Why did people fix stone tips on spears and arrows? Good question. What was the advantage over sharpened wood?
South African researchers have been experimenting on what were the advantages of stone tips. Wooden shafts can of course break – but having stone tips would not prevent that. I must admit this is something that has passed my mind on occasion. Attaching a stone tip to a wooden shaft is not exactly easy and must have taken a great deal of experimentation. It is normally assumed that the weight of the stone tip led to greater penetration. The researchers found this is not so. What they did was create a wider wound, and in a big animal that was an advantage. Go to http://phys.org/print328366421.html
Researchers have taken a new look at sea levels in the Late Pleistocene and how they might have affected human migration patterns – see http://phys.org/print328341297.html … the western coast of N America may have been quite different, especially the continental shelf around Alaska. Sea levels during the Late Glacial Maximum, around 20,000 years ago, are thought to have been 430 feet lower than present. We might ask – is this figure calculated from the amount of water that was locked up as ice during the last Ice Age? This is an interesting calculation as we don't really have the evidence to say the ice sheet was as extensive as imagined. In spite of this the researchers have played around on their computers, and keyed in various other factors, such as rebound, and in addition, the effect of greater water on the ocean basin. All very admirable but really just another projection made from an assumption – the northern hemisphere as a whole, and N America in particular, was covered by a huge ice sheet. What if the polar ice cap had moved – and was centred somewhere off Greenland. This would, for example, account for the colder temperatures during the last Ice Age, as recorded in Greenland ice cores. It would also explain the change in sea levels – in some localities. Unsurprisingly, they tell us the sea level did not rise uniformly.
The paper was published in the Journal of Archaeological Science and the research was prompted by evidence sea level did not rise at the same rate at any given location. Or that is the impression given. Perhaps that too is an artifact of the modelling. This kind of research sometimes seems too good to be true. By tweeking the sea level modelling they are saying that off Oregon the continental shelf remained dry land for a considerable period after the end of the Ice Age. Hence, humans could have migrated south by using this now submerged landscape – which is of course all a little convenient. What they fail to face up to is that humans could well have been in N America prior to the end of the Ice Age, mainly because the ice cap was centred on NE N America (rather than uniformly across the whole continent). In other words what we have here is another explanation in order to keep Clovis First in focus (with a few alterations such as a slightly earlier influx). This consensus is really hard to budge. People are mesmerised by Clovis First and cannot get their heads outside the parameters of humans entering the Americas after the Ice Age – instead of within it.