Lida Ajer

12 Aug 2017

At https://phys.org/print421573007.html ... human teeth from a cave on Sumatra has been analysed and it seems they date back over 60,000 years ago. This date supports recent findings that Aborigines were in Australia at least as early as 65,000 years ago. The evidence that modern humans, or people identified as modern humans by their teeth, has led to a revision of when these same people would have left Africa, their assumed place of origin. There are, however, some oddities in the report. The Lida Ajer cave is in the highland zone of Sumatra, a long way from the coast. It is assumed early humans migrated along the coast of SE Asia even though we have evidence of proto Austronesians (Denisova) in central Asia at an early period. Sediment from the cave floor is said to show Sumatra was a tropical rain forest environment at the time - and the teeth date from sometime between 73,000 and 63,000 years ago. Hence, from this we may assume modern humans were in SE Asia before these dates - possibly a long time before this. However, the researchers appear to ignore the fact Sumatra was part of Sunda Land up until 8000 years ago. All they say is that sea levels were lower - but nobody knows what the sea levels were 70,000 years ago - it is a projection of sea levels on the assumption Ice Ages lock up water as ice and interglacials melt ice and sea levels drop - but as we have seen, sea levels rose dramatically 8000 years ago and drowned most of what had been Sunda Land. If sea levels can change dramatically in the middle of an interglacial might they also fluctuate wildly during the last glacial episode?

William sent in another link on a similar topic - got to https://eos.org/articles/indonesian-cave-reveals-nearly-5000-years-of-ts... ... which concerns sediments from Aceh Province which have a record of tsunami waves striking Indonesia over the last 5000 years