tag:blogger.com,1999:blog-1228690739485734684.post9094324674851798921..comments2024-03-28T00:46:01.084+00:00Comments on Stonehenge and the Ice Age: The South Pembrokeshire problemBRIAN JOHNhttp://www.blogger.com/profile/00413447032454568083noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-1228690739485734684.post-27946834193437591832016-11-15T11:36:47.246+00:002016-11-15T11:36:47.246+00:00The high Arctic is not the best sort of environmen...The high Arctic is not the best sort of environment for big glaciers / ice caps / ice sheets to develop. Not dynamic enough. In the big glacial episodes, parts of the high Arctic are so cold and dry that there is insufficient snowfall to maintain glaciers -- so there are "Arctic deserts" and tundra instead. Further south, around 55 deg to 60 deg N, where winds are coming off an ice-free ocean, vast amounts of precipitation can cause ice sheets to grow quite rapidly, especially when positive feedback mechanisms come into play. But you can get arid and ice-free areas on the lee side of these big ice masses too.<br /><br />Most people think that most of Alaska was ice free during the Late Wisconsin glaciation. What is of greater interest to us is the "driftless" area of the American midwest, which may or may not have completely escaped glaciaton!BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-56385686440795003352016-11-15T11:00:04.645+00:002016-11-15T11:00:04.645+00:00I was looking at The Incredible Human Journey - 5....I was looking at The Incredible Human Journey - 5. The Americas, on Iplayer. <br /><br />Alice Roberts was discussing the Devensian glaciation of Canada and Alaska and showing a graphic of its extent. Obviously this was very generalised, but it showed the northern edge of the Alaskan archipeligo as ice free. Is this so? I'd have thought it would have been completely covered and the Bering Strait one block of ice. There may be some reason for this as opposed to a dumb graphic artist.<br /><br />DaveDave Maynardhttps://www.blogger.com/profile/14162915474983638825noreply@blogger.com