Neocomian

In geology, Neocomian was a name given to the lowest stage of the Cretaceous system. It was introduced by Jules Thurmann in 1835 on account of the development of these rocks at Neuchâtel (Neocomum), Switzerland. It has been employed in more than one sense. In the type area the rocks have been divided into two sub-stages, a lower, Valanginian (from Valengin, Pierre Jean Édouard Desor, 1854) and an upper, Hauterivian (from Hauterive, Eugène Renevier, 1874); there is also another local sub-stage, the infra-Valanginian or Berriasian (from Berrias, Henri Coquand, 1876). These three sub-stages constitute the Neocomian in its restricted sense. Adolf von Koenen and other German geologists extend the use of the term to include the whole of the Lower Cretaceous up to the top of the Gault or Albian. Eugène Renevier divided the Lower Cretaceous into the Neocomian division, embracing the three sub-stages mentioned above, and an Urgonian division, including the Barremian, Rhodanian and Aptian sub-stages. Sir A. Geikie (Text Book of Geology, 4th ed., 1903) regards Neocomian as synonymous with Lower Cretaceous, and he, like Renevier, closes this portion of the system at the top of the Lower Greensand (Aptian). Other British geologists (A. J. Jukes-Browne, &c.) restrict the Neocomian to the marine beds of Speeton and Tealby, and their estuarine equivalents, the Weald Clay and Hastings Sands (Wealden). Much confusion would be avoided by dropping the term Neocomian entirely and employing instead, for the type area, the sub-divisions given above. This becomes the more obvious when it is pointed out that the Berriasian type is limited to Dauphine; the Valanginian has not a much wider range; and the Hauterivian does not extend north of the Paris basin.

Characteristic fossils of the Berriasian are Hoplites euthymi, H. occitanicus; of the Valanginian, Natica leviathan, Belémnites pistilliformis and B. dilatatus, Oxynoticeras Gevrili; of the Hauterivian, Hoplites radiatus, Crioceras capricornu, Exogyra Couloni and Toxaster complanatus. The marine equivalents of these rocks in England are the lower Speeton Clays of Yorkshire and the Tealby beds of Lincolnshire. The Wealden beds of southern England represent approximately an estuarine phase of deposit of the same age. The Hils clay of Germany and Wealden of Hanover; the limestones and shales of Teschen; the Aptychus and Pygope diphyoides marls of Spain, and the Petchorian formation of Russia are equivalents of the Neocomian in its narrower sense.

References

  •  This article incorporates text from a publication now in the public domainChisholm, Hugh, ed. (1911). "Neocomian". Encyclopædia Britannica (11th ed.). Cambridge University Press.
1931 in paleontology

Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1931.

Araripe Basin

The Araripe Basin (Portuguese: Bacia do Araripe) is a rift basin covering about 8,000 square kilometres (3,100 sq mi), in Ceará, Piauí and Pernambuco states of northeastern Brazil. It is bounded by the Patos and Pernambuco lineaments, and is situated east of the Parnaíba Basin, southwest of the Rio do Peixe Basin and northwest of the Tucano and Jatobá Basins.The basin has provided a variety of unique fossils in the Crato and Santana Formations and includes the Araripe Geopark, a member of the UNESCO Global Geoparks since 2006. The pterosaurs Araripesaurus and Araripedactylus (now considered a nomen dubium), crocodylian Araripesuchus, the turtle Araripemys, amphibian Arariphrynus, the fish Araripelepidotes and the insect Araripenymphes were named after the basin. The bituminous shales of the Ipubi Formation in the Araripe Basin have potential for shale gas development.

Campos Basin

The Campos Basin is one of 12 coastal sedimentary basins of Brazil. It spans both onshore and offshore parts of the South Atlantic with the onshore part located near Rio de Janeiro. The basin originated in Neocomian stage of the Cretaceous period 145–130 million years ago during the breakup of Gondwana. It has a total area of about 115,000 square kilometres (44,000 sq mi), with the onshore portion small at only 500 square kilometres (190 sq mi).

