Coihaique Group | |
---|---|
Stratigraphic range: Late Jurassic–Aptian | |
Type | Geologic group |
Unit of | Aysén Basin |
Sub-units | Apeleg Formation Katterfeld Formation Toqui Formation |
Underlies | Divisadero Group |
Overlies | Ibáñez Formation |
Lithology | |
Primary | Shale, volcaniclastic rocks, sandstone |
Other | Turbidite |
Location | |
Region | Aysén Region, Patagonia |
Country | Chile |
The Coihaique Group is a group of geological formations in northwestern Patagonia. From top to bottom the formations that make the group are Apeleg, Katterfeld and Toqui. The contact between the formations of the group are diachronous with Katterfeld Formation interfingering with the formations on top and below it. The lower and upper boundaries of the group are unconformities formed by erosion. The older parts of Coihaique Group represent a marine transgression while the younger parts evidences a return to non-marine conditions. [1]
The rock formation preserves fossils from the Late Jurassic period of the Mesozoic Era.
Fossils of Chilesaurus (147 Ma) were found in the Aysén Region of Patagonia. It is an extinct genus of theropods in the family Tetanurae. [2] The fossil record also comprises a sauropod Titanosaur, a Camarasaur and a Diplodocid.
Patagonia is a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and glaciers in the west and deserts, tablelands and steppes to the east. Patagonia is bounded by the Pacific Ocean on the west, the Atlantic Ocean to the east, and many bodies of water that connect them, such as the Strait of Magellan, the Beagle Channel, and the Drake Passage to the south.
The Aysén del General Carlos Ibáñez del Campo Region, often shortened to Aysén Region or Aisén, is one of Chile's 16 first order administrative divisions. Although the third largest in area, the region is Chile's most sparsely populated region with a population of 102,317 as of 2017. The capital of the region is Coihaique, the region's former namesake.
Coyhaique, also spelled Coihaique in Patagonia, is the capital city of both the Coyhaique Province and the Aysén Region of Chile. Founded by settlers in 1929, it is a young city. Until the twentieth century, Chile showed little interest in exploiting the remote Aisén region. The Carretera Austral southern highway opened in the 1980s.
General Carrera Lake or Lake Buenos Aires is a deep lake located in Patagonia and shared by Argentina and Chile. Both names are internationally accepted, while the autochthonous name of the lake is Chelenko, which means "stormy waters" in Aonikenk. Another historical name is Coluguape from Mapuche, a derivative of this name is applied to Colhué Huapí Lake after Argentine explorer Francisco Moreno reached this lake in 1876 conflating it with Coluguape.
The Baker River is a river located in the Aysén del General Carlos Ibáñez del Campo Region of the Chilean Patagonia. It is Chile's largest river in terms of volume of water. The river flows out of Bertrand Lake, which is fed by General Carrera Lake. It runs along the east side of the Northern Patagonian Ice Field and empties into the Pacific Ocean, near the town of Caleta Tortel. The river forms a delta, dividing into two major arms, of which only the northernmost one is navigable.
Aristonectes is an extinct genus of large elasmosaurid plesiosaurs that lived during the Maastrichtian stage of the Late Cretaceous. Two species are known, A. parvidens and A. quiriquensis, whose fossil remains were discovered in what are now Patagonia and Antarctica. Throughout the 20th century, Aristonectes was a difficult animal for scientists to analyze due to poor fossil preparation, its relationships to other genera were uncertain. After subsequent revisions and discoveries carried out from the beginning of the 21st century, Aristonectes is now recognised as the type genus of the subfamily Aristonectinae, a lineage of elasmosaurids characterized by an enlarged skull and a reduced length of the neck.
The Magallanes Basin or Austral Basin is a major sedimentary basin in southern Patagonia. The basin covers a surface of about 170,000 to 200,000 square kilometres and has a NNW-SSE oriented shape. The basin is bounded to the west by the Andes mountains and is separated from the Malvinas Basin to the east by the Río Chico-Dungeness High. The basin evolved from being an extensional back-arc basin in the Mesozoic to being a compressional foreland basin in the Cenozoic. Rocks within the basin are Jurassic in age and include the Cerro Toro Formation. Three ages of the SALMA classification are defined in the basin; the Early Miocene Santacrucian from the Santa Cruz Formation and Friasian from the Río Frías Formation and the Pleistocene Ensenadan from the La Ensenada Formation.
Simpson River is a river of Chile located in the Aysén del General Carlos Ibáñez del Campo Region. The river originates east of the Andes mountains. It forms the western boundary of the city of Coihaique, which is bordered on the north by the Coihaique River, a tributary of the Simpson. In its inferior course, the river flows through Río Simpson National Reserve, which is named after the river. In this area, the river roughly parallels the Route CH-240, which connects Coihaique with Puerto Aisén and Puerto Chacabuco.
The Friasian age is a period of geologic time within the Early Miocene epoch of the Neogene, used more specifically within the SALMA classification of South America. It follows the Santacrucian and precedes the Colloncuran age.
The Baños del Flaco Formation is a Late Jurassic to Early Cretaceous (Tithonian to Berriasian geologic formation in central Chile. The formation comprises limestones and sandstones deposited in a shallow marine to fluvial environment. Fossil ornithopod tracks have been reported from the formation.
The 2012 Aysén protests were a series of protests that occurred in Aysén Region in central Chilean Patagonia in February 2012.
Traiguén Formation is a volcano-sedimentary formation of Miocene age, located in the archipelagoes of Aysén Region of western Patagonia.
The Toqui Formation is a geological formation in the Aysén Region of southern Chile. It has been dated to the Tithonian stage of the Late Jurassic by uranium–lead dating of zircons, providing an age of 147 ± 0.1 Ma. It consists of an sequence of clastic sedimentary sandstones and conglomerates, interbedded with volcanic tuffs and ignimbrite. The dinosaurs Chilesaurus and indeterminate diplodocids and the mesoeucrocodylian Burkesuchus are known from the formation. The formation was deposited in a fluvio-deltaic environment.
The Divisadero Group is a group of geological formations in the Magallanes Basin (Chile) or Austral Basin (Argentina) of northwestern Patagonia. It overlies the Coihaique Group. The group is chiefly made up of pyroclastic rocks and lavas of the calc-alkaline magma series. Rocks are of andesite and rhyolite composition.
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.
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.
The Cerro Colorado Formation is a geological formation to the south of General Carrera Lake in Patagonia. Sedimentary rocks of the Cerro Colorado Formation deposited under shallow marine conditions.
Río Frías Formation is a Middle Miocene geologic formation made up sedimentary rock located in Aysén Region, western Patagonia. The formation crops out along the upper couse of Cisnes River. Marsupial fossils have been found in the formation. The Friasian period in the South American Land Mammal Ages is named after the formation.
The Collón Curá Formation is a Middle Miocene fossiliferous geological formation of the southern Neuquén Basin in northwestern Patagonia and the western Cañadón Asfalto Basin of central Patagonia, Argentina. The formation crops out from the southern Neuquén Province, the western Río Negro Province to the northern Chubut Province.
Magallanodon is a genus of mammals from the extinct group Gondwanatheria. It contains a single species, Magallanodon baikashkenke. The species is the first Mesozoic mammal known from Chile, and is Late Cretaceous in age. It is known from individual teeth found in a quarry in the Río de Las Chinas Valley and La Anita Farm located in the Magallanes Basin in Patagonia. The fossils come from the Dorotea Formation and Chorrillo Formation, which is Late Campanian to Early Maastrichtian in age.