Ice-free corridor

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An immigration route for the first inhabitants of North America that was considered possible for a long time since 1935 has been referred to as the ice-free corridor , which thawed early at the end of the last ice age and should have opened a way for the colonization of America .

Location and dates

The term ice-free corridor was first used in 1935 by the Swedish geologist Ernst Antevs (1888–1974). The knowledge at that time about the glaciation of North America (there the last glacial period is called Wisconsin glaciation ) and the human settlement in the early Holocene were low, the thesis therefore largely speculative.

Since then, and especially since the availability and improvement of 14 C data , a more detailed picture of the settlement of America has emerged: The first people reached Alaska from Siberia via the Beringia land bridge , which was freely passable due to the lower sea level. This migration movement is dated to about 15,000 years Before Present (BP). The further way south and into the interior of the continent is the subject of research (see: Colonization of America ).

Two routes of the Paleo-Indians are scientifically discussed, along the coast or to the east over the present area of ​​the Yukon River and further into the interior of the continent and then between the large glacial masses of the North American Cordilleras and the Laurentid Ice Sheet , whose center is roughly above the area of ​​the Great Lakes lay, to the south. This second route would have used the fact that due to the climate change at the end of the Ice Age, an ice-free corridor between the two main ice masses thawed early and became passable for hunted game and the people who followed it as hunters and gatherers .

Recent dating and research into the paleogeography of the region cast doubt on these dates and the existence of a usable ice-free corridor. The surface exposure dating was developed in the 1990s and is considered since the turn of the millennium to be reliable. According to their results, in the course of the thawing of the large glacier areas in the intermediate space, which was assumed to be an ice-free corridor , an area-wide glacial lake developed that only broke up about 10,300 BP in individual lakes and previously prevented a migration to the south through the area. Since human artifacts have been found in the interior of the continent at 13,200 to 12,900 BP at the latest, the ice-free corridor cannot have played a role in the settlement of the interior of the continent. In line with these skeptical considerations, human traces in the area of ​​the ice-free corridor only come into question after 11,000 BP.

Web links

Individual evidence

  1. ↑ Unless otherwise stated, the illustration is based on: Lionel E. Jackson Jr., Michael C. Wilson: The Ice-Free Corridor Revisited . In: Geotimes, American Geological Institute, February 2004 edition
  2. ↑ Ernst Antevs: The Spread of Aboriginal Man to North America , in: Geographical Review 25.2 (1935) 302-309 (after C. Vance Haynes Jr .: The Antevs-Bryan Years and the Legacy for Paleoindian Geochronology. In Establishment of a Geologic Framework for Paleoanthropology , Geological Society of America Special Paper 242, ed. by LF Laporte, 1990, pp. 55-68, here: p. 58).
  3. Jump up ↑ Mark E. Swisher, Dennis L. Jenkins, Lionel E. Jackson, Jr., Fred M. Phillips: A Reassessment of the Role of the Canadian Ice-Free Corridor in Light of New Geological Evidence . Paleoamerican Odyssey - A Conference Focused on First Americans Archeology, October 2013
  4. ^ Thomas G Arnold: Radiocarbon Dates from the Ice-Free Corridor . In: Radiocarbon , Vol 44 No. 2 (2002), pp 437-454