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31-557: The formation was first described by Hettner in 1892, then by Hubach in 1931, 1945 and 1957, and named in 1963 by Julivert after the Colombian capital Bogotá and its savanna . The Bogotá Formation consists mainly of grayish-red, locally purplish, commonly greenish-gray, generally poorly stratified mudstone and silty claystone . Lithic arenite sandstone lenses, ranging from fine- to medium-grained, generally friable and variegated, are local constituents. Carbonaceous material

62-581: A riverine vertebrate fauna that includes lungfish , turtles, snakes, and crocodyliforms . Based on these fossils and the stratigraphy of the formation, the Cerrejón Formation was likely formed on a coastal plain, covered in a wet tropical rainforest and incised by a large river system. The rainforest is estimated to have been around 5°N paleolatitude . During the Paleocene, equatorial temperatures were much higher than they are today. Based on

93-662: A thickness of 436.5 metres (1,432 ft). The campus of the Universidad La Javeriana has the Bogotá Formation as solid basement rock. The Bogotá Formation forms the footwall of the eastward compressional Chicamocha Fault, and the footwall of the westward thrusting Bogotá Fault . Alfred Hettner Alfred Hettner (6 August 1859, in Dresden – 31 August 1941, in Heidelberg )

124-661: Is a stub . You can help Misplaced Pages by expanding it . Cerrej%C3%B3n Formation The Cerrejón Formation is a geologic formation in Colombia dating back to the Middle-Late Paleocene . It is found in the El Cerrejón sub-basin of the Cesar-Ranchería Basin of La Guajira and Cesar . The formation consists of bituminous coal fields that are an important economic resource. Coal from

155-525: Is evident on some of the plant macrofossils from the Cerrejón Formation. One survey of plant macrofossils showed that around half of the studied specimens had been attacked by herbivorous insects. The insects that damaged the leaves were predominantly generalist feeders, unlike modern Neotropical insects that are mainly specialist herbivores. There is no evidence of the elevated insect-feeding diversity or host -specialized feeding associations that are seen in later Neotropical forests. The insect diversity in

186-466: Is found near deformed zones such as faults or tight folds, and is older than the deformities themselves. They are thought to have combusted after the development of the Cerrejón thrust fault and alluvial fan . Fossils found from the Cerrejón Formation are the earliest record of Neotropical rainforests, with an abundance of plant macrofossils and palynomorphs . The Cerrejón Formation also records

217-419: Is likely to have been an adaptation for a more generalized diet in a transitional aquatic environment. It is possible that Cerrejonisuchus was a food source for Titanoboa , as the two inhabited the same riverine environment. The anaconda has been documented consuming caimans , a feeding habit that is similar to the inferred habit of Titanoboa . A second dyrosaurid, Acherontisuchus , was named in 2011 from

248-614: Is overlain by the Regadera Formation . The age has been estimated to be Late Paleocene to Early Eocene . The middle part of the succession has been dated using detrital zircons at 56.2 ± 1.6 Ma. The spread of ages based on zircons has been reported from 60.96 ± 0.7 to 53.6 ± 1.1 Ma. The Bogotá Formation is laterally equivalent with the shales of the Socha Formation , the San Fernando Formation ,

279-684: Is present as thin beds of low-grade argillaceous coal , north of Bogotá. Fossil remains of Etaoya bacatensis , named after Colombian geologist Fernando Etayo and the indigenous name for the Bogotá savanna, Bacatá , have been found in Ciudad Bolívar , close to the type locality of the Bogotá Formation. Additionally, macroflora of Palaeophytocrene hammenii , named after Dutch botanist Thomas van der Hammen , and pollen of Foveotriletes margaritae , Proxapertites operculatus and Foveotricolpites perforatus have been found, used for dating

310-475: Is quite low. This may be an indication of the early stage of Neotropical diversification, or a delayed recovery period following the Cretaceous–Paleogene extinction event . Many plants from the Cerrejón Formation belong to families that are still common today in modern Neotropical rainforests. There is a diverse variety of palms and legumes in the formation. In addition to palms and legumes, much of

