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48-400: A "large, ancient Mediterranean Sea" was first proposed by Austrian palaeontologist Melchior Neumayr in 1883. Studying the distribution of Jurassic faunas, he concluded that an equatorial ocean stretching from India to Central America must have separated a large continent in the northern hemisphere from one in the southern hemisphere. Austrian geologist Eduard Suess named this Mesozoic ocean

96-659: A continent-continent collision occurred there in the Late Triassic; pelagic sediments in the Changning-Menglian-Inthanon ophiolite belt (between Sibumasu and Indochina) ranges in age from Middle Devonian to Middle Triassic, while, in the Inthanon suture, in contrast, Middle to Late Triassic rocks are non-pelagic with radiolarian cherts and turbidic clastics indicating the two blocks had at least approached each other by that time; volcanic sequences from

144-779: A distinction is often made between two more recent Tethyan domains: the Alpine Tethys and the Neo-Tethys. The Alpine Tethys, the western domain in this scheme, separated south-western Europe from north-western Africa and was connected to the Central Atlantic. It is now completely closed and its suture encompasses the Maghrebids (stretching from Gibraltar to Sicily) as well as the Apennines and the Alps. The Neo-Tethys,

192-464: A higher relative geothermal gradient . This gradient can cause metamorphism in rocks, as seen in South Australia. Eustasy refers to a change in the relative sea level. It can have effects on the thermal subsidence during the formation of geological features such as mountain ranges . Sea level often changes in response to the formation of glaciers on land; the weight of these glaciers or

240-1155: A result of the massive uplifting of its continental crust, are unusually rich in a number of rare chalcophile elements . Apart from the Altiplano in Bolivia, almost all the world's deposits of antimony as stibnite are found in Cimmeria, with the major mines being in Turkey, Yunnan and Thailand. The major deposits of tin are also found in Malaysia and Thailand , whilst Turkey also has major deposits of chromite ore. [REDACTED] Africa [REDACTED] Antarctica [REDACTED] Asia [REDACTED] Australia [REDACTED] Europe [REDACTED] North America [REDACTED] South America [REDACTED] Afro-Eurasia [REDACTED] Americas [REDACTED] Eurasia [REDACTED] Oceania Melchior Neumayr Melchior Neumayr (24 October 1845 – 29 January 1890)

288-419: A section of the lithosphere. As the lithosphere cools, it causes the rock to contract. When conduction causes a section of the lithosphere to contract and increase in density, it does not directly add mass to the rock. Instead, it causes the volume to decrease, increasing the mass of the section for a given area. The lithosphere is isostatic with the mantle ; its weight is supported by the relative density of

336-434: A variety of contributing factors that can initiate thermal subsidence or affect the process as it is ongoing. As endogenous and exogenous processes cause denudation of the earth's surface, lower, warmer sections of the lithosphere are exposed to relative differences in weight and density. This relative difference creates buoyancy . Isostatic uplift can then further expose the lithosphere to conductive cooling, causing

384-426: A “rise and fall” phenomenon as warmer, less dense rock layers are pushed or buoyed up, then cooled, causing it to contract and sink back down. The conditions to create thermal subsidence can be initiated by various forms of uplift and denudation, but the actual process of thermal subsidence is governed by the loss of heat via thermal conduction . Contact with surrounding rock or the surface causes heat to leach out of

432-423: Is a stub . You can help Misplaced Pages by expanding it . Thermal subsidence In geology and geophysics , thermal subsidence is a mechanism of subsidence in which conductive cooling of the mantle thickens the lithosphere and causes it to decrease in elevation. This is because of thermal expansion : as mantle material cools and becomes part of the mechanically rigid lithosphere, it becomes denser than

480-762: Is separated from the Burma Block by the Gaoligong Suture Zone to the west, and from the South China and Indochina continents in the east by the Chongshan Suture Zone and Changning-Menglian Belt. Like other parts of eastern Cimmeria, it was highly deformed by the intra-continental strike-slip faulting that followed the India-Asia collision. Paleomagnetic data indicate South China and Indochina moved from near Equator to 20°N from

