Thor Lake is a deposit of rare metals located in the

Blachford Lake Blachford Lake is a remote lake in Northern Canada, near Yellowknife. The lake is and sits on precambrian rock. The lake is located to the north of the start of the eastern arm of the Great Slave Lake. It is home of the Dechinta: Centre for Res ...

intrusive complex. It is situated north of the Hearne Channel of

Great Slave Lake Great Slave Lake is the second-largest lake in the Northwest Territories, Canada (after Great Bear Lake), List of lakes by depth, the deepest lake in North America at , and the List of lakes by area, tenth-largest lake in the world by area. It ...

Northwest Territories The Northwest Territories is a federal Provinces and territories of Canada, territory of Canada. At a land area of approximately and a 2021 census population of 41,070, it is the second-largest and the most populous of Provinces and territorie ...

, Canada, approximately east-southeast of the capital city of

Yellowknife Yellowknife is the capital, largest community, and the only city in the Northwest Territories, Canada. It is on the northern shore of Great Slave Lake, about south of the Arctic Circle, on the west side of Yellowknife Bay near the outlet of t ...

. Geologically located on the

Canadian Shield The Canadian Shield ( ), also called the Laurentian Shield or the Laurentian Plateau, is a geologic shield, a large area of exposed Precambrian igneous and high-grade metamorphic rocks. It forms the North American Craton (or Laurentia), th ...

it is mostly composed of

peralkaline Peralkaline rocks include those igneous rocks which have a deficiency of aluminium such that sodium and potassium are in excess of that needed for feldspar. The presence of aegerine (sodium pyroxene) and riebeckite (sodium amphibole) are indicat ...

syenite Syenite is a coarse-grained intrusive igneous rock with a general composition similar to that of granite, but deficient in quartz, which, if present at all, occurs in relatively small concentrations (< 5%). It is considered a granitic rock A granitoid is a broad term referring to a diverse group of coarse-grained igneous rocks that are widely distributed across the globe, covering a significant portion of the Earth's exposed surface and constituting a large part of the continental ...

with low

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

content). The Blatchford Lake complex was created in the early

Proterozoic The Proterozoic ( ) is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, and is the longest eon of Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozo ...

, 2.14 Ga ago. The deposit is divided in several sub-structures. In a small zone at the northern edge of the

syenite Syenite is a coarse-grained intrusive igneous rock with a general composition similar to that of granite, but deficient in quartz, which, if present at all, occurs in relatively small concentrations (< 5%). It is considered a bastnäsite The mineral bastnäsite (or bastnaesite) is one of a family of three fluorocarbonate minerals, which includes bastnäsite-(cerium, Ce) with a formula of (Ce, La)CO3F, bastnäsite-(lanthanum, La) with a formula of (La, Ce)CO3F, and bastnäsite-(yt ...

phenakite Phenakite or phenacite is a fairly rare nesosilicate mineral consisting of beryllium orthosilicate, Be2 Si O4. Occasionally used as a gemstone, phenakite occurs as isolated crystals, which are rhombohedral with parallel-faced hemihedrism, and a ...

and

xenotime Xenotime is a rare-earth phosphate mineral, the major component of which is yttrium orthophosphate ( Y P O4). The phosphate ions are described by a tetrahedral shape and coordinate to the center Y3+ metal ion in a way that closely resembles the s ...

can be found. Within the Mackenzie mining district, Thor Lake may contain some of the largest deposits of light and heavy

rare-earth element The rare-earth elements (REE), also called the rare-earth metals or rare earths, and sometimes the lanthanides or lanthanoids (although scandium and yttrium, which do not belong to this series, are usually included as rare earths), are a set o ...

(REE) ores. The major elements of these ores are

europium Europium is a chemical element; it has symbol Eu and atomic number 63. It is a silvery-white metal of the lanthanide series that reacts readily with air to form a dark oxide coating. Europium is the most chemically reactive, least dense, and soft ...

terbium Terbium is a chemical element; it has Symbol (chemistry), symbol Tb and atomic number 65. It is a silvery-white, rare earth element, rare earth metal that is malleable and ductile. The ninth member of the lanthanide series, terbium is a fairly ele ...

dysprosium Dysprosium is a chemical element; it has symbol Dy and atomic number 66. It is a rare-earth element in the lanthanide series with a metallic silver luster. Dysprosium is never found in nature as a free element, though, like other lanthanides, it ...

neodymium Neodymium is a chemical element; it has Symbol (chemistry), symbol Nd and atomic number 60. It is the fourth member of the lanthanide series and is considered to be one of the rare-earth element, rare-earth metals. It is a hard (physics), hard, sli ...

gallium Gallium is a chemical element; it has Chemical symbol, symbol Ga and atomic number 31. Discovered by the French chemist Paul-Émile Lecoq de Boisbaudran in 1875, elemental gallium is a soft, silvery metal at standard temperature and pressure. ...

niobium Niobium is a chemical element; it has chemical symbol, symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and Ductility, ductile transition metal. Pure niobium has a Mohs scale of mineral hardness, Mohs h ...

thorium Thorium is a chemical element; it has symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive grey when it is exposed to air, forming thorium dioxide; it is moderately soft, malleable, and ha ...

zirconium Zirconium is a chemical element; it has Symbol (chemistry), symbol Zr and atomic number 40. First identified in 1789, isolated in impure form in 1824, and manufactured at scale by 1925, pure zirconium is a lustrous transition metal with a greyis ...

and

beryllium Beryllium is a chemical element; it has Symbol (chemistry), symbol Be and atomic number 4. It is a steel-gray, hard, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with ...

. Thor Lake represents one of the largest

tantalum Tantalum is a chemical element; it has Symbol (chemistry), symbol Ta and atomic number 73. It is named after Tantalus, a figure in Greek mythology. Tantalum is a very hard, ductility, ductile, lustre (mineralogy), lustrous, blue-gray transition ...

reserves in Canada having estimated reserves of of ore grading 0.03% tantalum and 0.04% niobium. A significant proportion of the REE deposits lie within the boundaries of the Nechalacho Rare Earth Element Project, funded by

Avalon Advanced Materials Avalon Advanced Materials Inc. is a Canadian mineral development company with a primary focus on the rare metals and minerals, headquartered in Toronto, Ontario, Canada. Avalon specializes in niche market of metals and minerals with growing demand ...

. The extraction of these resources could be important for the global REE production, which almost exclusively occurs in China, especially around the

Inner Mongolia Autonomous Region Inner Mongolia, officially the Inner Mongolia Autonomous Region, is an autonomous region of China. Its border includes two-thirds of the length of China's border with the country of Mongolia. Inner Mongolia also accounts for a small section of C ...

in Bayan Obo Mining District.

References

Further reading