Posted by Andy Clayton on August 22, 2013 at 05:55:23 user cousin_jack.
In Reply to: Re: Dick’s green rushes – what were they? posted by Tom Napier on August 22, 2013 at 05:41:07:
Down in Cornwall the granite bosses intrude into shale rock, called 'Killas' locally. So we have the deep metal mines and the Delabole slate quarry. Like the lakes, it's mostly gone now.
The transitional rocks are metamorphic.
Certainly the two examples are close. I'm not that familiar with lakes geology, but I believe the whole area has been domed up by intrusive activity, giving the radial pattern to the lakes and drainage, and laying down the copper deposits.