528-665: The Early Permian to Late Triassic. Baoshan, in contrast, moved from 42°S in the Early Permian to 15°N in the Late Triassic. These blocks and terranes occupied similar paleo-latitudes during Late Triassic to Jurassic which indicates that they probably collided in the Late Triassic. This is also supported by geological evidence: 200–230 Ma granite in Lincang , near the Changning-Menglian suture, indicate

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576-729: The Hellenic Trench resulted in extension in the Aegean and western Turkey. The subduction of western Neo-Tethys under Eurasia resulted in extensive magmatism in what is now northern Iran. In the Early Jurassic this magmatism had produced a slab pull force which contributed to the break-up of Pangea and the initial opening of the Atlantic. During the Late Jurassic-Early Cretaceous the subduction of

624-580: The Iranian plate from the Arabian plate , and that another southern suture must be the remains of the Neo-Tethys Ocean. The opening of this later ocean, Stöcklin realized, must have transformed Iran into a microcontinent. Those observations made Stöcklin the first to identify a small part of what would later be known as Cimmeria. Stöcklin also noted that his proposal resembled the old concept of

672-872: The Lancangjiang igneous zone indicate a post-collisional setting had developed before the eruptions there around 210 Ma; and, the Sibumasu fauna developed from a non-marine peri-Gondwanan assemblage in the early Permian, to an endemic Sibumasu fauna in the Middle Permian , and to an Equatorial-Cathaysian in the Late Permian. During the Early and Middle Palaeozoic Cimmeria was located at an Andean -style active margin . Glacial deposits and paleomagnetic data indicate that Qiangtang and Shan Thai-Malaya were still located far south adjacent to Gondwana during

720-655: The Svanetia region. The suture is older east of the Caucasus (northern Iran–Turkmenistan) but younger both west of the Caucasus and further east in Afghanistan and the northern Pamirs . The easternmost part of Cimmeria, the Sibumasu terrane , remained attached to north-western Australia until 295–290 Ma when it began to drift northward, as supported by paleomagnetic and biogeographic data. The Qiangtang terrane

768-791: The basement of the Sakarya Composite Terrane in the Pontides ). During the Late Triassic the Neo-Tethys began opening behind Cimmeria when the Eastern Mediterranean and its two eastern branches opened into the Bitlis–Zagros ocean (the southern branch of the Neo-Tethys). During Early Jurassic, Cimmeria began to disintegrate behind the Paleo-Tethyan volcanic arc. This opened the northern branch in

816-490: The Alps to Indonesia Şengör identified, using a simplified scheme, two distinct but superimposed orogenic systems containing a large number of anastomosing sutures: the older Cimmerides and the younger Alpides together forming what Şengör called the Tethysides super-orogenic system. These two orogenic systems are thus associated with two major periods of ocean closure: the earlier, northern, and much larger Cimmerides, and

864-571: The Carboniferous. The equatorial fauna and flora of China indicate that it was separated from Gondwana during the Carboniferous. The Lhasa terrane has been interpreted as part of Cimmeria and, if this is the case, must have rifted from Gondwana together with Sibumasu and Qiangtang. The timing of Lhasa's northward drift is still controversial, however, and paleomagnetic data is extremely scarce. Sedimentological and stratigraphical evidence, for example, suggest that it separated from Gondwana in

912-623: The Caribbean to Southeast Asia (also called as the central Mediterranean) which had flooded wide tracts of Eurasia. This was named by Suess in 1893 as the Tethys, named after the sister of Okeanos, the Greek ocean god. He dealt also with the zones of climate during the Jurassic and Cretaceous periods. He postulated the idea that during those periods, equatorial marine fauna differed from that of