Dryosauridae

Dryosaurids were primitive iguanodonts. They are known from Middle Jurassic to Early Cretaceous rocks of Africa, Europe, and North America.

Elrhazosaurus

Elrhazosaurus is a genus of basal iguanodontian dinosaur, known from isolated bones found in Lower Cretaceous rocks of Niger. These bones were initially thought to belong to a species of the related dryosaurid Valdosaurus, but have since been reclassified.

Georges de Tribolet

Georges de Tribolet (20 December 1830 in Neuchâtel – 18 May 1873) was a Swiss geologist. He was the older brother of geologist and paleontologist, Maurice de Tribolet (1852–1929).He studied chemistry at the University of Giessen as a pupil of Justus von Liebig, then continued his education at Zurich, where he studied chemistry, botany and geology, with geologist Arnold Escher von der Linth being an important influence to his career. In 1853 he received his PhD from the University of Heidelberg with a dissertation on porphyritic rocks. Following graduation, he furthered his education in Paris and Berlin, returning in 1855 to Neuchâtel, where he worked as a geologist and museum curator.While a student, he travelled extensively, conducting geological excursions in the Harz and Jura Mountains, the Alps and throughout the Black Forest. He is best remembered for his investigations of the Cretaceous terrain of the Jura, with the Neocomian strata being a specific subject of research.

Gobiconodon

Gobiconodon is an extinct genus of carnivorous mammal from the early Cretaceous. It weighed 10–12 pounds (4.5–5.4 kg) and measured 18–20 inches (460–510 mm). It was one of the largest mammals known from the Mesozoic. Like other gobiconodontids, it possesses several speciations towards carnivory, such as shearing molar teeth, large canine-like incisors and powerful jaw and forelimb musculature, indicating that it probably fed on vertebrate prey; rather uniquely among predatory mammals and other eutriconodonts, the lower canines were vestigial, with the first lower incisor pair having become massive and canine-like. Like the larger Repenomamus there might be some evidence of scavenging.

Jules Thurmann

Jules Thurmann (5 November 1804, Neuf-Brisach in Haut-Rhin, France – 25 July 1855, Porrentruy) was an Alsatian French-Swiss geologist and botanist.

He studied at the college in Porrentruy, then continued his education at the University of Strasbourg and at the École royale des mines in Paris. In 1832 he was appointed professor of mathematics and natural sciences at Porrentruy College. In 1837 he became the first director of the "normal school" for teachers in Porrentruy. In 1838 he was chairman of the first congress for the Société géologique de France, which took place in Porrentruy.

He devoted much of his time to geological studies of the Jura Mountains, being known for his pioneer investigations in regards to Jurassic orography. In the field of statigraphy, he introduced in 1834 the term "Neocomian" to define the lowest stage of Cretaceous formation. As a botanist, he conducted phytosociological research, and is credited with directing the last phases of development for the botanical garden at Porrentruy.He was the founder of the Société de statistique des districts du Jura (1832); co-founder and first president of the Société jurassienne d'émulation (1847–1855) and a member of the Grand Conseil bernois (1837–1839, 1844–1845).

Lebanoraphidia

Lebanoraphidia is an extinct genus of snakefly in the family Mesoraphidiidae. The genus is solely known from Cretaceous, Upper Neocomian, fossil amber found in Lebanon. Currently the genus is composed of a single species Lebanoraphidia nana.

Neocomian Sands

The Neocomian Sands is an Early Cretaceous geologic formation. Dinosaur remains have been recovered from it.

Noguerornis

Noguerornis is a genus of enantiornithine bird possibly related to Iberomesornis. It lived during the Early Cretaceous (early Barremian age) about 130 mya and is known from fossils found at El Montsec, Spain.

