Pliocene

The Pliocene is in Earth's history, a chronostratigraphic series ( = time interval ) of the Neogene. It began about 5.333 million years ago and ended about 2.588 million years. Before the Pliocene is the Miocene. After him followed by the Pleistocene ice age, with a change from warm to cold periods to the Holocene, the geological present.

Naming and history

The name ( from gr = πλεῖον more and καινός = new, unusual) comes from Charles Lyell, who in 1847 suggested him for the subdivision of the Tertiary.

By 2004, the Pliocene was considered a last series of the Tertiary before the Quaternary. Then from Gradstein et al. suggested in their publication "A Geologic Time Scale", completely abandoning the Quaternary Pleistocene and Holocene and to provide for the Neogene. However, this called fierce opposition from the various Quaternary associations forth with the result that the Quaternary is maintained as a system with the two series Pleistocene and Holocene. The Pleistocene was also the top step of the Pliocene, the Gelasian, slammed. The ratification of the proposal by the IUGS ​​in June 2009.

Definition and GSSP

The basis of the series ( and the basis of the stage of Zancleum ) the upper limit of the magnetic polarity chronozone C3R was defined ( about 100,000 years before the Thvera normal - polar Subchronozone C3n.4n ). In addition, the boundary is close to the calcareous nannoplankton Aussterbehorizont the -art Triquetrorhabdulus rugosus ( = base of CN10b zone) and the first appearance of calcareous nannoplankton - type Ceratolithus acutus. The upper limit of the Pliocene (after spin-off of Gelasiums ) is the isotope stage 103, the base of magnetic polarity chronozone C2r ( Matuyama Chrono zone), and something about it are the Aussterbehorizonte of calcareous nannoplankton species Discoaster pentaradiatus and Discoaster surculus. The GSSP ( = global calibration point ) for the beginning of the Pliocene (and hence also the limit Zancleum / Messinian ) is located near the ancient city Heraclea Minoa (Sicily, Italy).

Subdivision

The Pliocene was formerly divided into three stages, according to the spin-off of Gelasiums there are only two stages:

• System: the Neogene ( 23.03 to 2.588 mya ) Series: Pliocene ( 5.333 to 2.588 mya ) Level: Piacenzium ( 3.6 to 2.588 mya )
• Level: Zancleum ( 5.333 to 3.6 mya )

In the large sedimentation basins of Central Europe there deposited sediments are mainly organized with regional levels. For the central Paratethys Basin following regional levels are used:

• Romanium ( corresponding approximately to the Piacenzium )
• Dacium ( corresponding approximately to the Zancleum )

Climate

In the Pliocene the climate was relatively stable and warm. The carbon dioxide content in the atmosphere was determined using 13C/12C-Isotopen of organic matter in marine sediments and fossilized leaves and mid- Pliocene was about 400 ppm, the same proportion was reached again in 2013.

The annual average temperatures were about 2 ° C above today, announced towards the end of a gradual cooling of the impending Ice Age. With the ice of the polar caps began in Gelasian the Ice Age Quaternary, which continues to this day. Different climate proxies document a 15-25 meter elevated sea level, compared to today.

Paleogeography

The land bridge between North and South America began to form, which have a greater impact on the spread of many animal species, such as had the Russell animals from Africa to Asia to North and South America. The South American fauna, which had developed independently in isolation, changed: the saber-toothed cats supplanted the terror birds from the top of the food pyramid.

Fauna

Europe

Many animal species of the Pliocene had already lived in the preceding Miocene. The largest animals of Europe were represented at the beginning of the period by the mammoths Anancus and zygodonte mastodons ( genus Mammut ). Giraffes and boselaphine Bovidae (relatives of nilgai ) were once common in this era to last in Europe. Typical of Europe at that time were also gazelles ( Gazella, Hispanodorcas ). Large Bovidae survived with Parabos from the Miocene and brought to the genus Alephis even more forms out. The more advanced forms of deer ( Croizetoceros and Pliocervus ) brought forth ever more complex and larger antlers. Among the pigs survived Propotamochoerus from the Miocene. In addition, the first real pigs of the genus Sus Sus with arvernensis appeared. In Europe, temporarily disappeared the hippos ( Hexaprotodon ) during the camels in the Pliocene with Paracamelus were particularly common in the southeast. Fossil aardvark ( Orycteropus ) are known for example from the area of ​​Perpignan. The rhinos lost at the beginning of the Pliocene a large part of their shapes. Thus, in Europe and the Eastern Mediterranean all hornless forms became extinct. The genera Ceratotherium and Diceros, which are represented today in Africa nor white rhino and black rhino, and the hornless, hippo -like Brachypotherium were confined to Africa since the beginning of the Pliocene. In Europe, survived the rhinos only Stephanorhinus. The horses were spread with Hipparion, tapirs ( Tapirus ) occurred mainly in southern Europe.

The two saber-toothed cats and Machairodus Paramachairodus disappeared at the beginning of the Pliocene of Europe. Metailurus was replaced by Dinofelis. Hyenas were represented by bone- cracking forms such Pachycrocuta and small predators like Plioviverrops. In addition, there was the so-called Cheetah hyenas ( Chasmaporthetes ), which were adapted less to the break of bone, but rather to fast chases. The genus Chasmaportestes was also common in Africa and Asia and migrated across the Bering Strait to North America a. Also cheetahs were common in Europe with Acinonyx pardinensis. Smaller predators were represented by foxes ( vulpes) and raccoon dogs ( Nyctereutes ). With Agriotherium the bears from the Miocene survived into the Pliocene. The genus Ursus, which is likely to have developed from Ursavus in the Miocene of Asia, appeared in the Pliocene with Ursus minimus first time in Europe. Monkeys were also popular with Macaca prisca, a relative of Barbary apes, as well as the genera Paradolichopithecus, Dolichopithecus and Mesopithecus. The hominoids were against it in the late Miocene disappeared from Europe.

