The Geology of The South West of England.

[Mike Smith Cosmos]

I have just started a Geology Group in the South West of England in EXETER . It is part of The University of the Third Age. We are enjoying ,in the initial weeks , seeing how Devon and the south west of England fit into geological history. I am not a Geologist but am enthusiastic for understanding of our Earth and the processes behind its formation.

 

One of our members expressed the desire to know the setting of Geology of the Earth, as a whole, whats it all about Rocks,? Volcanoes,? Earthquakes,? Going out into the Field with a hammer?, or what ?,

 

Its easy to plunge into specific detail of areas of Geology. But they are asking ' Whats it all About. ?

 

Does anyone have a nice 'Succinct way' ( having had time on your side to get to grips with what its all about ) of explaining What Geology is all about ? This is so that we can discuss it in our meetings.

 

 

 

 

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Exeter is a few miles from where I live. As the above simple map shows some of geological surface rock strata that are within easy reach , easy access, so we can go on field trips, which we will start shortly. But they would like a succinct explanation of the setting of it all , before we get bogged down in details. ( Rocks, fossils, eras, millions, billions of years ago.)

 

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Hi Mike, I was using my favorite geology tool, Google Earth, and found your area fascinating. That Dartmoor National Park is interesting, I'm trying to figure out if it has some volcanic origin going way back, probably not. It makes our rocks look like they were made yesterday. See you on line. Marc

P.S. My other favorite tool is Geomapapp.

I do not know too much about it yet, but a local young research archeologist / geologist who said there was evidence of lava flow locally . We must go and see. This does show the need the group has for an overall setting .

Edited April 7, 2013 by Mike Smith Cosmos

[arc]

Hi Mike,

 

Great idea, here's two Geomapapps images we can use with proper credits.

The first is 2-D with the Dartmoor National Park in the center showing its topographical shape.

The second is a 3-D with a nice angle that picks-up the orientations in the terrain.

 

Images above were furnished through and in no way endorsed by://www.geomapapp.org using Global Multi-Resolution Topography (GMRT) Synthesis, Ryan, W. B. F., S.M. Carbotte, J. Coplan, S. O'Hara, A. Melkonian, R. Arko, R.A. Weissel, V. Ferrini, A. Goodwillie, F. Nitsche, J. Bonczkowski, and R. Zemsky (2009), Global Multi-Resolution Topography (GMRT) synthesis data set, Geochem. Geophys. Geosyst., 10, Q03014, doi:10.1029/2008GC002332.

[Mike Smith Cosmos]

Hi Mike,

 

Great idea, here's two Geomapapps images we can use with proper credits.

 

Marc

Great Pictures of Devon and Sw England. If you zoom in you can probably see me at the computer I will Wave !

 

Give some words of an introductory overview of Geology , as we can go forth into the subject and the field in the south west.of England . Remember the University of the third age ( means People over 50 years old. )

 

This is your moment to change peoples lives !

Edited April 7, 2013 by Mike Smith Cosmos

[arc]

I think that should be done by someone who has the formal education in these matters. I'm just a novice, an enthusiast. What I'm familiar with is mainly in the western U.S. and limited to my own personal interests. I'm hoping Ophiolite and others will contribute to this field trip. This area looks complex because of the multiple geologic periods that are exposed and heavily weathered, being a oceanic environment has contributed a great deal to this. There is about 415 million years of geologic processes exposed to the observer, It doesn't get any better than this.

[Ophiolite]

One of our members expressed the desire to know the setting of Geology of the Earth, as a whole, whats it all about Rocks,? Volcanoes,? Earthquakes,? Going out into the Field with a hammer?, or what ?,

Geology is the study of the Earth: how it formed, how it has changed over time and the processes that promote those changes. If you want the minimum soundbite - geology is about change in the planet.

 

There are many subdivisions of geology. Here are some of the more important:

• Historical geology
• Stratigraphy
• Sedimentology
• Pertrology
• Mineralogy
• Geophysics
• Palaeontology
• Structural geology

I was trained on the basis that field work was an essential ingrediant of geology: get out and hit the rocks with a hammer; see the lie of the land; sense the development of the environments and structures.

 

 

But they would like a succinct explanation of the setting of it all , before we get bogged down in details

Do you mean you would like a summary of the geology of the South West?

 

 

[Mike Smith Cosmos]

 

Geology is the study of the Earth: how it formed, how it has changed over time and the processes that promote those changes.

• I was trained on the basis that field work was an essential ingrediant of geology: get out and hit the rocks with a hammer; see the lie of the land; sense the development of the environments and structures.

 

 

I like it ! " get out and hit the rocks with a hammer; see the lie of the land;"

 

 

Do you mean you would like a summary of the geology of the South West?

