tag:blogger.com,1999:blog-1228690739485734684.post5359449377791006607..comments2024-03-28T22:13:17.139+00:00Comments on Stonehenge and the Ice Age: Another mystery erratic from AbermawrBRIAN JOHNhttp://www.blogger.com/profile/00413447032454568083noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-1228690739485734684.post-31441875996026268022014-10-05T08:47:39.687+01:002014-10-05T08:47:39.687+01:00Whoops their not there, written bct,
Before croiss...Whoops their not there, written bct,<br />Before croissant time.<br />MMyris of Alexandrianoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-62983737702715106092014-10-05T07:52:51.041+01:002014-10-05T07:52:51.041+01:00Mmmmmm, the first erratic could be a porphyritic.
...Mmmmmm, the first erratic could be a porphyritic.<br />Lambay Island has an axe quarry I think the only convincing one in the Irish Free State.<br />The Northern Six have the famous Rathlin Island and Tievebulliagh (spelling?)IPG group IX quarries.<br />In the British Isles Group IX is the largest group.<br />M<br />Maybe it is not an erratic but a lost traded roughout.I know that despite the main belief here, some axes were anthropogenically transported from their origin to there find spot.<br />M<br />Myris of Alexandrianoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-31603851491246417182014-10-04T18:58:14.157+01:002014-10-04T18:58:14.157+01:00Were you a mycologist would you say the same thing...Were you a mycologist would you say the same thing.<br />I am trying to avoid getting colic.<br />We are not dealing with simple rocks<br />but the unusual and non distinctive.<br />As my old friend would say there is only one truth.<br />M<br />Myris of Alexandrianoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-9215647988594149552014-10-04T18:48:41.013+01:002014-10-04T18:48:41.013+01:00Thin sections are all very well if you are a petro...Thin sections are all very well if you are a petrologist intent on publishing a peer-reviewed paper on something or other. But generations of geologists have had to learn to identify various rock types from hand samples with a lens giving 8x magnification or whatever. The hammer and the acid bottle also come in handy. For example, in Pembs I'm reasonably confident that I can identify most lumps of rock and make a reasonably intelligent guess as to which part of the county they might have come from -- and in cases such as that, 100% accuracy does not actually matter. Sid, for example, knows his stuff from long experience! Horses for courses.<br />BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-31005250411037679452014-10-04T18:41:27.511+01:002014-10-04T18:41:27.511+01:00I was not suggesting asking for a photo identifica...I was not suggesting asking for a photo identification is foolish but that anyone responding with a definitive answer is daft.<br />M<br />Myris of Alexandrianoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-77000535920612941282014-10-04T18:38:22.907+01:002014-10-04T18:38:22.907+01:00It starts and ends with thin sections
The trouble ...It starts and ends with thin sections<br />The trouble with photos is they are deceptive.<br />Macroscopical identification is also fraught with difficulties, even experts are only correct 70 80 per cent. <br />To rephrase an opening line. No identification (provenance) is better than wrong identification (provenance).<br />Charlatans come in all shapes, sizes and persuasions. They can be recognised by always being correct<br />despite being corrected.<br />M<br />Myris of Alexandrianoreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-49561809313756313702014-10-04T14:44:34.357+01:002014-10-04T14:44:34.357+01:00First photos, then hand specimens under a hand len...First photos, then hand specimens under a hand lens, and then thin sections. It all has to start somewhere, preferably in the hands of fools rather than charlatans.BRIAN JOHNhttps://www.blogger.com/profile/00413447032454568083noreply@blogger.comtag:blogger.com,1999:blog-1228690739485734684.post-67804332163044079442014-10-04T13:54:34.258+01:002014-10-04T13:54:34.258+01:00Again identifying rocks from photographs is for fo...Again identifying rocks from photographs is for fools.<br />However it is not spotted dolerite.<br />The alteration spots are round, these are angular.<br />M<br />Myris of Alexandrianoreply@blogger.com