Last week the IUGS (International Union of Geological Sciences) celebrated its 60th anniversary with the announcement of the creation of the first 100 IUGS Geological Heritage Sites. The International Union of Geological Sciences (IUGS) was founded in 1961 and with 121 national members and representing over a million geoscientists, it is one of the World’s largest scientific organizations.
The IUGS' commission on Geo-heritage was given the objective of recognizing Geological Heritage Sites and established a group to recognize Geo-collections around the world. A working group of 20 international experts on geo-heritage from 13 different countries set about evaluating the applications of 181 candidates from 56 countries resulting in the formal announcement on 28th October 2022 of the first 100 IUGS Geological Heritage Sites. The organisation described it "a great milestone that will inspire the work of this ambitious program. There will be more IUGS Geological Sites recognized in the coming years."
And within the 100 selected sites 2 unsurprisingly were from Scotland. I say unsurprisingly because those familiar with Scottish Geology are well aware of the important contributions made by Scots and the Scottish geological landscape to the understanding of the geological evolution of the earth.
The name of James Hutton is often referred to as the father of modern Geology and so the first site on the list of the 100 is Siccar Point, a seemingly unassuming rocky promontory off the Berwickshire coast.
It was here that the famed Geologist, arriving by boat in 1788. used the evidence from the rocks to decipher the earth processes and to argue that the planet was significantly older than thought.
He saw that there were two sets of rocks at Siccar Point. The underlying layers are dark-grey, steeply- tilted rocks called greywacke that formed in an ancient ocean in the Silurian Period. These were overlain by younger, almost horizontal red sandstone layers that formed in desert conditions on land during the Devonian Period. The deposition of the two different types of rock was not continuous, but separated by a gap of 65 million years during which time the older rocks were changed and eroded – a phenomenon known by geologists as an ‘unconformity’. James Hutton became associated with the notion of "deep time."
Whilst Siccar Point is a very precise location Scotland's second entry in the 100 is a geological event that is visible along a line that is 200km long and runs from the Tongue area in the top north coast to the Sleat Peninsula on the Isle of Skye. This is The Moine Thrust and has its place in the Tectonics category for it is along this thrust fault that older rocks have been pushed on top of younger rocks.
A great part of the thrust zone is within the NW Highlands Geopark, which has been a UNESCO Geopark since 2004, and is accessible at the Knockan Crag visitor centre just north of Ullapool. But perhaps one of the great viewing points which allows the amateur to fully grasp the enormity of this geological event is at Loch Glencoul near Kylesku. As you drive along the A894 (maybe you will know it as a part of the NC500) and arrive at Unapool you will look out across the Loch at the layers of rock thrusting over each other allowing you to fully understand what is going on in this thrust zone which IUGS describes as "one of the best exposed orogenic fronts in the world, representing a geological history of more than 2 billion years."
Below is a table of the IUGS Categories with the 2 Scottish Sites ( a full list is available at the IUGS website - see link below.)
| GEO-SCIENCE CATEGORY | No. Sites |
1 | HISTORY OF GEOSCIENCES - Siccar Point at No. 1 | 11 |
2 | STRATIGRAPHY AND SEDIMENTOLOGY | 12 |
3 | PALEONTOLOGY | 19 |
4 | IGNEOUS AND METAMORPHIC PETROLOGY | 8 |
5 | VOLCANOLOGY | 17 |
6 | TECTONICS - Moine Thrust No. 70 | 7 |
7 | MINERALOGY | 3 |
8 | GEOMORPHOLOGY AND ACTIVE GEOLOGICAL PROCESSES | 22 |
9 | IMPACT STRUCTURES AND EXTRATERRESTRIAL ROCKS | 1 |
As IUGS has pointed out there will be further additions over the coming years to the list
and quite possibly more Scottish sites will be added. The Scottish Geology Trust is a fantastic organisation working hard to promote Scotland's geological heritage and on their website they provide a list the best 51 places in Scotland to see Geology.
Further Reading:
Browse books on Scottish Geology:
Comments