An Alaska 'big wave' event at the end of the Pleistocene?

19 Feb 2012

Over at http://cosmictusk.com/alaska-big-wave-at-12900/ there is the claim of a huge tsunami wave at the YD boundary - or thereabouts, with some nice Native American artwork to kick it off. Deposits of sea shell and other oceanic detritus found in the Juneau area stratigraphy seems to have been washed ashore from a wave rather being laid down over time. The consensus opinion seems to be that the area was once beneath the sea - a common geological definition whenever sea creatures are found in what are now land-bound locations. The explanation here is interesting as consensus claims the region was pressed downwards as a result of glaciation during the Ice Age. However, there were no glaciers in this part of Alaska during the Late Glacial Maximum - or during the period between then and the YD event. So what is going on?

George Howard did a bit of snooping and came up with a paper from way back when - the late 19th century (see http://gsa.confex.com/gsa/2007AM/finalprogram/abstract_131294.htm ). The post continues 'Marine shells at the Pleistocene-Holocene boundary at Juneau, Alaska' (which is a little confusing as the Pleistocene is generally taken to include the YD event, all 1300 years). However, it too claims there was no glaciation in that part of Alaska in the period leading up to the YD event. The interesting aspect in this discussion, as far as SIS might be concerned, it that a tsunami wave could also have been responsible for the Alaskan muck deposits, in various river valleys of interior Alaska - but did the muck accumulate as late as the YD boundary? As attractive as this idea might be it is more than likely the muck was laid down a couple of thousand years earlier than the Juneau layer - but then, was the tsunami at Juneau also somewhat earlier and the link with the YD boundary a red herring?