Tethys Ocean

The Tethys Ocean /ˈtiːθɪs, ˈtɛθɪs/ (Greek: Τηθύς Tēthús), also called the Tethys Sea or the Neotethys, was an ocean during much of the Mesozoic Era located between the ancient continents of Gondwana and Laurasia, before the opening of the Indian and Atlantic oceans during the Cretaceous Period.

Laurasia-Gondwana
First phase of the Tethys Ocean's forming: the (first) Tethys Sea starts dividing Pangaea into two supercontinents, Laurasia and Gondwana.

Etymology

The name stems from the mythological Greek sea goddess Tethys, sister and consort of Oceanus, mother of the great rivers, lakes, and fountains of the world and of the Oceanid sea nymphs.

Terminology and subdivisions

The eastern part of the Tethys Ocean is sometimes referred to as Eastern Tethys. The western part of the Tethys Ocean is called Tethys Sea, Western Tethys Ocean, or Paratethys or Alpine Tethys Ocean. The Black, Caspian, and Aral seas are thought to be its crustal remains, though the Black Sea may, in fact, be a remnant of the older Paleo-Tethys Ocean.[1] The Western Tethys was not simply a single open ocean. It covered many small plates, Cretaceous island arcs, and microcontinents. Many small oceanic basins (Valais Ocean, Piemont-Liguria Ocean, Meliata Ocean) were separated from each other by continental terranes on the Alboran, Iberian, and Apulian plates. The high sea level in the Mesozoic flooded most of these continental domains, forming shallow seas. As theories have improved, scientists have extended the "Tethys" name to refer to three similar oceans that preceded it, separating the continental terranes: in Asia, the Paleo-Tethys (Devonian–Triassic), Meso-Tethys (late Early Permian–Late Cretaceous), and Ceno-Tethys (Late-Triassic–Cenozoic) are recognized.[2] None of the Tethys oceans should be confused with the Rheic Ocean, which existed to the west of them in the Silurian Period.[3] To the north of the Tethys, the then-land mass was called Angaraland and to the south of it, it was called Gondwanaland.

Modern theory

From the Ediacaran (600 Mya) into the Devonian (360 Mya), the Proto-Tethys Ocean existed and was situated between Baltica and Laurentia to the north and Gondwana to the south.

From the Silurian (440 Mya) through the Jurassic periods, the Paleo-Tethys Ocean existed between the Hunic terranes and Gondwana. Over a period of 400 million years, continental terranes intermittently separated from Gondwana in the Southern Hemisphere to migrate northward to form Asia in the Northern Hemisphere.[2]

Triassic Period

249 global
Plate tectonic reconstruction of the Tethys realm at 249 Mya

About 250 Mya,[4] during the Triassic, a new ocean began forming in the southern end of the Paleo-Tethys Ocean. A rift formed along the northern continental shelf of Southern Pangaea (Gondwana). Over the next 60 million years, that piece of shelf, known as Cimmeria, traveled north, pushing the floor of the Paleo-Tethys Ocean under the eastern end of northern Pangaea (i.e.Laurasia). The Tethys Ocean formed between Cimmeria and Gondwana, directly over where the Paleo-Tethys used to be.

Jurassic Period

During the Jurassic period about 150 Mya, Cimmeria finally collided with Laurasia and stalled, so the ocean floor behind it buckled under, forming the Tethyan Trench. Water levels rose, and the western Tethys shallowly covered significant portions of Europe, forming the first Tethys Sea. Around the same time, Laurasia and Gondwana began drifting apart, opening an extension of the Tethys Sea between them which today is the part of the Atlantic Ocean between the Mediterranean and the Caribbean. As North and South America were still attached to the rest of Laurasia and Gondwana, respectively, the Tethys Ocean in its widest extension was part of a continuous oceanic belt running around the Earth between about latitude 30°N and the Equator. Thus, ocean currents at the time around the Early Cretaceous ran very differently from the way they do today.