Owenodon

Owenodon is a genus of iguanodontian dinosaur known from a partial lower jaw discovered in Early Cretaceous-age rocks of Durlston Bay, Dorset, United Kingdom. The specimen, NHM R2998, comes from the Purbeck Limestone, dating to the middle Berriasian stage (approximately 143 million years ago). It was first described by Richard Owen, who in 1874 assigned it to Iguanodon as the type specimen of the new species I. hoggii, the specific name honouring naturalist A.J. Hogg who had originally collected the fossil in 1860. The bone was damaged during initial preparation but was freed from the surrounding rock matrix by an acid bath between 1975 and 1977. David Norman and Paul Barrett subsequently transferred the species to Camptosaurus in 2002, but this was challenged, and in 2009 Peter Galton assigned the species to the new genus Owenodon. Galton interpreted the genus as an iguanodontoid more derived than Camptosaurus but less derived than Lurdusaurus.

Patuxent Formation

The Patuxent Formation is a Cretaceous geologic formation of the Atlantic coastal plain.

Perceval de Loriol

Charles Louis Perceval de Loriol (24 July 1828, Geneva – 23 December 1908, Cologny) was a Swiss paleontologist and stratigraphist.

He studied natural sciences and paleontology in Geneva as a pupil of François-Jules Pictet. For a period of time, he worked as an estate manager in Geneva and Lorraine, then for nearly forty years was associated with the Natural History Museum of Geneva. He was one of the founders of the Schweizerische Paläontologische Gesellschaft and was an editor of the Mémoires de la Société suisse paléontologique. In 1902 he received an honorary doctorate from the University of GenevaHe is remembered for his investigations of fossil echinoderms found in Europe and North Africa from the Jurassic, Cretaceous and Upper Tertiary Eras. He was the author of numerous taxa, an example being the crinoid family Bourgueticrinidae (1882).

Salta Basin

Salta Basin or Salta Rift Basin is a sedimentary basin located in the Argentine Northwest. The basin started to accumulate sediments in the Early Cretaceous (Neocomian) and at present it has sedimentary deposits reaching thicknesses of 5,000 metres (16,000 ft). The basin contains seven sub-basins: Tres Cruces, Lomas de Olmedo, Metán, Alemanía, Salfity, El Rey, Sey and Brealito. The basin environment has variously been described as a "foreland rift" and an "intra-continental rift". The basin developed under conditions of extensional tectonics and rift-associated volcanism.

Valdosaurus

Valdosaurus ("Weald Lizard") is a genus of bipedal herbivorous iguanodont ornithopod dinosaur found on the Isle of Wight and elsewhere in England. It lived during the Early Cretaceous.

Walter Keeping

Walter Keeping MA (1854–1888) was a British geologist and museum curator.

Weald Clay

Weald Clay or the Weald Clay Formation is a Lower Cretaceous sedimentary rock underlying areas of South East England. It is part of the Wealden Group of rocks. The clay is named after the Weald, an area of Sussex and Kent. It varies from orange and grey in colour and is used in brickmaking.

The un-weathered form is blue/grey, and the yellow/orange is the weathered form; they have quite different physical properties. Blue looks superficially like a soft slate, is quite dry and hard and will support the weight of buildings quite easily.

Because it is quite impermeable, and so dry, it does not get broken by tree roots. It is typically found at 750mm down below a layer of yellow clay. Yellow, found on the surface, absorbs water quite readily so becomes very soft in the winter.

The two different types make quite different bricks.

West Siberian petroleum basin

The West Siberian petroleum basin (variously known as the West Siberian hydrocarbon province, Western Siberian oil basin, etc.) is the largest hydrocarbon (petroleum and natural gas) basin in the world covering an area of about 2.2 million km2.

Geographically it corresponds to the West Siberian plain. From continental West Siberia, it extends into the Kara Sea as the East-Prinovozemelsky field.

Beneath lie remnants of the Siberian traps, thought responsible for the Great Dying 250 mil years ago.

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