Meeting Report: Do You Know Scotland’s Earth History?

Date: 
9 April 2011
Occasion: 
Castle Douglas Meeting
Speaker(s): 
Professor Roger Crofts (Geosciences Schools, Universities of Edinburgh and Aberdeen)

Scotland has an intriguing and complex earth history. Indeed, it has greater diversity in its rocks and landforms than anywhere of the same size in the world. Less than 250 years ago, claims that the earth was only 6,000 years old were widely accepted - nightfall preceding 23 October (Julian calendar) 4004 BC as the date of its creation was one famous calculation by the Calvinist Church of Ireland Archbishop Ussher. Only the persuasive observations of James Hutton, commonly termed ‘the Father of Modern Geology’, dispelled that notion with the memorable and accurate phrase that, ‘I see no vestige of a beginning, no prospect of an end’.

There are several key elements of Scotland’s geological history. Firstly, the oldest rocks are very ancient, dating from around 3,500 million years ago. Secondly, the early parts of Scotland began life in the southern ocean near to the South Pole and gradually moved northwards. Third, Scotland is not one country geologically: it comprises 6 different parts. Next, Scotland and England joined together around 400 milion years ago with a great continental plate crash causing major effects through the country. During its journey from the southern hemisphere to its present position, Scotland has experienced every possible climate from the hottest to the coldest and from the driest to the wettest. More recently, with the opening of the North Atlantic Ocean, Scotland parted company with North America from 65 million years ago with a series of large volcanoes and accompanying lava flows. In recent geological times, Scotland has been covered by ice at least 5 times, resulting in many changes to the landscape and landforms. In the last few thousand years, parts of the country have continued to rise relative to the sea and others have sunk.

For the future, we can expect more flash flooding and slope movement, as the coast both retreats and builds outwards. And should the ocean water conveyor belt stop as a local consequence of global warming, then we could have another ice age at least. In the longer term, we will continue to move apart from North America and to feel the consequences of Africa colliding with Europe.