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71-539: The Tithonian was introduced in scientific literature by German stratigrapher Albert Oppel in 1865. The name Tithonian is unusual in geological stage names because it is derived from Greek mythology . Tithonus was the son of Laomedon of Troy and fell in love with Eos , the Greek goddess of dawn . His name was chosen by Albert Oppel for this stratigraphical stage because the Tithonian finds itself hand in hand with

142-460: A paleontologist is a stub . You can help Misplaced Pages by expanding it . This article about a German scientist is a stub . You can help Misplaced Pages by expanding it . Laurasia Laurasia ( / l ɔː ˈ r eɪ ʒ ə , - ʃ i ə / ) was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around 335 to 175 million years ago ( Mya ),

213-628: A diverse assemblage of benthos evolved, including the largest trilobites exceeding 1 m (3 ft 3 in). The Old Red Sandstone Continent stretched across northern Laurentia and into Avalonia and Baltica but for most of the Devonian a narrow seaway formed a barrier where the North Atlantic would later open. Tetrapods evolved from fish in the Late Devonian, with the oldest known fossils from Greenland. Low sea-levels during

284-536: A loss of diversity, simply looking at the raw data alone. Sampling bias may also explain apparent extinctions in terrestrial environments, which have a similar disconnect in fossil abundance. This is most obvious in sauropod-bearing deposits, which are abundant in the Late Jurassic and rare in the earliest Cretaceous. Most studies relevant to the Tithonian extinction attempt to counteract sampling biases when estimating diversity loss or extinction rates. Depending on

355-467: A lower estimate, with the extinction of 5.6 to 13.3% of genera in the Tithonian. Proportional extinction was higher for continental genera (5.8–17.6%) than marine genera (5.1–6.1%). Sepkoski (1996) estimated that about 18% of multiple-interval marine genera (those originating prior to the Tithonian) died out in the Tithonian. Based on an updated version of Sepkoski's genera compendium, Bambach (2006) found

426-637: A moderate (up to 5 ‰ ) negative organic δ13C excursion in the middle part of the Tithonian. This excursion, sometimes called the Volgian Isotopic Carbon Excursion (VOICE), may be a consequence of volcanic activity. The Tithonian stage saw the emplacement of the Shatsky Rise , a massive volcanic plateau in the North Pacific . During the Late Jurassic and Early Cretaceous, numerous volcanic deposits can be found along

497-548: A period that saw the emergence of the Pangaean megamonsoon . Heavy rainfall resulted in high groundwater tables, in turn resulting in peat formation and extensive coal deposits. During the Cambrian and Early Ordovician, when wide oceans separated all major continents, only pelagic marine organisms, such as plankton, could move freely across the open ocean and therefore the oceanic gaps between continents are easily detected in

568-570: A separate southern Asian continent. This continent collided 240–220 Mya with a northern continent – North China, Qinling, Qilian, Qaidam, Alex, and Tarim – along the Central China orogen to form a combined East Asian continent. The northern margins of the northern continent collided with Baltica and Siberia 310–250 Ma, and thus the formation of the East Asian continent marked Pangaea at its greatest extent. By this time,

639-577: A series of continental blocks – Peri-Gondwana – that now form part of Asia, the Cathaysian terranes – Indochina, North China, and South China – and Cimmerian terranes – Sibumasu , Qiangtang , Lhasa , Afghanistan, Iran, and Turkey – were still attached to the Indian–Australian margin of Gondwana. Other blocks that now form part of southwestern Europe and North America from New England to Florida were still attached to

710-700: A similar estimate of 20% of genera going extinct in the Late Tithonian. European bivalve diversity is severely depleted across the J–K boundary. However, bivalve fossils from the Andes and Siberia show little ecological turnover, so bivalve extinctions may have localized to the Tethys Sea . Only a fraction of Jurassic ammonite species survive to the Cretaceous, though extinction rates were actually lower in

