The Eriboll region is located in the highlands of north-west Scotland (Figure 2). General topographic structures seen in this area include mountainous terrain, such as Ben Arnaboll which is 232 m above sea level. The area has been shaped by glaciers with steep slopes (Figure 1) and U-shaped valleys (Mitchell et al., 2015), although relief along the northern coast is more subdued than in other areas of the highlands. Unusually, in the context of the rest of the UK, the land is uncultivated and, as a result, is one of the least inhabited areas of the country. Loch Eriboll, to the west of the mapped region, is a flooded glacial valley that transported glacial ice obliquely to the northwest, this is supported by striations and numerous erratics observed in the area (Mitchell et al., 2017). plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay The climate of Loch Eriboll and most of northwestern Scotland is mild, although such high latitudes would normally result in temperatures as low as those of Labrador in Canada which is at the same latitude yet experiences freezing seas and temperatures up at -31°C (Scotsman, 2013). The reason for north-west Scotland's mild climate is because it is warmed by the Gulf Stream. In summer the weather can be variable, often clear and sunny, sometimes cold and humid, but on the whole the summers are mild. Weather changes in this region can occur very quickly when weather systems arrive from the North Sea. The geological context of the Eriboll region is significant, it is a renowned site for British geology with rocks dating back almost as old as the Earth. This district features outcrops with superior exposure, which has led to this area and the wider region becoming a "mecca" for geologists. The easily accessible and relatively compact outcrop areas provide excellent exposures and examples of faults and thrust folds. The Eriboll region is best known for the discovery of the Moine Thrust Zone which runs submerged across Loch Eriboll. Here, late Proterozoic metasediments were found to be thrust northwest over two successions of sedimentary layers, the Archean basement and its sedimentary cover (Mitchell et al., 2017). This then underwent major faulting and intrusion: many examples of textbook faulting are observed here, in fact, the term 'thrust' was first coined here in 1884 (Leeds, n.d.). Early mapping in this region showed that older rocks, such as Lewisian gneisses, rested on younger Cambro-Ordovician sediments; this observation eventually led to the concept of thrust tectonics. Over 100 km of thrusting occurred along the Moine Thrust resulting in the formation of many features currently observable in the field, such as imbricate faults, duplexes, mylonites, and rock outcrops that are typically associated with major thrusting (Fossen, 2016). . The imbricate faulting caused repeated alternations of the main sedimentary units, i.e. the sandstone and fucoid beds. The rock units that were stacked in the overthrusts and that can be observed here are very characteristic and vary from traveled Lewisian Gneiss to Cambrian quartzites and imbricated sediments. The Moine Thrust continues to run to Sleat on the Isle of Skye from Scotland. These large-scale thrusts are the result of the Caledonian orogeny, which occurred approximately 430 million years ago. Before the Caledonian orogeny, most of Scotland's geology was formed by metamorphic processes, the remnants of which can be seen as the Lewisian gneiss complex observed on the summit of BenArnaboll, this unit is colored blue in the east of the map. Metamorphic gneiss material was transported from the Moine Thrust. The center of the map shows a series of alternating layers of Fucoid and Salterella Grit that are the result of this thrust fault. Their constituent ramps and apartments can be observed in many locations on this map. The western side of the map is dominated by basal quartzite which is Cambrian in age, this unit is bounded by the Durness Limestone which is the youngest unit mapped, it is Cambrian/Ordovician in age. The limestone generally slopes eastward. Alternating bands of Fucoid and Salterella Grit can be seen in the center of the map, stretching roughly north to south. This is where thrust and piggyback faults occurred and led to the repeated exposure pattern observable today. The seabed of Fucoide and Salterella generally slope towards the South-East. The eastern area of ​​the map consists mainly of the oldest unit, the Lewisian gneiss. Gneiss covers the summit of Ben Arnaboll (Figure 1.5), two million years ago an ice age engulfed this region and glaciers have significantly altered many outcrops, such as on the summit of Ben Arnaboll. The foliations within the gneiss are immersed towards the south-east. Finally, in the northwest corner of the map you can see a rock pipe leading down to the east. Results: The main feature of unit one is the appearance, it is fine grained and shows bands of foliation between the gray and white layers, also much of the foliation was folded. The thickness of this unit is not defined. The white layers showed coarser grains and the gray layers contained fragments of a darker mineral. Under a lens, it was visible that the mineral flakes were aligned with their long side parallel to the band in the rock. Some outcrops were even pink in color. Unit two is a very hard, whitish gray rock composed mainly of rounded grains embedded within a finer grained matrix. The entire unit is approximately 70 m thick. Multiple stratification planes are often visible on outcrops (Figure 4). Prominent cross-bedding is visible. There are clear straight bedding planes approximately 40cm apart and between these bands are curved, closer together bedding planes: this observed structure is called cross-bedding and was visible on many of the outcrops visited. This unit overlies the underlying bed on an angular