User:Frances Mamman/Late Pleistocene

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The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as the upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently defined as the time between c. 129,000 and c. 11,700 years ago. The late Pleistocene equates to the proposed Tarantian Age of the geologic time scale, preceded by the officially ratified Chibanian (commonly known as Middle Pleistocene). The beginning of the Late Pleistocene is the transition between the end of the Penultimate Glacial Period and the beginning of the Last Interglacial around 130,000 years ago (corresponding with the beginning of Marine Isotope Stage 5). The Late Pleistocene ends with the termination of the Younger Dryas, some 11,700 years ago when the Holocene Epoch began.

The term Upper Pleistocene is currently in use as a provisional or "quasi-formal" designation by the International Union of Geological Sciences (IUGS). Although the three oldest ages of the Pleistocene (the Gelasian, the Calabrian and the Chibanian) have been officially defined, the late Pleistocene has yet to be formally defined. Following the brief Last Interglacial warm period (~130-115,000 years ago), where temperatures were comparable to or warmer than the Holocene, the Late Pleistocene was dominated by the cool Last Glacial Period, with temperatures graduate lowering over the course of the period, reaching their lowest during the Last Glacial Maximum around 26-20,000 years ago.

The origins of modern human behaviour is first shown during the Upper Paleolithic (UP) transition in western Asia and Europe about 45 Ka and later in southern and eastern Asia, Australia and Africa Most of the world's large (megafaunal) animals became extinct during the Late Pleistocene as part of the Late Pleistocene extinctions, a trend that continued into the Holocene. This period is also important in the study of human origins because this was when human ancestry began to evolve and this is shown in genetic and fossil evidence from Africa dating back to 300Ka. There is also a significant amount of evidence showing the evolution of a Eurasian species called the Neanderthal.

Last Ice Age
The proposed beginning of the late Pleistocene is the end of the Penultimate Glacial Period (PGP) 126 ka when the Riß glaciation (Alpine) was being succeeded by the Eemian (Riß-Würm) interglacial period. The Riß-Würm ended 115 ka with the onset of the Last Glacial Period (LGP) which is known in Europe as the Würm (Alpine) or Devensian (Great Britain) or Weichselian glaciation (northern Europe); these are broadly equated with the Wisconsin glaciation (North America), though technically that began much later. The Last Glacial Maximum was reached during the later millennia of the Würm/Weichselian, estimated between 26 ka and 19 ka when deglaciation began in the Northern Hemisphere. The Würm/Weichselian endured until 16 ka with Northern Europe, including most of Great Britain, covered by an ice sheet. The glaciers reached the Great Lakes in North America. Sea levels fell and two land bridges were temporarily in existence that had significance for human migration: Doggerland, which connected Great Britain to mainland Europe; and the Bering land bridge which joined Alaska to Siberia.

The Last Ice Age was followed by the Late Glacial Interstadial, a period of global warming to 12.9 ka, and the Younger Dryas, a return to glacial conditions until 11.7 ka. Palaeoclimatology holds that there was a sequence of stadials and interstadials from about 16 ka until the end of the Pleistocene. These were the Oldest Dryas (stadial), the Bølling oscillation (interstadial), the Older Dryas (stadial), the Allerød oscillation (interstadial) and finally the Younger Dryas.

The end of the Younger Dryas marks the boundary between the Pleistocene and Holocene Epochs. Man in all parts of the world was still culturally and technologically in the Palaeolithic (Old Stone) Age. Tools and weapons were basic stone or wooden implements. Nomadic tribes followed moving herds. Non-nomadics acquired their food by gathering and hunting.

Africa
Due to the geological location of Africa and its landmass of over 30 million, it was able to support the spread of large terrestrial mammals, some of which has survived to this day. Africa plays a huge role in understanding human evolution and modern environments. This is where human evolution and the origins of modern humans were found. Due to its warm and dry atmosphere rainfall patterns is what largely determines the vegetation patterns. Its present physical geography and climate has undergone changes over time caused by movement of tectonic plates and volcanoes but glacial cycles and sea level variation has a more significant effect on the vertebrate communities during the Late Pleistocene.

