Geology of the Ross of Mull, Iona and Staffa - Term Paper Example

Geology of the Ross of Mull, Iona and Staffa Introduction The Ross of Mull, along with the islands of Iona and Staffa, has always been known as the ‘Mecca’ of geologists. This natural sight of Scotland, located in the Inner Hebrides, is the second largest island in that region. For over two hundred years, the Isle of Mull has been a popular destination for all visitors of Scotland. Not only has it gained geological importance, but even religious importance (Bird 511). The Ross of Mull is the main point of concentration. It is the largest peninsula in the island, filled with prehistoric geographical features that represent various geological events that took place millions of years ago. This includes steep cliffs of lava in the north and large mountainous roots in the south, which show clear proof of high volcanic activity in this region at some point of time in the past. Such is the sheer contrast of this region, that there are sandy beaches as well as hard granite deposits in this same region (Wilson 392). The entire geography of the Ross of Mull depicts various prehistoric activities that will help geologists understand the movement of land mass, tectonic plates and volcanic activity in the European and North Atlantic region which has resulted in the current formation European geography. It has become a haven for geologists in investigating the long lost past and helps them portray and predict future movements and activities. Activities that will further change the shape of Europe and the world as we know it. Solid Geology of Staffa The island of Staffa has been the result of pure land mass formation due to magma. The entire island covers an area of about 33 hectares and is located north side of the Ross of Mull. It is an island that used to be part of the Isle of Mull; however, it was later separated. By looking at its geography, it looks like a huge cliff when observed from the southern side; however, the island shelves into the ocean on the northern side. The island has been the result of pure volcanic formation, as it is clearly visible in its existence (MacArthur 63). The island has the formation of a cliff on its southern side as seen from the Ross of Mull. The cliff walls are made from fine tertiary basalt; however, underneath the basalt columned edges are basements of tuff, formed by pure volcanic ashes. However, these are not the main point of attractions of the island. The island is most famous for its caves, located on its far-east and west coast. The most famous of these caves, is Fingal’s Cave located on the western coastal region of the island (Pickard 124). The cave has an arch like entrance and has been formed by continuous erosion of the sea water. The cave has one entrance which tourists enter through a boat. The inside walls of the cave are majestic. They have been formed by fine basal columns, and due to the crystalline structure of magma, the columns are in perfect hexagonal shape. These columns form the entire walls of the cave. The formation occurred due to the separate cooling of the inner and outer layers of lava which resulted in tetragonal crystalline structuring of the magma (Harker 53). The cave has an entrance through sea, which has been formed by the continuous erosion of the cave from the water. The cave also has significance in literature, as Mendelsohn was inspired for his Hebrides Overture by visiting the cave way back in 1832. It has also been visited by many prominent figures such as, Jules Verne, J. M. W. Turner and even Queen Victoria. When looked at inside the inner formation of the Staffa, magma layers that have piled up for millions of years have taken the shape of layers. These layers contain mainly sedimentary rocks, folded in the Triassic, Jurassic and the Cretaceous period. These layers, that were once magma, have taken millions of years to form and cool down (Brook and Hinchliffe 44). After learning about such complicated geography of this small island, one might ask a question on how it was formed. The formation of this small piece of land dates back almost 60 million years, when Greenland, Europe and England were part of the same land mass. Due to constant movement of the Earth’s crust and the presence of the fault line in the region, Greenland eventually split away from England and Europe into a separate landmass. This caused deep ruptures in the Earth’s crust as well, seeping down into the mantle which contains magma. Magma then seeped out to the surface to form magma plumes, which eventually took the shape of land after millions of years of cooling. These sorts of bodies of land can be seen in various places around the world such as the Faroe Islands and the Small Isles. Such magma formations can also be seen in Greenland. One of these magma formations resulted in the formation of an island that is now known as Staffa (Porter and Prince 398). The inner parts of lava and magma are the hardest and most solid; hence, they attain a crystalline structure of tetragonal shape. This is clearly visible inside Fingal’s Cave and, hence, is the reason for its formation, which has caused thousands of visitors to pay a visit to this cave at least once. Geology of the Ross of Mull This single geological land mass is the largest peninsula in the Isle of Mull and, hence, has a lot of geological importance. When we look at the geological features of the Ross of Mull, there are some main deposits that must be seen before its evaluation. It consists of the Ross of Mull granite and Strontian granite towards the Far East side of the peninsula, the side which faces the Isle of Iona. This granite region of the Ross of Mull is of great significance to geologists in knowing the prehistory of this region. In this region, various granite deposits are visible in the entire region, which can be seen in Beinn à Ghraig and in the sound of Iona, where granite deposits are visible as outgrowths from the ocean. These rocks are popular as the Caledonian rocks (Wilson and Murphy 304). There are granites rocks like these in the entire region of South Western part of the Ross of Mull which have been the source of attention for many geologists. Around 58 million years ago, the Isle of Mull consisted of mainly an extremely active volcano. Beneath the volcano was a huge magma chamber which was the main source of activity of the entire volcano (MacGregor 74). However, the activity responsible for the granite deposits at the Ross of Mull dates back to almost 2.5 billion years ago. The rocks at this location have been the result of continuous pressure and heat for millions of years on the magma in this region. This is the geological activity that caused the formation of granite deposits at the Caledonian rocks in the Sound of Iona and in the Beinn à Ghraig, and the vast granite deposits in the Ross of Mull. Hence, after millions of years of eruptions, sinking and magma seeping, the once active volcano at the South Eastern region of Mull has now simply been left to its roots. The magma seepage and lava activity was so vast that it was also the origin for the formation of the mainland Ross of Mull. These volcanic activities have been the reason for the formation for the base and core of the Southern Mull region. However, the formation was terrain for this region was caused mainly by glacial movement. 