Late Cretaceous

100 global
Plate tectonic reconstruction of the Tethys realm at 100 Mya

Between the Jurassic and the Late Cretaceous, which started about 100 Mya, Gondwana began breaking up, pushing Africa and India north across the Tethys and opening up the Indian Ocean.

Cenozoic

Throughout the Cenozoic (66 million to the dawn of the Neogene, 23 Mya), a combination of the northern migration of Africa and global sea levels fall, lead eventually to the connections between the Atlantic and Indian Oceand across the Tethys to closed off in what is now the Middle East during the Miocene. This decoupling occurred in two steps, first around 20 Mya and another around 14 Mya.[5] During the Oligocene (33.9 to 23 Mya), large parts of central and eastern Europe were covered by a northern branch of the Tethys Ocean, called the Paratethys. The Paratethys was separated from the Tethys with the formation of the Alps, Carpathians, Dinarides, Taurus, and Elburz mountains during the Alpine orogeny. During the late Miocene, the Paratethys gradually disappeared, and became an isolated inland sea.

Historical theory

Eduard Suess 1869
Geologist Eduard Suess in 1869

In 1885, the Austrian palaeontologist Melchior Neumayr deduced the existence of the Tethys Ocean from Mesozoic marine sediments and their distribution, calling his concept Zentrales Mittelmeer and described it as a Jurassic seaway, which extended from the Caribbean to the Himalayas.[6]

In 1893, the Austrian geologist Eduard Suess proposed the theory that an ancient and extinct inland sea had once existed between Laurasia and the continents which formed Gondwana II. He named it the Tethys Sea after the Greek sea goddess Tethys. He provided evidence for his theory using fossil records from the Alps and Africa.[7] He proposed the concept of Tethys in his four-volume work Das Antlitz der Erde (The Face of the Earth).[8]

In the following decades during the 20th century, "mobilist" geologists such as Uhlig (1911), Diener (1925), and Daque (1926) regarded Tethys as a large trough between two supercontinents which lasted from the late Palaeozoic until continental fragments derived from Gondwana obliterated it.

After World War II, Tethys was described as a triangular ocean with a wide eastern end.

From 1920s to the 1960s, "fixist" geologists, however, regarded Tethys as a composite trough, which evolved through a series of orogenic cycles. They used the terms 'Paleotethys', 'Mesotethys', and 'Neotethys' for the Caledonian, Variscan, and Alpine orogenies, respectively. In the 1970s and '80s, these terms and 'Proto-Tethys', were used in different senses by various authors, but the concept of a single ocean wedging into Pangea from the east, roughly where Suess first proposed it, remained.[9]

In the 1960s, the theory of plate tectonics became established, and Suess's "sea" could clearly be seen to have been an ocean. Plate tectonics provided an explanation for the mechanism by which the former ocean disappeared: oceanic crust can subduct under continental crust.

Tethys was considered an oceanic plate by Smith (1971); Dewey, Pitman, Ryan and Bonnin (1973); Laubscher and Bernoulli (1973); and Bijou-Duval, Dercourt and Pichon (1977).

See also

  • Hațeg Island
  • Paleo-Tethys Ocean – An ocean on the margin of Gondwana between the Middle Cambrian and Late Triassic
  • Pannonian Sea – Shallow ancient sea where the Pannonian Basin in Central Europe is today
  • Paratethys – A large shallow sea that stretched from the region north of the Alps over Central Europe to the Aral Sea in Central Asia
  • Piemont-Liguria Ocean – A former piece of oceanic crust that is seen as part of the Tethys Ocean
  • Tethyan Trench – An oceanic trench that existed in the northern part of the Tethys Ocean during the middle Mesozoic to early Cenozoic eras
  • Ruhpolding Formation

