tag:blogger.com,1999:blog-1228690739485734684.post3730403533645267014..comments2024-03-28T14:00:12.372+00:00Comments on Stonehenge and the Ice Age: Rhosyfelin -- is it a quarry site?BRIAN JOHNhttp://www.blogger.com/profile/00413447032454568083noreply@blogger.comBlogger61125tag:blogger.com,1999:blog-1228690739485734684.post-19169932462311663562012-12-02T12:57:36.601+00:002012-12-02T12:57:36.601+00:00I cannot now think what the spanner was -it was no...I cannot now think what the spanner was -it was not a bluestone transport spanner I think it was more temporal than spatial. It was a response to some comment in one of the threads.<br />Cannot have been of importance.<br />I quite like the paper and await the time that we know the full Roman remodelling of the Stonehenge Landscape.<br />MMyris of Alexandrianoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-18060164926842934882012-12-01T18:30:16.211+00:002012-12-01T18:30:16.211+00:00The relevance is yet again why import different ro...The relevance is yet again why import different rock types to make rails when you have sufficient quantities of rock already present to complete the task in hand???Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-9365245463720899692012-12-01T11:22:58.391+00:002012-12-01T11:22:58.391+00:00Agree with Geo here -- on having a quick glance at...Agree with Geo here -- on having a quick glance at the paper I don't see any spanner in the works, let alone a big one......BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-68491532999655378312012-12-01T10:06:12.431+00:002012-12-01T10:06:12.431+00:00Myris , I never noticed any evidence based spanner...Myris , I never noticed any evidence based spanners relating to transportation glaciation or even a mention of Rhosyfelin , just some relatively minor changes to the sequence . There was however one comment "stones were probably present at the site from it's inception " Geocurnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-21773983625730030172012-12-01T08:41:23.781+00:002012-12-01T08:41:23.781+00:00I am unaware that anyone who is an ardent cryf qua...I am unaware that anyone who is an ardent cryf quarryman has contributed to Brians site ever. Indeed I know they will not and many do not read the site.<br />Equally I am unaware what Phil's views on the site are but I do think that his suggestions on what data to collect from the face and fallen blocks are important.<br />I fail to appreciate the import of limestone cave scrambling with or without crowbars has to this debate.<br />Bye the bye The new paper in Antiquity rather throws a big spanner in the works.<br />MMyris of Alexandrianoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-4095206092971025612012-11-30T21:06:20.731+00:002012-11-30T21:06:20.731+00:00So those who suggest that Rhosyfelin Crags were a ...So those who suggest that Rhosyfelin Crags were a quarry for the bluestones, are now reduced to using the "argument from authority". Namely the archeos have asked a professional mining engineer to give his opinion of the site based solely on one e:mailed photograph; being a generous sort he has done so. <br /><br />I respect Phil's opinion ( I suspect that he has unexpectedly found himself caught in the middle of an argument he didn't ask for)and there is no problem with this per se, but there is when it is presented as scientific evidence to support a hypothesis.<br /><br />The point I wish to make is as follows. My chums and I have found and explored many kilometers of limestone cave passage within the UK. The exploration of most of these passages has involved the excavation of a considerable quantity of boulders (hundreds of tons). <br /><br />From experience we have found that it is possible to move boulders of >1 ton in weight using little more than a crow bar and a couple of rock rails consisting of the rock we're digging through. <br /><br />When you're excavating hard volcanic rocks and have the debitage to hand, the idea that you'd import soft mudstones as rails is "utter bollocks!".<br /> <br />Alex Gee<br /> Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-14954451735043036382012-11-30T17:54:28.575+00:002012-11-30T17:54:28.575+00:00Myris, Brian et al,
Consider the photo, http://ww...Myris, Brian et al,<br /><br />Consider the photo, http://www.flickr.com/photos/sjorgs/6046643147/ . <br /><br />For such face to have the same “polish” as the NW face of Rhosyfelin, most likely water torrents would be needed.<br /><br />KostasConstantinos Ragazasnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-11262493499496940562012-11-30T15:04:07.496+00:002012-11-30T15:04:07.496+00:00Myris my friend,
I never had the need to have “st...Myris my friend,<br /><br />I never had the need to have <i>“stained tee-shirts with burn holes”.</i> And though words are important, ideas are more so. An amateur like me can, does, misuse nomenclature. But the essential question here is: can an amateur sometimes see something others (even experts, like your past Ptolemaic rulers) may have missed because of blind spots in their theories?<br /><br />If <i>“nothing wet is needed”</i> how do you explain the rounded rock edges of the fallen clutter that intrigues Brian? <i>“well-orientated rock samples and a compass-clinometer.”</i> provide no answers here.<br /> <br />KostasConstantinos Ragazasnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-5865096912532223512012-11-30T11:25:07.634+00:002012-11-30T11:25:07.634+00:00I despair Kostas.
