|
Villeta Group
The Villeta Group ( es, Grupo Villeta) is a geological group of the Eastern Ranges of the Colombian Andes, to the west of the Altiplano Cundiboyacense. The group, a sequence of shales, limestones and sandstones, is subdivided into various formations; Conejo, La Frontera, Simijaca, Hiló, Pacho, Chiquinquirá, Capotes, Socotá, El Peñón, and Trincheras, and dates to the Cretaceous period; Aptian- Coniacian epochs. The group stretches out across four departments, from Huila in the south, through Cundinamarca and Boyacá to southern Santander in the north. The upper part of the Villeta Group is time-equivalent with the La Luna Formation of the Middle Magdalena Valley (VMM) and Sierra Nevada del Cocuy, the Oliní and Güagüaquí Groups of the Guaduas- Vélez synclinal and the Chipaque Formation of the Altiplano Cundiboyacense. The lower part has been correlated with the Simití, Tablazo and Paja Formations of the VMM, the upper Tibasosa, Une and Fómeque Formations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), approximately. The Aptian succeeds the Barremian and precedes the Albian, all part of the Lower/Early Cretaceous. The Aptian partly overlaps the upper part of the Western European Urgonian Stage. The Selli Event, also known as OAE1a, was one of two oceanic anoxic events in the Cretaceous Period, which occurred around 120 Ma and lasted approximately 1 to 1.3 million years. The Aptian extinction was a minor extinction event hypothesized to have occurred around 116 to 117 Ma.Archangelsky, Sergio.The Ticó Flora (Patagonia) and the Aptian Extinction Event" ''Acta Paleobotanica'' 41(2), 2001, pp. 115-22. Stratigraphic definitions The Aptian was named after the small city of Apt in the Provence region of France, which is also known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trincheras Formation
The Trincheras Formation ( es, Formación Trincheras, Kitr) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consisting of a lower unit of calcareous shales and an upper sequence of shales dates to the Early Cretaceous period; Early Aptian epoch and has a maximum thickness of . The formation, deposited in a marine platform environment, part of a transgressive cycle, hosts ammonite, bryozoan, mollusc and echinoid fossils. Etymology The formation was defined and named in 1969 by Cáceres and Etayo after Quebrada Trincheras, Apulo, Cundinamarca.Acosta & Ulloa, 2002, p.39 Description Lithologies The Trincheras Formation has a maximum thickness of ,Acosta & Ulloa, 2001, p.23 and is characterised by a sequence of claystones with intercalated limestones and sandstones. Fossils of the ammonites '' Heinzia sp.'', '' Pseudohaploceras sp.'', '' Heminautilus etheringtoni'', '' Cheloniceras sp.'' and bryozoans, mollu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
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 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 porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-bearing sandstone can be changed into quartzite through metamorphism, usually relate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colombia
Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuela to the east and northeast, Brazil to the southeast, Ecuador and Peru to the south and southwest, the Pacific Ocean to the west, and Panama to the northwest. Colombia is divided into 32 departments and the Capital District of Bogotá, the country's largest city. It covers an area of 1,141,748 square kilometers (440,831 sq mi), and has a population of 52 million. Colombia's cultural heritage—including language, religion, cuisine, and art—reflects its history as a Spanish colony, fusing cultural elements brought by immigration from Europe and the Middle East, with those brought by enslaved Africans, as well as with those of the various Amerindian civilizations that predate colonization. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group (geology)
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 va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Huila Department
Huila () is one of the departments of Colombia. It is located in the southwest of the country, and its capital is Neiva, Colombia, Neiva. Demography and Ethnography Huila is a department that has a population of 1,122,622 inhabitants, of which 679,667 (60.54%) people live in municipal capitals and 442,955 (39.46%) in the rest of the Huilense territory. This corresponds to 2.5% of the total Colombian population. The majority of the population is settled in the Magdalena valley, with epicenters in Neiva, Huila, Neiva and Garzón, Huila, Garzón due to the possibilities offered by the commercial-type agricultural economy, oil exploitation, the best provision of services and the road axes connected to the central axis that borders the Magdalena Department, Magdalena. The rest of the populations are located on the coffee belt, standing out Pitalito and La Plata, Huila, La Plata, the North Subregion presents a decrease in its rural population, mainly attributable to the alterations o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boyacá Department
Boyacá () is one of the thirty-two departments of Colombia, and the remnant of Boyacá State, one of the original nine states of the "United States of Colombia". Boyacá is centrally located within Colombia, almost entirely within the mountains of the Eastern Cordillera to the border with Venezuela, although the western end of the department extends to the Magdalena River at the town of Puerto Boyacá. Boyacá borders to the north with the Department of Santander, to the northeast with the Bolivarian Republic of Venezuela and Norte de Santander, to the east with the departments of Arauca and Casanare. To the south, Boyacá borders the department of Cundinamarca and to the west with the Department of Antioquia covering a total area of . The capital of Boyacá is the city of Tunja. Boyacá is known as "The Land of Freedom" because this region was the scene of a series of battles which led to Colombia's independence from Spain. The first one took place on 25 July 1819 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Von Humboldt
Friedrich Wilhelm Heinrich Alexander von Humboldt (14 September 17696 May 1859) was a German polymath, geographer, naturalist, explorer, and proponent of Romantic philosophy and science. He was the younger brother of the Prussian minister, philosopher, and linguist Wilhelm von Humboldt (1767–1835). Humboldt's quantitative work on botanical geography laid the foundation for the field of biogeography. Humboldt's advocacy of long-term systematic geophysical measurement laid the foundation for modern geomagnetic and meteorological monitoring. Between 1799 and 1804, Humboldt travelled extensively in the Americas, exploring and describing them for the first time from a modern Western scientific point of view. His description of the journey was written up and published in several volumes over 21 years. Humboldt was one of the first people to propose that the lands bordering the Atlantic Ocean were once joined (South America and Africa in particular). Humboldt resurrected th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andes
The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S latitude), and has an average height of about . The Andes extend from north to south through seven South American countries: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile, and Argentina. Along their length, the Andes are split into several ranges, separated by intermediate depressions. The Andes are the location of several high plateaus—some of which host major cities such as Quito, Bogotá, Cali, Arequipa, Medellín, Bucaramanga, Sucre, Mérida, El Alto and La Paz. The Altiplano plateau is the world's second-highest after the Tibetan plateau. These ranges are in turn grouped into three major divisions based on climate: the Tropical Andes, the Dry Andes, and the Wet Andes. The Andes Mountains are the highest m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cordillera Oriental (Colombia)
The Cordillera Oriental ( en, Eastern Ranges) is the widest of the three branches of the Colombian Andes. The range extends from south to north dividing from the Colombian Massif in Huila Department to Norte de Santander Department where it splits into the Serranía del Perijá and the Cordillera de Mérida in Venezuelan Andes. The highest peak is Ritacuba Blanco at in the Sierra Nevada del Cocuy. Geography The western part of the Cordillera Oriental belongs to the Magdalena River basin, while the eastern part includes the river basins of the Amazon River, Orinoco River, and Catatumbo River. Within it, the Altiplano Cundiboyacense and the Sierra Nevada del Cocuy (with the only snowy peaks in this mountain range) stand out. The mountain range contains the most páramos in the world. Protected areas * Cueva de los Guácharos * Chingaza National Natural Park * Yariguíes National Park * Sierra Nevada del Cocuy * Sumapaz Páramo * Tamá National Natural Park * Los ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saunders_Quarry-1.jpg "Click for more on -> Sandstone")
.jpg "Click for more on -> Andes")