The Old Red Sandstone is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the eastern seaboard of North America. It also extends northwards into Greenland and Svalbard. These areas were a part of the ancient continent of Euramerica/Laurussia. In Britain it is a lithostratigraphic unit to which stratigraphers accord supergroup status and which is of considerable importance to early paleontology. For convenience the short version of the term, ORS is often used in literature on the subject. The term was coined to distinguish the sequence from the younger New Red Sandstone which also occurs widely throughout Britain.
The Great Glen Fault is a strike-slip fault that runs through the Great Glen in Scotland. The fault is mostly inactive today, but occasional moderate tremors have been recorded over the past 150 years.
The Acadian orogeny is a long-lasting mountain building event which began in the Middle Devonian, reaching a climax in the early Late Devonian. It was active for approximately 50 million years, beginning roughly around 375 million years ago, with deformational, plutonic, and metamorphic events extending into the Early Mississippian. The Acadian orogeny is the third of the four orogenies that formed the Appalachian orogen and subsequent basin. The preceding orogenies consisted of the Potomac and Taconic orogeny, which followed a rift/drift stage in the Late Neoproterozoic. The Acadian orogeny involved the collision of a series of Avalonian continental fragments with the Laurasian continent. Geographically, the Acadian orogeny extended from the Canadian Maritime provinces migrating in a southwesterly direction toward Alabama. However, the Northern Appalachian region, from New England northeastward into Gaspé region of Canada, was the most greatly affected region by the collision.
The Moine Thrust Belt or Moine Thrust Zone is a linear tectonic feature in the Scottish Highlands which runs from Loch Eriboll on the north coast 190 kilometres (120 mi) south-west to the Sleat peninsula on the Isle of Skye. The thrust belt consists of a series of thrust faults that branch off the Moine Thrust itself. Topographically, the belt marks a change from rugged, terraced mountains with steep sides sculptured from weathered igneous, sedimentary and metamorphic rocks in the west to an extensive landscape of rolling hills over a metamorphic rock base to the east. Mountains within the belt display complexly folded and faulted layers and the width of the main part of the zone varies up to 10 kilometres (6.2 mi), although it is significantly wider on Skye.
The Highland Boundary Fault is a major fault zone that traverses Scotland from Arran and Helensburgh on the west coast to Stonehaven in the east. It separates two different geological terranes which give rise to two distinct physiographic terrains: the Highlands and the Lowlands, and in most places it is recognisable as a change in topography. Where rivers cross the fault, they often pass through gorges, and the associated waterfalls can be a barrier to salmon migration.
The Caledonian orogeny was a mountain-building cycle recorded in the northern parts of the British Isles, the Scandinavian Caledonides, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that occurred from the Ordovician to Early Devonian, roughly 490–390 million years ago (Ma). It was caused by the closure of the Iapetus Ocean when the Laurentia and Baltica continents and the Avalonia microcontinent collided.
The Dalradian Supergroup is a stratigraphic unit in the lithostratigraphy of the Grampian Highlands of Scotland and in the north and west of Ireland. The diverse assemblage of rocks which constitute the supergroup extend across Scotland from Islay in the west to Fraserburgh in the east and are confined by the Great Glen Fault to the northwest and the Highland Boundary Fault to the southeast. Much of Shetland east of the Walls Boundary Fault is also formed from Dalradian rocks. Dalradian rocks extend across the north of Ireland from County Antrim in the north east to Clifden on the Atlantic coast, although obscured by later Palaeogene lavas and tuffs or Carboniferous rocks in large sections.
The Argyll Group is a thick sequence of metamorphosed Neoproterozoic sedimentary rocks that outcrop across the Central Highlands of Scotland, east of the Great Glen, as well as appearing in the north of Ireland. It is a subdivision of the Dalradian Supergroup and is itself divided into four units; from oldest to youngest these are the Islay, Easdale, Crinan and Tayvallich subgroups.
The geological structure of Great Britain is complex, resulting as it does from a long and varied geological history spanning more than two billion years. This piece of the Earth's crust has experienced several episodes of mountain building or 'orogenies', each of which has added further complexity to the picture.
The Lewisian complex or Lewisian gneiss is a suite of Precambrian metamorphic rocks that outcrop in the northwestern part of Scotland, forming part of the Hebridean Terrane and the North Atlantic Craton. These rocks are of Archaean and Paleoproterozoic age, ranging from 3.0–1.7 billion years (Ga). They form the basement on which the Torridonian and Moine Supergroup sediments were deposited. The Lewisian consists mainly of granitic gneisses with a minor amount of supracrustal rocks. Rocks of the Lewisian complex were caught up in the Caledonian orogeny, appearing in the hanging walls of many of the thrust faults formed during the late stages of this tectonic event.