341-458: Is subdivided into lower, middle, and upper groups based on the thickness and distribution of coal beds. On average the coal beds are 3 metres (9.8 ft) thick, and range from 0.7 metres (2.3 ft) to 10 metres (33 ft) in thickness. The thickest beds are in the upper part of the formation. The Cerrejón Formation is laterally equivalent with the Los Cuervos and Bogotá Formations to

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372-733: The Early Eocene Climatic Optimum (EECO). The faunal distribution has been correlated to the Carodnia -, Amphidolops -, and Wainka -bearing Peñas Coloradas Formation of the Golfo San Jorge Basin in Patagonia , Argentina . The Bogotá Formation, with a thickness of 169 metres (554 ft) close to Tunja to 1,415 metres (4,642 ft) near Bogotá, overlies the Cacho Formation and

403-648: The El Limbo Formation , Los Cuervos Formation , and the fossil-rich Cerrejón Formation of La Guajira . The Bogotá Formation is apart from its type locality , found in the synclinals of the Río Frío , Checua - Lenguazaque , Sesquilé , Sisga , Subachoque , around Lake Suesca , in the Tenza Valley , and in the synclinals of Teusacá and Usme . In the Usme Synclinal, the formation has

434-518: The University of Strasbourg , was also a pupil of Ferdinand von Richthofen and Friedrich Ratzel at Leipzig —where he obtained his habilitation . His book Europe was published in 1907. According to him, geography is a chorological science or it is a study of regions. Hettner rejected the view that geography could be either general or regional. Geography, like other fields of learning, must deal in both unique things (regional geography) and with

465-447: The anaconda , is likely to be a close living analogue of Titanoboa . A dyrosaurid crocodylomorph called Cerrejonisuchus improcerus was described in 2010 from the Cerrejón Formation in the same layer as Titanoboa . It was a small dyrosaurid, and had the shortest snout length relative to its skull length of any dyrosaurid. Most dyrosaurids were marine, with long snouts adapted for catching fish. The short snout of Cerrejonisuchus

496-411: The depositional environment fluctuated from an estuarine -influenced coastal plain at the base of the formation to a fluvial -influenced coastal plain at the top. In the geologically recent past, some coal in the formation has spontaneously and naturally combusted to form clinker, red and brick-looking burnt coal. These rocks outcrop irregularly and are up to 100 metres (330 ft) thick. Clinker

527-512: The universal (general geography), but the study of regions — especially in the form of his Länderkunde  [ de ] approach — is the main field of geography. Hettner supervised, among others, the PhDs of Martha Krug-Genthe , Oskar Schmieder , Friedrich Metz  [ de ] and Heinrich Schmitthenner  [ de ] . In 1895, he founded the journal Geographische Zeitschrift , which he also edited for many years. He

558-519: The Cerrejón Formation is low in comparison to the diversity of insects in Neotropical rainforests today, and it is likely that leaf damage was made by relatively few species. Remains of the giant boid Titanoboa cerrejonensis have been found from a gray claystone layer underlying Coal Seam 90 in the Cerrejón mine. Titanoboa is the largest known snake to have ever existed, reaching an estimated length of 12.8 metres (42 ft). Eunectes ,

589-531: The Cerrejón Formation is mined extensively from the Cerrejón open-pit coal mine, one of the largest in the world. The formation also bears fossils that are the earliest record of Neotropical rainforests . The formation was first named Septarias Formation and in 1958 renamed to Cerrejón Formation by Thomas van der Hammen , probably based on an earlier report by Notestein. The Cerrejón Formation, with an assigned total thickness of 750 metres (2,460 ft),

620-485: The Cerrejón Formation predict the mean annual temperature to be 6 to 8 °C (11 to 14 °F) lower than other estimates. However, such temperature estimates based on riparian and wetland rainforest paleoflora have been considered underestimates. Mean annual temperatures of 30 to 34 °C (86 to 93 °F) are considered to be too high for modern tropical forests, but the Cerrejón rainforest could have been maintained by increased atmospheric pCO 2 levels and

651-560: The Doña Juana dump, dyrosaurid mesoeucrocodylians, boid snakes, dipnoan fishes, frogs, lizards, sebecid crocodyliforms and 11 fossils of mammals. The find of a derived snake in the Lower Eocene section of the formation represents the oldest New World record. The finds of iguanians, including the fossil record of hoplocercines, and boine, caenophidian, and ungaliophiine snakes, indicate a tropical forest environment, present just before

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682-480: The Paleocene. The presence of these types of flora in Paleocene strata shows that plants characteristic of modern Neotropical rainforests have existed for geologically long periods of time, being able to withstand climatic and geographic changes in South America. It has been suggested that today's Neotropical rainforests are the result of environmental changes brought about by Quaternary glacial cycles (i.e.

