Introduction

This evening, I am focusing on Scotland’s fascinating and diverse geology.

Old Man of Storr, Isle of Skye (Above)

Information on Scotland’s Geology-Part 1

Over the past 500 million years the land which now comprises Scotland has drifted a considerable distance.From a position well south of the equator the land moved up across the equator to its current position. This location about 56 degrees north, on roughly the same latitude as Labrador and Moscow. This long journey entailed exposure to a wide range of forces. Such included submersion by oceans, desert conditions, tropical rain-forests, ice sheets and a physical join with England & Wales. All of these occurrences have impacted on landscapes and geology. The approximate chronology is as follows:

• 500m years ago ( Ordovican Period): Scotland and England both in southern hemisphere and separated by the very wide Iapetus Ocean.
• 410 m years ago (Silurian Period): Scotland unites with England and Wales at a position close to/connected with North America. The ‘join’ between England and Scotland is parallel with Hadrian’s Wall. The physical act of  joining England and Scotland creates a high mountain range, possibly comparable with today’s Himalayas.However, this has since been substantially eroded. At time of the join the lands were located about 10 degrees south of the equator. Prior to the joining the land which became Scotland was a series of terranes. These features subsequently joined together to form a single land mass. The Highland Boundary fault featuring Conic Hill at Loch Lomond is an example of a terrane boundary.

Hadrian’s Wall Escarpment, England

Conic Hill, Loch Lomond, Scotland

Information on Scotland’s Geology-Part 2

290m-360m years ago ( Carboniferous Period): Scotland is close to equator and landscape covered with tropical vegetation. During this period the Campsie Fells and Gargunnock Hills were formed by lava flows. Volcanic activity created Arthur’s Seat  and the volcanic plug on which Edinburgh Castle sits. Decomposing organic matter formed the genesis of Scotland’s extensive coal reserves at this time.

Arthur’s Seat, Edinburgh, Scotland

Edinburgh Castle, Scotland.

250m- 290m years ago ( Permian Period) : Desert conditions prevailed resulting in accumulations of red sandstone.

Video clip and image below show exposed strata at Kelburn Country Park near Largs, West of Scotland

Sandstone Layers at Largs, Scotland

• 135m-205m years ago (Jurassic Period): Initially most of Scotland was flooded by rising sea levels. But the water later subsided allowing the land to be recolonised by flora and fauna.
• 65m-135m years ago (Cretaceous Period): At end of this period the North Atlantic Ocean was formed. Cause was earth movements resulting in extensive volcanic activity over a period of about 5.0m years.Results can be seen at Ailsa Craig and Skye. From thereon Scotland and North America progressively drifted apart.

Quiraing, Isle of Skye, Scotland

Ailsa Craig off Ayrshire Coast

Information on Scotland’s Geology-Part 3

• 65m-2.4m years ago (Tertiary Period):  A humid climate, slightly warmer than today’s prevailed, a period coinciding with weathering of rocks.
• 2.4m -10,000 years ago (Quaternary): This was the Ice Age. At this time a succession of glaciations moulded the landscape into its present shapes. The weight of ice caused the land to be lowered. At this time sea levels were also lower. However, the melt reversed these processes causing creation of  ‘raised beaches’.

Raised Beach, Isle of Arran, Scotland.

On the Western Isles and coastal area of the N.W. Highlands can be found some of the most ancient rocks in the world. Such deposits date back about 3.0bn years. These are comprised of Lewisian Gneiss which emanates from deep in the earth’s crust.

All of the above features combine to make Scotland a haven for geologists. Indeed, Dr. James Hutton (1726-1797) is recognised as the father of modern geology. Hutton was active during the ‘Enlightenment’ period in Edinburgh His theories were supported by research on the Isle of Arran and elsewhere.

More information for the Visitor

When in Edinburgh visitors may wish to visit Dynamic Earth which is located near the Scottish Parliament. This is a science centre which explores the history of the planet earth. Additionally, the publication Visitors’ Guide to Scotland has a section focused on Scotland’s geology. ISBN of the book is 978-1-9161332-0-4. This is also available via Kindle.