The Late Glacial Maximum (ca. 13,000-10,000 years ago), or Tardiglacial ("Late Glacial"), is defined primarily by climates in the northern hemisphere warming substantially, causing a process of accelerated deglaciation following the Last Glacial Maximum (ca. 25,000-13,000 years ago). It is at this time that human populations, previously forced into refuge areas as a result of Last Glacial Maximum climatic conditions, gradually begin to repopulate the northern hemisphere's Eurasian landmass and eventually populate North America via Beringia for the first time.
Evidence for the occurrence of the Late GM stems from two main types of analysis. The first is the use of oxygen isotope stages (OIS) gathered from stratified deep sea sediment cores. Samples are gathered and measured for change in isotope levels to determine temperature fluctuation for given periods of time. The second is a proxy measurement, namely, the observation of certain reappearing fauna and flora fossils that can only survive in temperate climates thus indicating warming trends for a given geographic area. Archaeological evidence of settlement and re-settlement in certain areas by humans also serves as a proxy measurement. Towards the end of OIS 2 in which the Late Glacial Maximum occurs, the deep sea sediment cores indicate a gradually warming climate and the reappearance of certain warm weather flora and fauna remains throughout the Northern Hemisphere correlate with this trend. A period of relatively brief cold oscillation, referred to as the Younger Dryas, is detected during OIS 2 as can be inferred from an increase in isotope weight.
Read more about Late Glacial Maximum: Western Europe and The North European Plain, East European Plain, Siberian Plain, North America, Genetics
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