unconformity. Unit two transforms into unit three which is approximately 85 m thick. Unit three is lithologically similar to unit two, except that some areas are bioturbated by burrows perpendicular to the layer surface. The lengths of the tubes varied. The vertical white tubes stand out against the purple/brown stained matrix of the rock. The matrix grains are coarse. A horizontal bedding plane is visible, there is also a white coloration at the bottom of the unit which transitions to pink as you move towards the top of the unit. Unit four is approximately 15 meters thick and can be quite variable in appearance. Some outcrops were carbonate-rich and effervescent under dilute hydrochloric acid. Other outcrops were darker in color and very soft and crumbly like slate or shale. Most of the outcrops had a characteristic "rusty" orange-brown colour, fine to medium grain size and relatively soft - they would scratch under a steel knife. The upper surfaces of the outcrops showed pits caused by acid rain dissolving the carbonate. The unit contains small spiral shells, approximately 2 mm in diameter. The stratification planes are all parallel and the horizons of this unit are rich in quartz. Unit five hasa thickness of approximately 10 metres. This unit is a gray colored rather coarse grained, grainy, poorly graded quartzite rock. This unit is not as hard as unit two and has small calcified worm tubes, some of which have been weathered away, this would suggest the presence of carbonate in the concrete of this unit. This unit takes on a slightly brown color, but fresh surfaces are a dull gray. Unit six has only been observed at 30 meters thick but extends much further. This unit has a fine grain size, the surface of this unit was a dull, leaden gray color and lichen nor heather grew on it due to the limestone rich soil caused by the chemistry of this unit. This unit is aphanitic and medium to dark gray in color on fresh surfaces, the texture of these surfaces was smooth. It seemed that rainwater had dissolved the surface of the outcrops, this unit also effervescent with diluted hydrochloric acid, which would suggest the presence of carbonate. Many of the outcrops were fractured due to the passage of fluids through the cracks. In this unit you can see trace fossils such as feeding burrows and ooids. Planar laminations were observed. Tectonic features within the mapped area: The primary feature in this mapped area is the series of low-angle reverse faults, otherwise known as thrust faults. These thrust faults can be seen extending north to south in the center of the map, there are alternating bands of unit five and unit four. Surface exposure forms complex imbricated structures. The hanging wall of the faults is to the east. Thrust faults form in compressional regimes, subsequently, the thrusts seen in the center of the map probably formed in an orogeny, the older four-bedded unit being thrust onto the younger five-bedded unit. The thrusts move up the stratigraphy and form a flat-ramp fold geometry, otherwise known as a 'piggy-back' thrust, this is responsible for the repeated beds visible on the map. The tectonic activity responsible for the thrust fault will also have led to some folding, that is, when the rock undergoes plastic deformation but has not reached its critical failure, beyond which brittle deformation and faulting occurs. It's also worth noting that you can notice an angular unconformity at the base of unit two, located in the southeast corner of the map. Overshoot appears, where the unit crosses the boundaries of younger units such as unit six. There is also a difference between the dips of the unconformity and the underlying beds: unit two generally has shallower dips than unit six. Discussion: My unit 1 is equivalent to the Lewisian Gneiss complex. The Lewisian gneiss formed during the Late Archean, when plutonic suites intruded into the lower layers of the crust. It is likely that Gneiss protoliths formed at active plate margins (Mendum et al., 2009). The Lewisian gneiss probably comes from a medium-depth crustal area, most likely formed in an Andean-type margin or island arc. Island arcs were very common at the time of formation and were major areas for crustal growth. Island arcs have also led to the formation of cratons that are a fusion of numerous microplates (Mendum et al., 2009). Lewisian gneisses are the oldest rocks to be found in the British Isles, and indeed the oldest in the world, the Lewisian complex has a long and extensive history of study by geologists such as James Hutton, "the father of modern geology " . With recent technology the radiometric ageof the Lewisian gneiss can be precisely determined, this has significantly revised the understanding of the Scottish Archean crust and disproved the previously held idea where the Lewisian represented a continuous crustal block with the same geological history. The Eriboll Lewisian gneiss is younger, 1.7 billion years old, compared to some found elsewhere in north-west Scotland, such as Assynt, which is 3 billion years old, this highlights the different origins, in fact, it is only 1740 millions ago that fully share a common history (Mitchell et al., 2017). Because the Lewisian gneiss complex has been reworked into the thrust belt, it is difficult to reveal the geological history. Foliations, folds, and shear zones that would have occurred under ductile deformation are visible. Originally these rocks were probably granitic, then the heat and volcanic pressure caused metamorphism and altered their structure. This is why you see large variations within the layers of this unit, ranging from white to light gray to dark gray. The light bands in the band most likely contain feldspar while the darker bands are dense mafic minerals, perhaps mica biotite or hornblende (Mendum et al., 2009). Intense heat and pressures resulting from metamorphosis