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Galena Group
The Galena Group or Galena Limestone refers to a sedimentary sequence of Ordovician limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ... that was deposited atop the Decorah Shale. It is part of the Ordovician stratigraphy of the Upper Midwestern United States. It was deposited in a calm marine environment, and is fossiliferous.Mossler, J. and Benson, S., 1995, 1999, 2006Fossil Collecting in the Twin Cities Area Minnesota at a Glance: Minnesota Geological Survey: University of Minnesota. References Geologic groups of Minnesota Ordovician Minnesota Limestone groups of the United States {{US-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trochonema
Trochonema is an extinct genus of early marine snail from the Paleozoic, which lasted almost 215 million years. It was first described by John William Salter in 1859. Like many genera in the order Murchisoniina, the relationship between it and other large gastropod clades is uncertain. References Trochonematidae Fossil taxa described in 1859 Prehistoric gastropod genera {{Paleo-gastropod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platteville Limestone
The Platteville Limestone is the Ordovician limestone formation in the sedimentary sequence characteristic of the Upper Midwest, upper Midwestern United States. It is characterized by its gray color, rough texture, and numerous fossils. Its type locality (geology), type locality is Platteville, Wisconsin. It was heavily used in the early decades of the building of Minneapolis–Saint Paul and Faribault, Minnesota. In Illinois, the formation is elevated to group status and referred to as the Platteville Group. Formation Like almost all limestones, the Platteville variety is a marine creation. Platteville Limestone formed between 488 and 436 million years ago, when what became southeastern Minnesota and southwestern Wisconsin lay beneath an ancient sea. This sea was heavily populated by shellfish and other invertebrates. As they died, their shells and other hard parts, made of calcium carbonate, fell to the ocean floor. Over the centuries, the weight of these deposits crushed th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Groups Of Minnesota
Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology. It is integrated with Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface and the processes that have shaped that structure. Geologists study the mineralogical composition of rocks in order to get insight into their history of formation. Geology determines the relative ages of rocks found at a given location; geochemistry (a branch of geology) determines their absolute ages. By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle the geological history of the Earth as a whole. One aspect is to demonstrate the age of the Earth. Geology provides evidence for plate tectonics, the evolutionary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science), crystal forms of calcium carbonate . Limestone forms when these minerals Precipitation (chemistry), precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly Dolomite (rock), dolomite, a closely related rock, which contains a high percentage of the mineral Dolomite (mine ... [...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, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years from the end of the Cambrian Period Megaannum, Ma (million years ago) to the start of the Silurian Period Ma. 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 per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Illinois
Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its south. Of the fifty U.S. states, Illinois has the List of U.S. states and territories by GDP, fifth-largest gross domestic product (GDP), the List of U.S. states and territories by population, sixth-largest population, and the List of U.S. states and territories by area, 25th-most land area. Its capital city is Springfield, Illinois, Springfield in the center of the state, and the state's largest city is Chicago in the northeast. Present-day Illinois was inhabited by Indigenous peoples of the Americas#History, Indigenous cultures for thousands of years. The French were the first Europeans to arrive, settling near the Mississippi and Illinois River, Illinois rivers in the 17th century Illinois Country, as part of their sprawling colony of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wisconsin
Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders 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. With a population of about 6 million and an area of about 65,500 square miles, Wisconsin is the List of U.S. states and territories by population, 20th-largest state by population and the List of U.S. states and territories by area, 23rd-largest by area. It has List of counties in Wisconsin, 72 counties. Its List of municipalities in Wisconsin by population, most populous city is Milwaukee; its List of capitals in the United States, capital and second-most populous city is Madison, Wisconsin, Madison. Other urban areas include Green Bay, Wisconsin, Green Bay, Kenosha, Wisconsin, Kenosha, Racine, Wisconsin, Racine, Eau Claire, Wisconsin, Eau Claire, and the Fox Cities. Geography of Wiscon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minnesota
