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Laredo Formation
The Laredo Formation is a geologic formation and LagerstätteGarten & Gee, in Reitner et al., 2013, p.57 in Texas, United States and Nuevo León and Tamaulipas, Mexico. It preserves fossils dating back to the Lutetian stage of the Eocene period.Laredo Formation at Fossilworks
Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database
The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ... .org Among many other fossils, the formation has provided invertebrates, vert ...
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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] |
List Of Fossiliferous Stratigraphic Units In Mexico
This is a list of stratigraphic units (groups, formations and members), containing fossils and pertaining to the North American country of Mexico. List See also * Lists of fossiliferous stratigraphic units in North America References External links * {{DEFAULTSORT:Fossiliferous stratigraphic units in Mexico Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ... Mexico geology-related lists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shale Formations Of The United States
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone Formations Of The United States
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topography, topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porosity, porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-bearing sandstone can be changed into quartzite through metamorphism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone Formations
Limestone (calcium carbonate ) 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 . 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 (m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shale Formations
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone Formations
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topography, topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porosity, porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lutetian Stage
The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Middle Eocene Subepoch. Stratigraphic definition The Lutetian was named after Lutetia, the Latin name for the city of Paris. The Lutetian Stage was introduced in scientific literature by French geologist Albert de Lapparent in 1883 and revised by A. Blondeau in 1981. The base of the Lutetian Stage is at the first appearance of the nanofossil ''Blackites inflatus'', according to an official reference profile (GSSP) established in 2011. Of two candidates located in Spain, the Gorrondatxe section was chosen.See thwebsite of Eustoquio Molinafor these candidates. The top of the Lutetian (the base of the Bartonian) is at the first appearance of calcareous nanoplankton species ''Reticulofenestra reticulata''. The Lutetian overlaps with the Geisel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene Geology Of Texas
The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago (Mya) to the beginning of the Neogene Period Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon. The earlier term Tertiary Period was used to define the span of time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognised as a formal stratigraphic term, 'Tertiary' is still widely found in earth science literature and remains in informal use. Paleogene is often abbreviated "Pg" (but the United States Geological Survey uses the abbreviation PE for the Paleogene on the Survey's geologic maps). During the Paleogene, mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous–Paleogene extinction event that ended the preceding Cre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene Mexico
The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning of the Neogene Period Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon. The earlier term Tertiary Period was used to define the span of time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognised as a formal stratigraphic term, 'Tertiary' is still widely found in earth science literature and remains in informal use. Paleogene is often abbreviated "Pg" (but the United States Geological Survey uses the abbreviation PE for the Paleogene on the Survey's geologic maps). During the Paleogene, mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous–Paleogene extinction event that ended the preceding Cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene Series Of North America
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Formations Of Texas
Geology () is a branch of natural science concerned with Earth and other Astronomical object, astronomical objects, the features or rock (geology), rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth science, 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 dating, relative and Geochronology, 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 Eart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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