781-420: A trigger for a Cretaceous diversification event for plesiosaurs in the clade Xenopsaria , namely elasmosaurids and leptocleidians . This turnover of marine reptile faunas may be a consequence of the turnover of reefs and marine fishes, which would have benefited generalized predators more than specialists. It has long been suggested that ichthyosaurs and marine teleosauroid crocodyliforms declined across

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852-663: Is considered to have founded the study of zone stratigraphy and the use of index fossils , a term which he created, to compare the different strata. He also established the Tithonian stage, for strata (mainly equivalent to the English Portland and Purbeck Beds) that occur on the borders of Jurassic and Cretaceous . He was awarded the Chair of Paleontology at the University of Munich . This article about

923-642: Is debated. Laurentia and Baltica first formed a continental mass known as Proto-Laurasia as part of the supercontinent Columbia which was assembled 2,100—1,800 Mya to encompass virtually all known Archaean continental blocks. Surviving sutures from this assembly are the Trans-Hudson orogen in Laurentia; Nagssugtoqidian orogen in Greenland; the Kola-Karelian (the northwest margin of

994-614: Is good evidence for a marine regression in Europe across the Jurassic-Cretaceous boundary, which may explain the localized nature of the extinction. On the other hand, there is no clear consensus on a correlation between sea level and terrestrial diversity during the Jurassic and Cretaceous. Some authors support a fundamental correlation (the so-called "common cause hypothesis"), while others strongly voice doubts. Sea level fall

1065-622: Is preserved in the Central Asian Orogenic Belt , the largest orogen on Earth. North China, South China, Indochina, and Tarim broke off Gondwana during the Silurian-Devonian; Palaeo-Tethys opened behind them. Sibumasu and Qiantang and other Cimmerian continental fragments broke off in the Early Permian. Lhasa , West Burma , Sikuleh, southwest Sumatra, West Sulawesi, and parts of Borneo broke off during

1136-761: Is today the Gulf of Mexico to Nova Scotia, and in Africa and Europe, from Morocco to Greenland. By c.  83 Mya spreading had begun in the North Atlantic between the Rockall Plateau , a continental fragment sitting on top of the Eurasian Plate, and North America. By 56 Mya Greenland had become an independent plate, separated from North America by the Labrador Sea-Baffin Bay Rift . By 33 Mya spreading had ceased in

1207-606: The Caledonian orogeny c. 400 Ma to form Laurussia/ Euramerica . Laurussia/Euramerica then collided with Gondwana to form Pangaea. Kazakhstania and Siberia were then added to Pangaea 290–300 Ma to form Laurasia. Laurasia finally became an independent continental mass when Pangaea broke up into Gondwana and Laurasia. Laurentia, the Palaeozoic core of North America and continental fragments that now make up part of Europe, collided with Baltica and Avalonia in

1278-554: The Caledonian orogeny c. 430–420 Mya to form Laurussia. In the Late Carboniferous Laurussia and Gondwana formed Pangaea. Siberia and Kazakhstania finally collided with Baltica in the Late Permian to form Laurasia. A series of continental blocks that now form East and Southeast Asia were later added to Laurasia. In 1904–1909 Austrian geologist Eduard Suess proposed that the continents in

1349-665: The Franklin dike swarm in northern Canada and the Aldan Shield in Siberia. The Proto-Pacific opened and Rodinia began to breakup during the Neoproterozoic (c. 750–600 Mya) as Australia-Antarctica (East Gondwana) rifted from the western margin of Laurentia, while the rest of Rodinia (West Gondwana and Laurasia) rotated clockwise and drifted south. Earth subsequently underwent a series of glaciations –

1420-694: The Iapetus Ocean opened between them. Laurentia then began to move quickly (20 cm/year (7.9 in/year)) north towards the Equator where it got stuck over a cold spot in the Proto-pacific. Baltica remained near Gondwana in southern latitudes into the Ordovician . Laurentia, Baltica, and Siberia remained connected to each other within the short-lived, Precambrian - Cambrian supercontinent Pannotia or Greater Gondwana. At this time

