Yorkshire Lad
New member
Not with my thumbnail, but scratched it with a bit of gravel.
Geological Pics - Post any interesting photo here
- Thread starter BertyBasset
- Start date
Yorkshire Lad
New member
so this is a photo I took last summer in an old quarry near Mylor Creek in Cornwall, I have been wondering for some time as to what it maybe. I don’t know if it’s obvious, but it’s a mineral vein running over base rocks.
I suppose the obvious question is, why were they quarrying here? Were they looking for this mineral or was it that they wanted the rock and we’re discarding the minerals?
If it’s any help the grid ref of the quarry is: SW 812 357
Have you checked on the BGS website ?
The quarry is in the Porthleven Breccia Member of Devonian Age. God knows what they'd be quarrying from that. I'm not convinced that's a vein per se, but it certainly looks like a bit of a crush zone or fault. We need someone with a bit more rock info on this one!
Yorkshire Lad
New member
Here’s another photo from the same location, again strange geological occurrence
Looks like Britannia Mine stuff.
Yep know that one well. I grew up in Harrogate and Knaresborough was where i started to get interested in proper geology walkiing along the gorge with parents on a Sunday outing. The Cadeby Formation is Yorkshire is one of my private research topics looking at the associated mineralisation within the Formation.
Just folded as part of the roof fall deforming the soft shales. Disseminated Pyrite in the shales chemically reacts in contact with air and water producing Ferrous Sulphate , a mineral called Melanterite which are the brown areas. The process also forms sulphuric acid which reacts with any calcium carbonate in the shales to produce gypsum - the white mineral on the right hand side of the photo. The disruption of expansive minerals forming weakens the roof layers and they peel off.
Several coal mines used to mine and sell the iron sulphate which was colloquially named copperas.
We've got a couple of examples in the databse -
We've got a couple of examples in the databse -
I thought it was just me
at Easter I was in Knaresborough, performing the touristic tedium of over busy main car park, tea and slice of cake in Riverside cafe, then up steps to the castle -- all the time wishing I was doing something more worthwhile and subterranean. However Mrs cantclimbtom and accompanying friends are very much cake not cave. Anyhow... I got told off for overly admiring the rocks by the river and up to castle not noticing the boats etc. Didn't get chance to look that closely but there's some variety there, not all of one type. Immediately obvious that it's somewhere interesting geologically
AR.
Active member
Missing one, I think - there's the remains of a Copperas works at Ringinglow to the west of Sheffield at SK 2934 8340,. I've a feeling it's listed, I'll have a look on Magic.
AR.
Active member
Not listed like I thought, but there's a photo of it on the wikipedia page for copperas works - https://en.wikipedia.org/wiki/Copperas_works . There are good remains of the settling tanks to the rear of the building.
I'll add an entry when I have a bit of time!
Thanks.
Thanks.
Yorkshire Lad
New member
Not only are the rock interesting at Knaresborough, but further up the gorge, are the remains of Medieval Coal Mines along Bilton Banks, and just before you get to Ripley some old limestone quarries.I thought it was just me
Yep remember visiting them. Then there is the cave at Old Mother Shiptons with the petrified items sitting in the spring flow.
Yorkshire Lad
New member
Haven’t been there in an age… gotta pay to go in!
I was recently privileged to see some amazing layered sediments in a mine level in the Alston Moor area - I was entrusted to be discrete about location. But this is amazing - trying to imagine the processes that created this is difficult! I am pretty sure this is not ground movement - I think this is the mudstone, or whatever, as exposed in the level.
Nice. That seems to show several cyclical episodes of deposition, deformation and erosion. It's presumably deltaic and some of the layering might be cross bedding as opposed to 'true' beds. There's definitely deformation - that white 'marker' layer's been almost overturned at the top - and that's before to 'top' layer's been deposited.