Minnesota ( ) is a U.S. state, state in the Upper Midwestern region of the United States. It is bordered by the Canadian provinces of Manitoba and Ontario to the north and east and by the U.S. states of Wisconsin to the east, Iowa to the south, and North Dakota and South Dakota to the west. It is the List of U.S. states and territories by area, 12th-largest U.S. state in area and the List of U.S. states and territories by population, 22nd-most populous, with about 5.8 million residents. Minnesota is known as the "Land of 10,000 Lakes"; it has 14,420 bodies of fresh water covering at least ten acres each. Roughly a third of the state is Forest cover by state and territory in the United States, forested. Much of the remainder is prairie and farmland. More than 60% of Minnesotans (about 3.71 million) live in the Minneapolis–Saint Paul metropolitan area, known as the "Twin Cities", which is Minnesota's main Politics of Minnesota, political, Economy of Minnesota, economic, and C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maquoketa Group
The Maquoketa Group is an assemblage of several geologic formations. It is Upper Ordovician in age and named for the Maquoketa River in Iowa. It exists in Missouri, Wisconsin, Iowa, Illinois, and Indiana. It is equivalent to the all but the basal formations of the Cincinnati Group in Ohio. Illinois and Indiana are the only states where the Maquoketa is considered a group. In other states it is a formation. The Maquoketa was deposited in a shallow intercontinental sea. Most of the clastic sediments are derived from the Appalachians, which were being raised at the end of the Ordovician. To a lesser degree some of the sediments were derived from the Ozarks, Ozark highlands to the southwest. Scales Formation In Illinois, the basal formation is called the Scales Formation and consists mainly of dark brown and gray dolomite (mineral), dolomitic shale. In north central Illinois, the bottom half is dominantly a yellowish gray coarse crystalline dolomite (rock), dolomite (rock form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group (stratigraphy)
In geology, a group is a lithostratigraphy, lithostratigraphic Stratigraphic unit, unit consisting of a series of related Geological formation, formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into Supergroup (geology), supergroups. Groups are useful for showing relationships between formations, and they are also useful for small-scale mapping or for studying the stratigraphy of large regions. Geologists exploring a new area have sometimes defined groups when they believe the strata within the groups can be divided into formations during subsequent investigations of the area. It is possible for only some of the strata making up a group to be divided into formations. An example of a group is the Glen Canyon Group, which includes (in ascending order) the Wingate Sandstone, the Moenave Formation, the Kayenta Formation, and the Navajo Sandstone. Each of the formations can be distingui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dubuque Formation
The Dubuque Formation is a geologic formation in Illinois, Iowa, Wisconsin and Minnesota. It preserves fossils dating back to the Ordovician period. It comprises carbonate and argillaceous rocks that are between 35 and 45 feet deep. See also * List of fossiliferous stratigraphic units in Illinois * List of fossiliferous stratigraphic units in Iowa * List of fossiliferous stratigraphic units in Minnesota * List of fossiliferous stratigraphic units in Wisconsin This article contains a list of fossil-bearing stratigraphic units in the state of Wisconsin, U.S. Sites See also * Paleontology in Wisconsin References * {{DEFAULTSORT:Fossiliferous stratigraphic units in Wisconsin Wisconsin Stratigr ... References Ordovician Minnesota Ordovician Iowa Ordovician Illinois Ordovician Wisconsin Ordovician southern paleotropical deposits Geologic formations of Minnesota Geologic formations of Iowa Geologic formations of Illinois Geologic formations of Wiscons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wise Lake Formation
The Wise Lake Formation is a geologic formation in Illinois. It preserves fossils dating back to the Ordovician period. See also * List of fossiliferous stratigraphic units in Illinois This article contains a list of fossil-bearing stratigraphic units in the state of Illinois, U.S. Sites See also * Paleontology in Illinois References * {{DEFAULTSORT:Fossiliferous stratigraphic units in Illinois Illinois Stratigraph ... References * Ordovician Iowa Ordovician Illinois Ordovician geology of Wisconsin Geologic formations of Illinois {{Illinois-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