1491-569: The Old Red Sandstone during the Devonian. The continent covered 37,000,000 km (14,000,000 sq mi) including several large Arctic continental blocks. With the Caledonian orogeny completed Laurussia was delimited thus: During the Devonian (416-359 Mya) the combined landmass of Baltica and Avalonia rotated around Laurentia, which remained static near the Equator. The Laurentian warm, shallow seas and on shelves

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1562-634: The Proto-Tethys Ocean (between Armorica and Gondwana) to form the supercontinent Pangaea. The Variscan orogeny is complex and the exact timing and the order of the collisions between involved microcontinents has been debated for decades. Pangaea was completely assembled by the Permian except for the Asian blocks. The supercontinent was centred on the Equator during the Triassic and Jurassic,

1633-731: The Svecokarelian/Svecofennian orogen ) and the Volhyn—Central Russia and Pachelma orogenies (across western Russia) in Baltica; and the Akitkan Orogen in Siberia. Additional Proterozoic crust was accreted 1,800—1,300 Mya, especially along the Laurentia—Greenland—Baltica margin. Laurentia and Baltica formed a coherent continental mass with southern Greenland and Labrador adjacent to

1704-702: The Turgai Sea separated Europe and Asia from the Middle Jurassic to the Oligocene and as this sea or strait dried out, a massive faunal interchange took place and the resulting extinction event in Europe is known as the Grande Coupure . The Coraciiformes (an order of birds including kingfishers) evolved in Laurasia. While this group now has a mostly tropical distribution, they originated in

1775-603: The Valanginian stage. Marine actinopterygians (ray-finned fishes) show elevated extinction rates across the Tithonian-Berriasian boundary. Most losses were quickly offset by substantial diversification in the Early Cretaceous. Sharks, rays, and freshwater fishes were nearly unaffected by the extinction. Marine reptiles were strongly affected by the Tithonian extinction. Thalassochelydians ,

1846-729: The Varanger (c. 650 Mya, also known as Snowball Earth ) and the Rapitan and Ice Brook glaciations (c. 610-590 Mya) – both Laurentia and Baltica were located south of 30°S, with the South Pole located in eastern Baltica, and glacial deposits from this period have been found in Laurentia and Baltica but not in Siberia. A mantle plume (the Central Iapetus Magmatic Province ) forced Laurentia and Baltica to separate ca. 650–600 Mya and

1917-505: The sauropods , theropods , and ornithischians  – was similar to that of the crocodilians. East Asia remained isolated with endemic species including psittacosaurs (horned dinosaurs) and Ankylosauridae (club-tailed, armoured dinosaurs). Meanwhile, mammals slowly settled in Laurasia from Gondwana in the Triassic, the latter of which was the living area of their Permian ancestors . They split in two groups, with one returning to Gondwana (and stayed there after Pangaea split) while

1988-700: The African-South American margin of Gondwana. This northward drift of terranes across the Tethys also included the Hunic terranes , now spread from Europe to China. Pannotia broke apart in the late Precambrian into Laurentia, Baltica, Siberia, and Gondwana. A series of continental blocks – the Cadomian–Avalonian, Cathaysian, and Cimmerian terranes – broke away from Gondwana and began to drift north. Laurentia remained almost static near

2059-684: The Arctic in the late Eocene c. 35 Mya from where they diversified across Laurasia and farther south across the Equator. The placental mammal group of Laurasiatheria is named after Laurasia. In the Triassic–Early Jurassic (c. 200 Mya), the opening of the Central Atlantic Ocean was preceded by the formation of a series of large rift basins, such as the Newark Basin , between eastern North America, from what

2130-571: The Arctic margin of Baltica. A magmatic arc extended from Laurentia through southern Greenland to northern Baltica. The breakup of Columbia began 1,600 Mya, including along the western margin of Laurentia and northern margin of Baltica (modern coordinates), and was completed c. 1,300—1,200 Mya, a period during which mafic dike swarms were emplaced, including MacKenzie and Sudbury in Laurentia. Traces left by large igneous provinces provide evidences for continental mergers during this period. Those related to Proto-Laurasia includes: In

