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Hueco Formation
The Hueco Formation is a geologic formation in west Texas and southern New Mexico.Richardson 1904Richardson 1908Richardson 1914 It preserves fossils dating back to the early Permian period.Nelson 1940Bachman and Hayes 1958 Description The formation is composed most of massive gray fossiliferous limestone with some shale and sandstone, with a thickness in excess of . It overlies the Panther Seep FormationKelley and Matheny 1983 with a slight disconformity, and its base is typically a thick biostromal limestone bed.Kues and Giles 2004 The formation unconformably underlies the Wilkie Ranch Formation.Cys 1976 It intertongues with the Abo Formation in the southern San Andres Mountains. In the Robledo Mountains, the Hueco is promoted to group rank and divided into (in ascending stratigraphic order) the Shalem Colony, Community Pit, Robledo Mountains, and Apache Dam Formations.Lucas ''et al.'' 1998 In the Hueco Mountains, the uppermost formation is the Alacran Mountain Formation.Will ... [...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] |
Abo Formation
The Abo Formation is a geologic formation in New Mexico. It contains fossils characteristic of the Cisuralian epoch of the Permian period. Description The Abo Formation consists of fluvial redbed mudstones and sandstones, including river channel deposits in its lower beds (Scholle Member) and distinctive sandstone sheets in its upper beds (Cañon de Espinoso Member.) Its depositional environment was typical of the "wet red beds" of tropical Pangaea. It is extensively exposed in the mountains and other uplifts bordering the Rio Grande Rift, with a thickness of at the type section. It is also present in the subsurface in the Raton Basin. The base of the Abo is gradational with the Madera Group, and is usually placed at the first massive marine limestone bed below the fluvial sediments of the Abo. It is overlain by the Yeso Formation, with the base of the Yeso placed at the first massive sandstone bed showing frosted grains and other eolian features. The transition zone between th ... [...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 co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleontology In Texas
Paleontology in Texas refers to paleontological research occurring within or conducted by people from the U.S. state of Texas. Author Marian Murray has remarked that "Texas is as big for fossils as it is for everything else." Some of the most important fossil finds in United States history have come from Texas. Fossils can be found throughout most of the state. The fossil record of Texas spans almost the entire geologic column from Precambrian to Pleistocene. Shark teeth are probably the state's most common fossil. During the early Paleozoic era Texas was covered by a sea that would later be home to creatures like brachiopods, cephalopods, graptolites, and trilobites. Little is known about the state's Devonian and early Carboniferous life. However, evidence indicates that during the late Carboniferous the state was home to marine life, land plants and early reptiles. During the Permian, the seas largely shrank away, but nevertheless coral reefs formed in the state. The rest of Texas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Fossiliferous Stratigraphic Units In Texas
This article contains a list of fossil-bearing stratigraphic units in the state of Texas, U.S. Sites See also * Paleontology in Texas References * * {{DEFAULTSORT:Fossiliferous stratigraphic units in Texas Fossil Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ... Texas geography-related lists United States geology-related lists Geology of Texas .Stratigraphic units ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spencer G
Spencer may refer to: People *Spencer (surname) **Spencer family, British aristocratic family ** List of people with surname Spencer * Spencer (given name), a given name (including a list of people with the name) Places Australia *Spencer, New South Wales, on the Central Coast *Spencer Gulf, one of two inlets on the South Australian coast United States *Spencer, Idaho *Spencer, Indiana *Spencer, Iowa *Spencer, Massachusetts **Spencer (CDP), Massachusetts *Spencer, Missouri *Spencer, Nebraska *Spencer, New York **Spencer (village), New York *Spencer, North Carolina *Spencer, Ohio *Spencer, Oklahoma *Spencer, South Dakota *Spencer, Tennessee *Spencer, Virginia *Spencer, West Virginia *Spencer, Wisconsin **Spencer (town), Wisconsin *Spencer County, Indiana *Spencer County, Kentucky Ireland *Spencer Dock, North Wall, Dublin Arts and entertainment Fictional characters *Spencer, character in ''Beyblade'' *Spencer, character from ''Final Fantasy Mystic Quest'' * Spencer family (''G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franklin Mountains (Texas)
The Franklin Mountains of Texas ( es, Sierras de los Mansos) are a small range long, wide that extend from El Paso, Texas north into New Mexico. The Franklins were formed due to crustal extension related to the Cenozoic Rio Grande rift. Although the present topography of the range and adjoining basins is controlled by extension during rifting in the last 10 million years, faults within the range also record deformation during the Laramide orogeny, between 85 and 45 million years ago. The highest peak is North Franklin Peak at . Much of the range is part of the Franklin Mountains State Park. The mountains are composed primarily of sedimentary rock with some igneous intrusions. Geologists refer to them as tilted-block fault mountains and in them can be found 1.25 billion-year-old Precambrian rocks, the oldest in Texas. __NOTOC__ Gallery File:Richardson 1908 FranklinMts.jpg, View of the south end of Franklin Mountains from El Paso, showing the abrupt termination of the range, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvanian (geology)
The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, in the International Commission on Stratigraphy, ICS geologic timescale, the younger of two period (geology), subperiods (or upper of two system (stratigraphy), subsystems) of the Carboniferous Period. It lasted from roughly . As with most other geochronology, geochronologic units, the stratum, rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain by a few hundred thousand years. The Pennsylvanian is named after the U.S. state of Pennsylvania, where the coal-productive beds of this age are widespread. The division between Pennsylvanian and Mississippian (geology), Mississippian comes from North American stratigraphy. In North America, where the early Carboniferous beds are primarily marine limestones, the Pennsylvanian was in the past treated as a full-fledged geologic period between the Mississippian and the Permian. In parts of Europe, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Delta
A river delta is a landform shaped like a triangle, created by deposition (geology), deposition of sediment that is carried by a river and enters slower-moving or stagnant water. This occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more rarely) another river that cannot carry away the supplied sediment. It is so named because its triangle shape resembles the Greek letter Delta. The size and shape of a delta is controlled by the balance between watershed processes that supply sediment, and receiving basin processes that redistribute, sequester, and export that sediment. The size, geometry, and location of the receiving basin also plays an important role in delta evolution. River deltas are important in human civilization, as they are major agricultural production centers and population centers. They can provide Coast, coastline defense and can impact drinking water supply. They are also Ecology, ecologically important, with different species' assemblages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Progradation
In sedimentary geology and geomorphology, the term progradation refers to the growth of a river delta farther out into the sea over time. This occurs when the volume of incoming sediment is greater than the volume of the delta that is lost through subsidence, sea-level rise, or erosion. Progradation can be caused by: * Periods of sea-level fall which result in marine regression. This can occur during major continental glaciations within ice ages, be caused by changes in the rates of seafloor spreading that affects the volume of the ocean basins, or tectonic effects on the regional mantle density structure that can change the geoid elevation. * Extremely high sediment input, such as by the Huang He (Yellow River) in China, which drains the Loess plateau, or from high sediment loads in proglacial river A proglacial river is a river that flows from the margin of a glacier. These rivers are strongly affected by the highly-seasonal water supply from the glacier and by the large supply ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alacran Mountain Formation
The Alacran Mountain Formation is a geologic formation in Texas. It preserves fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ... dating back to the Permian period. See also * List of fossiliferous stratigraphic units in Texas * Paleontology in Texas References * Permian geology of Texas {{Permian-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group (stratigraphy)
In geology, a group is a lithostratigraphic unit consisting of a series of related formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into 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 distinguished from its neighbor by its lithology, but all were deposited in the same vast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
