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Copper Harbor Conglomerate
The Copper Harbor Conglomerate is a geologic formation in Michigan. It is part of the larger Oronto Group and its formation dates to the Stenian period of the Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided .... References * Stratigraphy of Michigan {{Michigan-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (stratigraphy)
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 (geology), 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proterozoic
The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided into three geologic eras (from oldest to youngest): the Paleoproterozoic, Mesoproterozoic, and Neoproterozoic. The Proterozoic covers the time from the appearance of oxygen in Earth's atmosphere to just before the proliferation of complex life (such as trilobites or corals) on the Earth. The name ''Proterozoic'' combines two forms of ultimately Greek origin: meaning 'former, earlier', and , 'of life'. The well-identified events of this eon were the transition to an oxygenated atmosphere during the Paleoproterozoic; the evolution of eukaryotes; several glaciations, which produced the hypothesized Snowball Earth during the Cryogenian Period in the late Neoproterozoic Era; and the Ediacaran Period (635 to 538.8 Ma) which is characterize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michigan
Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and the largest by area east of the Mississippi River.''i.e.'', including water that is part of state territory. Georgia is the largest state by land area alone east of the Mississippi and Michigan the second-largest. Its capital is Lansing, and its largest city is Detroit. Metro Detroit is among the nation's most populous and largest metropolitan economies. Its name derives from a gallicized variant of the original Ojibwe word (), meaning "large water" or "large lake". Michigan consists of two peninsulas. The Lower Peninsula resembles the shape of a mitten, and comprises a majority of the state's land area. The Upper Peninsula (often called "the U.P.") is separated from the Lower Peninsula by the Straits of Mackinac, a channel that joins Lak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wisconsin
Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. The bulk of Wisconsin's population live in areas situated along the shores of Lake Michigan. The largest city, Milwaukee, anchors its largest metropolitan area, followed by Green Bay and Kenosha, the third- and fourth-most-populated Wisconsin cities respectively. The state capital, Madison, is currently the second-most-populated and fastest-growing city in the state. Wisconsin is divided into 72 counties and as of the 2020 census had a population of nearly 5.9 million. Wisconsin's geography is diverse, having been greatly impacted by glaciers during the Ice Age with the exception of the Driftless Area. The Northern Highland and Western Upland along wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oronto Group
The Oronto Group is a thick group of arkose sandstone and shale located beneath the Bayfield Group in northern Wisconsin,Bulletin, p. 48. along the northwestern side of the Keweenaw Peninsula and southern Isle Royale, and believed to extend into Minnesota. Because it is almost entirely red in color and highly tilted, it is considered separate from the Bayfield Group. The Oronto Group is divided into the Copper Harbor Conglomerate, Freda Sandstone, and Nonesuch Shale.Scott W. Imbus and others, "Organic geochemistry and sedimentology of middle Proterozoic Nonesuch Formation - hydrocarbon source rock assessment of a lacustrine rift deposit," in ''Lacustrine Basin Exploration'', Tulsa, Okla.: American Association of Petroleum Geologists, p.197-208 As the group is devoid of fossils, its age is difficult to ascertain,Bulletin, p. 100. though it may be of Keweenawan Age (about 1100 Mya).Bulletin, p. 105. The group is composed of conglomerate, sandstone and shale. It is typically red, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonesuch Shale
The Nonesuch Shale is a Proterozoic geologic formation that outcrops in Michigan and Wisconsin, United States, but has been found by drill holes to extend in the subsurface as far southwest as Iowa. The Nonesuch is a lacustrine sequence of shale, siltstone, and sandstone, 150 to 210 m thick, that conformably overlies the alluvial Copper Harbor Conglomerate and is conformably overlain by the fluvial Freda Sandstone. Together, the Copper Harbor, Nonesuch, and Freda make up the Oronto Group. The Nonesuch is Middle Proterozoic, with an estimated age of approximately 1.1 billion years. It was deposited in the Midcontinent Rift. The Nonesuch beds contain common organic carbon and pyrite. Natural resources The Nonesuch Formation has been a major source of copper, and is considered a prospective source of petroleum. Copper Copper was discovered in the Nonesuch in the 1800s, but early mining efforts, such as those at the Nonesuch Mine in Ontonagon County, Michigan, failed becau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (geology)
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] |
Stenian
The Stenian Period (, from grc, στενός, stenós, meaning "narrow") is the final geologic period in the Mesoproterozoic Era and lasted from Mya to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined chronometrically. The name derives from narrow polymetamorphic belts formed over this period. Preceded by the Ectasian Period and followed by the Neoproterozoic Era. The supercontinent Rodinia assembled during the Stenian. It would last into the Tonian The Tonian (from grc, τόνος, tónos, meaning "stretch") is the first geologic period of the Neoproterozoic era (geology), Era. It lasted from to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined by t ... Period. This period includes the formation of the Keweenawan Rift at about 1100 Mya. Fossils of the oldest known sexually reproducing organism, '' Bangiomorpha pubescens'', first appeared in the Stenian. See also * * Notes References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