2201-571: The Carboniferous–Permian Siberia, Kazakhstan, and Baltica collided in the Uralian orogeny to form Laurasia. The Palaezoic-Mesozoic transition was marked by the reorganisation of Earth's tectonic plates which resulted in the assembly of Pangaea, and eventually its break-up. Caused by the detachment of subducted mantle slabs, this reorganisation resulted in rising mantle plumes that produced large igneous provinces when they reached

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2272-698: The Devonian-Carboniferous boundary resulted in anoxic events that left black shales in the basins of Laurentia. The subduction of the Iapetus Ocean resulted in the first contact between Laurussia and Gondwana in the Late Devonian and terminated in full collision or the Hercynian/Variscan orogeny in the early Carboniferous (340 Mya). The Variscan orogeny closed the Rheic Ocean (between Avalonia and Armorica) and

2343-402: The Early Cretaceous c. 130 Mya in competition with faster growing flowering plants . Pines adapted to cold and arid climates in environments where the growing season was shorter or wildfire common; this evolution limited pine range to between 31° and 50° north and resulted in a split into two subgenera: Strobus adapted to stressful environments and Pinus to fire-prone landscapes. By

2414-831: The Early Devonian produced natural barriers in Laurussia which resulted in provincialism within the benthic fauna. In Laurentia the Transcontinental Arch divided brachiopods into two provinces, with one of them confined to a large embayment west of the Appalachians. By the Middle Devonian, these two provinces had been united into one and the closure of the Rheic Ocean finally united faunas across Laurussia. High plankton productivity from

2485-629: The Early Ordovician and collided with Baltica near the Ordovician–Silurian boundary (480–420 Mya). Baltica-Avalonia was then rotated and pushed north towards Laurentia. The collision between these continents closed the Iapetus Ocean and formed Laurussia , also known as Euramerica. Another historical term for this continent is the Old Red Continent or Old Red Sandstone Continent , in reference to abundant red beds of

2556-638: The Equator throughout the early Palaeozoic, separated from Baltica by the up to 3,000 km (1,900 mi)-wide Iapetus Ocean . In the Late Cambrian, the mid-ocean ridge in the Iapetus Ocean subducted beneath Gondwana which resulted in the opening of a series of large back-arc basins . During the Ordovician, these basins evolved into a new ocean, the Rheic Ocean , which separated a series of terranes – Avalonia , Carolinia , and Armorica  – from Gondwana. Avalonia rifted from Gondwana in

2627-411: The J-K boundary. These groups include lissamphibians , lepidosaurs , choristoderes , and mammaliaforms . Albert Oppel Carl Albert Oppel (19 December 1831 – 23 December 1865) was a German paleontologist . He was born at Hohenheim in Württemberg , on 19 December 1831. He first went to the University of Tübingen , where he graduated with a Ph.D. in 1853. The results of his work

2698-416: The J–K boundary, with the latter group even going extinct. More recent finds suggest that ichthyosaurs diversity remained stable or even increased in the Early Cretaceous. Early Cretaceous ichthyosaur fossils are rare enough that this hypothesis is still a matter of debate. European teleosauroids did indeed suffer total extinction, but teleosauroids as a whole survived into the Early Cretaceous in other parts of

2769-401: The Late Jurassic were concentrated around Gondwana, in contrast to the extinction event, which was centered on Laurasian ecosystems. It has been suggested that the putative extinction is a consequence of sampling biases . The Late Jurassic is packed with marine lagerstätten , exceptionally diverse and well-preserved fossil beds. A lack of earliest Cretaceous marine lagerstätten may appear as

2840-406: The Late Triassic-Late Jurassic. During the Carboniferous and Permian, Baltica first collided with Kazakhstania and Siberia, then North China with Mongolia and Siberia. By the middle Carboniferous, however, South China had already been in contact with North China long enough to allow floral exchange between the two continents. The Cimmerian blocks rifted from Gondwana in the Late Carboniferous. In

