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You didn't see me climbing!

@@OneMinuteGeology If that lot fell, you would be oozing, not climbing. It looks just like a deadfall trap.

I've been watching these from the USA for a couple of years. You have great geology over there. It's just that it rains all the time😂

Yes, there are loads of classic sites. The problem is we are normally on our way somewhere else.

@@mikelong9638 true, not quite always. But at least we don’t have rattlers.

@@OneMinuteGeology You had to mention that!

I do offer guided geology days in the UK. Are you UK based?

They are a type of slickenside (or in modern terminology fault-plane lineations - I prefer the old slickenside). There are two main types of FPL - aligned crystals and gouge-type FPLs. These are aligned crystals, which have the sense of roughness as described here. The gouge-type FPLs have the opposite sense of roughness (and since slickenside means 'polished surface' in the original German) they are possibly 'true slickensides'. So you have to be a little careful when determining fault kinemantics from these features. As always, it is a bit more complex....

Thank you, for today lesson.

Yes. Technical term meaning 'with hints of blue colour', as in 'bluey-grey'.

Hah, Great! I guess the seafloor is quite rugged off the Point - do Cod like nooks to hide in or are they more open water fish? I remember fishing with my uncle out of Carnoustie as a lad and one side of the boat being super abundant for a spell of half an hour or so, but the other side catching nothing. We assumed the line had found a crevice in the seafloor. But I don't remember what fish we caught.

Cheers, Glad you liked it!

Glad you like them.

Good afternoon from Japan, via China! Watch this space for a few non-UK vids in the coming months

The closure of the Iapetus ocean started around 450 Milion years and by 300 million the collision was pretty much over - but yes, that was the event which brought N America and Eurasia together as part of building the Pangea supercontinent.

yes they are - often at the surface.

the films of the cut cut together well. Hope you are all well as well.

Thanks Mike.

Ah yes, the Old Red Sandstone has plenty of iron in it.

Thanks for your concern. I was with the mine custodian so in very safe hands.

Yes indeed!

SO glad you liked it. Thanks.

😀😀😀 Hope you are enjoying the mountains!

Thank you so much. Glad you liked it.

Yes, While Skolithos is a generic term for vertical burrows which covers a wide range of geological time, I guess yours are similar age in rocks deformed by the Appalacian Orogeny? Glad you like the vids.

It took a bit of explaining but the cameraman got the idea in the end

These trace fossils aren’t great for dating rocks as they occur across a wide range of time. But in this case it is their very first appearance at the start of the Cambrian. Around 550 million years ago.

The peaks around here are around 1100 m altitude here on the ridge we are around 800 m.

Thanks for the question.. as I understand it opal forms during diagenesis - as sediments consolidate to turn into rock. That occurs at really low pressures and temperatures 100s of m to a few km of burial depth. This milky quartz is metamorphic, requiring burial to at least 10 km depth - probably much more.

Cheers. I was just at Cligga Head a couple of weeks back where there are some great Tin-Tungsten greisen veins. You saw my old vid on Cligga?

@@OneMinuteGeology Thanks. I'll catch up soon. We've some splendid examples of Sn/W/Ta mineralisation here as well.

@@lineinthesand663 ruclips.net/video/Ep4nJhhvCvg/видео.html

@@OneMinuteGeology Remiss of me. So I had seen it and commented.

I’m sure Joe will be chuffed.

Cheers Will.

Yes indeed! The geological past stretches back a looong way.

👍👍👍

Hi, I'm not entirely sure I understand your question. But I think the answer is (probably) maybe not if I am interpreting it correctly. The model ends up forming these fold systems sequentially, but it is just a very simple model with totally different flow physics and boundary conditions from the Earth. In real world systems you can get several fold and fault systems developing concurrently (although strain weakening rheologies tends to cause one fault to dominate at any given time, this isn't so true for folding). Once you are into fully ductile regimes (say lower crust or even the mantle in somewhere like Ronda) there is a continuum between distributed ("fold-like") and locallised ("fault-like") deformation, but you still produce structures with a nappe-like geometry. Does that help?

Glad you like it!

Elton mine in Derbyshire, England

Ecton mine, not Elton mine - autocorrect strikes again

Thanks sir

Thank you! Glad you like it.

Hi Mike, The Cornish granites were emplaced into the deep upper crust/shallow mid crust (perhaps 5-10 km depth) - the cuntry rock is Mylor Slate which shows extensive ductile folding but is only metamorphosed to greenschis facies (hence my estimate of 8+/- km). There is contact metamorphism - we commonly see quite extensive zonbes where the slate contains the low-P, high-T form of Al2SiO5 (Andalusite) and also cordierite, a magnesium-aluminosilicate mineral. I am actually writing this from Perranporth where there are great examples of cordierite 'spotted' slate - will record a video. The strange thing is granites are quite cool melts (around 700 C) compared to say basalt (1200 C) but the contact metamorphism is much more extensive around granites. This comes from 2 factors - granite bodies are large (so cool down slowly) and granitic melt is very wet and the water which is exolved as the granite crystallises enhances reaction rates in the surrounding rock.

@@OneMinuteGeology Thanks for taking the time to answer this. Please keep your videos coming.

Hi David, geologists borrowed the term from mining. Stoping is a way to follow a near-vertical seam. You drive a tunnel along the seam and then cut into the ore above and let it fall into the ore bucket - it is quite efficient as it saves having to lift the ore back up from the tunnel floor and was the preferred method in pre industrial mines in the UK. The method was called overhand stoping. Geologically it carries the idea that intrusions into the roof of a magma chamber can allow the country rock to fall into the magma, displacing an equal volume of magma upwards.

Andesite is intermediate between granite/dacite and basalt, so has lower silica than granite and dacite. Dacite has similar silica to granite, but lower potassium and higher calcium. So one way to produce dacite is to crystallise an andesite, preferentially removing mafic components as pyroxenes/ amphiboles and enriching the melt in silica.