Misplaced Pages

#919080

23-587: The Beestonian precedes the Cromerian Stage and follows the Pastonian Stage . This stage consists of alternating glacial and interglacial phases instead of being a continuous glacial epoch. It is equivalent to Marine isotope stages 22 to (60?). The Beestonian Stage and Marine Isotope Stage 22 ended about 866,000 years ago. The Beestonian corresponds temporally to the Danube Stage in the glacial history of

46-415: A 100,000 year periodicity, with the glacial cycles becoming asymmetric, having long glacial periods punctuated by short warm interglacial periods. Millennial-scale climatic variability continued to be highly sensitive to precession and obliquity cycles. In central Italy, the climate became noticeably more arid from 600 ka to 400 ka. The late Middle Pleistocene was a time of regional aridification in

69-676: A million years ago. It is named after the East Anglian town of Cromer in Great Britain where interglacial deposits that accumulated during part of this stage were first discovered. The stratotype for this interglacial is the Cromer Forest Bed situated at the bottom of the coastal cliff near West Runton . The Cromerian stage preceded the Anglian and Elsterian glacials and show an absence of glacial deposits in western Europe, which led to

92-614: Is plenty of evidence in Russia for a major glaciation during this stage, which is called the Don Glaciation and believed to correspond to MIS 16. It is not clear why western Europe seems so unaffected by this major glacial. In 1990 the West Runton Mammoth skeleton was found, the best example of the species Mammuthus trogontherii to be unearthed so far. A significant fossil site, with animal remains dating about 600,000 years ago,

115-638: Is the Mosbach Sands in Germany, named after an abandoned village near Wiesbaden , Germany. Middle Pleistocene The Chibanian , more widely known as the Middle Pleistocene (its previous informal name), is an age in the international geologic timescale or a stage in chronostratigraphy , being a division of the Pleistocene Epoch within the ongoing Quaternary Period. The Chibanian name

138-802: The Alpine region . Based on findings in the Low Countries , the corresponding timespan in northern continental Europe is divided into four stages, the Bavelian, Menapian, Waalian, and Eburonian. The Beestonian had also been equated to the Nebraskan glaciation in North America . However, the Nebraskan Stage, along with the Kansan and Aftonian Stages, have been abandoned by North American Quaternary geologists and merged into

161-700: The Levant , with a shallow lake covering what is now the Shishan Marsh drying and developing into a marsh. Eastern Africa's hydroclimate was governed primarily by orbital precession, although modulated significantly by the 100 kyr eccentricity cycle. Along the northwestern Australian coast, the intensification of the Leeuwin Current resulted in an expansion of reefs coincident with the Great Barrier Reef's formation. The Early-Middle Pleistocene boundary saw

184-506: The Middle Pleistocene (Ionian) before the Anglian glaciation , the Cromerian was originally thought to be a period without major glaciations. However, there is evidence for ice-rafting of material across the North Sea from this period. Investigations in the 1950s of oxygene isotopes in deep sea core samples revealed five glacial cycles during MIS 22 - MIS 13. The Mid-Pleistocene Transition to

207-609: The Pre-Illinoian . At this time, the Cromerian is correlated with the period of time, which includes the Pre-Illinoian C, Pre-Illinoian D, and Pre-Illinoian E glaciations of North America. Proposals for structuring the Cromerian complex have become quite confusing. Great potential for a full breakdown has been provided by the extensive, continental series at Gorleben . Based on a lack of glacial evidence in Western Europe for

230-656: The Pre-Illinoian Stage . As of 2011, the Beestonian stage is correlated with the period of time that includes the Pre-Illinoian F, Pre-Illinoian G, and Pre-Illinoian H glaciations of North America. Cromerian Stage The Cromerian Stage or Cromerian Complex , also called the Cromerian ( German : Cromerium ), is a stage in the Pleistocene glacial history of north-western Europe, mostly occurring more than half

253-527: The 100,000 year glacial cycle became established during the Cromerian. Four of the glaciations (MIS 22, MIS 20, MIS 18, MIS 14) were moderate, probably involving low-land glaciation in Scandinavia, but not spreading to England and northern Germany. One of the glaciations, Marine Isotope Stage 16 (MIS 16), is globally as strong as the most recent glaciations, MIS 6 (main Saale ) and MIS 2 ( Weichsel/Devensian ). There

SECTION 10

#1733084809920

276-801: The Chibanian is the Brunhes–Matuyama reversal , when the Earth's magnetic field last underwent reversal. Its end roughly coincides with the termination of the Penultimate Glacial Period and the onset of the Last Interglacial period (corresponding to the beginning of Marine Isotope Stage 5 ). The term Middle Pleistocene was in use as a provisional or "quasi-formal" designation by the International Union of Geological Sciences (IUGS). While

