Mull Lava Group Stratigraphic range: Palaeocene epoch, Palaeogene | |
---|---|
Type | Group |
Sub-units | Mull Central Lava Formation, Mull Plateau Lava Formation, Staff Lava Formation |
Overlies | Moine Supergroup and Mesozoic sedimentary rocks |
Area | 840sq km |
Thickness | 1800 m (estimated) |
Lithology | |
Primary | basalt lavas |
Location | |
Country | Scotland |
Extent | Isle of Mull, Ardnamurchan, Morvern |
Type section | |
Named for | Isle of Mull |
The Mull Lava Group is a Palaeogene lithostratigraphic group (a sequence of rock strata) in the west Highlands of Scotland. The name is derived from the Isle of Mull where they are most extensively seen, forming the bedrock across much of the island. They extend into the mainland peninsulas of Ardnamurchan and Morvern and also out to sea.
The Group consists of around 1800 m thickness of lavas erupted from the Mull Central Volcanic Complex and display a range of chemistries. The Group includes (in descending order, i.e. oldest last):
These three formations were formerly known as the Staffa, Main and Pale ‘suites’ of the Plateau Group [1]
Staffa is an island of the Inner Hebrides in Argyll and Bute, Scotland. The Vikings gave it this name as its columnar basalt reminded them of their houses, which were built from vertically placed tree-logs.
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 northeastern 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 geology of Great Britain is renowned for its diversity. As a result of its eventful geological history, Great Britain shows a rich variety of landscapes across the constituent countries of England, Wales and Scotland. Rocks of almost all geological ages are represented at outcrop, from the Archaean onwards.
Ben More is the highest mountain and only Munro on the Isle of Mull, Scotland.
The geology of Scotland is unusually varied for a country of its size, with a large number of differing geological features. There are three main geographical sub-divisions: the Highlands and Islands is a diverse area which lies to the north and west of the Highland Boundary Fault; the Central Lowlands is a rift valley mainly comprising Palaeozoic formations; and the Southern Uplands, which lie south of the Southern Uplands Fault, are largely composed of Silurian deposits.
Watson's Dodd is a fell in the English Lake District, a minor rise on the main ridge of the Helvellyn range in the Eastern Fells, but a prominent shoulder on the west side of that range.
The North Atlantic Igneous Province (NAIP) is a large igneous province in the North Atlantic, centered on Iceland. In the Paleogene, the province formed the Thulean Plateau, a large basaltic lava plain, which extended over at least 1.3 million km2 (500 thousand sq mi) in area and 6.6 million km3 (1.6 million cu mi) in volume. The plateau was broken up during the opening of the North Atlantic Ocean leaving remnants existing in Northern Ireland, bits of western Scotland, the Faroe Islands, bits of northwestern Iceland, eastern Greenland and western Norway and many of the islands located in the north eastern portion of the North Atlantic Ocean. The igneous province is the origin of the Giant's Causeway and Fingal's Cave. The province is also known as Brito-Arctic province and the portion of the province in the British Isles is also called the British Tertiary Volcanic Province or British Tertiary Igneous Province.
The Fintry Hills form the western end of a range of hills which stretch west from the city of Stirling, Scotland. They culminate in the 511-metre (1,677 ft) peak of Stronend, which overlooks Strathendrick and the village of Fintry.
For the Skiddaw group of hills, see Skiddaw Group
In geology, the Inner Hebrides Group is a lithostratigraphical division containing a range of rocks mainly of Upper Cretaceous age which occur around the west coast of the Scottish Highlands. It comprises the following formations:
The geology of Skye in Scotland is highly varied and the island's landscape reflects changes in the underlying nature of the rocks. A wide range of rock types are exposed on the island, sedimentary, metamorphic and igneous, ranging in age from the Archaean through to the Quaternary.