The Hebridean Terrane is one of the terranes that form part of the Caledonian orogenic belt in northwest Scotland. Its boundary with the neighbouring Northern Highland Terrane is formed by the Moine Thrust Belt. The basement is formed by Archaean and Paleoproterozoic gneisses of the Lewisian complex, unconformably overlain by the Neoproterozoic Torridonian sediments, which in turn are unconformably overlain by a sequence of Cambro–Ordovician sediments. It formed part of the Laurentian foreland during the Caledonian continental collision.
The Colonsay Group is an estimated 5,000 m thick sequence of mildly metamorphosed Neoproterozoic sedimentary rocks that outcrop on the islands of Colonsay, Islay and Oronsay and the surrounding seabed. They have been correlated with the Grampian Group, the oldest part of the Dalradian Supergroup.
The North Sea basin is located in northern Europe and lies between the United Kingdom, and Norway just north of The Netherlands and can be divided into many sub-basins. The Southern North Sea basin is the largest gas producing basin in the UK continental shelf, with production coming from the lower Permian sandstones which are sealed by the upper Zechstein salt. The evolution of the North Sea basin occurred through multiple stages throughout the geologic timeline. First the creation of the Sub-Cambrian peneplain, followed by the Caledonian Orogeny in the late Silurian and early Devonian. Rift phases occurred in the late Paleozoic and early Mesozoic which allowed the opening of the northeastern Atlantic. Differential uplift occurred in the late Paleogene and Neogene. The geology of the Southern North Sea basin has a complex history of basinal subsidence that had occurred in the Paleozoic, Mesozoic, and Cenozoic. Uplift events occurred which were then followed by crustal extension which allowed rocks to become folded and faulted late in the Paleozoic. Tectonic movements allowed for halokinesis to occur with more uplift in the Mesozoic followed by a major phase of inversion occurred in the Cenozoic affecting many basins in northwestern Europe. The overall saucer-shaped geometry of the southern North Sea Basin indicates that the major faults have not been actively controlling sediment distribution.
The Nordfjord—Sogn Detachment (NSD) is a major extensional shear zone in Norway up to 6 km in thickness, which extends about 120 km along strike from Nordfjord to Sognefjord, bringing Devonian continental coarse clastic sedimentary rocks into close contact with eclogite facies metamorphic rocks of the Western Gneiss Region. It formed towards the end of the Caledonian Orogeny and was mainly active during the Devonian. It has an estimated displacement of at least 70 km and possibly as much as 110 km. It was reactivated during the Mesozoic and may have influenced the development of fault structures in the North Sea rift basin.
The Badenoch Group is a sequence of metamorphosed Tonian age sedimentary rocks that outcrop across the Central Highlands of Scotland, east of the Great Glen. This rock sequence has formerly been referred to as the Central Highland Migmatite Complex and the Central Highland Division.
The Highlands controversy was a scientific controversy which started between British geologists in the middle of the nineteenth century concerning the nature of the rock strata in the Northwest Highlands of Scotland. The debate became contentious, even acrimonious, because of some of the personalities involved and because it pitted professional geologists of the Geological Survey against academic and amateur geologists. An initial resolution was achieved by about 1886 but the great complexity and scientific importance of the discovery of the Moine Thrust Belt and the geological processes involved in its creation led to field work continuing for a further twenty years culminating in the 1907 publication by the Geological Survey of a book of fundamental geological significance: The Geological Structure of the North-West Highlands of Scotland.
This article describes the geology of the Cairngorms National Park, an area in the Highlands of Scotland designated as a national park in 2003 and extended in 2010. The Cairngorms National Park extends across a much wider area than the Cairngorms massif itself and hence displays rather more varied geology.
The Durness Group is a geological group, a carbonate-dominated stratigraphic unit that forms a c. 170 km long narrow and discontinuous outcrop belt along the north-western coast of Scotland from the Isle of Skye and Loch Kishorn in the south to Durness and Loch Eriboll in the north. It forms the youngest part of the foreland basin of the Moine Thrust Belt in the Scottish Northwest Highlands and is incorporated into this belt's lowermost thrust sheets, where it is often affected by thrust faulting. It overlies the Ardvreck Group.
The geology of South Korea includes rocks dating to the Archean and two large massifs of metamorphic rock as the crystalline basement, overlain by thick sedimentary sequences, younger metamorphic rocks and volcanic deposits. Although extent is small, Geology is diverse, and there are diverse rocks that were formed during the Precambrian to Cenozoic Era in the Korea Peninsula.
The Hornelen Basin is a sedimentary basin in Vestland, Norway, containing an estimated 25 km stratigraphic thickness of coarse clastic sedimentary rocks of Devonian age. It forms part of a group of basins of similar age along the west coast of Norway between Sognefjord and Nordfjord, related to movement on the Nordfjord-Sogn Detachment. It formed as a result of extensional tectonics as part of the post-orogenic collapse of crust that was thickened during the Caledonian Orogeny towards the end of the Silurian period. It is named for the mountain Hornelen on the northern margin of the basin.
