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.
Argyll, sometimes called Argyllshire, is a historic county and registration county of western Scotland.
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 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 Moine Supergroup is a sequence of Neoproterozoic metamorphic rocks that form the dominant outcrop of the Scottish Highlands between the Moine Thrust Belt to the northwest and the Great Glen Fault to the southeast. The sequence is metasedimentary in nature and was metamorphosed and deformed in a series of tectonic events during the Late Proterozoic and Early Paleozoic. It takes its name from A' Mhòine, a peat bog in northern Sutherland.
The Rhinns complex is a deformed Palaeoproterozoic igneous complex that is considered to form the basement to the Colonsay Group of metasedimentary rocks. The largest outcrop of the complex is on the Rhinns of Islay, from where the complex gets its name. It has also been recognised in three other inliers extending to the southwest as far as Inishtrahull, off the north coast of County Donegal.
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 Bowmore Sandstone Group is a sequence of metasedimentary rocks, dominantly sandstones, of probable Neoproterozoic age. Their outcrop on the island of Islay in the Inner Hebrides is entirely fault-bounded, between the Loch Gruinart Fault to the west and the Loch Skerrols Shear Zone to the east.
The Grampian Group is an estimated 9,000 m thick sequence of metamorphosed Neoproterozoic sedimentary rocks that outcrop across the Central Highlands of Scotland, east of the Great Glen. It forms a part of the Dalradian Supergroup. The sequence thickness at any one place is limited to 5km.
The Appin Group is a thick sequence of metamorphosed Neoproterozoic sedimentary rocks that outcrop across the Central Highlands of Scotland, east of the Great Glen. It forms a part of the Dalradian Supergroup.
The Southern Highland Group is a sequence of metamorphosed Neoproterozoic sedimentary rocks that outcrop across the Central Highlands of Scotland, east of the Great Glen. It forms the uppermost/youngest part of the Dalradian Supergroup and is divided into two formations. Volcanism is recorded by the Loch Avich Lavas Formation which divides the Loch Avich Grits Formation into lower and upper parts – the grits are turbidite and submarine fan deposits. In Perthshire and on Deeside, the Leny Limestone, which has been dated to 514 Ma, is present. A tillite, the Macduff Boulder Bed is known from the upper part of the group in northeast Scotland.
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.
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 Ladder Hills are a range of hills in northeast Scotland which straddle the border between Aberdeenshire and Moray and form a part of the Grampian Mountains. The highest point of the range is Càrn Mòr at 804 metres (2,638 ft), which is classed as a Corbett; other named tops include Monadh an t-Sluich Leith (800m), Carn Liath (792m), Dun Muir (754m) and Little Geal Charn (742m).
The geology of national parks in Britain strongly influences the landscape character of each of the fifteen such areas which have been designated. There are ten national parks in England, three in Wales and two in Scotland. Ten of these were established in England and Wales in the 1950s under the provisions of the National Parks and Access to the Countryside Act 1949. With one exception, all of these first ten, together with the two Scottish parks were centred on upland or coastal areas formed from Palaeozoic rocks. The exception is the North York Moors National Park which is formed from sedimentary rocks of Jurassic age.
The geology of Loch Lomond and The Trossachs National Park in the southwestern part of the Scottish Highlands consists largely of Neoproterozoic and Palaeozoic bedrock faulted and folded and subjected to low grade metamorphism during the Caledonian orogeny. These older rocks, assigned to the Dalradian Supergroup, lie to the northwest of the northeast – southwest aligned Highland Boundary Fault which defines the southern edge of the Highlands. A part of this mountainous park extends south of this major geological divide into an area characterised by younger Devonian rocks which are assigned to the Old Red Sandstone.
The Grampian orogeny was an orogeny mountain building event which affected Scotland in the middle of the Ordovician. At the time, Scotland was part of proto-North American continent Laurentia.
The geology of the Isle of Mull in Scotland is dominated by the development during the early Palaeogene period of a ‘volcanic central complex’ associated with the opening of the Atlantic Ocean. The bedrock of the larger part of the island is formed by basalt lava flows ascribed to the Mull Lava Group erupted onto a succession of Mesozoic sedimentary rocks during the Palaeocene epoch. Precambrian and Palaeozoic rocks occur at the island's margins. A number of distinct deposits and features such as raised beaches were formed during the Quaternary period.