References

Notes

  1. ^ Van der Voo 1993
  2. ^ a b Metcalfe 2013, Introduction, p. 2
  3. ^ Stampfli & Borel 2002, Figs. 3–9
  4. ^ Palaeos Mesozoic: Triassic: Middle Triassic Archived May 16, 2008, at the Wayback Machine
  5. ^ Bialik et al.
  6. ^ Kollmann 1992
  7. ^ Suess 1893, p. 183: "This ocean we designate by the name "Tethys" after the sister and consort of Oceanus. The latest successor of the Tethyan Sea is the present Mediterranean."
  8. ^ Suess 1901, Gondwana-Land und Tethys, p. 25: "Dasselbe wurde von Neumayr das 'centrale Mittelmeer' genannt und wird hier mit dem Namen Tethys bezeichnet werden. Das heutige europäische Mittelmeer ist ein Rest der Tethys."
  9. ^ Metcalfe 1999, How many Tethys Oceans?, pp. 1–3

Sources

  • Bialik, Or M.; Frank, Martin; Betzler, Christian; Zammit, Ray; Waldmann, Nicolas D. (2019). "Two-step closure of the Miocene Indian Ocean Gateway to the Mediterranean". Scientific Reports. 9 (8842). doi:10.1038/s41598-019-45308-7.
  • Kollmann, H. A. (1992). "Tethys—the Evolution of an Idea". In Kollmann, H. A.; Zapfe, H. (eds.). New Aspects on Tethyan Cretaceous Fossil Assemblages. Springer-Verlag reprint ed. 1992. pp. 9–14. ISBN 978-0387865553. OCLC 27717529. Retrieved 6 October 2015.
  • Metcalfe, I. (1999). "The ancient Tethys oceans of Asia: How many? How old? How deep? How wide?". UNEAC Asia Papers. 1: 1–9. Retrieved 6 October 2015.
  • Metcalfe, I. (2013). "Gondwana dispersion and Asian accretion: tectonic and palaeogeographic evolution of eastern Tethys". Journal of Asian Earth Sciences. 66: 1–33. Bibcode:2013JAESc..66....1M. doi:10.1016/j.jseaes.2012.12.020. Retrieved 6 October 2015.
  • Stampfli, G. M.; Borel, G. D. (2002). "A plate tectonic model for the Paleozoic and Mesozoic constrained by dynamic plate boundaries and restored synthetic oceanic isochrons". Earth and Planetary Science Letters. 196 (1): 17–33. Bibcode:2002E&PSL.196...17S. doi:10.1016/S0012-821X(01)00588-X.
  • Suess, E. (1893). "Are ocean depths permanent?". Natural Science: A Monthly Review of Scientific Progress. 2. London. pp. 180–187. Retrieved 6 October 2015.
  • Suess, E. (1901). Der Antlitz der Erde (in German). 3. Wien F. Tempsky. Retrieved 6 October 2015.

Van der Voo, Rob (1993). Paleomagnetism of the Atlantic, Tethys and Iapetus Oceans. Cambridge University Press. doi:10.2277/0521612098. ISBN 978-0-521-61209-8.

External links

Alpide belt

The Alpide belt or Alpine-Himalayan orogenic belt is a seismic belt and orogenic belt that includes an array of mountain ranges extending for more than 15,000 km along the southern margin of Eurasia, stretching from Java and Sumatra, through the Indochinese Peninsula, the Himalayas and Transhimalayas, the mountains of Iran, Caucasus, Anatolia, the Mediterranean, and out into the Atlantic. It includes, from west to east, the major ranges of the Atlas Mountains, the Alps, the Caucasus Mountains, Alborz, Hindu Kush, Karakorum, and the majestic Himalayas. It is the second most seismically active region in the world, after the circum-Pacific belt (the Ring of Fire), with 17% of the world's largest earthquakes.The Alpide belt is being created by ongoing plate tectonics such as the Alpine orogeny. The belt is the result of Mesozoic-to-Cenozoic-to-recent closure of the Tethys Ocean and process of collision between the northward-moving African, Arabian and Indian plates with the Eurasian plate.

