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Middlesex Shale
The Middlesex Formation is a carbon rich black shale geologic formation found in the Appalachian Basin. It represents one of several transgressive events (rising sea levels) during the Late Devonian. Description The Middlesex is a laminated dark grey to black mudstones and siltstone. It developed in an Anoxic environment. Further evidence of this is the lack of bioturbation Bioturbation is defined as the reworking of soils and sediments by animals or plants. It includes burrowing, ingestion, and defecation of sediment grains. Bioturbating activities have a profound effect on the environment and are thought to be a pr .... There are also sparse sand and silt layers suggesting that they were single event deposits. References * * * * Devonian geology of New York (state) Devonian Pennsylvania {{NewYork-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 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 W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frasnian
The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage. Major reef-building was under way during the Frasnian Stage, particularly in western Canada and Australia. On land, the first forests were taking shape. In North America, the Antler orogeny peaked, which were contemporary with the Bretonic phase of the Variscan orogeny in Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti .... The Frasnian coincides with the second half of the "charcoal gap" in the fossil record, a time when atmospheric oxygen levels were below 13 percent, the minimum necessary to sustain wildfires. North American subdivisions of the Frasnian include * Wes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.Blatt, Harvey and Robert J. Tracy (1996) ''Petrology: Igneous, Sedimentary and Metamorphic'', 2nd ed., Freeman, pp. 281–292 Shale is characterized by its tendency to split into thin layers ( laminae) less than one centimeter in thickness. This property is called '' fissility''. Shale is the most common sedimentary rock. The term ''shale'' is sometimes applied more broadly, as essentially a synonym for mudrock, rather than in the more narrow sense of clay-rich fissile mudrock. Texture Shale typically exhibits varying degrees of fissility. Because of the parallel orientation of clay mineral flakes in shale, it breaks into thin layers, often splintery and usually parallel to the otherwise indistinguishable bedding p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonyea Group
The Sonyea Group is a geologic group in the northern part of the Appalachian Basin. It preserves fossils dating back to the Devonian period. In the western part, it is divided into the Cashaqua Shale at the top, and the Middlesex Shale at the bottom. In the east, various shale formations are included between the Cashaqua and Middlesex members, including Rye Point Shale, Rock Stream Formation ("Enfield Formation") Siltstone, Pulteney shale The Pulteney Shale is a geologic formation in New York. It preserves fossils dating back to the Devonian period. See also * List of fossiliferous stratigraphic units in New York This article contains a list of fossil-bearing stratigraphic uni ..., Sawmill Creek Shale, Johns Creek Shale and Montour Shale. See also * List of fossiliferous stratigraphic units in Pennsylvania * Paleontology in Pennsylvania References * * Geologic groups of Pennsylvania Devonian geology of New York (state) {{Pennsylvania-geologic-formation- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cashaqua Shale
The Cashaqua Shale is a geologic formation in New York. It preserves fossils dating back to the Devonian period. The Cashaqua shale underlies the Rhinestreet Shale member of the West Falls Group, and overlies various other members of the Sonyea Group. In the western part of New York State, it overlies the Middlesex Shale, and moving eastward, it overlies the Pulteney shale and then the Rock Stream Formation The Rock Stream Formation (or Rock Stream siltstone) is a geologic formation in New York. It preserves fossils dating back to the Devonian period. See also * List of fossiliferous stratigraphic units in New York This article contains a list of ... in west-central New York. References * * * * * * Devonian geology of New York (state) Devonian Pennsylvania {{NewYork-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulteney Shale
The Pulteney Shale is a geologic formation in New York. It preserves fossils dating back to the Devonian period. See also * List of fossiliferous stratigraphic units in New York This article contains a list of fossil-bearing stratigraphic units in the state of New York, U.S. Sites See also * Paleontology in New York References * {{DEFAULTSORT:Fossiliferous stratigraphic units in New York New York Stratigraph ... References * * * * * Devonian geology of New York (state) {{NewYork-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genesee Group
The Genesee Group is a geologic formation in Pennsylvania. It preserves fossils dating back to the Devonian period. It includes submembers: * West River Shale * Genundewa Limestone * Penn Yan Formation * Geneseo Shale * North Evans Limestone North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' i ... See also * List of fossiliferous stratigraphic units in Pennsylvania * Paleontology in Pennsylvania References * * Geologic groups of Pennsylvania {{Pennsylvania-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appalachian Basin
The geology of the Appalachians dates back to more than 480 million years ago. A look at rocks exposed in today's Appalachian Mountains reveals elongate belts of folded and thrust faulted marine sedimentary rocks, volcanic rocks and slivers of ancient ocean floor – strong evidence that these rocks were deformed during plate collision. The birth of the Appalachian ranges marks the first of several mountain building plate collisions that culminated in the construction of the supercontinent Pangaea with the Appalachians and neighboring Anti-Atlas mountains (now in Morocco) near the center. These mountain ranges likely once reached elevations similar to those of the Alps and the Rocky Mountains before they were eroded. Geological history Paleozoic Era During the earliest part of the Paleozoic Era, the continent that would later become North America straddled the equator. The Appalachian region was a passive plate margin, not unlike today's Atlantic Coastal Plain Provinc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anoxic Waters
Anoxic waters are areas of sea water, fresh water, or groundwater that are depleted of dissolved oxygen. The US Geological Survey defines anoxic groundwater as those with dissolved oxygen concentration of less than 0.5 milligrams per litre. Anoxic waters can be contrasted with hypoxic waters, which are low (but not lacking) in dissolved oxygen. This condition is generally found in areas that have restricted water exchange. In most cases, oxygen is prevented from reaching the deeper levels by a physical barrier, as well as by a pronounced density stratification, in which, for instance, heavier hypersaline waters rest at the bottom of a basin. Anoxic conditions will occur if the rate of oxidation of organic matter by bacteria is greater than the supply of dissolved oxygen. Anoxic waters are a natural phenomenon, and have occurred throughout geological history. The Permian–Triassic extinction event, a mass extinction of species from the world's oceans, may have resulted fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioturbation
Bioturbation is defined as the reworking of soils and sediments by animals or plants. It includes burrowing, ingestion, and defecation of sediment grains. Bioturbating activities have a profound effect on the environment and are thought to be a primary driver of biodiversity. The formal study of bioturbation began in the 1800s by Charles Darwin experimenting in his garden. The disruption of aquatic sediments and terrestrial soils through bioturbating activities provides significant ecosystem services. These include the alteration of nutrients in aquatic sediment and overlying water, shelter to other species in the form of burrows in terrestrial and water ecosystems, and soil production on land.Shaler, N. S., 1891, The origin and nature of soils, in Powell, J. W., ed., USGS 12th Annual report 1890-1891: Washington, D.C., Government Printing Office, p. 213-45. Bioturbators are deemed ecosystem engineers because they alter resource availability to other species through the physical ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian Geology Of New York (state)
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
