Advent calendar

The Great Geoadvent: Door 18

This year’s geoadvent features some of our favourite entries from photography competitions past and present – all of which feature the beautiful geology of the UK and Ireland.

You can purchase a copy of this year’s calendar, featuring our 2018 competition winners, on our online bookshop, or by visiting us at Burlington House!

Door 18: Borrowdale Volcanics & Crinkle Crags

Jamie Farquharson sent us this image of the Borrowdale Volcanics for the 2015 Earth Science Week photography competition, based on our 100 Great Geosites.

Borrowdale Volcanics c. Jamie Farquharson

Further info:

Borrowdale is a valley in the English Lake District in the Borough of Allerdale in Cumbria. The valley lends its name to the Borrowdale Volcanic Group, which make up most of the mountains at the head of Borrowdale including Scafell Pike.

Crinkle CragsThe Crinkle Crags are a classic and complex area of volcanic geology, dating from the late Ordovician. The Borrowdale volcanic group are a series of andesitic lavas and pyroclastic rocks, erupted from an arc of volcanoes that had developed above an active subduction zone – in this case, along the southern margin of the Iapetus ocean.

The complexities of the volcanic geology of arc volcanoes – which show rapid variations in lithofacies and depositional environments, and post-depositional modification ranging from redeposition to caldera-formation – means that much of the detail of the eruptive history has only been worked out within the past couple of decades.

Text courtesy of D.L. Pyl
Image: Fell Runners descending Crinkle Crags © Mick Garratt (Source Geograph.org.uk) Creative Commons Attribution-ShareAlike 2.0 license.

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