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Selkirk Member
The Red River Formation is a stratigraphical unit of Late Ordovician age in the Williston Basin. It takes the name from the Red River of the North, and was first described in outcrop in the Tyndall Stone quarries and along the Red River Valley by A.F. Foerste in 1929.Foerste, A.F., 1929b. The cephalopods of the Red River Formation of southern Manitoba. Denison Univ. Sci. Lab J., v. 24, p. 129-235. Lithology Subdivisions The Red River Formation is composed of the following subdivisions from top to base: * Fort Garry Member: crystalline and micritic dolomite with an argillaceous dolomite breccia in the middle * Selkirk Member: fossiliferous, dolomitic limestone * Cat Head Member: cherty dolomite, becoming calcareous to the south * Dog Head Member: fossiliferous dolomitic limestone Distribution The Red River Formation reaches a maximum thickness of in the center of the Williston Basin. At the along the Manitoba outcrop belt, it is thick and thins out northwards. Relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob Wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician
The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Celtic Britons, Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same Rock (geology), rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed Stratum, strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Union of Geological Sciences, Intern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herald Formation
The Herald Formation is a stratigraphical unit of Late Ordovician age in the Western Canadian Sedimentary Basin. It was defined in well ''Imperial Herald 1-31-1-20W2M'' by the Lower Paleozoic Names and Correlations Committee of the Saskatchewan Geological Society in 1958.Saskatchewan Geological Society, 1958. Report of the Lower Paleozoic Names and Correlation Committee, Regina. Lithology The Herald Formation is composed of dolomitic limestone and dolomite, which can be microcrystalline, argillaceous or microlaminated. In the centre of the basin, it is represented by anhydrite. Distribution The Herald Formation reaches a maximum thickness of in the Lake Alma area. Relationship to other units The Herald Formation is disconformably overlain by the Stony Mountain Formation and conformably overlays the Yeoman Formation. It can be correlated with the Fort Garry Member of the Red River Formation in Manitoba and in the Williston Basin. Subdivisions In south-eastern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yeoman Formation
Yeoman is a noun originally referring either to one who owns and cultivates land or to the middle ranks of servants in an English royal or noble household. The term was first documented in mid-14th-century England. The 14th century also witnessed the rise of the yeoman longbow archer during the Hundred Years' War, and the yeoman outlaws celebrated in the Robin Hood ballads. Yeomen also joined the English Navy during the Hundred Years' War as seamen and archers. In the early 15th century, yeoman was the rank of chivalry between page and squire. By the late 17th century, yeoman became a rank in the new Royal Navy for the common seamen who were in charge of ship's stores, such as foodstuffs, gunpowder, and sails. References to the emerging social stratum of wealthy land-owning commoners began to appear after 1429. In that year, the Parliament of England re-organized the House of Commons into counties and boroughs, with voting rights granted to all freeholders. The Act of 1430 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Shield
The Canadian Shield (french: Bouclier canadien ), also called 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), the ancient geologic core of the North American continent. Glaciation has left the area with only a thin layer of soil, through which exposures of igneous bedrock resulting from its long volcanic history are 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. Geographical extent The Canadian Shield is a physiographic division comprising four smaller physiographic provinces: the Laurentian Upland, Kazan Region, Davis and James. The shield extends into the United States as the Adirondack Mountains (connected by the Fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saskatchewan
Saskatchewan ( ; ) is a Provinces and territories of Canada, province in Western Canada, western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and on the south by the United States, U.S. states of Montana and North Dakota. Saskatchewan and Alberta are the only landlocked provinces of Canada. In 2022, Saskatchewan's population was estimated at 1,205,119. Nearly 10% of Saskatchewan’s total area of is fresh water, mostly rivers, reservoirs and List of lakes in Saskatchewan, lakes. Residents primarily live in the southern prairie half of the province, while the northern half is mostly forested and sparsely populated. Roughly half live in the province's largest city Saskatoon or the provincial capital Regina, Saskatchewan, Regina. Other notable cities include Prince Albert, Saskatchewan, Prince Albert, Moose Jaw, Yorkton, Swift Current, North Battleford, Melfort, Saskatchewan, Melfort, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deadwood Formation