 

Yes please ! That would be just Great for our next meeting/discussion . I wondered where you had gone, I thought you had fallen into a mid Atlantic trench !

 

Talking of which this morning I painted an interpretation of Richard Fortey's Book " The Earth an Intimate history " Pages 200-215. He describes ficticiously being in a satellite just before Pangea split , with the formation of the Atlantic. , looking onto the Appalation mountains at the back of New York. beyond would be seen the peaks of Newfoundland, Behind that the mountains of Ireland, Wales, The lake District and Scotland ( Calidonian) and still further East.Nor East the Scandinavian mountains, All Stuck together. Then Pangea split between Newfoundland and the UK forming the Atlantic Ocean and the Rest. ( is history )

 

 

 

Just a symbolic impression.

Edited April 8, 2013 by Mike Smith Cosmos

[Ophiolite]

Talking of which this morning I painted an interpretation of Richard Fortey's Book " The Earth an Intimate history " Pages 200-215. He describes ficticiously being in a satellite just before Pangea split , with the formation of the Atlantic. , looking onto the Appalation mountains at the back of New York. beyond would be seen the peaks of Newfoundland, Behind that the mountains of Ireland, Wales, The lake District and Scotland ( Calidonian) and still further East.Nor East the Scandinavian mountains, All Stuck together. Then Pangea split between Newfoundland and the UK forming the Atlantic Ocean and the Rest. ( is history )

The normal appellation for the Appalachians is Appalachian. Calling them Appalation is not palatable, though it may be thought appalling.; definitely not appealing.

 

Worth noting that there was a stillborn split in the North Sea, which gave rise (or more accurately fall) to the Central North Sea Graben, which is where most of the North Sea oil is to be found. Google triple junction.

 

Yes please ! That would be just Great for our next meeting/discussion .

I am passingly familiar with the geology along the Jurassic coast, as one of the courses my department offers is a combined classroom and field trip to the area. (Don't get excited: it is purely an internal course for our employees only - and if we did offer it publicly it would set you back £2,000 +.) I'm less familiar with the older material to the east, though it does contain an ophiolite complex. This is a slice of ancient ocean crust and mantle that has been thrust onto continental crust during plate collision. I'll see what I can put together for you.

[arc]

Mike, I did a little research. The Dartmoor National Park is a 647 square km granite intrusion that is connected at depth to the adjacent Cornwall granite masses forming a single enormous batholith. The granite formed 300 million years ago from a magma source at several kilometers of depth (some sources say 5 or more) and was exposed through a still not fully understood processes of ascent to its current state. Heat from the mass of magma of nearly 1000 C. transformed the surrounding rock of several hundred meters into a metamorphic known as hornfels. Downward surface erosion sped the exposure of the slowly rising batholith.

 

There are basaltic lava's in the Exeter area that are found in sedimentary deposits, they are dated to and believed someway related to the granite formation period. I would assume it was the same magma source with the difference being the granite formed at great depth having tremendous pressures for a long period with pressure and temperature slowly mitigating as the batholith gradually moved to the surface. Whereas the basalt surfaced around the time of the batholith pluton formation and was subsequently buried in layered sediments for tens of millions of years, then exposed through erosion where it can now be viewed. Better check that with Ophiolite. One of these is a volcanic cone at Rougemont under the Exeter castle.

 

As an interesting comparison we have had massive basalt flows here in the Northwestern U.S., one named the Ginkgo is believed to have surfaced and traveled 500 km at 1- 8 meters per sec. taking maybe a week to run the full coarse with just a 20 C. drop in maximum temperature. The combined flows that occurred during the late Miocene and early pliocene epochs totaled upwards of 163,700 km² and reached a maximum thickness of 1.8 km.

[tomgwyther]

While you're at it, I'd be interested to know why there are large deposits of sand in the New Forest (To the east of Exeter) I can only presume that at one time, the area was coastal.

There's an enormous sand dune just to the south of my at Linwood, and there are two massive piles of sand down the road from where I live, rather comically named 'Sandy Balls'.

[studiot]

Exeter Huh?

 

There is a well established U3A geology group in nearby Taunton.

 

You could contact the organiser to see what they do.

PM me if you can't make contact through U3A.

 

Just to add to Ophiolite's list (He is a pure scientist to looks at why and how and how did it get there etc)

 

I see you are an engineer so you might like to also explore the question

 

Of what use can we make of it?

 

How does it affect the geography of the area and in turn the people of the area and their lifestyles?

Edited April 16, 2013 by studiot

[Mike Smith Cosmos]

Exeter Huh?

