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29-599: Paratethys was peculiar due to its paleogeography : it consisted of a series of deep basins, formed during the Oxfordian stage of the Late Jurassic as an extension of the rift that formed the Central Atlantic Ocean . These basins were connected with each other and the global ocean by narrow and shallow seaways that often limited water exchange and caused widespread long-term anoxia . Paratethys

58-633: A brackish sea in the Pannonian Basin . Many of these would disappear before the start of the Pleistocene . At present, only the Black Sea , Caspian Sea and the Aral Sea remain of what was once a vast inland sea. Paleogeography Palaeogeography (or paleogeography ) is the study of historical geography , generally physical landscapes . Palaeogeography can also include

87-518: A stage is a succession of rock strata laid down in a single age on the geologic timescale , which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries. Rock series are divided into stages, just as geological epochs are divided into ages. Stages are divided into smaller stratigraphic units called chronozones or substages, and added together into superstages. The term faunal stage

116-679: A giant anoxic sea . The western and central Paratethys basins experienced intense tectonic activity and anoxia during the Oligocene and early Miocene and became filled with sediments . Local gypsum and salt evaporitic basins formed in the East Carpathian region during the early Miocene. The Eastern Paratethys basin, holding most of the water of Paratethys, remained anoxic for almost 20 million years (35–15 Mya), and during this time Paratethys acted as an enormous carbon sink trapping organic matter in its sediments. The Paratethys anoxia

145-459: A key role in the field of petroleum geology , because ancient geomorphological environments of the Earth 's surface are preserved in the stratigraphic record. Palaeogeographers also study the sedimentary environment associated with fossils for clues to the evolutionary development of extinct species. Palaeogeography is furthermore crucial to the understanding of palaeoclimatology , due to

174-459: A lesser extent, in the Pannonian depression in central Hungary . Some 12 million years ago, slightly before the onset of the late Miocene , the ancient sea transformed into a megalake that covered more than 2.8 million square kilometers, from the eastern Alps to what is now Kazakhstan , and characterized by salinities generally ranging between 12 and 14%. During its five-million-year lifetime,

203-430: Is sometimes used, referring to the fact that the same fauna (animals) are found throughout the layer (by definition). Stages are primarily defined by a consistent set of fossils ( biostratigraphy ) or a consistent magnetic polarity (see paleomagnetism ) in the rock. Usually one or more index fossils that are common, found worldwide, easily recognized, and limited to a single, or at most a few, stages are used to define

232-654: The International Commission on Stratigraphy (ICS) of the International Union of Geological Sciences . As of 2008, the ICS is nearly finished with a task begun in 1974, subdividing the Phanerozoic eonothem into internationally accepted stages using two types of benchmark. For younger stages, a Global Boundary Stratotype Section and Point (GSSP), a physical outcrop clearly demonstrates

261-784: The Outer Carpathians , Transylvanian and Pannonian basins. Salt mines extract this middle-Miocene salt in Transylvania: Turda , Ocna Mures , Ocna Sibiului and Praid ; in the Eastern and Carpathians: Wieliczka , Bochnia , Cacica and Slanic Prahova ; and Ocnele Mari in the Southern Carpathians, but evaporites are also present in areas west of the Carpathians: Maramureș , eastern Slovakia (Solivar mine near Prešov ) and, to

290-523: The supercontinent Pangaea broke up during the Triassic (200 million years ago). The name Paratethys was first used by Vladimir Laskarev in 1924. Laskarev's definition included only fossils and sedimentary strata from the sea of the Neogene system . This definition was later adjusted also to include the Oligocene series . The existence of a separate water body in these periods was deduced from

319-639: The Mediterranean fell dry during the Messinian salinity crisis (about 6 million years ago) there were phases when Paratethys water flowed into the deep Mediterranean basins. During the Pliocene epoch (5.33 to 2.58 million years ago) the former Paratethys was divided into a couple of inland seas that were at times completely separated from each other. An example was the Pannonian Sea ,

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348-747: The Paratethys Sea. Paratethys formed about 34 Mya (million years ago) at the beginning of the Oligocene epoch, when the northern region of the Tethys Ocean (Peri-Tethys) was separated from the Mediterranean region of the Tethys realm due to the formation of the Alps , Carpathians , Dinarides , Taurus and Elburz mountains. During the Jurassic and Cretaceous periods, this part of Eurasia

377-461: The adjective "faunal" has been dropped as regional and global correlations of rock sequences have become relatively certain and there is less need for faunal labels to define the age of formations. A tendency developed to use European and, to a lesser extent, Asian stage names for the same time period worldwide, even though the faunas in other regions often had little in common with the stage as originally defined. Boundaries and names are established by

406-422: The boundary. For older stages, a Global Standard Stratigraphic Age (GSSA) is an absolute date. The benchmarks will give a much greater certainty that results can be compared with confidence in the date determinations, and such results will have farther scope than any evaluation based solely on local knowledge and conditions. In many regions local subdivisions and classification criteria are still used along with

435-422: The development of seismology and radioactive dating in the second half of the 20th century. Microscopic analysis of the rock ( petrology ) is also sometimes useful in confirming that a given segment of rock is from a particular age. Originally, faunal stages were only defined regionally. As additional stratigraphic and geochronologic tools were developed, they were defined over ever broader areas. More recently,

