Centre for Alternative Technology

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Deglaciation - how the Welsh landscape emerged from the last ice-age

  • Sat 23rd - Sun 24th Sept 2017.
    Course starts at 10am and ends at 4pm on the Sunday.
    Course fee (not including food or accommodation):-
    Waged £100, Low waged / Concessions £80

  • Dates, Times & Fees

Course details

Deglaciation and Cantre'r Gwaelod: the last 23,000 years of climate change in Wales.

The stunning Welsh landscape owes its modern features to the repeated glaciations of the past 2.5 million years. Glacial ice is an immensely powerful agent of erosion, carving out valleys, grinding down hillsides and dumping vast amounts of debris out on the plains. Each successive glaciation modified the evidence left behind by the previous one, so that the remains we can see today are the handiwork of processes that took place up to and following the Last Glacial Maximum, 23,000 years ago.

In this course, participants learn why ice-ages happen at all, how they affect the landscape and the consequences of their ending. There are two morning lectures and two afternoon field-trips, both coastal. In the first trip, we examine the exotic sediments left behind as the great ice-sheets retreated up the Irish Sea, the unusual boulders gouged up from what is now the Cardigan Bay sea-bed and, on the way back, the remains of one of the biggest landslides in Europe. In the second, we look at the stark evidence for the great sea-level rise that accompanied deglaciation and consider whether ancient Welsh legends have a grounding in real events that took place, thousands of years ago.

Day 1: start 10:00 (coffee etc.)

Morning 10:30-12:00: Talk and Q&A on the key drivers of past fluctuations in Earth's climate. Learn how the planet has switched, on a number of occasions, from its Hothouse state to Icehouse – when glaciations can occur. Discover how glaciations are triggered and the time-scales involved – and how glacial ice goes on to shape a landscape.

12:00-12:30: Lunch at CAT then meet at Tonfanau railway station, 1300 (map supplied).

13:00-15:00: Walk to beach (400m) then 500m along beach, examining low cliffs (from a safe distance) along the way. Discover the sediments left behind by the retreating Irish Sea ice-sheet (including stones that have dropped out from melting icebergs). There will also be the opportunity to learn to distinguish between sedimentary and igneous rocks too – there's a great diversity of different types of these rocks at Tonfanau. Walk back to transport.

15:00-15:30: Travel to Talyllyn.

15:30-16:00: Contemplate the vast Graig-Goch landslide that buried the entire valley along a length of over 1200 metres and to a depth of 100 metres, with a pint or a pot of tea at one of the two hotels by the lake (great views up the valley, too).

Day 2: start 10:00 (coffee etc.)

Morning 10:30-12:00: Talk and Q&A on deglaciation and its effects on the Welsh landscape past and present. Learn how Cardigan Bay formed over several thousand years and how fertile wooded plains were gradually lost to the advancing seas. Contrast such changes with current man-made climate change.

12:00-12:30: Lunch at CAT then meet at Ynylas, 13:00 (map supplied).

13:00-16:00: Walk along the beach, examining the clays, peat beds and tree-stumps of the famous Submerged Forest. Sometimes, ancient footprints, thousands of years old, may be visible: it depends on sand movements. Hear the tale of the lost plain of Cantre'r Gwaelod – West Wales' own version of the Flood Legend - and contemplate its possible basis.

Participant requirements:

Walking boots for day 1, Wellies for day 2, Waterproofs. Binoculars for spotting wildlife (Tonfanau is especially good).

Course participants are expected to travel to the locations from CAT either using their own vehicles or car-sharing with other course participants. We also suggest that you bring a packed lunch or snacks with you or purchase from our restaurant before leaving CAT.

The tutor for this course is John Mason.

Things you need to know

Due to the nature of this course some practical work will be done outside. We strongly advise you to bring waterproof clothing and good walking boots. Wellington boots will be required for day 2.

You must be over the age of 18 years when this course starts.

Booking, Fees and Cancellation policy

To book a place on a course, please choose one of the following options:

• Book Online- the “Book online” button is either below, or in the top right corner of the screen and follow the instructions.

• Call the Courses Department on 01654 704 966 with your bank card details.


Our course fees include tuition and materials, unless otherwise stated.

Please also note our Cancellation & Refund Policy
a) 1 day course fees are non-refundable.
b) CAT reserves the right to cancel any courses. Deposits and fees will be returned in full should this happen.

Course Fees.

Start Date

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Email courses@cat.org.uk
or phone 01654 704 966

There are places available on this course.

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