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Last Glacial Maximum refugia
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The Last Glacial Maximum (LGM) is defined as a point in time where ice sheets were at their peak sizes and did not change in their physical appearance[1]. According to the Last Glacial Maximum, the LGM occurred around 26,500 years to 19-20,000 years ago and the harsh cold temperatures did not allow for much occupation in these locations. The LGM actually caused much drought and desertification resulting in the migration of former or nearby occupants[1].This migration lead to the search for refugium during LGM. This was common as species would stay in a location for a good amount of time to be away from these very low temperatures[2]. Refugium (in this context) is an area where a species survived an inter-glacial cycle.[3]
Locations of Refugia
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Since temperatures were extremely cold there were many refugia in place for the early humans but only six to nine were stated to be important. Some of these important refugia were: Gulf plains/ Einasleigh uplands, Murray Darling Depression and Tasmanian Central Highlands.[3] These refugia were stated to being important because they were said to have been continuously compared to other refugias such as the following: South Eastern Highlands, NSW Southern Western Slopes, Sydney Basin, Central and Northern Kimberley, central ranges, Arnhem plateau, MacDonnell Ranges, Murchison and Warren.[3] These refugias were not used continuously but still had a considerable amount of information when talking about periods of activity. Refugium occurs during the LGM and is influenced by a species' adaptations and tolerances.[4]
- Different types of these isolated areas are embedded, coastal and periglacial refugia.[5]
- Embedded: areas that are like hot springs
- Coastal: areas that are near the coastal region or an island
- Periglacial: areas that are near an ice sheet or glacier
Haida Gwaii
[edit]An archipelago formerly known as the "Queen Charlotte Islands" that archaeologists refer to as ".. an option for a pacific coastal route taken by the first humans migrating to the Americas from the Bering Strait."[6]
- Activists refer to these islands using the term "Galapagos of the North"
- Archaeological sites have proved there to have been human occupants on these islands.
- Research from Simon Fraser University suggests that Haida Gwaii was most likely covered by "tundra" and "low-meadows"
Species Involved
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Slowly, through various ice filled events in time, there was the creation of a split between these species and their original roots. Species would proceed to progress into new species due to the long period of time they spent in isolation[4]. As the continents began to be covered with ice sheets the species range starts to shift towards the south.The location of these species was hard to track as fossils are the clearest evidence of a species in a certain location.[7] Although fossils work as evidence of where a species might have stayed there is a slight problem with fossils and that is that they are rare. Populations in refugia differed from each other through their responses to environmental conditions being changed through natural selection.[7] AMH (Modern humans) seemed to have moved away from these areas within these cold temperatures which allowed for the arrival of populations responsible for the Aurignacian industries as well as the Gravettian stone tool industry.[7]
Aurignacian Industries
[edit]Main Article: "Archaeology and the Dispersal of Modern Humans in Europe:Deconstructing Aurignacian"
"What relevance, if any, does the "Aurignacian" have for the dispersal of anatomically and behaviorally modern populations across Europe? The answer in my view may well be fairly straightforward. The most critical single discovery is that of the so called Egbert skeleton from Ksar Akil excavated by Ewing, clearly embedded in brechiated deposits within level 17 of his stratigraphy, According to the detailed analysis by Bergman and Stringer, this is unquestionably a fully modern human in both cranial and postcranial terms.[8]
- Skeletal finds are "scarce" but the remains that have been found are very useful when concluding that they are associated with modern population.
- Series of teeth were discovered and were stated to have been "..anatomically modern".
References
[edit]- ^ a b Straus, Lawrence Guy (2015-12). "The Human Occupation of Southwestern Europe during the Last Glacial Maximum". Journal of Anthropological Research. 71 (4): 465–492. doi:10.3998/jar.0521004.0071.401. ISSN 0091-7710.
{{cite journal}}: Check date values in:|date=(help) - ^ Clark, Peter U.; Dyke, Arthur S.; Shakun, Jeremy D.; Carlson, Anders E.; Clark, Jorie; Wohlfarth, Barbara; Mitrovica, Jerry X.; Hostetler, Steven W.; McCabe, A. Marshall (2009-08-07). "The Last Glacial Maximum". Science. 325 (5941): 710–714. doi:10.1126/science.1172873. ISSN 0036-8075. PMID 19661421.
- ^ a b c Williams, Alan N.; Ulm, Sean; Cook, Andrew R.; Langley, Michelle C.; Collard, Mark (2013-12-01). "Human refugia in Australia during the Last Glacial Maximum and Terminal Pleistocene: a geospatial analysis of the 25–12 ka Australian archaeological record". Journal of Archaeological Science. 40 (12): 4612–4625. doi:10.1016/j.jas.2013.06.015. ISSN 0305-4403.
{{cite journal}}: no-break space character in|title=at position 120 (help) - ^ a b Stewart, J. R.; Stringer, C. B. (2012-03-16). "Human Evolution Out of Africa: The Role of Refugia and Climate Change". Science. 335 (6074): 1317–1321. doi:10.1126/science.1215627. ISSN 0036-8075. PMID 22422974.
- ^ "Examples of refugia", Wikipedia, 2019-04-16, retrieved 2020-05-23
- ^ "Haida Gwaii", Wikipedia, 2020-05-23, retrieved 2020-05-23
- ^ a b c Hampe, Arndt; Rodríguez‐Sánchez, Francisco; Dobrowski, Solomon; Hu, Feng Sheng; Gavin, Daniel G. (2013). "Climate refugia: from the Last Glacial Maximum to the twenty-first century". New Phytologist. 197 (1): 16–18. doi:10.1111/nph.12059. ISSN 1469-8137.
- ^ Mellars, Paul (2006). "Archeology and the dispersal of modern humans in Europe: Deconstructing the "Aurignacian"". Evolutionary Anthropology: Issues, News, and Reviews. 15 (5): 167–182. doi:10.1002/evan.20103. ISSN 1520-6505.