52 million years ago, the volcanic activity and the igneous activity ceased in the Mull region. The tectonic plates hadn’t faced any serious activity since the separation of Greenland. During that time, this region mainly had a sub-tropical climate. However, there was a huge shift in climatic conditions around 2.6 million years ago. Such severe was this shift that it caused the formation of glacial movement in the region of Scotland. The glacial movement was the main reason that eroded the entire landscape and shortened the height of the lava plateau in the mainland Ross of Mull, which once rose to around 6000ft. in height. Valleys were deepened and land formation was eroded by the glacial movement which can be seen in the lava plateau. In the southern regions of the isle, the landscape is particularly polished and it is even polished in regions like the Iona and the lava plateau (Marsh 143). This polished landscape was due to the erosion caused by the glacial movement. During the last 450,000 years, it is seen that there have been 4 spells of glacial movements, once every 100,000 years. These movement, whose direction has mainly been from Scotland to the North east have cleared out the landscape of the Mull region and, hence, have wiped out almost every geological proof of any sub-tropical climate which once thrived in this region. This movement has cleared out the volcanic proof in the Isle of Mull; hence, it redefines a whole different era for the Mull region. This erosion has also caused the formation of some landscapes such as valleys, ridges streams etc. Another region of interest for geologists is the Carsaig bay. This region is the most different of all regions of the Ross of Mull. When looked at the land formation, the bay has more of a limestone deposits on its coastal regions which are extremely similar to the chalk deposits in North Eastern region of England. The terrain here and rock formation dates back to the Jurassic Period and so do the deposits (Marsh 143). Due to the chalk deposits, scientists have finally discovered that this region was once a part of the English chalk deposits, back when the Mull was part of England before the Ice ages 2.6 million years ago and before the separation of tectonic plates some 60 million years ago. Some of the deposits were hence carried forward by the Mull, hence, causing the formation of this unique landscape and proving the fact further of the movement of plates in this region. The Island of Iona The island of Iona is far different from the other regions of Mull. The sedimentary rock deposits in this region date back even further, to about 2500 million years. Iona is home to one of the oldest rocks present in the entire England. The west of Iona mainly comprises of Caledonian Mountain which is the Ancient gneisses of the Lewisian Complex. Towards the east coast, there are deformed and metamorphosed sedimentary rocks of the late Precambrian age (Wilson and Murphy 304). The metamorphic rocks found in this region date back almost 2.5 billion years, along with a wide variety of other rocks. These hard rocks have been formed under millions of years under intense pressure and heat. The other rocks consisted of both, sedimentary rocks and granite formed by crystalline magma. However, due to the rapid Earth Movements and the erosion process due to glaciers, those rocks have been streaked and branded and, hence, have created a much rugged landscape in the western region as visible at the Knolls of Lewisian gneiss. In the foreland area, there are special rocks known as the Iona Marble, which is a special kind of Metamorphosed limestone. Its history is not as traumatic as the Lewisian deposits on the west coast, however, little is known about its history. This rock has been used in the formation of structures in the Iona Abbey, such as the popular Iona cross and the church located in the abbey. These rocks were so hard, that they couldn’t have been carved by any rock present in the Mull. Hence, rocks had to be ordered from south-west Argyll to give the Celtic cross and the church proper shape (Marsh 143). As mentioned before, the Isle of Mull is one of the most geologically diverse regions of the world. In this single system of islands, there is proof of the great tectonic separation of Greenland, there is proof of volcanic activity that has given birth to some of the most amazing landscapes known to man, and it has also been the source of inspiration for writers, poets and even musicians (Wilson and Murphy 304). Due to these geological changes that these islands have faced, it has always been a huge place of attraction for geologists. These islands, not only have witnessed some great geological changes of the world, but also continue to tell us about various accounts of the past which had always been unknown to man. Not only will they be able to know more about our past, but they will also be able to predict the geological future of our mother, Earth. Works Cited Bird, Eric. Encyclopedia of the Worlds Coastal Landforms. UK: Springer, 2010. Print. Brook, Denis and Phil Hinchliffe. Scotlands Far West: Walks on Mull and Ardnamurchan. UK: Cicerone Press Limited, 2012. Print. Harker, Alfred. The West Highlands and the Hebrides: A Geologists Guide for Amateurs. UK: CUP Archive, 1941. Print. MacArthur, Mairi. Columbas Island: Iona from Past to Present. London: Edinburgh University Press, 2008. Print. MacGregor, Malcolm. Mull, Iona and Staffa. NJ: Frances Lincoln ltd, 2011. Print. Marsh, Terry. The Isle of Mull. London: Cicerone Press Limited, 2011. Print. Pickard, Jan S. Out of Iona. Scotland: Wild Goose Publications, 2001. Print. Porter, Darwin and Danforth Prince. Frommers Scotland. NY: John Wiley & Sons, 2009. Print. Wilson, John E. The Gazetteer of Scotland. Scotland: Heritage Books, 1882. Print. Wilson, Neil and Alan Murphy. Scotland. Scotland: Lonely Planet, 2008. Print. Read More