Nomenclature is precisely used ...I despair Kostas. <br />Nomenclature is precisely used so that long elaborate explanations are not needed and everyone knows what is being said. DO NOT misuse it. Science is not some new age, charm-swinging, pot smoking, mix and match past time. (not for me anyway, not anymore, done it and still have the stained tee-shirts with burn holes)<br />Google jointing and foliation. <br />The planar face is a major foliation plane the other planes are jointing. It is all in Ixer and Bevins 2012 the Arch in Wales paper. Also to the trained eye it is in the aerial photo of Craig etc.<br />Sorry to pour cold water on your guesses but nothing wet is needed just well-orientated rock samples and a compass-clinometer.<br />M<br />Myris of Alexandrianoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-48975593440012245452012-11-29T18:05:41.612+00:002012-11-29T18:05:41.612+00:00Brian,
By 'strata' I mean the sections of...Brian,<br /><br />By 'strata' I mean the sections of rock (igneous or any other) between successive fault lines. These 'strata' are clearly visible in all the photos I have seen of Crag Rhosyfelin. Including the photo Chris made of the SE 'hang face'. We also see such 'strata' in all of your photos of the Preseli 'bluestones' overhangs.<br /><br />At Rhosyfelin, these vertical 'strata' are indeed PERPENDICULAR to the NW “polished” face.<br /><br />You can fault my use of this word, but you can't fault my logic.<br /><br />KostasConstantinos Ragazasnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-17158396017469404952012-11-29T16:38:40.308+00:002012-11-29T16:38:40.308+00:00Kostas -- there are no strata here. This is an ig...Kostas -- there are no strata here. This is an igeneous rock, not a sedimentary one. There are fractures and maybe faults -- and one such is the plane away from which the blocks and debris have fallen.BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-83943276711485791762012-11-29T15:22:35.381+00:002012-11-29T15:22:35.381+00:00Brian et al,
I have also seen “clean flat faces” ...Brian et al,<br /><br />I have also seen <i>“clean flat faces”</i> on rock cliffs that I would not attribute to torrents but to other natural causes. What makes the NW face of Rhosyfelin different and interesting for me, however, is the polished flat NW face is PERPENDICULAR to the vertical strata that make up this crag. I can think of no other natural process that can do this so cleanly and effectively than water torrents. The rounded rock edges of the fallen clutter that Brian speaks about and finds very intriguing also point to this conclusion. And MPP, as Brian strongly suggests, better take mind of this 'fact on the ground'.<br /><br />KostasConstantinos Ragazasnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-65943394053580453362012-11-29T14:06:50.055+00:002012-11-29T14:06:50.055+00:00That would be nice -- or even some striae......That would be nice -- or even some striae......BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-67196931012076465952012-11-29T13:54:01.203+00:002012-11-29T13:54:01.203+00:00Pity there are no slickensides on the rock face th...Pity there are no slickensides on the rock face that would have answered that question.<br />Planar polished faces due to natural causes are Brian says are very very common and why restrict faulting to the last 5000 years we have 100s of million years.<br />Remember these rocks occur in volcaniclastics and what do we know about volcaniclastic piles??<br />exactly!in the literature.mnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-70053482691895346172012-11-29T10:28:02.668+00:002012-11-29T10:28:02.668+00:00Re Chris's comment on how clean the rock face ...Re Chris's comment on how clean the rock face is (implying that if it was entirely natural it wouldn't be that clean) I'm not bothered by that at all. If you have a fracture or fault or a bedding plane in sedimentary rocks you can get clean flat faces a great deal more extensive than this one, simply because of the manner in which rocks shear off and fall away from the face of natural weakness. I am aware of similar flat faces all over the place, inland and on the Pembs coast.BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-29989967655028804572012-11-29T10:03:52.699+00:002012-11-29T10:03:52.699+00:00We can't rule out earthquakes as causing some ...We can't rule out earthquakes as causing some rock face collapses -- they can occur at any time almost anywhere, but I would assume that their frequency would have been greater close to the end of the last glacial episode while unloading / isostatic readjustment was still going on. Whether the great pile of clutter beneath the Rhosyfelin rock face accumulated gradually or as a result of one large collapse is an interesting question. my guess is that there was a slow accumulation under a severe periglacial regime. But the rounding of rock edges on much of the clutter as we see it today is interesting, and is something MPP and his friends should be thinking about.BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-86420338664302763492012-11-29T01:41:47.786+00:002012-11-29T01:41:47.786+00:00Chris,
