Sip back as we discover Scotland and explore Arthur’s Seat a small, ancient and now extinct composite or stratovolcano. Arthur's Seat is today an iconic skyline feature of this nation’s capital city of Edinburgh dating back 360 million years. Now standing at 251 meters some 200 meters lower than the original volcanic cone. Arthur's Seat is a great hike to the summit and offers the visitor on a clear day a panoramic view of Edinburgh and the surrounding area of the Lothians. Located in Holyrood Park, Arthur’s Seat tells a story of hundreds of millions of years of Earth's history.
Edinburgh is among the most captivating destinations to visit in Scotland as well as the United Kingdom. It is a place that blends centuries of history and tradition and you will be met with a traditional Celtic Fàilte gu Alba or warm welcome. The skyline not only includes Arthur's Seat but also the indomitable looking Edinburgh Castle perched atop Castle Rock one of the oldest fortified places in Europe dating back to the Iron Age as a hill fort.
At the heart of Edinburgh lies the Royal Mile or ‘Scots mile’ a bustling thoroughfare that connects the two royal residences of Edinburgh Castle with the Palace of Holyrood House the official residence of King Charles III when he is visiting Scotland.
When strolling along these cobblestone streets into Old Town's narrow alleys your senses are sure to be overwhelmed with the range of Scottish crafts and possibly you can take the opportunity acquaint yourself with finding your clan or family tartan.
Art and culture thrive in Edinburgh, particularly during August when the city hosts the world-renowned Edinburgh Festival Fringe and spectacle that is The Royal Edinburgh Military Tattoo. These events bring performers, artists and service people from around the world transforming the City into a vibrant hub of creativity. For literary enthusiasts the City of Edinburgh’s was in 2004 designated as a UNESCO City of Literature recognising the City’s significant contributions to literature and connections to many well known authors such as Sir Ian Rankin, Sir Walter Scott, Arthur Conan Doyle, Robert Louis Stevenson, Irvine Welsh and Julia Donaldson.
Alternatively you can take one of five self-guided geowalks in Holyrood Park suitable for a range of abilities to hike to the summit of Arthur’s Seat generally taking between 1-2+ hours depending upon your choice of route. For more information you can visit the Holyrood Park Visitor Centre (Queen's Drive, Edinburgh EH8 8HG) or their website to download the app or buy for £6.00 the Holyrood Park Guidebook from Historic Scotland.
Arthur’s Seat has long been described by some to resemble a giant sleeping lion with the peak forming the Lion’s Head and an adjoining part of the old volcano forming the Lion’s Haunch. But its Edinburgh born writer Robert Louis Stevenson in his lyrical and evocative 1878 published travelogue titled, Edinburgh: Picturesque Notes that he conjures up the essence and scale of Arthur's Seat as, “a hill for magnitude, a mountain in virtue of its bold design”.
Though Arthur’s Seat is internationally recognised the timeline of geological events involved in its formation are still today debated along with the origin of the name that still remains an unsolved mystery.
Before volcanic eruptions created Arthur’s Seat the area of Edinburgh lay at the water’s edge of a shallow sea within the Midland Valley of Scotland itself an ancient low lying rift valley between the Grampian Highlands and the Southern Uplands. It was a time when central Scotland underwent the Dinantian succession from the Late Devonian Period in to the Early Carboniferous Period and a change from a terrestrial semi-arid environment where sandstone prevailed to an environment influenced by widespread marine transgressions and sea levels rise relative to the land.
Now located near to the equator and having a warm and humid climate the marine sediments of grey mudstones, siltstones and limestone formed the Inverclyde Group between 359.2 – 341 million years ago during the Courceyan and Chadian Substage covering the Late Tournaisian and Early Viséan Ages of the Carboniferous Period.
The sediments of the Inverclyde Group were laid down around Edinburgh in a low-energy peritidal coastal floodplain environment of shallow lagoons just outside the influence of the tide.
Underlying Holyrood Park is the fossiliferous Ballagan Formation often referred to as "cementstone" and is part of the Inverclyde Group. With a depth of up to 900 meters in the West Lothian area this sedimentary rocks can be seen at exposures on the north side of Holyrood Park in the remains of Camstone Quarry.
The Ballagan Formation is indicative of a brackish coastal environment made up of mudstone, siltstone, anhydrite, gypsum and beds of iron rich ferroan dolostone a rare source of cemented macro and micro fossil assemblages of fish and aquatic invertebrates including the bivalve Modiolus and several species of the micro-crustacean known as Ostracods as well as Palynomorphs of pollen and spores.
Interestingly, this formation represents an important time in Earth’s history when globally early tetrapod's were beginning to evolve from fish to walk onto land and when terrestrial ecosystems were beginning to recover from the Hangenberg Crisis a significant global extinction event that effectively ended the Devensian Period and the "Age of Fishes".
During the early Carboniferous Period approximately between 341 - 335 million years ago million years ago a volcanic system of magma pushed through the Earth's crust to form five main vents and fissures in the older sedimentary rock. This volcanic activity produced a small stratovolcano from where multiple streams of viscous lava flowed across the landscape and cooling to form a hard layer of dark basalt.
The volcanic activity at Arthur’s Seat was not limited to surface eruptions. Beneath the surface magma intruded into the surrounding sedimentary rocks forming sills and dykes. These igneous intrusions are visible at Salisbury Crags where the intrusion of igneous rock was horizontal forming a sill.
It was at Salisbury Crags that in the late 18th century James Hutton a Scottish farmer and naturalist who is today recognised as the “Father of modern geology” for his work on the theories of Earth’s processes and his appreciation for deep time recognised that the molten igneous rock had intruded into the existing sedimentary rocks to form dolerite.
At the time, understanding that rocks and specifically igneous rocks were formed through volcanic activity and heat-driven processes from within the Earth was important in countering the doctrine of Neptunism a religious interpretation of Earth's history that believed all rocks were formed from the precipitation of minerals from a primordial global ocean.
Another feature of Arthur’s Seat is a vertical wall of hexagonal columns known as Samson’s Ribs. Formed when molten lava pooled and cooled relatively quickly and uniformly and contracted creating the ideal conditions for the phenomena of columnar jointing to happen forming hexagonal columns. The columns have a hexagonal pattern because the structural integrity of a hexagon shape can distribute stress evenly because the 120-degree angles make it mechanically stable for the efficient and balanced release of surface tension in each direction during contraction.
Around 300 million years ago the volcanic activity stopped and Arthur's Seat would now experience millions of years of slow environmental erosion from rainwater, ice, wind and soil leading to the removal of most of the volcanic cone crowning Arthur’ s Seat.
The current crag and tail appearance of Arthur’s Seat and surrounding area has also been heavily influenced by the abrasion of ice from multiple glacial advances and retreats across the landscape over the past 2.6 million years of the Quaternary Period until it completely disappeared some 11,300 years ago. The "crag" is the steep and rugged hill of resistant volcanic rock whilst the "tail" extends westward comprising gentler slopes formed by sedimentary rocks and glacial deposits.