Barbatteiidae

Barbatteiidae is an extinct family of lizards, endemic to the paleoisland Hațeg Island in the Tethys Ocean during the final stages of the Cretaceous, In what is now Romania. It contains two monotypic genera, Barbatteius and Oardasaurus, alongside some indeterminate material. It appears to be closely related to the Barremian lizard genus Meyasaurus

Cimmeria (continent)

Cimmeria was an ancient continent, or, rather, a string of microcontinents or terranes, that rifted from Gondwana in the Southern Hemisphere and was accreted to Eurasia in the Northern Hemisphere. It consisted of parts of what is today Turkey, Iran, Afghanistan, Tibet, Shan–Thai, and Malay Peninsula. Cimmeria rifted from the Gondwanan shores of the Paleo-Tethys Ocean during the Carboniferous-earliest Permian and as the Neo-Tethys Ocean opened behind it, during the Permian, the Paleo-Tethys closed in front of it. Cimmeria rifted off Gondwana from east to west, from Australia to the eastern Mediterranean.

It stretched across several latitudes and spanned a wide range of climatic zones.

Geology of Iraq

The geology of Iraq includes thick sequences of marine and continental sedimentary rocks over poorly understood basement rock, at the junction of the Arabian Plate, the Anatolian Plate, and the Iranian Plate.

Geology of Romania

The geology of Romania is structurally complex, with evidence of past crustal movements and the incorporation of different blocks or platforms to the edge of Europe, driving recent mountain building of the Carpathian Mountains. Romania is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders the Black Sea to the southeast, Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, and Moldova to the east.

Gigantatypus

Gigantatypus is an extinct late Maastrichtian sea turtle that lived in the southern regions of the Tethys Ocean about 100–120 kilometres (62–75 mi) off the north eastern margins of Cretaceous Africa immediately before the Cretaceous–Paleogene extinction events . Fossil remains of Gigantatypus are so far only represented in sediments from Jordan. Estimated at over 3.5 metres (11 ft) in length, members of this genus reached remarkably large proportions equivalent to that of or possibly even exceeding Archelon Wieland, 1896 , considered as the largest marine turtles to ever roam the oceans of the world. Although Gigantatypus apparently did not survive the K/T boundary, which also was the fate of other gigantic marine turtles such as protostegids, other genera of Cheloniidae, though significantly smaller in size survived the mass extinction and continued on until the present day.

Himalayacetus

Himalayacetus is an extinct genus of carnivorous aquatic mammal of the family Ambulocetidae. The holotype was found in Himachal Pradesh, India, (31.0°N 77.0°E / 31.0; 77.0: paleocoordinates 3.5°N 69.7°E / 3.5; 69.7) in what was the remnants of the ancient Tethys Ocean during the Early Eocene. This makes Himalayacetus the oldest archaeocete known, extending the fossil record of whales some 3.5 million years.Himalayacetus lived in the ancient coastline of the ancient Tethys Ocean before the Indian Plate had collided with the Cimmerian coast. Just like Gandakasia, Himalayacetus is only known from a single jaw fragment, making comparisons to other Ambulocetids difficult.

List of ancient oceans

This is a list of former oceans that disappeared due to tectonic movements and other geographical and climatic changes. In alphabetic order:

Bridge River Ocean, the ocean between the ancient Insular Islands (i.e. Stikinia) and North America

Cache Creek Ocean, a Paleozoic ocean between the Wrangellia Superterrane and Yukon-Tanana Terrane

Iapetus Ocean, the southern hemisphere ocean between Baltica and Avalonia

Khanty Ocean, the Precambrian to Silurian ocean between Baltica and the Siberian continent

Mezcalera Ocean, the ocean between the Guerrero terrane and Laurentia

Mirovia, the ocean that surrounded the Rodinia supercontinent

Mongol-Okhotsk Ocean, the early Mesozoic ocean between the North China and Siberia cratons

Oimyakon Ocean, the northernmost part of the Mesozoic Panthalassa Ocean

Paleo-Tethys Ocean, the ocean between Gondwana and the Hunic terranes

Pan-African Ocean, the ocean that surrounded the Pannotia supercontinent

Panthalassa, the vast world ocean that surrounded the Pangaea supercontinent, also referred to as the Paleo-Pacific Ocean

