Tag: DGAG Talk Series

Talk -The Variscan Orogeny; it’s Causes and Consequences

Dorset Geologist’s Association Group (DGAG) will host a talk on the Tuesday 22nd April 2025.
Title: The Variscan Orogeny; it’s Causes and Consequences
Speaker: Alan Driscole (DGAG member) who has forty plus years in exploration geology (Oil/Gas) in many parts of the globe including the Atlantic margin.
Time: Talk will start at 7pm; finish approximately 8pm
Venue: Activity Meeting Room: Dorford Centre, Bridport Road, Dorchester, DT1 1RR
Lecture Entry Cost: All welcome: £6 non-members (£5 for DGAG members) cash
Booking a seat: contact Chris Webb at email: events@dorsetgeologistsassociation.org
Talk Description: The talk is another from Alan and on a topic that there have been discussions on at previous talks and field trips. If you’re exploring geology in the southern UK, Ireland or much of Europe it is a subject that comes up regularly so it is timely to review the orogeny, it’s causes, history & influence on later structure through the Mesozoic and Tertiary age rocks.
The Variscan orogeny culminated in final consolidation of the Pangea supercontinent, with closure of the Rheic Ocean and collision between Laurasia and Gondwana. Rather than a simple single collision, the Variscan incorporates several tectonic phases as small micro-continents, originally split off from the margin of Gondwana, which then collided with Laurasia during a 100 million year period from the early Devonian to the end of the Carboniferous. As can be imagined, these events had a profound influence on the structural and environmental development of southern and central Europe during late Palaeozoic, including in England, Wales and Ireland. In this talk we will look at the story of this prolonged orogeny in Europe; how it influenced Carboniferous geology in the southern UK and its subsequent geological development through to the Alpine orogeny, from the mid Cretaceous to mid Tertiary.
Photo: Courtesy of the speaker –is from Millock Haven, Cornwall & shows Variscan chevron folds in Carboniferous Culm. (Can you spot the “Z” or “S” folds! – Editor)
Additional Links:
1. A good summary by the geological society of UK main orogenic phases

https://www.geolsoc.org.uk/Plate-Tectonics/Chap4-Plate-Tectonics-of-the-UK/Variscan-Orogeny

2. An introduction for geological enthusiasts to SW England and the wonderfully named Variscan Coast.

https://variscancoast.co.uk/

 

 

Talk -The Art of Sand from the Isle of Wight to Iowa: Part 2: Iowa

Dorset Geologist’s Association Group (DGAG) will host a talk on the Tuesday 18th March 2025.
Title: The Art of Sand from the Isle of Wight to Iowa: Part 2: Iowa
Speaker: Phil James
Time: Talk will start at 7pm; finish approximately 8pm
Venue: Activity Meeting Room: Dorford Centre, Bridport Road, Dorchester, DT1 1RR
Lecture Entry Cost: All welcome: £6 non-members (£5 for DGAG members) cash
Booking a seat: contact Chris Webb at email: events@dorsetgeologistsassociation.org
Talk Description:  The Art of Sand Part 2 will firstly give a brief recap of Part 1, the Isle of Wight, for those that couldn’t make the January talk. Next will be a look at the most incredible Isle of Wight coloured sand bell ever created and which now resides in the USA. Following that the main focus of Part 2 will be the life and astounding work of Andrew Clemens who produced the most amazing coloured sand creations. They are absolutely staggering and have to be seen to be believed. This time the coloured sands are from a much older geological formation, the Ordovician, 460 million years ago!

The 1st part of these two talks on the art of sand was held on the 21st Jan and featured “The Isle of Wight” and looked at the fascinating 19th century history of the artistic use of 45 million year old (Eocene age) coloured sands of Alum Bay.

Photo: Courtesy of the speaker

Additional Links:
1.  Link to the 1st talk held on 21st Jan 2025 in this two part series https://dorsetgeologistsassociation.org/wp-content/uploads/2025/02/1.21-Writeup_DGAG-Talk_series-21Jan_2025_final.pdf

2. Link to Smithsonian Institution
https://americanart.si.edu/blog/andrew-clemens-sand-art