The Canadian Shield, also called the Laurentian Plateau, is a large area of exposed Precambrian igneous and high-grade metamorphic rocks that forms the ancient geologic core of the North American continent. Glaciation has left the area with only a thin layer of soil, through which the composition of igneous rock resulting from long volcanic history is frequently visible. As a deep, common, joined bedrock region in eastern and central Canada, the Shield stretches north from the Great Lakes to the Arctic Ocean, covering over half of Canada and most of Greenland; it also extends south into the northern reaches of the United States. Human population is sparse and industrial development is minimal, but mining is prevalent.
Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. At room temperature and pressure, another solid form of carbon known as graphite is the chemically stable form of carbon, but diamond converts to it extremely slowly. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools. They are also the reason that diamond anvil cells can subject materials to pressures found deep in the Earth.
Kimberlite is an igneous rock, which sometimes contains diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an 83.5-carat (16.70 g) diamond called the Star of South Africa in 1869 spawned a diamond rush and the digging of the open-pit mine called the Big Hole. Previously, the term kimberlite has been applied to olivine lamproites as Kimberlite II, however this has been in error.
Prospecting is the first stage of the geological analysis of a territory. It is the search for minerals, fossils, precious metals, or mineral specimens. It is also known as fossicking.
Amateur geology or rock collecting is the non-professional study and hobby of collecting rocks and minerals or fossil specimens from the natural environment. In Australia, New Zealand and Cornwall, the activities of amateur geologists are called fossicking. The first amateur geologists were prospectors looking for valuable minerals and gemstones for commercial purposes. Eventually, however, more people have been drawn to amateur geology for recreational purposes, mainly for the beauty that rocks and minerals provide.
Diopside is a monoclinic pyroxene mineral with composition MgCaSi
2O
6. It forms complete solid solution series with hedenbergite and augite, and partial solid solutions with orthopyroxene and pigeonite. It forms variably colored, but typically dull green crystals in the monoclinic prismatic class. It has two distinct prismatic cleavages at 87 and 93° typical of the pyroxene series. It has a Mohs hardness of six, a Vickers hardness of 7.7 GPa at a load of 0.98 N, and a specific gravity of 3.25 to 3.55. It is transparent to translucent with indices of refraction of nα=1.663–1.699, nβ=1.671–1.705, and nγ=1.693–1.728. The optic angle is 58° to 63°.
The Ekati Diamond Mine ("Ekati") is Canada's first surface and underground diamond mine. It is located 310 km (190 mi) north-east of Yellowknife, Northwest Territories, and about 200 km (120 mi) south of the Arctic Circle, near Lac de Gras. Until 2014 Ekati was a joint venture between Dominion Diamond Mines (80%), and the two geologists who discovered kimberlite pipes north of Lac de Gras, Chuck Fipke and Stewart Blusson each holding a 10% stake in the mine, until Fipke sold his share to Dominion.
Ultramafic rocks are igneous and meta-igneous rocks with a very low silica content, generally >18% MgO, high FeO, low potassium, and are composed of usually greater than 90% mafic minerals. The Earth's mantle is composed of ultramafic rocks. Ultrabasic is a more inclusive term that includes igneous rocks with low silica content that may not be extremely enriched in Fe and Mg, such as carbonatites and ultrapotassic igneous rocks.
Uranium mining in Colorado, United States, goes back to 1872, when pitchblende ore was taken from gold mines near Central City, Colorado. The Colorado uranium industry has seen booms and busts, but continues to this day. Not counting byproduct uranium from phosphate, Colorado is considered to have the third largest uranium reserves of any US state, behind Wyoming and New Mexico.
Ralph Jackson Roberts (1911–2007) was an American geologist and research scientist with the USGS. He is credited with the discovery of the Carlin and Battle Mountain Gold Belts, which make up the richest gold-mining region in Nevada as well as the United States.
Gold mining in Alaska, a state of the United States, has been a major industry and impetus for exploration and settlement since a few years after the United States acquired the territory in 1867 from the Russian Empire. Russian explorers discovered placer gold in the Kenai River in 1848, but no gold was produced. Gold mining started in 1870 from placers southeast of Juneau, Alaska.
The following outline is provided as an overview of and topical guide to mining:
The Seminoe Mountains greenstone belt represents a fragment of an Archean greenstone terrane within the Wyoming craton. The greenstone belt was mapped by Hausel, who identified significant gold anomalies at Bradley Peak in banded iron formation, quartz veins and in a large altered zone of metabasalts. Mapping differentiated three mappable units that included the Bradley Peak metavolcanics, the Seminoe Formation and the Sunday Morning metasediments.
The South Pass greenstone belt is located within the Wyoming craton in the US. The region was the site of Wyoming's initial gold discovery in 1842.
The Great Falls Tectonic Zone is a major intracontinental shear zone between the Hearne craton and Wyoming craton basement rock of the Archean Eon which form part of the North American continent. The zone is an area about 100 miles wide extending from the southwestern Idaho-Montana border across Montana to the northwestern Montana-Saskatchewan-North Dakota border. It is named for the Great Falls of the Missouri River, a major geologic feature of the area. The central and western portions of the zone are believed to be about 1.1 to 3.3 billion years old. The central part of the zone lacks Archean rock, however, leading at least one group of scientists to speculate that it was formed very late in the Paleoproterozoic Era.
Hugo T. Dummett (1940–2002) was a South African mineral-exploration geologist who is best known for his role in the discovery of the Ekati Diamond Mine in the Barren Lands of Canada's Northwest Territories. Dummett has been described as "the brains, the ideas and the energy" behind the discovery of Ekati, which led to the creation of a new Canadian diamond-mining industry.
The geology of Liberia is largely extremely ancient rock formed between 3.5 billion and 541 million years ago in the Archean and the Neoproterozoic, with some rocks from the past 145 million years near the coast. The country has rich iron resources as well as some diamonds, gold and other minerals in ancient sediment formations weathered to higher concentrations by tropical rainfall.
The geology of Ghana is primarily very ancient crystalline basement rock, volcanic belts and sedimentary basins, affected by periods of igneous activity and two major orogeny mountain building events. Aside from modern sediments and some rocks formed within the past 541 million years of the Phanerozoic Eon, along the coast, many of the rocks in Ghana formed close to one billion years ago or older leading to five different types of gold deposit formation, which gave the region its former name Gold Coast.
The geology of Namibia encompasses rocks of Paleoproterozoic, Mesoproterozoic and Neoproterozoic and Paleozoic to Cenozoic age. About 46% of the countryʼs surface are bedrock exposure, while the remainder is covered by the young overburden sediments of the Kalahari and Namib deserts.
Chi Jishang(Chinese: 池际尚, 1917 – 1994) was a Chinese geologist, petrologist, and a member of the Chinese Communist Party. She is a pioneer in petrofabric studies in China, primarily known for her work on kimberlite diamond deposits. She was the first scientist to propose a formula that can help identify which kimberlites contain diamonds.