2911-425: The Southern Hemisphere were once merged into a larger continent called Gondwana. In 1915 German meteorologist Alfred Wegener proposed the existence of a supercontinent called Pangaea. In 1937 South African geologist Alexander du Toit proposed that Pangaea was divided into two larger landmasses, Laurasia in the Northern Hemisphere and Gondwana in the Southern Hemisphere, separated by the Tethys Ocean. "Laurussia"

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2982-441: The Tithonian include limestones, which preserve fossilized remains of, for example, cephalopods . The Solnhofen limestone of southern Germany, which is known for its fossils (especially Archaeopteryx ), is of Tithonian age. The later part of the Tithonian stage experienced an extinction event . It has been referred to as the Tithonian extinction , Jurassic-Cretaceous (J–K) extinction , or end-Jurassic extinction . This event

3053-449: The climate had become arid and these rainforests collapsed , lycopsids (giant mosses) were replaced by treeferns . In the dry climate a detritivorous fauna – including ringed worms , molluscs , and some arthropods  – evolved and diversified, alongside other arthropods who were herbivorous and carnivorous, and tetrapods – insectivores and piscivores such as amphibians and early amniotes . During

3124-418: The crust. This tectonic activity also resulted in the Permian–Triassic extinction event . Tentional stresses across Eurasia developed into a large system of rift basins (Urengoy, East Uralian-Turgay and Khudosey) and flood basalts in the West Siberian Basin , the Pechora Basin , and South China. Laurasia and Gondwana were equal in size but had distinct geological histories. Gondwana was assembled before

3195-423: The dawn of the Cretaceous. The base of the Tithonian stage is at the base of the ammonite biozone of Hybonoticeras hybonotum . A global reference profile (a GSSP or golden spike ) for the base of the Tithonian had in 2009 not yet been established. The top of the Tithonian stage (the base of the Berriasian Stage and the Cretaceous System ) is marked by the first appearance of small globular calpionellids of

3266-482: The early Permian, the Neo-Tethys Ocean opened behind the Cimmerian terranes (Sibumasu, Qiantang, Lhasa) and, in the late Carboniferous, the Palaeo-Tethys Ocean closed in front. The eastern branch of the Palaeo-Tethys Ocean, however, remained opened while Siberia was added to Laurussia and Gondwana collided with Laurasia. When the eastern Palaeo-Tethys closed 250–230 Mya, a series of Asian blocks – Sibumasu, Indochina, South China, Qiantang, and Lhasa – formed

3337-404: The end of the Cretaceous, pines were established across Laurasia, from North America to East Asia. From the Triassic to the Early Jurassic, before the break-up of Pangaea, archosaurs (crurotarsans, pterosaurs and dinosaurs including birds) had a global distribution, especially crurotarsans, the group ancestral to the crocodilians . This cosmopolitanism ended as Gondwana fragmented and Laurasia

3408-409: The end of the Devonian similar species were found on both sides of what remained of the Variscan barrier. The oldest tree fossils are from the Middle Devonian pteridophyte Gilboa forest in central Laurussia (today New York, United States). In the late Carboniferous, Laurussia was centred on the Equator and covered by tropical rainforests, commonly referred to as the coal forest . By the Permian,

3479-536: The end of the Jurassic. Practically no earliest Cretaceous sites are known to preserve pterosaur fossils, so the precise timing of non- pterodactyloid extinctions is very uncertain. Coastal and freshwater crocodyliforms experienced high extinction rates across the J–K boundary, preceding a significant diversification of more terrestrially-adapted metasuchians in the Cretaceous. Coastal and freshwater turtle diversity also declined, at least in Europe. Many tetrapod groups saw strong (albeit gradual) ecological turnover through

3550-440: The formation of Pangaea, but the assembly of Laurasia occurred during and after the formation of the supercontinent. These differences resulted in different patterns of basin formation and transport of sediments. East Antarctica was the highest ground within Pangaea and produced sediments that were transported across eastern Gondwana but never reached Laurasia. During the Palaeozoic, c. 30–40% of Laurasia but only 10–20% of Gondwana