Pharusian Ocean, Neoproterozoic

Poseidon Ocean, Mesoproterozoic

Pontus Ocean, the western part of the early Mesozoic Panthalassa Ocean

Proto-Tethys Ocean, Neoproterozoic

Rheic Ocean, the Paleozoic ocean between Gondwana and Laurussia

Slide Mountain Ocean, the Mesozoic ocean between the ancient Intermontane Islands (i.e. Wrangellia) and North America

South Anuyi Ocean, Mesozoic ocean related to the formation of the Arctic Ocean

Tethys Ocean, the ocean between the ancient continents of Gondwana and Laurasia

Thalassa Ocean, the eastern part of the early Mesozoic Panthalassa Ocean

Ural Ocean, the Paleozoic ocean between Siberia and Baltica

Paleo-Tethys Ocean

The Paleo-Tethys or Palaeo-Tethys Ocean was an ocean located along the northern margin of the paleocontinent Gondwana that started to open during the Middle Cambrian, grew throughout the Paleozoic, and finally closed during the Late Triassic; existing for about 400 million years.Paleo-Tethys was a precursor to the Tethys Ocean (also called the Neo-Tethys) which was located between Gondwana and the Hunic terranes (continental fragments that broke-off Gondwana and moved north). It opened as the Proto-Tethys Ocean subducted under these terranes and closed as the Cimmerian terranes (that also broke-off Gondwana and moved north) gave way to the Tethys Ocean. Confusingly, the Neo-Tethys is sometimes defined as the ocean south of a hypothesised mid-ocean ridge separating Greater Indian from Asia, in which case the ocean between Cimmeria and this hypothesised ridge is called the Meso-Tethys, i.e. the "Middle-Tethys".The so-called Hunic terranes are divided into the European Hunic (today the crust under parts of Europe – called Armorica – and Iberia) and Asiatic Hunic (today the crust of parts of southern Asia). A large transform fault separated the two terranes.

The role the Paleo-Tethys played in the supercontinent cycle, and especially the break-up of Pangaea, is unresolved. Some geologists argue that the opening of the North Atlantic was triggered by the subduction of Panthalassa under the western margins of the Americas while other argue that the closure of the Paleo-Tethys and Tethys resulted in the break-up. In the first scenario, mantle plumes caused the opening of the Atlantic and the break-up of Pangaea and the closure of the Tethyan domain was one of the consequences of this process; in the other scenario, the longitudinal forces that closed the Tethyan domain were transmitted latitudinally in what is today the Mediterranean region, resulting in the initial opening of the Atlantic.

Pangaea

Pangaea or Pangea ( ) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 335 million years ago, and it began to break apart about 175 million years ago. In contrast to the present Earth and its distribution of continental mass, much of Pangaea was in the Southern Hemisphere and surrounded by a superocean, Panthalassa. Pangaea was the most recent supercontinent to have existed and the first to be reconstructed by geologists.

Paratethys

The Paratethys ocean, Paratethys sea or just Paratethys was a large shallow inland sea that stretched from the region north of the Alps over Central Europe to the Aral Sea in Central Asia. The sea was formed during the Oxfordian stage of the Late Jurassic as an extension of the rift that formed the Central Atlantic Ocean and was isolated during the Oligocene epoch (about 34 million years ago). It was separated from the Tethys Ocean to the south by the formation of the Alps, Carpathians, Dinarides, Taurus and Elburz mountains. During its long existence the Paratethys was at times reconnected with the Tethys or its successors, the Mediterranean Sea or Indian Ocean. From the Pliocene epoch onward (after 5 million years ago), the Paratethys became progressively shallower. Today's Black Sea, Caspian Sea, Aral Sea, Lake Urmia, Namak Lake and others are remnants of the Paratethys Sea.