 

There is a well established U3A geology group in nearby Taunton.

 

You could contact the organiser to see what they do.

PM me if you can't make contact through U3A.

 

Just to add to Ophiolite's list (He is a pure scientist to looks at why and how and how did it get there etc)

 

I see you are an engineer so you might like to also explore the question

 

Of what use can we make of it?

 

How does it affect the geography of the area and in turn the people of the area and their lifestyles?

 

Thanks for your ideas. We have now been to the Museum. They all want to get Hammers ! and get out there , and look at the lie of the land. A fearsome looking group !

[Mike Smith Cosmos]

I am passingly familiar with the geology along the Jurassic coast, as one of the courses my department offers is a combined classroom and field trip to the area.

 

Our New geology group are heading out this week Fri 3rd May . To Dawlish South Devon Coast.

 

I understand this was built up by blowing Permian wind, heaping up desert sands into vast RED Dunes. Presumably at this time Devon would have been on the equator ?

 

Note the hammer. We go to see " the lie of the land" I have heard Snow cover is good to see the Lie more easily. However we are now into SUN.

 

 

 

 

[studiot]

In the UK the Permian and Triassic are usually lumped into one system and the permo triassic New Red Sandstone outcrops from the South west diagonally across the country towards the North East, running from Exeter to Watchet, up the Severn valley, through and under the heart of the Midlands and the Vale of York and into the North Sea at Middlesborough. In part it marks the boundary of the former Zechstein Sea of that era where marine limestones were laid along its edges.

Edited April 27, 2013 by studiot

[Mike Smith Cosmos]

In the UK the Permian and Triassic are usually lumped into one system and the permo triassic New Red Sandstone outcrops from the South west diagonally across the country towards the North East, running from Exeter to Watchet, up the Severn valley, through and under the heart of the Midlands and the Vale of York and into the North Sea at Middlesborough. In part it marks the boundary of the former Zechstein Sea of that era where marine limestones were laid along its edges.

 

This is a link from one of our members As to what to anticipate this Friday May 3rd 2013. If we come back alive !

 

link http://www.southampton.ac.uk/~imw/Teignmouth-Dawlish

 

EEk we are all over 60 !

[Mike Smith Cosmos]

. THE DAWLISH VISIT of U3A EXETER Spring 2013

 

The following is a brief record of the field work visit .(size of upload limited )

 

 

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Exeter Huh?

 

There is a well established U3A geology group in nearby Taunton.

 

You could contact the organiser to see what they do.

PM me if you can't make contact through U3A.

 

Just to add to Ophiolite's list (He is a pure scientist to looks at why and how and how did it get there etc)

 

I see you are an engineer so you might like to also explore the question

 

Of what use can we make of it?

 

How does it affect the geography of the area and in turn the people of the area and their lifestyles?

 

Dawlish Warren/Dawlish was always a beach, fun and swimming when I was a boy. Now taking on a Whole new perspective.

 

Mike

 

 

That's me with the hammer and the big lump of rock !

Edited May 14, 2013 by Mike Smith Cosmos

[studiot]

Nice pictures, good job your visit wasn't today.

 

[Mike Smith Cosmos]

U3A University of the Third [OLD] age GEOLOGY GROUP EXETER

 

Jurassic Coast Trip World Heritage Site 20th July 2013

 

 

. Landing on the Beach SEATON

 

. Cretaceous

 

. Triassic

 

. Glacial Valley opening into the sea at SIDMOUTH

 

...

 

. looking back along Jurrasic Coast

 

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Edited July 21, 2013 by Mike Smith Cosmos

[arc]

WOW, what a nice day. By the looks of the ocean surface you had little wind and a smooth ride, just perfect. Are those white Cretaceous rocks calcium, bird droppings or ? Thanks for sharing Mike.

[Mike Smith Cosmos]

WOW, what a nice day. By the looks of the ocean surface you had little wind and a smooth ride, just perfect. Are those white Cretaceous rocks calcium, bird droppings or ? Thanks for sharing Mike.

This was at the end of the trip pulling back into EXMOUTH. Think this is Red Permian Sandstone Rock , With Bird Droppings. We were about 10 feet away .

 

 

 

Docking Back on Terra Firma

 

 

 

There appear to be many different geological layers down here in the South West of England ALL coloured with this RED look. It is a Major World Heritage Site I suppose this is All IRON staining. Some large Blocks were Red in the Cliff but white as they had fallen to the foot of the cliff and exposed to sea water. The Iron Content seems to be very present.

 

As Picture below

 

. Note .Where sea gets at RED blocks .

They are White. At the foot of the cliff.

 

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Edited July 21, 2013 by Mike Smith Cosmos