Southern Africa
Around 270 Ka certain modern fauna grew in southern Africa until Pleistocene - Holocene boundary (11.5ka). This timeline is referred to as the Florisian Land Mammal Age. At the Duinefontein 2 site in South Africa, deposits of modern fauna was dated to ca. 270ka using Optically-Simulated Luminescence. The Late Pleistocene was the time when most animals evolved to resemble modern-day animals and they managed to live through the Late mid-Pleistocene since there were no extinction events of megafauna until the end of the Late Pleistocene. The region housed a large number of grazing species like alcelaphines and equids compared to the late Holocene and historic fauna which means there were more feeders living during this period compared to the present. There were also Suidae and Bovidae fossil records. Some species which went extinct at the end of the Late Pleistocene are the Giant Warthog, Long-horn buffalo, Southern Springbok, etc. These species were common because their distribution changed in response to climatic influences on vegetation. Canivores were more widespread due to their varying habitat requirements.

Northern Africa
Most of the knowledge of the Late Pleistocene is gotten from regions like Morocco, Algeria, Tunisia, some coastal regions of Maghreb, Libya and Egypt. The only issue with interpreting the data from this region is due to the lack chronological information. The paleontological record shows some species which are found in Eurasia and some local species. The resemblance of Late Pleistocene species in Northern Africa to modern animals is the same as Southern Africa but its extremely difficult to date when these fauna came into place because of the was a lack of reliable samples from the mid-Pleistocene. The presence of alcelaphines, gazelles and oryx signifies the presence of a dry atmosphere compared to the early Holocene which as moist. few species such as cervids and long-horned buffalo go extinct. Unfortunately the current data from the Maghreb can't be used to make any comparisons between glacial and interglacial cycles. Most of the significant fossil records are from the Maghreb because its geology which helps to create deep caves which is a good area for preserving fossils while the other sites are just open-air sites. data indicated that faunal communities where similar between the western and eastern region of North Africa

In Egypt, the Late (or Upper) Palaeolithic began sometime after 30,000 BC. People in North Africa had relocated to the Nile Valley as the Sahara was transformed from grassland to desert. The Nazlet Khater skeleton was found in 1980 and has been radiocarbon dated to between 30,360 and 35,100 years ago.

Eurasia
Early humans migrated into Eurasia about 40-45 ka ago. which has been proven using evidence of a human femur which was found at Ust'-Ishim, Siberia dating back to 45 ka and the appearance of initial Upper Paleolithic technology found at various archaeological sites in Lake Baikal region and in Mongolia.the sites found at the Balkal region have a significant amount of evidence showing the early migration patterns of H. sapiens despite there were earlier sightings in Southeast Asia and Southern China. Through the analysis of lacustrine sediments, Regional paleoenvironmental reconstructions of marine isotope stage 3 has made it possible to interpret when H.sapiens with "modern features" began to appear in Eurasia.

Neanderthal hominins (Homo neanderthalensis) inhabited Eurasia until becoming extinct between 40 and 30 ka. towards the end of the Late Pleistocene and possibly into the early Holocene and were replaced with modern humans (Homo sapiens) who emerged from East Africa about 195,000 years ago .The Neanderthals co-existed with the Homo sapiens until they died out. the Upper Palaeolithic stone artifacts made by the Homo sapiens had more finely and sophisticated features compared to the ones made by the Neanderthals.

Upper paleolithic people also made paintings and engravings on walls. Some cave paintings have been found at Lascaux in the Dordogne which may be more than 17,000 years old. These are mainly of buffalo, deer and other animals hunted by man. Later paintings occur in caves throughout the world with further examples at Altamira (Spain) and in India, Australia and the Sahara.

In Eurasia, extinction happened throughout the Pleistocene but those that happened during the Later Pleistocene were of megafauna and there were no replacements for the extinct species. Some Molluscan species went extinct but not on the same scale as the mammals living during the time. Some examples of species which extinct without replacements include the Straight-tusked elephant (Palaeoloxodon antiquus), Giant deer (Megaloceros giganteus), cave beer (Ursus spelaeus) and woolly rhinoceros (Coelodonta antiquitatis). Several large mammalian species including the mammoth, mastodon and Irish elk became extinct.