The rodents were in the Pliocene of Europe by various genera of murids ( Apodemus etc.) and continue to be represented by Cricetiden ( Ruscinomys and Apocricetus ) from the Miocene. In addition, flying squirrels ( Pliopetaurista ) and beaver (Castor ) are common. In southern Europe, crocodiles and giant turtles came before. A brief cool phase in the otherwise mild climate of the early Pliocene, about 4 million years ago led to the migration of steppe rodents with teeth like sigmodonten Trilophomys, Celadensia and Bjornkurtenia to Europe.

Towards the end of the Pliocene about 3.2 million years ago disappeared in Europe the last giraffes. The large Bovidae Parabos was replaced at that time by the generic Leptobos, the already highly reminiscent of today's cattle of the genus Bos. More Bovidae, who immigrated to Europe, were Gazellospira, Megalovis, Pliotragus. Then there were the first deer of the genus Cervus today and first representative of the giant deer ( Arvernoceros ). Among the predators also appeared on the puma -like cat Viretailurus schaubi for the first time about 3 million years ago. In addition, first published in highly developed machirodontine saber-toothed cats like Megantereon and Homotherium.

At the end of the Pliocene about 2.6 million years ago I insert a cooling of the Earth's climate, during which mammoths (Mammuthus ) migrated and the old mammoths as Anancus replaced. At the same time Hipp Arionen were replaced by modern horses of the genus Equus, which developed before in America Pliohippus. Two other immigrants at the end of the era were Eucladoceros, a large deer with antlers very complex and Libralces an early elk. Then there were the Bovidae Gallogoral and Preaovibos. The latter was a forerunner of today's musk oxen and apparently replaced Megalovis and Pliotragus. At the same time disappeared gazelles ( Gazella, Gazellospira ) from Europe. The new immigrants also included forerunner of today's wolves appeared in Europe with Canis etruscus, as well as the European Jaguar (Panthera gombaszoegensis ). The cheetah hyena disappeared at this time, the big cat Dinofelis had even already retired a little earlier from Europe. The crocodiles, giant tortoises and tapirs also disappeared from Europe. Due to these changes resembled the fauna of the succeeding epoch of the Pleistocene already heavily today's wildlife.

Asia

Asia was connected to Europe and home to most of similar animal forms. However, here survived several forms, such as the longer Chalicotherien and giraffes. Typical of the Pliocene of Asia is also the genus Rhinoceros Rhinoceros.

Africa

The Proboscidea rich by elephants ( Elephas, Loxodonta, Mammuthus ), gomphotheres ( Anancus ) and Dinotherien ( Deinotherium ) were represented in the Pliocene Africa. Since the middle Pliocene, the two still living species of rhinoceros ( Rhinoceros and Black Rhinoceros ) came before. By the end of the Pliocene about 2 million years ago the Chalicotherien survived with Ancylotherium hennigi in Africa. The horses were represented by Hipp Arionen until the beginning of the Pleistocene the genus Equus appeared. Various Pigs ( Notochoerus, Kolpochoerus, Metridichoerus ) and numerous Bovidae are known. Today's Impala was, like the genera Gazella and Tragelaphus already represented. Giraffes were by long-necked forms (Giraffa jumae ) as well as by the extinct cattle Giraffes ( Sivatherium ) represented. Hippos are mainly represented by the genus Hexaprotodon. Camels are in the fossil record in Africa generally rare, but reached the Pliocene southward after all, Malawi. The large predators were represented by various hyenas, dogs and cats. Among the big cats counted Dinofelis, Megantereon, Homotherium and since the Pliocene, the genus Panthera and Acinonyx. Large lion Panthera forms are known, for example from Laetoli in Tanzania. In the Pliocene also bear with Agriotherium were common to southern Africa. In addition, in the Pliocene australopithecines lived as human ancestors.

North America

At the beginning of the Pliocene of North America horses, tapirs, mammoths, camels and large saber-toothed cats ( Megantereon ) were represented. The bone ends sticking hyenas were represented in the Pliocene of North America by big dogs of the genus Osteoborus. During the Pliocene, the Central American land bridge that the North American Association for the first time since million plus years of isolation with the South American continent was formed. During this great American Faunenaustauschs ground sloths, glyptodons, Pampatherien and armadillos of South America immigrated and settled North America. In contrast, the rhinos disappeared during the Pliocene with genres such as Teleoceras definitively from North America.

South America

The South American continent was more affected by major faunal than North America. Many today typical of South America mammal families emigrated in the Pliocene of the newly formed Central American land bridge. Among them were the cats, dogs, camels, deer, peccaries and tapirs. Also, some families only at the very end of the Pleistocene disappeared from South America, such as the horse and gomphotheres wandered a time. They replaced the unique fauna of the South African Pliocene for the most part. Many South American mammal that had developed in isolation in South America, died out and were replaced by immigrants from the north. Among them was the saber-toothed predators Thylacosmilus. Among the forms that could be argued mainly different Xenarthra ( sloths, anteaters, glyptodons, armadillos ) and some Urhuftiere ( Toxodon, Macrauchenia ) were located. Also, survived numerous rodents and primates who've been migrated significantly earlier than " island hopping " across narrow estuaries to South America.

Alpidic orogeny

The the Neogene (mainly Miocene ) running Alpidic orogeny of the Alps, Carpathians and other mountains in Eurasia ( Himalayas ) almost came to a standstill (low elevations there to this day ). The large sediment masses in Europe levels and tectonic basins were covered in the Pliocene only by a relatively thin formation before the glaciers and gravel of the first major glacial periods shaped the present-day landscapes.