How much do we know about Stonehenge? Less than we think. And what has Stonehenge got to do with the Ice Age? More than we might think. This blog is mostly devoted to the problems of where the Stonehenge bluestones came from, and how they got from their source areas to the monument. Now and then I will muse on related Stonehenge topics which have an Ice Age dimension...
THE BOOK Some of the ideas discussed in this blog are published in my new book called "The Stonehenge Bluestones" -- available by post and through good bookshops everywhere. Bad bookshops might not have it.... To order, click HERE
Friday, 1 October 2021
Raised beach ridges in Bathurst Inlet, Arctic Canada
Now this is the sort of thing that brings great joy to an old codger like me, having spent to much of my research life pondering on the wonders of raised marine features on coasts subject to isostatic recovery.........
Would you like to indicate the different features on these images? I always find it difficult to know which is the base or top of raised beaches, although a close examination will always help.
Dave -- regular shingle or pebble ridges like this can't really be anything else than beach ridges, either associated with a lake shore or a sea shore. They need to be horizontal of course. If you look at them closely you usually find that the finer sediment fractions have been washed out. You can also find raised delta terraces in places where there was a plentiful sediment supply during isostatic uplift. In Greenland in 1962 we studied a huge "raised delta staircase" with terrace "steps" all the way up to 101m above sea level. The best raised beach ridges tend to be in embayments. On exposed headlands you may find a "washing limit" which represents the highest shoreline -- with undisturbed till or slope deposits above the line and "washed material"m from which the fines have been removed down below. Hills with caps of undisturbed till above the marine limit in Sweden are called "kalottberg" summits. You can find plenty of other posts on this blog by using the search facility....
I found it on Wikipedia, covered by a Creative Commons license for free use. No photographer was credited, but on doing further digging it looks as if the person who uploaded the pic was PD Tillman or Mike Beauregard...........
5 comments:
Would you like to indicate the different features on these images?
I always find it difficult to know which is the base or top of raised beaches, although a close examination will always help.
Dave
Dave -- regular shingle or pebble ridges like this can't really be anything else than beach ridges, either associated with a lake shore or a sea shore. They need to be horizontal of course. If you look at them closely you usually find that the finer sediment fractions have been washed out. You can also find raised delta terraces in places where there was a plentiful sediment supply during isostatic uplift. In Greenland in 1962 we studied a huge "raised delta staircase" with terrace "steps" all the way up to 101m above sea level. The best raised beach ridges tend to be in embayments. On exposed headlands you may find a "washing limit" which represents the highest shoreline -- with undisturbed till or slope deposits above the line and "washed material"m from which the fines have been removed down below. Hills with caps of undisturbed till above the marine limit in Sweden are called "kalottberg" summits. You can find plenty of other posts on this blog by using the search facility....
Take a look at this:
https://www.youtube.com/watch?v=8JVcEc95dSM
You don't really need to understand Swedish.....
Hi Brian, did you take this photo yourself? If not, do you know the source? Thanks!
I found it on Wikipedia, covered by a Creative Commons license for free use. No photographer was credited, but on doing further digging it looks as if the person who uploaded the pic was PD Tillman or Mike Beauregard...........
https://en.wikipedia.org/wiki/Post-glacial_rebound#/media/File:Rebounding_beach,_among_other_things_(9404384095).jpg
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