tag:blogger.com,1999:blog-1228690739485734684.post1655865613295363958..comments2024-03-28T00:46:01.084+00:00Comments on Stonehenge and the Ice Age: The Waun Mawn quarrying complexBRIAN JOHNhttp://www.blogger.com/profile/00413447032454568083noreply@blogger.comBlogger15125tag:blogger.com,1999:blog-1228690739485734684.post-23258799988746846162018-05-08T18:48:47.424+01:002018-05-08T18:48:47.424+01:00Thank you Rob -- that's very helpful. As you ...Thank you Rob -- that's very helpful. As you said, difficult rock. Next time I go up there I'll try to collect some bigger bits for you!BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-14011282423507887282018-05-08T13:22:21.958+01:002018-05-08T13:22:21.958+01:00I have taken a look at the 6 very small!!! bits of...I have taken a look at the 6 very small!!! bits of rock.<br /><br />The little surface pebble is probably a little bit of a dolerite chilled margin.<br /> <br />The other five are all (I think)meta-mudstone meta-very fg siltstone.<br /><br />I can see why you wanted them to be banded rhyolite but they are too green-grey indicative of chlorite. They are similar macroscopically to the meta-mudstones quarried at Carn Menyn.<br /><br />My guess is they are close to the contact zone of a dolerite body.<br />Mmmmmm<br />Rob Ixernoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-74427103877975036062018-05-03T20:19:31.488+01:002018-05-03T20:19:31.488+01:00It's interesting that lots of people seem to b...It's interesting that lots of people seem to be reading this post -- 242 views so far. Well, that's great -- maybe those of us that have info can share it with each other. I'm quite open to whatever turns up here and whatever it shows -- and just hope that the evidence, when it gets to be unearthed in the autumn, is not all forced into a "proto-Stonehenge" ruling hypothesis..... but MPP's pronouncements thus far do not inspire confidence on that score......BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-33560006239389195142018-05-02T07:54:01.536+01:002018-05-02T07:54:01.536+01:00No les frere Grimme were always quiet on the reaso...No les frere Grimme were always quiet on the reason for the metamudstone quarrying and still are.<br />Axe production is an obvious first suggestion but there is no axe group that fits although there are many 'fit' ungrouped axes. <br />It remains an enigma. Perhaps.<br />GCU:In two minds.GCU:In two mindsnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-28251726066885828352018-05-02T07:52:34.156+01:002018-05-02T07:52:34.156+01:00No les frere Grimme were always quiet on the reaso...No les frere Grimme were always quiet on the reason for the metamudstone quarrying and still are.<br />Axe production is an obvious first suggestion but there is no axe group that fits although there are many 'fit' ungrouped axes. <br />It remains an enigma. Perhaps.<br />GCU:In two minds.GCU:In two mindsnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-84846171331516535602018-05-01T17:16:55.581+01:002018-05-01T17:16:55.581+01:00But the Pembs coast is not short of rocks, Gordon!...But the Pembs coast is not short of rocks, Gordon! They could have obtained -- both in Lower Town Fishguard and in Newport -- thousands of tonnes of broken shale or even boulders and cobbles for ballast, if they had wanted it. Why would they have gone off up into the Preseli Hills to collect rock from the top of a hill?BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-5595561579834870712018-05-01T15:55:47.926+01:002018-05-01T15:55:47.926+01:00If they were building ships they would most certai...If they were building ships they would most certainly have needed rocks for ballast.The Mary Rose had over 100 tons of ballast.The town wall of Kings Lynn has been constructed from re used ballast and contains many types of rock even dolerite.Gordonnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-33005301773898324542018-05-01T14:12:33.978+01:002018-05-01T14:12:33.978+01:00Hey diddy doddy doo -- I meant "did".......Hey diddy doddy doo -- I meant "did".......BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-53322542943572614352018-05-01T14:11:18.511+01:002018-05-01T14:11:18.511+01:00Re the meta-mudstones at Carn Meini, and the suppo...Re the meta-mudstones at Carn Meini, and the supposed "Mesolithic quarrying", as I recall Darvill and Wainwright always were a bit coy on the subject of "Why would they have wanted to dig out rather ordinary flaky slabs of rock from a hole in the ground? Dod they ever express an opinion on that?BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-88230728260258968572018-05-01T14:08:32.116+01:002018-05-01T14:08:32.116+01:00Plenty of shipbuilding at both places. But if the...Plenty of shipbuilding at both places. But if they had wanted ballast, they could have got it easily in the immediate neighbourhood.BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-65069864125845415622018-05-01T12:09:47.439+01:002018-05-01T12:09:47.439+01:00Was there much shipbuilding in Fishguard or Newpor...Was there much shipbuilding in Fishguard or Newport? Ballast? Gordonnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-43454295496386547452018-05-01T11:09:18.360+01:002018-05-01T11:09:18.360+01:00See Carn Menyn Report 2007-2008 on R.Ixer's ac...See Carn Menyn Report 2007-2008 on R.Ixer's academia.edu page; discussion and description of meta-mudstones.<br />GCUGCU:In two mindsnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-44924629229795224212018-05-01T10:59:50.490+01:002018-05-01T10:59:50.490+01:00My guess is they are meta-mudstones but I await th...My guess is they are meta-mudstones but I await the bits of rock.<br />Often a thin section is needed and then sometimes that is not enough and geochem is required.<br />GCU:In two mindsGCU:In two mindsnoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-63208164590830495722018-05-01T10:24:00.965+01:002018-05-01T10:24:00.965+01:00Sorry Rob -- yes, my mistake. I should have said ...Sorry Rob -- yes, my mistake. I should have said diabase.........<br /><br />I really need you to have a look at the rocks from this area -- in trying to work out what they are, I flip between thinking they are light-coloured mudstones (very unlike the black ones found in other parts of the Ordovician), or meta-mudstones, partly converted to slate by proximity to dolerite intrusions, or volcanic ashes, or rhyolites. Maybe all of these are present -- I would not be surprised..........<br /><br />I shall send some fragments for you to have a look at! As you say, these are not easy rocks.BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-15060920722652388252018-05-01T06:18:03.082+01:002018-05-01T06:18:03.082+01:00Dolerite is now called microgabbro. It is not the ...Dolerite is now called microgabbro. It is not the same as diorite that is a totally different rock with a totally different chemistry and mineralogy. You probably meant to say diabase a term not used in British geology for nigh on a century.<br />Diorites are uncommon but pretty rocks.<br /><br />Note that at the dolerite country rock junction at Carn Menyn there are small quarries in the metamudstone. Sounds similar.<br />In one of the SPACES reports.<br /><br />You should have a professional geologist identify the rocks, these are not easy rocks.<br /><br />GCU:In two minds.<br />GCU:In two mindsnoreply@blogger.com