The Deadwood Formation is a geologic formation of the Williston Basin and Western Canada Sedimentary Basin. It is present in parts of North and South Dakota and Montana in the United States, and in parts of Alberta, Saskatchewan, and southwestern corner of Manitoba in Canada. It is of Late Cambrian to Early Ordovician age and was named for exposures in Whitewood Creek near Deadwood, South Dakota.Glass, D.J. (editor) 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba. Canadian Society of Petroleum Geologists, Calgary, 1423 p. on CD-ROM. . It is a significant aquifer in some areas, and its conglomerates yielded significant quantities of gold in the Black Hills of South Dakota. It preserves trace fossils such as ''Skolithos'', and remains of Late Cambrian trilobites and brachiopods, as well as Ordovician fossils. A 20 MW geothermal power plant is under construction, drilling 3.5 kilometers d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manitoba
Manitoba ( ) is a Provinces and territories of Canada, province of Canada at the Centre of Canada, longitudinal centre of the country. It is Canada's Population of Canada by province and territory, fifth-most populous province, with a population of 1,342,153 as of 2021, of widely varied landscape, from arctic tundra and the Hudson Bay coastline in the Northern Region, Manitoba, north to dense Boreal forest of Canada, boreal forest, large freshwater List of lakes of Manitoba, lakes, and prairie grassland in the central and Southern Manitoba, southern regions. Indigenous peoples in Canada, Indigenous peoples have inhabited what is now Manitoba for thousands of years. In the early 17th century, British and French North American fur trade, fur traders began arriving in the area and establishing settlements. The Kingdom of England secured control of the region in 1673 and created a territory named Rupert's Land, which was placed under the administration of the Hudson's Bay Company. Rupe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unconformity
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record. The significance of angular unconformity (see below) was shown by James Hutton, who found examples of Hutton's Unconformity at Jedburgh in 1787 and at Siccar Point in 1788. The rocks above an unconformity are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents time during which no sediments were preserved in a region or were subsequently eroded before the next deposition. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area. The interval of geologic time not represented is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chert
Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a precipitation (chemistry), chemical precipitate or a diagenesis, diagenetic replacement, as in petrified wood. Chert is typically composed of the petrified remains of siliceous ooze, the biogenic sediment that covers large areas of the deep ocean floor, and which contains the silicon skeletal remains of diatoms, Dictyochales, silicoflagellates, and radiolarians. Precambrian cherts are notable for the presence of fossil cyanobacteria. In addition to Micropaleontology, microfossils, chert occasionally contains macrofossils. However, some chert is devoid of any fossils. Chert varies greatly in color (from white to black), but most often manifests as gray, brown, grayish brown and light green to rusty redW.L. Roberts, T.J. Campbell, G.R. Rapp Jr. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolomite (mineral)
Dolomite () is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally The term is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite. An alternative name sometimes used for the dolomitic rock type is dolostone. History As stated by Nicolas-Théodore de Saussure the mineral dolomite was probably first described by Carl Linnaeus in 1768. In 1791, it was described as a rock by the French naturalist and geologist Déodat Gratet de Dolomieu (1750–1801), first in buildings of the old city of Rome, and later as samples collected in the mountains now known as the Dolomite Alps of northern Italy. Nicolas-Théodore de Saussure first named the mineral (after Dolomieu) in March 1792. Properties The mineral dolomite crystallizes in the trigonal-rhombohedral system. It forms white, tan, gray, or pink crystals. Dolomite is a double carbonate, having an alternating structural arrangement of calcium and magnesium ions. Unless it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breccia
Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of different origins, as indicated by the named types including sedimentary breccia, tectonic breccia, igneous breccia, impact breccia, and hydrothermal breccia. A megabreccia is a breccia composed of very large rock fragments, sometimes kilometers across, which can be formed by landslides, impact events, or caldera collapse. Types Breccia is composed of coarse rock fragments held together by cement or a fine-grained matrix. Like conglomerate, breccia contains at least 30 percent of gravel-sized particles (particles over 2mm in size), but it is distinguished from conglomerate because the rock fragments have sharp edges that have not been worn down. These indicate that the gravel was deposited very close to its source area, since otherwise th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
