Human traces in North America during the last maximum glacial expansion

A new study, Evidence of humans in North America during the Last Glacial Maximum, published on Science, focuses on human traces left just north of the American continent

by Lorenzo Ciotti
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Human traces in North America during the last maximum glacial expansion

The conditions created during the maximum glacial expansion persisted for approximately 2000 years; during this period, all of northern Europe, most of Canada and the northern half of Russia, Tibet and much of Kashmir, were covered with huge glaciers.

Glaciers covered most of the British archipelago excluding the southern end of Great Britain, Iceland, the Alpine area, part of the Po Valley and a series of glaciers also dotted the Apennine ridge; other smaller glaciers formed in Africa in the Atlas Mountains and in the Bale Mountains in Ethiopia.

In the southern hemisphere, the Patagonian glacier covered southern Chile up to the 41st parallel south, as well as the Andean plateau: glaciers were also developed in New Guinea. In Russia, the course of the Ob 'and Enisej rivers, which flow into the Arctic Ocean, was blocked by ice and this led to the formation of gigantic lakes.

Around the glaciers there were vast expanses of permafrost that covered Eurasia up to the latitude of Seghedino and Peking. In North America, however, the extent of permafrost coverage was not that large and covered a few kilometers south of the glaciers, apart from the high altitudes.

A new study, Evidence of humans in North America during the Last Glacial Maximum, published on Science, focuses on human traces left just north of the American continent. Scientists explain: "Archaeologists and researchers in allied fields have long sought to understand human colonization of North America.

Questions remain about when and how people migrated, where they originated, and how their arrival affected the established fauna and landscape. Here, we present evidence from excavated surfaces in White Sands National Park (New Mexico, United States), where multiple in situ human footprints are stratigraphically constrained and bracketed by seed layers that yield calibrated radiocarbon ages between ~23 and 21 thousand years ago.

These findings confirm the presence of humans in North America during the Last Glacial Maximum, adding evidence to the antiquity of human colonization of the Americas and providing a temporal range extension for the coexistence of early inhabitants and Pleistocene megafauna."