Denisovan is the name given to an extinct sub-species of hominid(a). Their name is derived from the Denisova cave in the Altai mountains of Siberia. Only fragments of four individuals have been identified so far. While the first Denisovan remains were found in Siberia, there is now evidence that they were the earliest hominins on the Tibetan Plateau (b).
It has also been determined that they interbred with Neanderthals, a sister race.
It did not take long for the speculative history brigade to jump on this new bandwagon. Andrew Collins has now prepared for publication The Cygnus Key in which he claims to present “compelling evidence showing that the earliest origins of human culture, religion, and technology derive from the Denisovans, the true creators of the lost civilization long known to exist but never before proved.”
*In 2019, Collins co-authored Denisovan Origins  with Greg Little in which they combine their speculative abilities to produced a full book on the physical and intellectual attributes of the Denisovans, based on a few bone fragments! The book received the imprimatur of Graham Hancock, so the collective name recognition value of Collins, Hancock and Little should boost sales. Jason Colavito has critiqued this volume(c), highlighting the amount of dubious material that the authors have previously published is included in this offering.*
This comment is nearly identical to that expressed by the late Colin Wilson relating to the Neanderthals whom he claimed had possessed highly sophisticated mathematical and astronomical knowledge and were precursors of the Atlantis civilisation. This extremely speculative assertion is made in Wilson’s Atlantis and the Kingdom of the Neanderthals.
Ice Dams were not uncommon following the ending of the last Ice Age. Glacial Lake Missoula in North West America has been estimated to have burst out every fifty years or so over a two thousand year period between 13,000 and 11,000 BC. These events are dealt with in detail by David Alt in his Glacial Lake Missoula. Lake Agassiz was another enormous lake formed by glacial run-off after the last Ice Age and at its maximum extent was larger than any lake existing in the world today. There is evidence that Lake Agassiz like Missoula also breached ice dams from time to time, discharging into the Atlantic. Other large and frequent breaching of ice dams occurred in the Siberian Altai Mountains(c)(d)(e). A USGS report listing the largest of these events is available online(b).
Recent reports(g)(h)(i) claim that around 6200 BC the bursting of an ice dam in Canada released the melt water contents of Lake Agassiz and Lake Ojibway into the North Atlantic that resulted in Greenland being cooled by an average of 7.4ºC and Europe by about 1ºC and raising the global sea level by between one and three metres (3-10 feet).
Equally dramatic was the extent of the flooding in Eurasia following the collapse of north Asian ice dams. Ronnie Gallagher has an interesting article about this on Graham Hancock’s website(a). Gallagher favours a Eurasian location for Atlantis.
*Professor Neil Glasser from Aberystwyth University is the lead author of a report published in 2016 in Scientific Reports, in which the breaching of an ice dam in South America, between 11,000 and 6,000 BC, was on such a scale that it altered the circulation of the Pacific Ocean. Glasser noted(f) that: “This was a massive lake. When it drained, it released around 1150km3 of fresh water from the melting glaciers into the Atlantic and Pacific oceans – equivalent to around 600 million Olympic-sized swimming pools. This had a considerable impact on the Pacific Ocean circulation and regional climate at the time.”*
(c) http://www.ica.csic.es/dpts/suelos/hidro/images/chapter_27_phefra.pdf (offline 1/6/15)
(g) Science – Dec. 22, 2000
(h) Proceedingsof the National Academyof Sciences – DOI:10.1073/pnas.0510095103]
(i) Quaternary Science Reviews –vol 25, p 63]