True. The 'other side' of an earth...Chris,<br /><br />True. The 'other side' of an earthquake sheer could be buried. But how do you explain the very rounded fallen blocks that even Brian expressed amazement and intrigue? I don't believe these could have formed in any other way than through torrents of water running along the NW side and “polishing” it. <br /><br />Brian's listed possibilities, whether it be <i>“frost-shattering”, “beneath the Devensian ice”</i> or <i>“plucking and entrainment”</i> likewise can't explain such 'facts on the ground'. <br /><br />So that leaves torrents and the possibility this occurred more recently than Brian believes. My sense is MPP's “quarry” was under water and his “quarry theory” is taking water and will sink!<br /><br />KostasConstantinos Ragazasnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-76337881684479108142012-11-28T19:30:00.882+00:002012-11-28T19:30:00.882+00:00Kostas, I don't want to start a hare running w...Kostas, I don't want to start a hare running without any support, but had the outcrop sheered in the earthquake way then the other side would be metres underground by now and covered by the eroding material coming down from the hill-side, the surface flattened by regular flooding of the Brynberian river.<br /><br />Likely all very fanciful, but I am puzzled by the regularity of this rock face in the middle of an irregular environment.chris johnsonhttps://www.blogger.com/profile/16210890033354730381noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-76011518819579827142012-11-28T16:14:02.901+00:002012-11-28T16:14:02.901+00:00Chris,
I don't believe earthquakes can explain...Chris,<br />I don't believe earthquakes can explain the NW “polish” of Rhosyfelin. Earthquakes will not sheer off a cliff with just one side. There would be a corresponding other side to that sheer.<br /> <br />KostasAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-48928083409121654662012-11-28T14:53:40.211+00:002012-11-28T14:53:40.211+00:00I see today that Brynberian has regular earthquake...I see today that Brynberian has regular earthquakes - every 50 years at 5-6 on the Richter scale. Google points to a post by Jane Tomlinson about a major earthquake in this area but I could not find it - can anyone shed any light?chris johnsonhttps://www.blogger.com/profile/16210890033354730381noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-42944115291724439462012-11-28T14:13:03.047+00:002012-11-28T14:13:03.047+00:00Chris,
I think you have listed some likely scenar...Chris,<br /><br />I think you have listed some likely scenarios for the “polishing” of the NW side of Rhosyfelin. As Brian also has, with his supposition of glacial lake Brynberian. You both have the advantage of being there and seeing the landscape. I can only rely on Brian's photos and descriptions of the land. And what I know convinces me the “polish” was the result of water torrents. The river just off this site, and the immediate contour of the surrounding land (as more clearly seen in the aerial photo Brian posted) all point to this conclusion.<br /><br />As for meltwater being the source for these torrents, I am only guessing. It may have been other sources of water. Like a glacier lake Bryberian draining with great force. Your observations about features of the landscape seem to suggest this. I would also add the very fragile nature of the rock at Rhosyfelin (as reported by Brian) would make erosion of this crag so much faster. So the idea I suggested Rhosyfelin was a much bigger and taller crag at some time in the past seems very plausible to me.<br /><br />I realize the details in what I argue may sometimes be wrong; but not essential to my main reasoning. So I ask you consider the larger argument and not hold me to the not-so-relevant details.<br /><br />KostasConstantinos Ragazasnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-71790980869295096492012-11-28T12:01:54.684+00:002012-11-28T12:01:54.684+00:00Dear Kostas, thanks for answering my question.
Th...Dear Kostas, thanks for answering my question.<br /><br />The idea that the NW face could have been sheered by meltwater seems implausible - the valley does not run in the required direction and nor are there any signs of where it might have gone to after "polishing" the rock face.<br /><br />Following the face away from the river you come to a big hill and I can imagine some of the scree you can see in the photo was deposited during normal erosion.<br /><br />Your idea that the quarry site is susceptible to flooding seems more plausible. The land in front of the face is fairly flat and might well be submerged even today should the river be in flood.<br /><br />I like the sound of Brian's Lake Brynberian. South of the site is a huge natural bowl of land. I suppose he is studying the contours to see where such a lake might have been bounded on the Northern side and where it might have been drained. My guess would be a few miles East where there is a very sharp river valley running towards the Teifi.<br /><br />The Brynberian river does not look to me like it was shaped by catastrophic natural forces although it would be interesting to know how much water it carried in the recent flood.<br /><br />I am interested to know which natural forces are most plausibly responsible for the sheer face on the NW - meltwater is unlikely imhau (in my humble amateur opinion).<br /><br />chris johnsonhttps://www.blogger.com/profile/16210890033354730381noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-26893947659468757132012-11-27T19:04:46.704+00:002012-11-27T19:04:46.704+00:00Brian,
I don't mind being “a bit carried away...Brian,<br /><br />I don't mind being <i>“a bit carried away”</i> as long as I am moving in the right direction! <br /><br />Which of my many presumptions are you disputing? Let me guess! The one about MPP's “quarry” being underwater! Did it remind you of Robert Langdon's biblical inundation? No wonder you reacted!<br /><br />KostasConstantinos Ragazasnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-63938673177841405992012-11-27T17:11:54.522+00:002012-11-27T17:11:54.522+00:00Sorry -- typing error. I meant "a bit carrie...Sorry -- typing error. I meant "a bit carried away." On second thoughts, more than just a bit...BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-71540000562592512992012-11-27T16:01:21.997+00:002012-11-27T16:01:21.997+00:00Kostas -- I fear you are getting a bot carried awa...Kostas -- I fear you are getting a bot carried away here -- not for the first time....<br /><br />Please look at the map. Google will help you.BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.com