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Chaicayán Group
Chaicayán Group is a group of poorly defined sedimentary rock strata found in Taitao Peninsula in the west coast of Patagonia. The most common rock types are siltstone and sandstone. Conglomerate occur but is less common. Study of fossils and uranium–lead dating of detrital zircons indicate a Miocene age, at least for the upper sequences. The Chaicayán Group deposited likely as a result of a marine transgression that drowned much of Patagonia and Central Chile in the Late Oligocene and Miocene. The group is intruded by porphyritic stocks and sills of Pliocene age. See also * Geology of Chile * Ayacara Formation * La Cascada Formation * Puduhuapi Formation * Vargas Formation The Vargas Formation is a sedimentary formation on the left bank of Palena River in the western Patagonian Andes of southern Chile. The formation is made of black shale and sandstone that deposited in the Late Oligocene or Early Miocene epoch some ... References {{Geology of Chile Geologic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratigraphic Unit
A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize it. Units must be ''mappable'' and ''distinct'' from one another, but the contact need not be particularly distinct. For instance, a unit may be defined by terms such as "when the sandstone component exceeds 75%". Lithostratigraphic units Sequences of sedimentary and volcanic rocks are subdivided the basis of their shared or associated lithology. Formally identified lithostratigraphic units are structured in a hierarchy of lithostratigraphic rank, higher rank units generally comprising two or more units of lower rank. Going from smaller to larger in rank, the main lithostratigraphic ranks are Bed, Member, Formation, Group and Supergroup. Formal names of lithostratigraphic units are assigned by geological surveys. Units of formation or hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transgression (geology)
A marine transgression is a geologic event during which sea level rises relative to the land and the shoreline moves toward higher ground, which results in flooding. Transgressions can be caused by the land sinking or by the ocean basins filling with water or decreasing in capacity. Transgressions and regressions may be caused by tectonic events such as orogenies, severe climate change such as ice ages or isostatic adjustments following removal of ice or sediment load. During the Cretaceous, seafloor spreading created a relatively shallow Atlantic basin at the expense of deeper Pacific basin. That reduced the world's ocean basin capacity and caused a rise in sea level worldwide. As a result of the sea level rise, the oceans transgressed completely across the central portion of North America and created the Western Interior Seaway from the Gulf of Mexico to the Arctic Ocean. The opposite of transgression is regression in which the sea level falls relative to the land and expo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Formations Of Chile
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 E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Groups Of South America
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 Earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vargas Formation
The Vargas Formation is a sedimentary formation on the left bank of Palena River in the western Patagonian Andes of southern Chile. The formation is made of black shale and sandstone that deposited in the Late Oligocene or Early Miocene epoch some 26 million years ago. The formation has contact across a fault plane with granitoids of Cretaceous age of the North Patagonian Batholith. The exposures of Vargas Formation are small and its fossils poorly preserved. Gastropods, bivalves, echinoderms, and planktic foraminifer fossils have been found in the formation. Hans Steffen was the first to investigate Vargas Formation with his research being published in 1944. See also * Geology of Chile * Chaicayán Group * Ayacara Formation * La Cascada Formation La Cascada Formation a sedimentary formation near Futaleufú in the western Patagonian Andes of southern Chile. Lithologies vary from sandstone, siltstone and conglomerate. The sediment that now forms the rock deposited duri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puduhuapi Formation
The Puduhuapi Formation is a sedimentary formation whose only known outcrops are on Puduhuapi Island of the Chiloé Archipelago, west of Chaitén in western Patagonia, Chile. Lithologies vary from sandstone and siltstone to conglomerate. The sediment that now forms the rock deposited during the Miocene no earlier than 23 million years ago. See also * Geology of Chile * Chaicayán Group * Ayacara Formation * La Cascada Formation * Vargas Formation The Vargas Formation is a sedimentary formation on the left bank of Palena River in the western Patagonian Andes of southern Chile. The formation is made of black shale and sandstone that deposited in the Late Oligocene or Early Miocene epoch some ... References {{Geology of Chile Geologic formations of Chile Miocene Series of South America Neogene Chile Sandstone formations Siltstone formations Conglomerate formations Geology of Los Lagos Region Mapuche language ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
La Cascada Formation