713-453: The biomass of the Paleocene forest consisted of laurales , malvales , menisperms , aroids , zingiberaleans , cocoa bean plants, banana plants, and avocado plants. Studies of fossil plants from Cretaceous -age sites indicate that the floral composition below the Cretaceous–Paleogene boundary (K–T boundary) was very different from that of the Paleocene. Legumes are absent from Cretaceous strata, and likely appeared or diversified during

744-588: The formation. Other pollen and flora, as Ulmoideipites krempii , Carpolithus , Anemocardium margaritae , and Hickeycarpum peltatum have been found in the Bogotá Formation. The abundant paleosols of the Bogotá Formation show an increase in chemical weathering across the Paleocene-Eocene (P-E) transition; the Paleocene–Eocene Thermal Maximum . Later analysis has found several other species, such as pleurodire turtles, found at

775-450: The formation. With a large body and long snout, it resembles most other dyrosaurids. A third dyrosaurid, Anthracosuchus , was named in 2014. Unlike other dyrosaurids, it had blunt teeth and a short skull. Anthracosuchus likely had massive jaw muscles allowing it to feed on large turtles, a behavior which is corroborated by predation marks found at the site. The Cerrejón Formation contains extensive coal seams that are mined primarily at

806-421: The high regional rainfall, which is estimated to have been around 4 metres (13 ft) per year. The floral record of the Cerrejón Formation is well known, with many identifiable and well preserved plant microfossils having been found from the Cerrejón mine. The fossils are well preserved, and in some cases their cell structure is intact. In comparison to modern Neotropical rainforests, the diversity of plants

837-543: The recent ice age). These cycles would have caused fluctuation in the diversity and extent of rainforests. If this was the case, the current diversity of the Amazon rainforest would be a recent speciation in a changing environment. However, the floral record from the Cerrejón Formation shows that the current diversity of the Amazon Rainforest can be traced back into the early Cenozoic. Feeding damage from insects

868-570: The size of the giant boid Titanoboa , specimens of which have been found in the Cerrejón Formation, the mean annual temperature of Paleocene equatorial South America was between 30 °C (86 °F) and 34 °C (93 °F). This is the minimum annual temperature range that a poikilotherm as large as Titanoboa could live. It is consistent with Paleocene climate models which predict greenhouse temperatures and an atmospheric pCO 2 concentration of around 2,000 parts per million. Paleotemperature estimates based on fossil leaf assemblages from

899-890: The south; Llanos Orientales and Altiplano Cundiboyacense respectively. The formation is also time-equivalent with the Marcelina Formation of the Venezuelan Serranía del Perijá and the Catatumbo Formation of the southwestern Colombian part of the Maracaibo Basin , the Catatumbo Basin . The formation has also been described as laterally equivalent to the Mostrencos and Santa Cruz Formations of Venezuela. Based on lithofacies associations and paleofloral composition,

930-530: Was a German geographer . His parents were art historian Hermann Theodor Hettner and Marie von Stockmar. His maternal grandfather was Christian Friedrich, Baron Stockmar . His half-brother was Otto Hettner . He is known for his concept of chorology , the study of places and regions, a concept that influenced both Carl O. Sauer and Richard Hartshorne . Apart from the geography of Europe , his fieldwork concentrated mainly on that of Colombia , Chile and Russia . Alfred Hettner, who obtained his PhD from

961-415: Was a lecturer briefly at Tübingen (1894-1897) and Leipzig (1897-1899). In 1899, he joined University of Heidelberg as an associate professor. By 1906, he became the first Chair of Geography at Heidelberg. He held this office until his retirement in 1928. This biographical article about a geographer is a stub . You can help Misplaced Pages by expanding it . This article about a German scientist

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