The geology of County Durham in northeast England consists of a basement of Lower Palaeozoic rocks overlain by a varying thickness of Carboniferous and Permo-Triassic sedimentary rocks which dip generally eastwards towards the North Sea. These have been intruded by a pluton, sills and dykes at various times from the Devonian Period to the Palaeogene. The whole is overlain by a suite of unconsolidated deposits of Quaternary age arising from glaciation and from other processes operating during the post-glacial period to the present. The geological interest of the west of the county was recognised by the designation in 2003 of the North Pennines Area of Outstanding Natural Beauty as a European Geopark.
The geology of Tyne and Wear in northeast England largely consists of a suite of sedimentary rocks dating from the Carboniferous and Permian periods into which were intruded igneous dykes during the later Palaeogene Period.
The geology of Northumberland in northeast England includes a mix of sedimentary, intrusive and extrusive igneous rocks from the Palaeozoic and Cenozoic eras. Devonian age volcanic rocks and a granite pluton form the Cheviot massif. The geology of the rest of the county is characterised largely by a thick sequence of sedimentary rocks of Carboniferous age. These are intruded by both Permian and Palaeogene dykes and sills and the whole is overlain by unconsolidated sediments from the last ice age and the post-glacial period. The Whin Sill makes a significant impact on Northumberland's character and the former working of the Northumberland Coalfield significantly influenced the development of the county's economy. The county's geology contributes to a series of significant landscape features around which the Northumberland National Park was designated.
The geology of the Isle of Man consists primarily of a thick pile of sedimentary rocks dating from the Ordovician period, together with smaller areas of later sedimentary and extrusive igneous strata. The older strata was folded and faulted during the Caledonian and Acadian orogenies The bedrock is overlain by a range of glacial and post-glacial deposits. Igneous intrusions in the form of dykes and plutons are common, some associated with mineralisation which spawned a minor metal mining industry.
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 geology of Northumberland National Park in northeast England includes a mix of sedimentary, intrusive and extrusive igneous rocks from the Palaeozoic and Cenozoic eras. Devonian age volcanic rocks and a granite pluton form the Cheviot massif. The geology of the rest of the national park is characterised largely by a thick sequence of sedimentary rocks of Carboniferous age. These are intruded by Permian dykes and sills, of which the Whin Sill makes a significant impact in the south of the park. Further dykes were intruded during the Palaeogene period. The whole is overlain by unconsolidated sediments from the last ice age and the post-glacial period.
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.
Loch Spelve is a sea loch on the southeast coast of the Isle of Mull, off the west coast of Scotland. It is almost landlocked with a relatively narrow opening onto the Firth of Lorn. The A849 road runs past the northern arm of the loch and a minor road runs south from it and around the shore of the western arm via Kinlochspelve as far as the settlement of Croggan. Raised beaches are notable features of the loch, particularly on the shores of the narrows through which it enters the open waters of the firth. There are a few rocky islets within the loch, the largest of which is Eilean Amalaig on which are the ruins of a castle. There is a terminal moraine at Kinlochspelve dating from the last ice age. The southern and eastern shores of Loch Spelve are formed from basalt lava flows of Palaeogene age, intruded by numerous dolerite dykes. The northern and western shores are formed in granophyres and Triassic sandstones, the latter intruded by olivine-dolerite cone sheets associated with the Palaeogene volcanism. Though unseen at the surface, the Great Glen Fault is usually considered to run beneath this loch and nearby Loch Buie.
Loch Don is a sea loch on the east coast of the Isle of Mull, off the west coast of Scotland. It is an intricately shaped loch opening onto the Firth of Lorn near the easternmost point of Mull. Its waters are shallow and the loch dries almost completely at low tide. The community of Lochdon sits on the A849 at the head of the loch. A minor road runs south from Lochdon and around to Grass Point at the point where the loch meets the open waters of the firth. There are both a terminal moraine and deltaic sand deposits around the northern end of the loch, a product of meltwater flow at the end of the last ice age. The shores of the outer part of the loch are formed from basalt lava flows of Palaeogene age whilst the inner parts of the loch extend across Palaeozoic basalt and also Mesozoic sedimentary rocks including Triassic sandstones and Jurassic Lias strata.