User:Abyssal/Prehistory of South America
Portal maintenance status: (July 2018)
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The Prehistory of South America PortalIntroductionThe Prehistory of South America portal collects and presents articles, images and categories on the prehistorical period in time (before 10,000 years ago) of the continent South America. South America has a rather unique prehistory, both regarding the human settlement prehistory and early history and the flora and fauna prehistory of the continent. For approximately 115 million years, since the Aptian, the continent was no longer connected to Africa and the other landmasses of Eurasia and North America and during the early Cenozoic, the continent became unconnected to Australia. The only connection to another continent was with Antarctica, that drifted away in the late Eocene, approximately 35 million years ago. The next 30 million years, until the late Miocene to early Pliocene (6-4 million years ago), South America was completely isolated from the other landmasses, separated by the Atlantic, Pacific, Antarctic and paleo-Caribbean oceans. This caused the evolution of a unique prehistoric fauna and flora in South America. Due to plate tectonic movements in the Neogene, the isthmus of Panama was formed, leading to the Great American Biotic Interchange (GABI), drastically reshaping the faunal assemblages of both Americas, but South America in particular, with many more migration from north to south than vice versa. The history of human settlement was equally recent, with the oldest evidences dating to approximately 18,500 years ago (Monte Verde, Chile). Human migration resembled the migration of prehistoric animals; via the Isthmus of Panama, arriving first in what is now Colombia. The indigenous people spread out across the continent with hunter-gatherer lifestyles. The human prehistory is followed by a period of sedentary settlement and the development of agriculture into various civilizations. Selected article on prehistoric South AmericaIn the geologic record, the K–Pg event is marked by a thin layer of sediment called the K–Pg boundary, which can be found throughout the world in marine and terrestrial rocks. The boundary clay shows high levels of the metal iridium, which is rare in the Earth's crust but abundant in asteroids. It is now generally believed that the K–Pg extinction was triggered by a massive comet/asteroid impact and its catastrophic effects on the global environment, including a lingering impact winter that halted photosynthesis in plants and plankton. However, some scientists maintain the extinction was caused or exacerbated by other factors, such as volcanic eruptions, climate change, and/or sea level change. Whatever the cause, many of the surviving animal groups diversified during the ensuing Paleogene period. Mammals in particular radiated into new forms such as horses, whales, bats, and primates. (see more...) Need help?Do you have a question about Abyssal/Prehistory of South America that you can't find the answer to? Consider asking it at the Wikipedia reference desk. Selected image
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