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Rosablanca Formation
The Rosablanca Formation ( es, Formación Rosablanca, Kir) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes and the Middle Magdalena Basin. The formation consists of grey limestones, dolomites and shales with at the upper part sandstones. The formation dates to the Early Cretaceous period; Valanginian epoch and has a thickness of in the valley of the Sogamoso River. Definition The formation was first defined by Wheeler in 1929. Description Lithologies The Rosablanca Formation is characterised by a sequence of grey limestones, dolomites and shales with a maximum thickness of in the Sogamoso River valley.Galvis & Valencia, 2009, p.17 Stratigraphy and depositional environment The Rosablanca Formation overlies the Arcabuco Formation and is overlain by the Ritoque Formation. The age has been estimated to be Valanginian. Stratigraphically, the formation is time equivalent with the Macanal Formation. Fossils Fossils of the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valanginian
In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretaceous and precedes the Hauterivian Stage of the Lower Cretaceous. Stratigraphic definitions The Valanginian was first described and named by Édouard Desor in 1853. It is named after Valangin Valangin () is a former municipality in the district of Val-de-Ruz in the canton of Neuchâtel in Switzerland. On 1 January 2021 the former municipalities of Corcelles-Cormondrèche, Peseux and Valangin merged into the municipality of Neuchâ ..., a small town north of Neuchâtel in the Jura Mountains of Switzerland. The base of the Valanginian is at the first appearance of Calpionellidae, calpionellid species ''Calpionellites darderi'' in the stratigraphic column. A global reference section (a GSSP) had in 2009 not yet been appointed. The top o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Magdalena Basin
The Middle Magdalena Valley, Middle Magdalena Basin or Middle Magdalena Valley Basin ( es, Valle Medio del Magdalena, commonly abbreviated to VMM) is an intermontane basin, located in north-central Colombia between the Central and Eastern Ranges of the Andes. The basin, covering an area of , is situated in the departments of Santander, Boyacá, Cundinamarca and Tolima. The basin is structurally bounded by the Palestina Fault to the west and the Bucaramanga Fault to the east. The Middle Magdalena Valley hosts the middle course of the Magdalena River, the main river of Colombia, flowing from the Upper Magdalena Valley in the south to the Lower Magdalena Valley to the northwest. The basin is elongated with an approximate width of and extends to the north for approximately , where it terminates against the Santander Massif and Cesar Valley. To the south, it terminates against the Upper Magdalena Valley, which consists of the Girardot and Neiva Sub-basins where the Central and East ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pterodactyloids
Pterodactyloidea (derived from the Greek words ''πτερόν'' (''pterón'', for usual ''ptéryx'') "wing", and ''δάκτυλος'' (''dáktylos'') "finger" meaning "winged finger", "wing-finger" or "finger-wing") is one of the two traditional suborders of pterosaurs ("wing lizards"), and contains the most derived members of this group of flying reptiles. They appeared during the middle Jurassic Period, and differ from the basal (though paraphyletic) rhamphorhynchoids by their short tails and long wing metacarpals (hand bones). The most advanced forms also lack teeth, and by the late Cretaceous, all known pterodactyloids were toothless. Many species had well-developed crests on the skull, a form of display taken to extremes in giant-crested forms like ''Nyctosaurus'' and ''Tupandactylus''. Pterodactyloids were the last surviving pterosaurs when the order became extinct at the end of the Cretaceous Period, together with the non-avian dinosaurs and most marine reptiles. "Pteroda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2019 In Paleontology
Flora Plants Fungi Paleomycological research * Fossil sporocarps indistinguishable from sporocarps of members of the extant genus ''Stemonitis'' are described from the Cretaceous amber from Myanmar by Rikkinen, Grimaldi & Schmidt (2019). * A study on the impact of major historical events such as the Cretaceous–Paleogene extinction event on the evolution of two major subclasses of lichen-forming fungi ( Lecanoromycetidae and Ostropomycetidae) is published by Huang ''et al.'' (2019). * Description of crustose lichens from European Paleogene amber is published by Kaasalainen ''et al.'' (2019). * Fungi belonging to the genera '' Periconia'', ''Penicillium'' and ''Scopulariopsis'', representing the first and the oldest known fossil record of these taxa, are described from the Eocene Baltic amber by Tischer ''et al.'' (2019). Sponges Research * Sponge spicules and spicule-like structures that probably represent sponge fossils are described from four sections of the Ediacaran-Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macanal Formation
The Macanal Formation or Macanal Shale ( es, (Formación) Lutitas de Macanal, Kilm, K1m) is a fossiliferous geological formation of the Altiplano Cundiboyacense and Tenza Valley in the Eastern Ranges of the Colombian Andes. The predominantly organic shale formation dates to the Early Cretaceous period; Berriasian to Valanginian epochs and has a maximum thickness of . The Macanal Formation contains numerous levels of fossiliferous abundances. Bivalves, ammonites and fossil flora have been found in the formation. The formation is a source rock for oil and gas in the Eastern Cordillera Basin and adjacent Llanos Basin foothills and provides emeralds in the vicinity of Macanal, after which the formation is named. Etymology The formation was defined and named in 1979 by Rodríguez and Ulloa after Macanal, Cundinamarca.Acosta & Ulloa, 2002, p.51 The name Macanal is either derived from the Muysccubun word ''Macana'', meaning garrote, or from the ''Macana'' palm tree. Descriptio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arcabuco Formation
The Arcabuco Formation ( es, Formación Arcabuco, Jar, JKa) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consists of thick beds of light-coloured quartzitic sandstones and conglomerates with occasional shales and dates to the Late Jurassic and Early Cretaceous periods; Tithonian to Berriasian epochs. Dinosaur footprints have been found in the Arcabuco Formation near the Iguaque anticlinal outside Chíquiza, Boyacá. Etymology The formation was first defined by Scheibe in 1938 and named after Arcabuco, Boyacá. The type section of the Arcabuco Formation was redefined in 1985 by Galvis and Rubiano around Villa de Leyva.Galvis & Valencia, 2009, p.15 Description Lithologies The Arcabuco Formation is characterised by a sequence of light- to pink-coloured fine quartzitic sandstones and conglomerates with red shales up to in thickness intercalated.Galvis & Valencia, 2009, p.17Rodríguez & Solano, 2000, p.28 In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolomite (rock)
Dolomite (also known as dolomite rock, dolostone or dolomitic rock) is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite, CaMg(CO3)2. It occurs widely, often in association with limestone and evaporites, though it is less abundant than limestone and rare in Cenozoic rock beds (beds less than about 66 million years in age). The first geologist to distinguish dolomite rock from limestone was Belsazar Hacquet in 1778. Most dolomite was formed as a magnesium replacement of limestone or of lime mud before lithification. The geological process of conversion of calcite to dolomite is known as dolomitization and any intermediate product is known as dolomitic limestone. The "dolomite problem" refers to the vast worldwide depositions of dolomite in the past geologic record in contrast to the limited amounts of dolomite formed in modern times. Recent research has revealed sulfate-reducing bacteria living in anoxic conditions precipitate dolomite which ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sogamoso River
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Sogamoso River () is a river of northern Colombia. It flows into the Magdalena River and on to the Caribbean Sea. The Sogamoso Dam on the river near Bucaramanga was completed in 2014. See also * List of rivers of Colombia References Further reading * Rivers of Colombia Magdalena River Rivers A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...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 related to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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