3621-434: The fossil records of marine bottom dwellers and non-marine species. By the Late Ordovician, when continents were pushed closer together closing the oceanic gaps, benthos (brachiopods and trilobites) could spread between continents while ostracods and fishes remained isolated. As Laurussia formed during the Devonian and Pangaea formed, fish species in both Laurussia and Gondwana began to migrate between continents and before

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3692-411: The late Tithonian relative to adjacent time intervals. Moderate diversity declines have been estimated or observed in gastropods , brachiopods , radiolarians , crustaceans , and scleractinian corals . This may have been related to the replacement of Jurassic-style coral reefs by Cretaceous-style rudist reefs. Reef decline was likely a gradual process, stretched out between the Oxfordian stage and

3763-483: The margin of Gondwana, which was beginning to fragment into smaller continents. Three large impact craters have been tentatively dated to the Tithonian: the Morokweng Impact Structure (South Africa, 80+ km diameter), Mjølnir crater ( Barents Sea , 40 km diameter), and Gosses Bluff crater (Australia, 22 km diameter). These impacts would have caused local devastation, but likely had minimal impact on global ecosystems. Most volcanic events or extraterrestrial impacts in

3834-405: The most important was Paläontologische Mittheilungen aus dem Museum des Königlichen Bayerischen Staates (1862–1865). He died on 23 December 1865 at the age of 34. The wrinkle ridge Dorsum Oppel on the Moon is named after him, as is the fossil prawn genus Albertoppelia . Oppel devoted his life to the study of fossils and the examination of the strata of the Jurassic period deposits. He

3905-414: The most prominent Jurassic clade of marine turtles , were pushed to the brink of extinction. Only a single thalassochelydian fossil (an indeterminate skull from the Purbeck Group of England) is known from the Cretaceous. Among plesiosaurs , only a few species of Pliosauridae and Cryptoclididae persisted, and they too would die out in the Early Cretaceous. Conversely, the Tithonian extinction acted as

3976-409: The northern shores of Gondwana (north of Australia in modern coordinates) and the closure of the same ocean reassembled them along the same shores 500–460 Mya resulting in Gondwana at its largest extent. The break-up of Rodinia also resulted in the opening of the long-lived Paleo-Asian Ocean between Baltica and Siberia in the north and Tarim and North China in the south. The closure of this ocean

4047-527: The opportunity to diversify in the Cretaceous. Turiasaurs also survived the extinction and even expanded into North America during the Early Cretaceous. Theropod diversity declined through the entire Late Jurassic, with medium-sized predators such as megalosaurids being the hardest hit. Ornithischian (particularly stegosaur ) diversity saw a small drop across the J–K boundary. Theropod and ornithischian extinctions were notably less pronounced than in sauropods. Most non-pterodactyloid pterosaurs perished by

4118-431: The other staying in Laurasia (until further descendants switched to Gondwana starting from the Jurassic ). In the early Eocene a peak in global warming led to a pan-Arctic fauna with alligators and amphibians present north of the Arctic Circle. In the early Palaeogene, landbridges still connected continents, allowing land animals to migrate between them. On the other hand, submerged areas occasionally divided continents:

4189-420: The other being Gondwana . It separated from Gondwana 215 to 175 Mya (beginning in the late Triassic period) during the breakup of Pangaea, drifting farther north after the split and finally broke apart with the opening of the North Atlantic Ocean c. 56 Mya. The name is a portmanteau of Laurentia and Eurasia . Laurentia, Avalonia , Baltica , and a series of smaller terranes , collided in

4260-433: The rifting of western Pangaea had already begun. Pangaea split in two as the Tethys Seaway opened between Gondwana and Laurasia in the Late Jurassic. The fossil record, however, suggests the intermittent presence of a Trans-Tethys land bridge, though the location and duration of such a land bridge remains enigmatic. Pine trees evolved in the early Mesozoic c. 250 Mya and the pine genus originated in Laurasia in

4331-404: The sampling method or the taxonomic group, the Tithonian extinction may still be apparent even once sampling biases are accounted for. In 1986, Jack Sepkoski argued that the Late Tithonian extinction was the largest extinction event between the end of the Triassic and the end of the Cretaceous. He estimated that a staggering 37% of genera died out during the Tithonian stage. Benton (1995) found