960-661: The Late Paleocene-Early Eocene. This closed the Ankara-Erzincan branches of the northern Neo-Tethys. During this closure, slab roll-back and break-off in the Eocene resulted in inversion in the Pontides and widespread magmatism in northern Turkey. Extension and upwelling followed, resulting in melting of lithospheric material beneath the Pontides. In southern Turkey the northward subduction of

1008-682: The Late Paleozoic and Early Mesozoic. The Greater and Lesser Caucasus have a complicated geological history involving the accretion of a series of terranes and microcontinents from the Late Precambrian to the Jurassic within the Tethyan framework. These include the Greater Caucasian, Black Sea-Central Transcaucasian, Baiburt-Sevanian, and Iran-Afghanistan terranes and island arcs. In the Caucasus region remnants of

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1056-690: The Late Triassic when Qiangtang was already being accreted to Eurasia. This proposed Late Triassic rifting of Lhasa has also been documented along the north-western shelf of Australia where the West Burma and Woyla terranes eventually separated from Gondwana in the Late Jurassic. Today the Bangong suture separates the Lhasa terrane from the Qiangtang terrane. The present remains of Cimmeria, as

1104-549: The Late Triassic ;– Iran had clearly drifted from Gondwana to Laurasia. In the 1980s Turkish geologist Celâl Şengör finally extended Stöcklin's Iranian microcontinent further west to Turkey and further east to Tibet and the Far East. Şengör also reused the name introduced by Suess in 1901, the "Kimmerisches Gebirge" – the " Crimean " or "Cimmerian Mountains". In the mountain range that now stretches from

1152-674: The Meliata-Maliac-Pindos back-arc oceans in the eastern Mediterranean) leading to the formation of younger back-arc oceans. Turkey is an assemblage of continental blocks that during the Permian were part of the northern margin of Gondwana. During the Permian-Triassic, as the Paleo-Tethys subducted under this margin (in what is today northern Turkey) a marginal sea opened and quickly filled with sediments (today

1200-599: The Munich Gymnasium and then started with law studies at the University of Munich but gave it up for the natural sciences which he completed at Heidelberg studying under Beneke and Robert Bunsen . He received a doctorate in 1867. After some experience in field-geology under Karl Wilhelm von Gümbel , he joined the Austrian geological survey in 1868. Four years later he returned to Heidelberg, but in 1873 he

1248-458: The Neo-Tethys mid-ocean ridge contributed to the break-up of Gondwana, including the detachment of the Argo-Burma terrane from Australia. The Central-East Iranian Microcontinent (CEIM) sutured with Eurasia in the Late Triassic during the regional "Eocimmerian" orogenic event in northern Iran, but Iran is made of several continental blocks and the area must have seen a number of ocean closures in

1296-712: The Neo-Tethys—the Intra-Pontide, Izmh–Ankara, and the Inner Tauride oceans. The closure of the Paleo-Tethys in the Middle Jurassic reduced the Cimmerian archipelago in Anatolia. South of the Cimmerian blocks there were now two branches of the Neo-Tethys, a northern, larger and more complex, and a southern, more reduced. The Anatolide–Tauride continent separated them; the small Sakarya continent

1344-891: The Neo-tethys along the Bitlis – Zagros subduction zone resulted in magmatism in the Maden-Helete arc (south-eastern Turkey) during the Late Cretaceous-Eocene and back-arc magmatism in the Taurides. The Bitlis–Zagros subduction zone finally closed in the Miocene and throughout the Oligocene-Neogene and Quaternary volcanism became increasingly localised. In the Late Oligocene, slab roll-back in

1392-630: The Paleo-Tethys opened a series of back-arc basins along the Eurasian margin and resulted in the collapse of the Variscan cordillera . As the Paleo-Tethys subducted under the Eurasian southern margin, back-arc oceans formed from Austria to China. Some of these back-arcs closed during the Cimmerian orogeny (e.g. the Karakaya-Küre sequence of back-arc oceans in Turkey), others remained open (e.g.