Magdalenian hunter-gatherers were widespread in western Europe about 20 -12.500 cal BP years ago until the end of the Pleistocene. An example of this is the antler-working done by the human groups who lived in the Santimamine cave in the Magdalenian. They invented the earliest known harpoons using reindeer horn

The only domesticated animal in the Pleistocene was the dog, which evolved from the grey wolf into its many modern breeds. It is believed that the grey wolf became associated with hunter-gatherer tribes around 15 ka. The earliest remains of a true domestic dog have been dated to 14,200 years ago. Domestication first happened in Eurasia but could have been anywhere from Western Europe to East Asia. Domestication of other animals such as cattle, goats, pigs and sheep did not begin until the Holocene when settled farming communities became established in the Near East. The cat was probably not domesticated before c. 7500 BC at the earliest, again in the Near East.

A butchered brown bear patella found in Alice and Gwendoline Cave in County Clare and dated to 10,860 to 10,641 BC indicates the first known human activity in Ireland.

Climatic conditions during the Late Pleistocene in Eurasia were predominantly cold with glaciation events happening in northern Europe, northwest Siberia and the Alps and interglacials (temperate phase). the evidence of the changes in climatic conditions were from fragmentary sequences in former glaciated areas in northern Europe. The Last Cold Stage was smaller compared to earlier glaciations. the sea level around the seaboard of northwest Europe also experienced changes during the Last Cold Stage. during this time the boundary between warm and polar waters was depressed reaching Spain and freezing the adjacent lands.

Far East
The Topography and geography of Asia were subject to frequent changes such as he creation of bridges when sea levels dropped which helped with the expansion and migration of human populations. A example of this is the Bering Land Bridge which formed between Siberia and Alaska The very first human habitation in the Japanese archipelago has been traced to prehistoric times between 40,000 BC and 30,000 BC. The earliest fossils are radiocarbon dated to c. 35,000 BC. The Neanderthals were also found in this area along with two other Hominin populations called the Denisovans and Homo floresiensis.

Japan was once linked to the Asian mainland by land bridges via Hokkaido and Sakhalin Island to the north, but was unconnected at this time when the main islands of Hokkaido, Honshu, Kyushu and Shikoku were all separate entities.

North America
During the Late Pleistocene about 35 genera of megafauna went extinct including species such as mastodons, saber-toothed cats and giant ground sloths. Some other species went extinct in North America but not globally. it is still heavily debated what caused the extinctions.

The 12-10 ka BP time period known as the terminal Pleistocene is an important part of this debate because this was when the Clovis hunter-gatherers appeared in North America and when the Younger Dryas (≈12.9 ka B.P.) cold interval began. In order to reach a consensus on the chronology of the extinctions in North America, the data has to correlate with each other but due to incomplete fossil records its hard to give an certain answer.

Bison occidentalis and Bison antiquus, an extinct subspecies of the smaller present-day bison, survived the late Pleistocene period, between about 12 and 11 ka ago. Clovis peoples depended on these bison as their major food source. Earlier kills of camels, horses, and muskoxen found at Wally's beach were dated to 13.1–13.3 ka B.P.

Human migrations happened from during this time with people coming in from Eurasia. From about 28 ka, there were migrations across the Bering land bridge from Siberia to Alaska. The people became the Native Americans. It is believed that the original tribes subsequently moved down to Central and South America under pressure from later migrations.

In the North American land mammal age scale, the Rancholabrean spans the time from c. 240,000 years ago to c. 11,000 years ago. It is named after the Rancho La Brea fossil site in California, characterised by extinct forms of bison in association with other Pleistocene species such as the mammoth.

South America
A large number of megafauna in South and North America went extinct during the Pleistocene. In North America, about 70% of mammals weighing about 44 kg went extinct during the time period of 13 -12 k cal BP. During this period there was a major cooling event called the Younger dryas and the Clovis culture of capturing game became more prominent. Diverse factors such as climate change may have triggered this extinctions but its still in debate what the major factors were.

The South American land mammal age Lujanian corresponds with the late Pleistocene.

Oceania
There is evidence of human habitation in mainland Australia, Indonesia, New Guinea and Tasmania from c. 45,000 BC. The finds include rock engravings, stone tools and evidence of cave habitation

In Australia, there are sites which shows evidence of pollen records from the Late Pleistocene and they are mostly found in more temperate regions of the continent. as for the megafauna, not all of them went. some evolved to dwarfs of their ancestors while others remained the same but there isn't much fossil record to show the exact chronologies of the extinctions.

In general, various reasons have been stated to have cause the extinctions during the Late Pleistocene but the topic is still being debated.