation infrastructure for shipping by rail, air, road and sea

  • Supportive business climate and highly competitive mining tax regime

  • Easily accessible geoscience and exploration data

  • World-class deposits and high mineral potential in large underexplored regions

For more information, visit the Manitoba Mining Sector Profile.

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