1440-536: The Paleo-Tethys suture can be found in the Dzirula Massif which outcrops Early Jurassic sequences in central Georgia . It consists of Early Cambrian oceanic rocks and the possible remnants of a magmatic arc; their geometry suggests that suturing was followed by strike-slip faulting. Ophiolites also outcrop in the Khrami Massif in southern Georgia and another possible segment of the suture is present in

1488-831: The Rhodope-Pontide island arc there. In the Cretaceous, this basin pushed the Istanbul terrane (near today's Istanbul) southward in front of it, from the Odesa Shelf in the north-western Black Sea. In the Eocene, the terrane finally collided with Cimmeria thereby ending the extension in the western Black Sea. Contemporaneously, the East Black Sea Basin opened when the East Black Sea Block was rotated counter-clockwise towards Caucasus. In

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1536-448: The Siluran opening of Paleo-Tethys. Carboniferous to Permian ophiolites along suture zones in Tibet and north-eastern Iran indicate that the active margin of Paleo-Tethys was located here. It was slab-pull forces in the Paleo-Tethys that detached Cimmeria from Gondwana and opened the Neo-Tethys. The mid-ocean ridge in the Paleo-Tethys subducted under Eurasia, as evidenced by Permian MORB (mid-ocean ridge basalt) in Iran. Slab roll-back in

1584-497: The Tethys, a mythical ocean which separated a mythical continent – Gondwanaland, home of the tongue-shaped flora  – from a boreal continent. German geophysicist Alfred Wegener , in contrast, developed a concept of a single, global continent – the supercontinent Pangea  – which, in his view, left no room for an equatorial ocean. A wedge-shaped, east-facing Tethys within Pangea was, nevertheless, proposed by Australian geologist Samuel Warren Carey in 1958. This ocean

1632-424: The countervailing isostatic uplift is eliminated, causing them to subside and create an atoll . Thermal subsidence can drive metamorphism in rocks. The conduction of heat out of a section of lithosphere causes the rock to thicken and become more insulated to heat flowing in from the mantle; as this thicker section is buried by the descending column of the lithosphere, it descends into surrounding rock layers with

1680-493: The eastern domain, opened between Arabia and the Cimmerian terranes. The East Mediterranean Basin and the Gulf of Oman are considered relics of the Neo-Tethys which is thus still closing. These two domains were connected east of Sicily until the end of the Jurassic. In the Late Paleozoic, when the Cimmerian blocks were still located on the northern margin of Gondwana, they were far away from any active margins and orogenic belts, but they had been affected by thermal subsidence since

1728-421: The late Cretaceous northwards intra-oceanic subduction within the Neotethys gave way to the obduction of ophiolitic nappes over the Arabian platform from Turkey to Oman region. North of this subduction zone, remnants of the Neotethys ocean started to subduct northwards and led to the collision of Tauride Block with the Arabian plate during post-Oligocene times. North of these systems, the Tauride block collided with

1776-471: The later, southern, and smaller Alpides. Cimmeria was the long continental "archipelago" that separated the two oceans before the Paleo-Tethys closed. This realm of Tethys thus covers most of Eurasia and a large time span (from north to south): This simple scheme, however, partly obscures the complex nature of the Tethyan cycles and terms such as "Eocimmerian" and "Neocimmerian" is often used for Late Triassic and Late Jurassic events respectively. Furthermore,

1824-413: The southern margin of Eurasia by the end of the Cretaceous. Convergence continued until the end of Oligocene. The Arabian-Eurasian collision in eastern Turkey during the Late Eocene closed the two basins. During the Paleogene Neo-Tethyan oceanic crust attached to the African plate subducted along the Crete and Cyprus trenches. The Anatolide-Tauride continent collided with the Pontide and Kırşehir blocks in

1872-409: The surrounding material. Additional material added to the lithosphere thickens it and further causes a buoyant decrease in the elevation of the lithosphere. This creates accommodation space into which sediments can deposit, forming a sedimentary basin . Thermal subsidence can occur anywhere in which a temperature differential exists between a section of the lithosphere and its surroundings. There are

