tag:blogger.com,1999:blog-1228690739485734684.post1556901145263652142..comments2024-03-28T22:13:17.139+00:00Comments on Stonehenge and the Ice Age: The strange valleys of the MendipsBRIAN JOHNhttp://www.blogger.com/profile/00413447032454568083noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-1228690739485734684.post-49730748748027893942011-08-10T20:32:15.681+01:002011-08-10T20:32:15.681+01:00Brian,
Let me clarify my reasoning.
Certainly ...Brian,<br /> <br />Let me clarify my reasoning. <br /><br />Certainly there are many faults and fissures in the rock strata as you well point out. But these are due to pressure stress and shifting of land masses. And they generally are more linear, planar and often somewhat vertical -- distinguishing one 'block' of the strata from the adjacent 'block'. I don't think anyone can argue that the Gordale Scar, for example, is such kind of a fissure or fault. I certainly do not argue this!<br /> <br />But the cracks caused by an intense cold/hot interface will have different characteristics. For example, they would be more on the surface of the strata and not deep into the strata. They will also exhibit a more zigzag pattern than a linear pattern. And they will also be oriented in rather random fashion relative to the land geomorphology. Such cracks in the rock strata will look much like the cracks in a crusty French dinner roll! Not at all like the faults and fissures in your argument to me.<br /><br />I just needed to clarify this very important point. And not leave the wrong impression with your learned readers of an 'unbaked idea'. I think deep and hard any idea I think. But I also think freely and without prejudgements or fear of rejection. These are also the reasons why I am not afraid to admit when I am wrong and change my mind when I am.<br /><br />KostasConstantinos Ragazashttp://knol.google.com/k/constantinos-ragazas/the-un-henging-of-stonehenge/ql47o1qdr604/16#noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-60389652973083029602011-08-10T07:22:38.512+01:002011-08-10T07:22:38.512+01:00When H and K were writing, there was a great vogue...When H and K were writing, there was a great vogue for "overflow spillways" associated with lakes -- but now it is realized that many "overflow channels" were in fact caused bu water flowing either under ice or along the ice edge. Supposed overflow channels flowing in precisely the opposite direction to the ice surface gradient must have more complex origins - and of course subglacial meltwater can flow uphill and over cols.<br /><br />Almost all strata contain cracks and fissures -- they are called faults! If you look at the geological maps of the Mendips, there are hundreds of them -- and many of them have "directed" subterranean drainage and surface fluvial features. You do not need to invoke hot spots in order to explain the presence of faults.BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-69243327016273089312011-08-09T22:49:25.354+01:002011-08-09T22:49:25.354+01:00Brian you write,
“Hawkins and Kellaway do get the...Brian you write,<br /><br />“Hawkins and Kellaway do get themselves into a spot of lather by assuming that the channels are "spillways" or overflow channels related to the drainage of pro-glacial lakes during the deglaciation of the area.”<br /><br />Can't say I know how these channels are oriented, but if these cannot be related to “the drainage of pro-glacial lakes during the deglaciation of the area”, could they perhaps be related to strata cracks due to cold/hot interfaces of an ice cover over geothermal 'hot spots'? <br /><br />Just a thought to think … since drainage flow must conform to the geomorphology of the area while strata cracks do not.<br /><br />KostasConstantinos Ragazashttp://knol.google.com/k/constantinos-ragazas/the-un-henging-of-stonehenge/ql47o1qdr604/16#noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-16894281816519134142011-08-09T20:36:27.129+01:002011-08-09T20:36:27.129+01:00With ref to the presence of Triassic conglomerates...With ref to the presence of Triassic conglomerates in or near the combe, this is what the SSSI citation says:<br /><br />"Geological - The site covers the whole of Burrington Combe and also the limestone sections of its three southern tributary valleys. The Combe is a fluvial karst feature comparable in many ways with Cheddar Gorge but showing a close relationship to geological structure. Sinking streams disappear along the limestone shale boundary and a number of caves are intersected by the gorge. In its lower reaches it partly intersects a buried and filled gorge of Triassic age."<br /><br />This suggests that there was a Triassic gorge, but that it does not coincide with the one we see today.BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-47458327488428523422011-08-09T20:28:41.261+01:002011-08-09T20:28:41.261+01:00Interesting, Tony! Enjoy -- and keep us posted on...Interesting, Tony! Enjoy -- and keep us posted on what transpires!!BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-26495763667809130902011-08-09T20:14:43.972+01:002011-08-09T20:14:43.972+01:00For the record, the Bath & Camerton Archaeolog...For the record, the Bath & Camerton Archaeological Society is running a (fully booked) excursion to Burrington Combe (combined with Stanton Drew Stone Circles) on 11th September, and I am booked on this. The summary information says Burrington Combe contains the entrances to many of the caves of the Mendip Hills, including Aveline's Hole, Sidcot Swallet & Goatchurch Cavern, which show evidence of human occupation from the Bronze Age and before. This will be a 2 hour circular walk in the morning from Burrington to Blackdown Moor, passing some of these caves, which have views to Dolebury Fort and the Bristol Channel.Tony Hinchliffenoreply@blogger.com