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The Younger Dryas impact hypothesis (YDIH) proposes that the onset of the Younger Dryas (YD) cool period (stadial) at the end of the Last Glacial Period, around 12,900 years ago was the result of some kind of extraterrestrial event with specific details varying between publications. [1]: Sec 1 The hypothesis is controversial and not widely ...
The Younger Dryas (YD) was a period in Earth's geologic history that occurred circa 12,900 to 11,700 years Before Present (BP). [2] It is primarily known for the sudden or "abrupt" cooling in the Northern Hemisphere, when the North Atlantic Ocean cooled and annual air temperatures decreased by ~3 °C (5.4 °F) over North America, 2–6 °C (3.6–10.8 °F) in Europe and up to 10 °C (18 °F ...
Extinctions in northern Eurasia were staggered over tens of thousands of years between 50,000 and 10,000 years ago, [2] while extinctions in the Americas were virtually simultaneous, spanning only 3000 years at most. [4][8] Overall, during the Late Pleistocene about 65% of all megafaunal species worldwide became extinct, [9] rising to 72% in ...
The Pleistocene (/ ˈplaɪstəˌsiːn, - stoʊ -/ PLY-stə-seen, -stoh-; [ 5 ][ 6 ] often referred to colloquially as the Ice Age) is the geological epoch that lasted from c.2.58 million to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International ...
The Siberian Traps are thought to have played a significant role in the Permian–Triassic extinction event 252 million years ago. Formation of the Emeishan Traps began 260 million years ago. The Late Devonian extinction occurs about 374 million years ago. The Ordovician–Silurian extinction event occurs between 450 and 440 million years ago.
Early human migrations are the earliest migrations and expansions of archaic and modern humans across continents. They are believed to have begun approximately 2 million years ago with the early expansions out of Africa by Homo erectus. This initial migration was followed by other archaic humans including H. heidelbergensis, which lived around ...
Before 12,000 years ago, South America was home to about 25 species of herbivores weighing more than 1,000 kg (2,200 lb), consisting of Neotropic ground sloths, glyptodonts, and toxodontids, as well as gomphotheres and camelids of Nearctic origin. [n 14] Native South American forms made up about 75% of these species. However, none of these ...
Ukok Plateau, one of the last remnants of the mammoth steppe [1]. The mammoth steppe, also known as steppe-tundra, was once the Earth's most extensive biome.During glacial periods in the later Pleistocene it stretched east-to-west, from the Iberian Peninsula in the west of Europe, across Eurasia to North America, through Beringia (the region including the far northwest of Siberia and Alaska ...