464-508: The fossil fauna, including mollusks, fish and ostracods . In periods in which the Paratethys or parts of it were separated from each other or from other oceans, a separate fauna developed which is found in sedimentary deposits. In this way, the paleogeographical development of the Paratethys can be studied. Laskerev's description of the Paratethys was anticipated much earlier by Sir Roderick Murchison in chapter 13 of his 1845 book. One of

493-534: The geologic records from Paratethys particularly difficult to correlate with those from other oceans or seas because their faunas evolved separately at times. Stratigraphers of the Paratethys, therefore, have their own sets of stratigraphic stages which are still used as alternatives for the official geologic timescale of the ICS . The Paratethys spread over a large area in Central Europe and western Asia. In

522-519: The impact of the positions of continents and oceans on influencing global and regional climates. Palaeogeographical evidence contributed to the development of continental drift theory, and continues to inform current plate tectonic theories, yielding information about the shape and latitudinal location of supercontinents such as Pangaea and ancient oceans such as Panthalassa , thus enabling reconstruction of prehistoric continents and oceans. Stage (stratigraphy) In chronostratigraphy ,

551-520: The key characteristics of the Paratethys realm, that is differentiating it from the Tethys Ocean , is the widespread development of endemic fauna, adapted to fresh and brackish waters like those that still exist in recent waters of the Caspian Sea. This distinctive fauna in which univalves of freshwater origin such as Limnex and Neritinex are associated with forms of Cardiacae and Mytili, common to partially saline or brackish waters, makes

580-561: The megalake was home to many species found nowhere else, including molluscs and ostracods as well as miniature versions of whales, dolphins and seals. In 2023, Guinness World Records named this lake the largest in earth's history. Near the end of the Miocene, an event known as the Khersonian crisis, marked by rapidly fluctuating environmental factors and sea levels, wiped out much of the unique fish fauna of this megalake. When parts of

609-669: The neighbouring Mediterranean region, probably via the Trans-Tethyan Corridor, an ancient sea-strait located in modern Slovenia . The open marine environments of Paratethys were short-lived, and halfway through the middle Miocene, progressive uplift of the central European mountain ranges and a eustatic drop isolated Paratethys from the global ocean triggering a salinity crisis in Central Paratethys. The " Badenian Salinity Crisis " spanned between 13.8 and 13.4 Mya. Thick evaporitic beds (salt and gypsum) formed in

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638-432: The newer internationally coordinated uniform system, but once the research establishes a more complete international system, it is expected that local systems will be abandoned. Stages can include many lithostratigraphic units (for example formations , beds , members , etc.) of differing rock types that were being laid down in different environments at the same time. In the same way, a lithostratigraphic unit can include

667-544: The same time the Alpine orogeny , a tectonic phase by which the Alps, Carpathians , Dinarides , Taurus , Elburz and many other mountain chains along the southern rim of Eurasia were formed. The combination of a drop in sea level and tectonic uplift resulted in the partial disconnection of the Tethys and Paratethys domains. Due to poor connectivity with the global ocean, the Paratethys realm became stratified and turned into

696-514: The stage's bottom. Thus, for example in the local North American subdivision, a paleontologist finding fragments of the trilobite Olenellus would identify the beds as being from the Waucoban Stage whereas fragments of a later trilobite such as Elrathia would identify the stage as Albertan . Stages were important in the 19th and early 20th centuries as they were the major tool available for dating and correlating rock units prior to

725-413: The study of human or cultural environments. When the focus is specifically on landforms , the term paleogeomorphology is sometimes used instead. Paleomagnetism , paleobiogeography , and tectonic history are among its main tools. Palaeogeography yields information that is crucial to scientific understanding in a variety of contexts. For example, palaeogeographical analysis of sedimentary basins plays

754-799: The west it included in some stages the Molasse basin north of the Alps ; the Vienna Basin , the Outer Carpathian Basin , the Pannonian Basin , and further east to the basin of the current Black Sea and the Caspian Sea until the current position of the Aral Sea . The boundary between the Eocene and Oligocene epochs was characterized by a big drop of the global ( eustatic ) sea level and sudden steep cooling of global climates. At

783-716: Was "shut down" during the middle Miocene, some 15 million years ago, when a widespread marine transgression , known as the Badenian Flooding, improved connections with the global ocean and triggered the ventilation of the deep waters of Paratethys. After the Badenian Flooding , in the middle Miocene , Paratethys was characterized by open-marine environments. Brackish and lacustrine basins turned into ventilated seas. Rich marine fauna containing sharks (e.g., megalodon ), corals , marine mammals , foraminifera and nanoplankton spread throughout Paratethys from

812-659: Was at times reconnected with the Tethys or its successors (the Mediterranean Sea or the Indian Ocean ) during the Oligocene and the early and middle Miocene times, but at the onset of the late Miocene epoch, the tectonically trapped sea turned into a megalake from the eastern Alps to what is now Kazakhstan . From the Pliocene epoch onward (after 5 million years ago), Paratethys became progressively shallower. Today's Black Sea , Caspian Sea , Aral Sea , Lake Urmia , Namak Lake and others are remnants of

841-688: Was covered by shallow seas that formed the northern margins of the Tethys Ocean. However, because Anatolia, the southern boundary of the Paleo-Tethys Ocean , is a part of the original continent of Cimmeria , the last remnant of the Paleo-Tethys might be oceanic crust under the Black Sea. The Tethys Ocean formed between Laurasia (Eurasia and North America) and Gondwana (Africa, India, Antarctica, Australia and South America) when

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