and burial allowed minerals to grow within the unit (Heb, 2014). My unit two is equivalent to basal quartzite. Cross-stratification is a common feature of many sandstones, this is because sediments tend to be deposited in relatively flat layers, this is called the principle of native horizontality (Dawes, 2011). The principle of original horizontality is one of the most important principles for determining relative geological age, however, not all sedimentary beds are horizontal to begin with. Crossbeds begin as tilted beds, formed by sediment that accumulates on the slopes of ripples in the sediment. Therefore the cross-bedding is due to the downdraft. This could suggest a shallow marine environment, such as an alluvial area. In the case of unit two, the clean quartz sand may have been deposited in a flat, near-shore environment and the crossing beds have the sloping sides of the sand bars against which the sand layers were deposited (Waters, 2003) . Outcrops in the Eriboll district showed extensive cross-stratification. The depositional origin of the basal quartzite is probably marine in origin similar to unit three. My unit three equals the pipe rock formation. Outcrops were often purple in color due to coloration by iron manganese oxide (Mitchell et al., 2017), the vertical burrows observed in the pipe rock are useful as they act as natural deformation indicators, which can be used to evaluate thrust transport directions (Mitchell et al., 2017). This unit is mature, heavily bioturbated, with long vertical Skolithos burrows that probably belong to filter-feeding organisms. The abundant cylindrical burrows are oriented perpendicular to the bedding plane. These trace fossils are very useful for inferring the deposition environment of the unit, this organism would have existed in a near-shore, shallow subtidal, high-energy marine environment where food was delivered to the burrowing organism by currents and tides and sunlight would have been abundant for algae and suspended nutrients to thrive. My unit four is equivalent to the Fucoid beds, the outcrops were particularly rich in potassium which has been attributed to diagenesis following deposition of the Durness Limestone. The environment ofdeposition was probably an offshore shallow marine environment due to the presence of shallow marine fossils such as Skolithos. In the Fucoid unit it is possible to observe a number of fossils, including trace fossils formed by invertebrates excavating deposits. The presence of these fossils allows us to deduce a shallow marine, perhaps lagoonal, depositional environment. Low-angle graded, laminated planar beds may also indicate a storm-dominated tidal environment (Trewin, 2018). My unit five is equivalent to the Salterella Grit, the presence of calcified trace fossils of Salterella tube worms, in addition to the Skolithos burrows also seen in the pipe rock unit, suggests a marine environment of deposition. The worms would have burrowed into the silt on the bottom of a shallow sea. This unit perhaps represents a regressive episode during which sandboxes migrated onto a mud platform and were replaced by sand sheets indicative of renewed transgression (McKie 1990). My unit six is ​​equivalent to the Durness Limestone formation, only 30m of this unit has been observed but it continues over 1km thick. Fossils within the Durness Limestone are very rare, partly due to recrystallisation of the original limestone, but those still found, such as small cephalopods, gastropods and sponges, were exceptionally complex for their time. Some trace fossils can be observed such as burrow traces and ooids, now as rounded mineralized bodies, usually composed of calcite or aragonite. The sequence is extremely abundant in algal structures such as stromatolites. This life increased oxygen levels in Earth's atmosphere through photosynthesis, encouraging evolution to continue. This unit indicates a shallow marine depositional environment, due to planarization laminations have been observed in the outcrops (Scott, 2016). This type of environment would have created the necessary conditions for the now fossilized organisms to form. Some subsidence was also observed at the base of the limestone unit which may indicate an unstable paleoenvironment on the reef slope. The deposition of the carbonate that constitutes this unit usually occurs only in environments in which the siliciclastic supply in the water is missing, the siliciclastic supply increases the turbidity of the water which prevents the entry of light. Silicate minerals are much harder than carbonate, meaning that carbonate minerals would be eroded away from the silicates. Carbonate deposition usually requires warm water because this increases the abundance of carbonate-secreting organisms. Tectonic features within the mapped area: Features indicative of the Caledonian orogeny include shearing between beds and thrusts between tubular rock and limestone. The cross sections in my map are also helpful in illustrating these imbricate thrusts and faults. After the orogeny, deformation took place in the form of extensional faulting, evidence of this extensional regime are the slick sides on the fault planes. The geological history of the Eriboll region is broad, spanning from the Archean to the Holocene, and the outcrops provide a rich diversity of rock types. The basement of this region is the Lewis Gneiss, which is located in the south-eastern corner of the map, this unit was the first to form, approximately 3 billion years ago. Small outcrops of Lewisian gneiss can also be found at various other locations in the Eriboll region, but these small outcrops are likely to be fallen stones from glacial processes. The protolithic gneiss probably underwent high-grade metamorphism, then subsequently high-temperature reworking that formed migmatite (Scott, 2016). This was then followed by the.