La Cascada Formation a sedimentary formation near Futaleufú in the western Patagonian Andes of southern Chile. Lithologies vary from sandstone, siltstone and conglomerate. The sediment that now forms the rock deposited during the Oligocene and Early Miocene epoch in shallow marine environment. The formation contain fossils of bivalves and gastropods. The formation unconformably overlies sedimentary rock of Jurassic age, Cretaceous sedimentary rocks of Divisadero Group and Cretaceous granite plutons. Further south in Aysén Region, the Guadal Formation is a geologically equivalent formation. See also * Geology of Chile The geology of Chile is a characterized by processes linked to subduction such as volcanism, earthquakes and orogeny. The buildings blocks of Chile's geology assembled during the Paleozoic Era. Chile was by then the southwestern margin of the su ... * Chaicayán Group * Ayacara Formation * Puduhuapi Formation * Vargas Formation References { ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ayacara Formation
The Ayacara Formation is a sedimentary formation made up of interbedded sand and siltstone cropping out around Hornopirén and Ayacara Peninsula in western Los Lagos Region, Chile. Less common rocks are tuff and conglomerate. The formation dates to the Early and Middle Miocene (no earlier than 21.8–17.6 million years ago) when it deposited during a marine transgression. See also * Geology of Chile * Chaicayán Group * La Cascada Formation * Puduhuapi Formation * Vargas Formation The Vargas Formation is a sedimentary formation on the left bank of Palena River in the western Patagonian Andes of southern Chile. The formation is made of black shale and sandstone that deposited in the Late Oligocene or Early Miocene epoch some ... References {{Geology of Chile Geologic formations of Chile Miocene Series of South America Aquitanian (stage) Burdigalian Langhian Serravallian Neogene Chile Sandstone formations Siltstone formations Conglomerate formations Tuff fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Chile
The geology of Chile is a characterized by processes linked to subduction such as volcanism, earthquakes and orogeny. The terrane, buildings blocks of Chile's geology accretion (geology), assembled during the Paleozoic, Paleozoic Era. Chile was by then the southwestern margin of the supercontinent Gondwana. In the Jurassic Gondwana began to split and the ongoing period of crustal deformation and mountain building known as the Andean orogeny began. In the Cenozoic, Late Cenozoic Chile definitely separated from Antarctica, the Andes experienced a great rise accomplained by a cooling climate and the onset of glaciations. The subduction interactions shaped four main wikt:morphostructure, morphostructures of Chile: the Andes; the Chilean Central Valley, Intermediate Depression, the Chilean Coast Range, Coast Range, and the Peru–Chile Trench off the coast. Since Chile is on an active continental margin, it has many volcanoes. Almost the entire country is subject to earthquakes arising ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58See the 2014 version of the ICS geologic time scale million years ago. It is the second and most recent epoch of the Neogene Period in the . The Pliocene follows the Epoch and is followed by the Epoch. Prior to the 2009 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sill (geology)
In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or along the direction of foliation in metamorphic rock. A ''sill'' is a ''concordant intrusive sheet'', meaning that a sill does not cut across preexisting rock beds. Stacking of sills builds a sill complex . and a large magma chamber at high magma flux. In contrast, a dike is a discordant intrusive sheet, which does cut across older rocks. Sills are fed by dikes, except in unusual locations where they form in nearly vertical beds attached directly to a magma source. The rocks must be brittle and fracture to create the planes along which the magma intrudes the parent rock bodies, whether this occurs along preexisting planes between sedimentary or volcanic beds or weakened planes related to foliation in metamorphic rock. These planes or weakened areas allow the intrusion of a thin sheet-like body of magma paralleling the existing bedding pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stock (geology)
In geology, a stock is an igneous intrusion that has a surface exposure of less than ,Whittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, 1984, p. 513. . differing from batholiths only in being smaller. A stock has a discordant relationship with the rocks that it intrudes. Many stocks are cupolas of hidden batholiths. Some circular or elliptical stocks may be volcanic plugs, which fill the vents of now extinct volcanoes. A boss is a small stock. Examples * the Alta and Clayton Peak stocks (composed of granodiorite), near Park City, Utah * the Hellroaring Creek and Salal Creek stocks (of granite-granodiorite and quartz monzonite, respectively) in British Columbia, Canada * the Céret stock (of gabbro and diorite) in Pyrénées-Orientales, France * the Parashi stock (of tonalite) in La Guajira Department, Colombia * stocks of syenite in the Caldera de Tejeda on Gran Canaria * Ailsa Craig Ailsa Craig (; sco, Ailsae Craig; gd, Creag Ealasaid) i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