Piemont-Liguria Ocean

The Piemont-Liguria basin or the Piemont-Liguria Ocean (sometimes only one of the two names is used, for example: Piemonte Ocean) was a former piece of oceanic crust that is seen as part of the Tethys Ocean. Together with some other oceanic basins that existed between the continents Europe and Africa, the Piemont-Liguria Ocean is called the Western or Alpine Tethys Ocean.

Proto-Tethys Ocean

The Proto-Tethys Ocean was an ancient ocean that existed from the latest Ediacaran to the Carboniferous (550–330 Ma).

Rudists

Rudists are a group of extinct box-, tube- or ring-shaped marine heterodont bivalves belonging to the order Hippuritida that arose during the Late Jurassic and became so diverse during the Cretaceous that they were major reef-building organisms in the Tethys Ocean, until their complete extinction at the close of the Cretaceous.

South China (continent)

South China, also known as South China Craton, South Chinese Craton, or Yangtze Craton, was an ancient continent (craton) that contained today's South and Southeast China, Indochina, and parts of Southeast Asia (i.e. Borneo and adjacent islands). South China had been part of past supercontinents, including Rodinia, Pannotia, Gondwana, Pangaea and Laurasia.

Tanystropheidae

Tanystropheidae is an extinct family of mostly marine archosauromorph reptiles that lived throughout the Triassic Period. They are characterized by their long, stiff necks formed from elongated cervical vertebrae with very long cervical ribs. Some tanystropheids such as Tanystropheus had necks that were several meters long, longer than the rest of their bodies.

Tanystropheids are known from Europe, Asia (Russia, China, and Saudi Arabia), North America and probably South America (Brazil). The presence of tanystropheids in Europe and China indicate that they lived along much of the coastline of the Tethys Ocean. However, species in western North America are found in terrestrial deposits, suggesting that as a group, tanystropheids were ecologically diverse.Relationships among tanystropheid species have been difficult to resolve because most specimens were flattened during fossilization and are preserved two-dimensionally. Three-dimensional fossils are known from Europe and North America.

Tethytheria

Tethytheria is a clade of mammals that includes the sirenians and proboscideans, as well as the extinct order Embrithopoda.Though there is strong anatomical and molecular support for the monophyly of Tethytheria, the interrelationships between the included taxa remain disputed. The tethytheres are united by several characters, including anteriorly facing orbits and more or less bilophodont cheek teeth (double transverse ridges on the crowns of the teeth). Proboscidea and Sirenia are linked together based on auditory characters in their petrosal bones, but this link may be a homoplasy. Desmostylians, traditionally considered tethytheres, have been tentatively assigned to Perissodactyla, along with the Early Eocene family Anthracobunidae, which was considered a sister group to Tethytheria.Tethytheria is thought to have evolved from primitive hoofed mammals ("condylarths") along the shores of the ancient Tethys Ocean.

Upware Bridge Pit North

Upware Bridge Pit North is a 2.5 hectare geological Site of Special Scientific Interest north-west of Wicken in Cambridgeshire. It is a Geological Conservation Review site.This site shows exposes rocks of Oxfordian age, around 160 million years ago. It was then a sea which was connected to the Tethys Ocean, and it has many Tethyan invertebrate fossils. It is described by Natural England as "an essential site for the study of Oxfordian palaeontology and palaeogeography in the English midlands".The site is a working quarry and there is no public access, but there is a viewing platform. The Fen Rivers Way goes past the site.

Upware South Pit

Upware South Pit is a 1.1 hectare geological Site of Special Scientific Interest (SSSI) north of Upware in Cambridgeshire. It is a Geological Conservation Review site.This site has rocks dating to the Oxfordian stage, around 160 million years ago. It was then a coral reef, and has fossils of bivalves and ammonites, as well as corals, which show affinities with the fauna of the Tethys Ocean. It is described by Natural England as a key site in study of the Oxfordian.There is access to the site from the Fen Rivers Way north of Upware. A small area of pasture in the north of the site, which is not open to the public, is also part of the Cam Washes biological SSSI.

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