Homo erectus - and boats

19 Aug 2011

The Boston Herald had an interesting story, possibly a rehash of something from last year, on Homo erectus and discovery of stone tools on Crete, the large island in the middle of the Mediterranean/Aegean (see www.bostonherald.com/news/international/general/view.bg?articleid=135915...). Researchers say human ancestors were crossing the Mediterranean Sea at least 130,000 years ago, a claim based on stone tools found on Crete. This island, it is alleged, has been cut off from the mainland for 'eons' - whatever the reporter concerned may mean. These stone tools were so old they predate modern humans and apparently belong to Homo erectus and examples exist in North Africa from as early as 700,000 years ago. The inference is that Homo erectus crossed the water, by boat, in order to reach Crete - which doesn't sit well with the idea that Homo erectus was rather backward (more so even than Neanderthals). A geologist was consulted as some of the tools were embedded in ancient beach sands (a rock formation) possibly as a result of ancient tectonic activity - or most probably so. Nowadays these beach sands are found hundreds of feet above the present shore line - and it is thought that Crete is being pushed upwards out of the sea by tectonic activity as a result of the African plate grinding up against the Eurasian plates. The beach lines are preserved as terraces along the coast but exactly why is unclear as the process is ongoing at half an inch a year (in geological terminology) per the theory of gradualism that dominates geological think (academically at least). Fossil beaches are preserved as terraces along the coast, much as terraces were formed along the Thames valley in Britain - and roughly of the same date. Exactly why is unclear as the process is thought to be ongoing and continuous - slower than fingernails grow according to the imaginative reporter. The lower terraces were C14 dated to around 40,000 years ago, which is just about at the C14 threshold. They were dated by seashells and the upper terraces, where the stone tools were found, were calculated by measuring the difference in the beach elevation - at the rate of half an inch per year. As a consequence the upper terraces with the embedded stone tools were dated to around 130,000 years ago - but this is smack in the middle of the last interglacial episode. What is missing from the estimate is always as interesting as the study itself and in that respect it is the possibility that elevation, on occasion, might have taken place more rapidly and catastrophically - creating the terraces, or former beach lines. While this suggests that indeed Crete was an island - why else would there have been beaches, it doesn't actually encompass all the possibilities as far as sea level changes are concerned. The conclusions of the research involve a C14 date that is notoriously difficult to pinpoint - anywhere between 40 and 30,000 years ago, and extrapolates a rate of uplift that is conjecture and avoids any possibility of changes in the shape of the geoid as a result of non-uniformitarian processes. In fact, in spite of all this they still come up with a surprisingly early date for Homo erectus on Crete as their tools in North Africa are one of the mainstays of archaeology of the Palaeolithic, established over a hundred years ago - and they are much earlier in date. Why should this be so. The Eemian Interglacial is itself a subject where a large dollop of speculation is in order - as it relies on essentially the 100,000 year Milankovitch cycle, small changes exerted on the earth's orbit around the sun by the other planets in the solar system, in particular the larger gas giants. In many ways this cycle is reminiscent of the Rhodes Fairbridge cycle of the sun around its barycentre - and not too far adrift in time value (and also involves the larger planets of the solar system exerting an influence - on the sun). Hence, are we quite sure there was a 100,000 year cycle of Ice Ages, or an Eemian interglacial where it is postulated to exist (in the passage of time). An Eemian warm period did exist, as far as western Europe was concerned, but the question is when - and how.