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4402-406: The species Calpionella alpina , at the base of the Alpina Subzone . The Tithonian is often subdivided into Lower/Early, Middle and Upper/Late substages or subages. The Late Tithonian is coeval with the Portlandian Age of British stratigraphy. The Tithonian stage contains seven ammonite biozones in the Tethys domain , from top to base: Sedimentary rocks that formed in the Tethys Ocean during

4473-432: The vast majority of plate tectonic reconstructions, Laurentia formed the core of the supercontinent Rodinia , but the exact fit of various continents within Rodinia is debated. In some reconstructions, Baltica was attached to Greenland along its Scandinavian or Caledonide margin while Amazonia was docked along Baltica's Tornquist margin . Australia and East Antarctica were located on Laurentia's western margin. Siberia

4544-463: The world. Metriorhynchoids , the other major group of marine crocodyliforms, were not strongly affected by the Tithonian extinction. On land, sauropod dinosaur diversity was significantly reduced according to many (but not all) estimates. Diplodocids , basal macronarians , and mamenchisaurids took the brunt of the extinction, though a few species of each group survived to the Early Cretaceous. Conversely, rebbachisaurids and somphospondyls saw

4615-403: Was assembled. Pterosaur diversity reach a maximum in the Late Jurassic—Early Cretaceous and plate tectonic didn't affect the distribution of these flying reptiles. Crocodilian ancestors also diversified during the Early Cretaceous but were divided into Laurasian and Gondwanan populations; true crocodilians evolved from the former. The distribution of the three major groups of dinosaurs  –

4686-429: Was covered by shallow marine water. During the assembly of Pangaea Laurasia grew as continental blocks broke off Gondwana's northern margin; pulled by old closing oceans in front of them and pushed by new opening oceans behind them. During the Neoproterozoic-Early Paleozoic break-up of Rodinia the opening of the Proto-Tethys Ocean split the Asian blocks – Tarim, Qaidam, Alex, North China, and South China – from

4757-599: Was defined by Swiss geologist Peter Ziegler in 1988 as the merger between Laurentia and Baltica along the northern Caledonian suture. The "Old Red Continent" is an informal name often used for the Silurian-Carboniferous deposits in the central landmass of Laurussia. Several earlier supercontinents proposed and debated in the 1990s and later (e.g. Rodinia, Nuna, Nena) included earlier connections between Laurentia, Baltica, and Siberia. These original connections apparently survived through one and possibly even two Wilson Cycles , though their intermittent duration and recurrent fit

4828-436: Was fairly minor and selective, by most metrics outside the top 10 largest extinctions since the Cambrian . Nevertheless, it was still one of the largest extinctions of the Jurassic Period, alongside the Toarcian Oceanic Anoxic Event (TOAE) in the Early Jurassic . The Tithonian extinction has not been studied in great detail, but it is usually attributed to habitat loss via a major marine regression (sea level fall). There

4899-401: Was likely related to the Tithonian climate, which was substantially colder and drier than the preceding Kimmeridgian stage. Northern coral reef ecosystems, such as those of the European Tethys, would have been particularly vulnerable to global cooling during this time. Few Jurassic-Cretaceous boundary sections are precisely associated with carbon isotope anomalies. Several Arctic outcrops show

4970-445: Was located near but at some distance from Laurentia's northern margin in most reconstructions. In the reconstruction of some Russian geologists, however, the southern margin (modern coordinates) of Siberia merged with the northern margin of Laurentia, and these two continents broke up along what is now the 3,000 km (1,900 mi)-long Central Asian Foldbelt no later than 570 Mya and traces of this breakup can still be found in

5041-411: Was published in Die Juraformation Englands, Frankreichs und des südwestlichen Deutschlands (1856–1858). He went to the Palaeontological Museum at Munich in 1858 and became an assistant there. It was in 1860 that he became the Professor of Palaeontology at the University of Munich . Then, a year later, he became the director of the Palaeontological Collection . Of his later works, it can be said that

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