299-796: The European straight-tusked elephant ( Palaeoloxodon antiquus ). With the extinction of Sinomastodon in East Asia at the Early-Middle Pleistocene boundary, gomphotheres became completely extinct in Afro-Eurasia, but continued to persist in the Americas into the Late Pleistocene. There was a major extinction of carnivorous mammals in Europe around the Early-Middle Pleistocene transition, including

322-793: The Ionian as the Subcommission on Quaternary Stratigraphy's preferred GSSP proposal for the age that should replace the Middle Pleistocene sub-epoch. The "Chibanian" name was ratified by the IUGS in January 2020. By early Middle Pleistocene, the Mid-Pleistocene Transition had changed the glacial cycles from an average 41,000 year periodicity present during most of the Early Pleistocene to

345-653: The continental Cromerian continues beyond its end in Britain and Ireland and runs in parallel to the Anglian and Hoxnian Stages (MIS 12-11). In the Alpine region the corresponding stage is called Günz . The Cromerian had been equated to the Aftonian in North America . However, the Aftonian, along with the Yarmouthian (Yarmouth) , Kansan , and Nebraskan, have been abandoned by North American Quaternary geologists and merged into

368-603: The family Palaeobatrachidae became extinct. The Chibanian includes the transition in palaeoanthropology from the Lower to the Middle Paleolithic : i.e., the emergence of Homo sapiens sapiens between 300 ka and 400 ka. The oldest known human DNA dates to the Middle Pleistocene, around 430,000 years ago. This is the oldest found, as of 2016 . After analyzing 2,496 remains of Castor fiber (Eurasian beaver) and Trogontherium cuvieri found at Bilzingsleben in Germany,

391-453: The giant hyena Pachycrocuta . The mid-late Middle Pleistocene saw the emergence of the woolly mammoth ( Mammuthus primigenius ), and its replacement of Mammuthus trogontherii , with the replacement of M. trogontherii in Europe by woolly mammoths being complete by around 200,000 years ago. The last member of the notoungulate family Mesotheriidae , Mesotherium , has its last records around 220,000 years ago, leaving Toxodontidae as

414-465: The historical terms Cromerian interglacial and the Cromerian warm period ( German : Kromer-Warmzeit ). It is now known that the Cromerian consisted of multiple glacial and interglacial periods. The core of the Cromerian is the first half of the Middle Pleistocene stage (Ionian) approximately 800-500 ka ago, just before the Anglian glaciation . In terms of Marine isotope stages (MIS) this corresponds to MIS 19 to MIS 13. Some authors instead put

437-455: The migration of true horses out of North America and into Eurasia. Also around this time, the European mammoth species Mammuthus meridionalis became extinct and was replaced by the Asian species Mammuthus trogontherii (the steppe mammoth). This was coincident with the migration of the elephant genus Palaeoloxodon out of Africa and into Eurasia, including the first appearance of species like

460-553: The sole family of notoungulates to persist into the Late Pleistocene. During the late Middle Pleistocene, around 195,000-135,000 years ago, the steppe bison (the ancestor of the modern American bison ) migrated across the Bering land bridge into North America, marking the beginning of the Rancholabrean faunal stage. Around 500,000 years ago, the last members of the largely European aquatic frog genus Palaeobatrachus and by extension

483-616: The start at MIS 22, corresponding to a start 900 ka ago, which includes the last 100 ka of the Calabrian stage , after the Beestonian Stage . Some sources today correlate the Elster glaciation to MIS 10 instead of MIS 12, while keeping the Cromerian running up to the start of the Elsterian. The result is an end to the Cromerian stage in continental Europe at the end of MIS 11 (400 ka ago), and that

SECTION 20

#1733084809920

506-711: The three lowest ages of the Pleistocene, the Gelasian , Calabrian and Chibanian have been officially defined, the Late Pleistocene has yet to be formally defined. The International Union of Geological Sciences (IUGS) had previously proposed replacement of the Middle Pleistocene by an Ionian Age based on strata found in Italy. In November 2017, however, the Chibanian (based on strata at a site in Chiba Prefecture , Japan) replaced

529-403: Was officially ratified in January 2020. It is currently estimated to span the time between 0.770 Ma (770,000 years ago) and 0.129 Ma (129,000 years ago), also expressed as 770–126 ka. It includes the transition in palaeoanthropology from the Lower to the Middle Paleolithic over 300 ka. The Chibanian is preceded by the Calabrian and succeeded by the proposed Tarantian . The beginning of

#919080