1920-679: The surrounding rock. When a section cools and its density increases, it sinks, causing the relative elevation to decrease. This can create a basin in which sediments are deposited, which adds weight on top of the sinking section of the lithosphere and increase the total mass of the section per unit area, causing it to sink further. Thermal subsidence can have an effect on island formation. Isostatic uplift can be balanced with thermal subsidence in response to erosion on islands without barrier reefs , which sink only when subjected to wave erosion . However, volcanic islands and seamounts with barrier reefs are shielded from wave and stream erosion, and thus

1968-518: The two temperate zones, and that the marine fauna of the latter two zones also differed from that of the arctic zone, much as the faunas of similar zones differ from each other in the present day; see his Über klimatische Zonen während der Jura und Kreidezeit (Denkschr. K. Akad. Wiss. Wien, 1883); he was author also of Erdgeschichte (2 vols, 1887); and Die Stämme des Thierreiches (vol. 1 only, 1889). Neumayr married Paula, daughter of his colleague Eduard Suess in 1879 and they had three daughters. He

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2016-403: The world in which there were two continents, Angaraland in the north and Gondwana in the south, separated by an elongated ocean, the Tethys. Iran belonged to neither continent but was part of the realm of Tethys. Stöcklin's southern suture was later confirmed by observations of the evolution of microflora in Iran, which had a Gondwanan affinity during the Carboniferous but a Eurasian affinity during

2064-565: Was a keen climber and was a member of the Deutscher und Oesterreich Alpin Verein but gave up membership in 1872 and in later life heart problems prevented him from outdoor activity but he continued to write in the Mittheilungen of the Deutscher und Oesterreich Alpin Verein. [REDACTED]   This article incorporates text from a publication now in the public domain :  Chisholm, Hugh , ed. (1911). " Neumayr, Melchior ". Encyclopædia Britannica (11th ed.). Cambridge University Press. This Austrian biographical article

2112-428: Was an palaeontologist from Austria-Hungary and the son of Max von Neumayr , a Bavarian Minister of State. He specialized on the Jurassic and Cretaceous of the Alps. Neumayr introduced the concept of the Tethys sea in 1885, calling it the Jurassic seaway. The name " Tethys " was given by his father-in-law Eduard Suess. Neumayr was born in Munich but grew up in Stuttgart where his father was an ambassador. He went to

2160-403: Was appointed professor of palaeontology in Vienna , and occupied this post until his death. His more detailed researches pertained to the Jurassic and Cretaceous ammonites and to Tertiary freshwater molluscs ; in these studies he sought to trace the descent of the species. Based on the gastropod fauna, Neumayr established the idea of what he called a Jurassic seaway extending from

2208-489: Was later identified as a succession of oceans separated by north-migrating terranes or continental blocks, one of which was Cimmeria. In 1974, after extensive field work in the Middle East, Swiss geologist Jovan Stöcklin identified the northern foot of the Alborz Range in northern Iran as the suture which in the Paleozoic was the northern shore of Gondwana and the remains of the Paleo-Tethys Ocean. Stöcklin also noted that an early Mesozoic or late Paleozoic rift separated

2256-433: Was located west of Sibumasu and contiguous with it. Lower Permian layers in Sibumasu contain glacial-marine diamictites and Gondwanan faunas and floras which then developed independently before Sibumasu docked with Cathaysia. Sibumasu's rapid northern journey is especially evident in the development of brachiopods and fusulinids . The Baoshan terrane in western Yunnan , China, forms the northern part of Sibumasu. It

2304-416: Was located within the northern branch. The Apulian continent was connected to the Anatolide–Tauride continent. These Neo-Tethyan branches reached their maximum width during the Early Cretaceous, after which subduction under Eurasia gradually consumed them. During the Middle-Late Cretaceous this subduction opened a back-arc basin , the Western Black Sea Basin, which stretched west into the Balkans north of

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