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Tonoloway Formation
The Late Silurian Tonoloway Formation is a mapped limestone bedrock unit in Pennsylvania, Maryland, Virginia and West Virginia. The Tonoloway is roughly equivalent to the Salina group that is found to the north and west. Description The basal 50 m consists of medium-dark-gray laminated to thin-bedded calcisiltite with shale partings and interbeds. Overlying 5 m are light-yellowish-gray to olive-gray mudstone and shale. Above this interval are 75 m of laminated calcisiltite with interbeds of thick to very thick bedded calcisiltite. The remainder of the formation is cyclic, consisting of three or four resistant ledges of laminated limestone and shale. Uppermost 20 m contains a variety of limestones. Lower contact with the Wills Creek is probably conformable. Upper contact is conformable and undulatory, occurring at the base of the "calico" limestone of the Keyser Formation.Faill, R.T., Glover, A.D., and Way, J.H., 1989, Geology and mineral resources of the Blandburg, Tipton, Alto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fin (geology)
A fin is a geological formation that is a narrow, residual wall of hard sedimentary rock that remains standing after surrounding rock has been eroded away along parallel joints or fractures. Fins are formed when a narrow butte or plateau develops many vertical, parallel cracks. There are two main modes of following erosion. The first is when water flows along joints and fractures and opens them wider and wider, eventually causing erosion. The second is where the rock type (stratum) is harder and more erosion resistant than neighboring rocks, causing the weaker rock to fall away. Fins are considered an intermediary stage of many other erosional geologic features like windows, arches, and hoodoos. The formation of such features is a simplified four-step process. The first step is uplift that results in deep parallel, vertical fractures within the plateau. The second step is weathering and erosion that enlarges the fractures, producing fins. The third step is erosion attacking fins fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depositional Environment
In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be formed after lithification, if the sediment is preserved in the rock record. In most cases, the environments associated with particular rock types or associations of rock types can be matched to existing analogues. However, the further back in geological time sediments were deposited, the more likely that direct modern analogues are not available (e.g. banded iron formations). Types of depositional environments Continental * – type of Fluvial deposit. Caused by moving water in a fan shape (Alluvial Fan) and containing mostly impermeable and nonporous sediments well sorted. * . Often in deserts and coastal regions and well sorted, large scale cross-beds * – processes due to moving water, mainly streams. Common sediments are gra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone Formations Of The United States
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals 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, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limestone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pridoli Geology
Pridoli ''(Přídolí)'' may refer to: * Pridoli epoch, part of the Silurian period * Přídolí, a small town in the southern Czech Republic * Pridoli (Bajina Bašta), a village in Serbia {{disambiguation, geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian West Virginia
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods (myriapods, arachnids and hexapods) became fully terrestrialized. A significant evolutionary milestone durin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian Geology Of Virginia
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods (myriapods, arachnids and hexapods) became fully terrestrialized. A significant evolutionary milestone durin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian Maryland
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods (myriapods, arachnids and hexapods) became fully terrestrialized. A significant evolutionary milestone durin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Formations Of Pennsylvania
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology, and so is treated as one major aspect of integrated 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. It also provides tools to determine the relative and absolute ages of rocks found in a given location, and also to describe the histories of those rocks. By combining these tools, geologists are able to chronicle the geological history of the Earth as a whole, and also to demonstrate the age of the Earth. Geology provides the primary evidence for plate tectonics, the evolutionary history of life, and the Earth's past climates. Geologists broadly study the properties and processes of Ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardy County, West Virginia
Hardy County is a county in the U.S. state of West Virginia. As of the 2020 census, the population was 14,299. Its county seat is Moorefield. The county was created from Hampshire County in 1786 and named for Samuel Hardy, a distinguished Virginian. History The first European known to visit this area was John Van Meter in 1725. The earliest permanent European settlements were established in the 1730s. Hardy County was formed in 1786 from Hampshire County in Virginia. It was one of fifty counties admitted to the Union as the state of West Virginia in 1863. That year, the newly independent state's counties were divided into civil townships, with the intention of encouraging local government. This proved impractical in the heavily rural state, and in 1872 the townships were converted into magisterial districts. Hardy County was divided into three districts: Capon, Lost River, and Moorefield. A fourth district, South Fork, was formed in 1873 from part of Moorefield Distr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trout Pond
Trout Pond — formerly called Old Pond — located near Wardensville in Hardy County, West Virginia, USA, is the state's only natural lake. The small "lake" is situated in the Trout Pond Recreation Area (TPRA) of the George Washington National Forest. Formerly, the pond had fluctuated in surface area between 2 and 3 acres, but recently it has appeared to be disappearing due to underground structural changes. History Trout Pond was created by a sinkhole that filled with water from a series of mountain streams running off Long Mountain (). Much of the region surrounding Trout Pond lies on layers of limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ... that have been slowly eroded away by rainfall, causing conical holes to open up within the ground. Many of these sinkholes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bellwood, Pennsylvania
Bellwood is a borough in Blair County, Pennsylvania, United States. It is part of the Altoona, PA Metropolitan Statistical Area. The population was at 1,829 as of the 2020 census. Geography Bellwood is located at (40.601566, -78.333616). According to the United States Census Bureau, the borough has a total area of , all land. Bellwood is a rural area situated in the Tuckahoe Valley, part of the Logan Valley area. Bellwood was originally called Bell's Mills. The Borough of Bellwood is surrounded by the Township of Antis. History Bellwood's first resident was Edward Bell who moved here with his wife, mother, and father John Bell in 1806. Edward Bell's son, Martin Bell, founded the Sabbath Rest Foundry located in Antis Township ( Pinecroft) so-called because he invented a new way to stoke the fires and leave them burn Sunday without having any person attend to them. Demographics As of the census of 2000, there were 2,016 people, 776 households, and 555 families residing i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Little Juniata River
The Little Juniata River, sometimes called the "Little J," is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed August 8, 2011 tributary of the Juniata River in the Susquehanna River watershed of Pennsylvania. It is formed at Altoona by the confluence of several short streams. It flows northeast in the Logan Valley at the foot of Brush Mountain. At Tyrone, the river receives the southern Bald Eagle Creek, then turns abruptly southeast, passing through a water gap between the Brush and Bald Eagle Mountain ridges and enters Sinking Valley where it receives Sinking Run. Approximately northwest of Huntingdon, near Petersburg, it joins the Frankstown Branch Juniata River, forming the Juniata River. In colonial America, the river was used to float freight downriver on boats called "arcs". Shipments were placed on board in Birmingham, just east of Tyrone, to await water high enough to clear the rocky stream bed. Thus the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
