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Argyll Group
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. Islay Subgroup The lower boundary of the Islay Subgroup and hence the Argyll Group as a whole is defined at the base of the Port Askaig tillite, a diamictite which displays limestone clasts overlain by quartzite and granite clasts. The tillite is thickest in its type area and on the Garvellachs. The Schiehallion Boulder Bed of the eastern Grampians correlates with this tillite. The tillite is overlain by the Bonahaven Dolomite and then the Jura Quartzite which can reach up to 5 km thick but which is more typically between 500 and 1000m thick. Psammites and pelites occur within the sequence in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group (stratigraphy)
In geology, a group is a lithostratigraphic unit consisting of a series of related formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into supergroups. Groups are useful for showing relationships between formations, and they are also useful for small-scale mapping or for studying the stratigraphy of large regions. Geologists exploring a new area have sometimes defined groups when they believe the strata within the groups can be divided into formations during subsequent investigations of the area. It is possible for only some of the strata making up a group to be divided into formations. An example of a group is the Glen Canyon Group, which includes (in ascending order) the Wingate Sandstone, the Moenave Formation, the Kayenta Formation, and the Navajo Sandstone. Each of the formations can be distinguished from its neighbor by its lithology, but all were deposited in the same vast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tillite
image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is diagnostic of till. image:Glacial till exposed in roadcut-750px.jpg, Glacial till with tufts of grass Till or glacial till is unsorted glacier, glacial sediment. Till is derived from the erosion and entrainment of material by the moving ice of a glacier. It is deposited some distance down-ice to form terminal, lateral, medial and ground moraines. Till is classified into primary deposits, laid down directly by glaciers, and secondary deposits, reworked by fluvial transport and other processes. Description Till is a form of ''glacial drift'', which is rock material transported by a glacier and deposited directly from the ice or from running water emerging from the ice. It is distinguished from other forms of drift in that it is deposi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moray Firth
The Moray Firth (; Scottish Gaelic: ''An Cuan Moireach'', ''Linne Mhoireibh'' or ''Caolas Mhoireibh'') is a roughly triangular inlet (or firth) of the North Sea, north and east of Inverness, which is in the Highland council area of north of Scotland. It is the largest firth in Scotland, stretching from Duncansby Head (near John o' Groats) in the north, in the Highland council area, and Fraserburgh in the east, in the Aberdeenshire council area, to Inverness and the Beauly Firth in the west. Therefore, three council areas have Moray Firth coastline: Highland to the west and north of the Moray Firth and Highland, Moray and Aberdeenshire to the south. The firth has more than 800 kilometres (about 500 miles) of coastline, much of which is cliff. Etymology The firth is named after the 10th-century Province of Moray, whose name in turn is believed to derive from the sea of the firth itself. The local names ''Murar'' or ''Morar'' are suggested to derive from , the Gaelic for sea, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knapdale
Knapdale ( gd, Cnapadal, IPA: kraʰpət̪əɫ̪ forms a rural district of Argyll and Bute in the Scottish Highlands, adjoining Kintyre to the south, and divided from the rest of Argyll to the north by the Crinan Canal. It includes two parishes, North Knapdale and South Knapdale. The area is bounded by sea to the east and west (Loch Fyne and the Sound of Jura respectively), whilst the sea loch of West Loch Tarbert almost completely cuts off the area from Kintyre to the south.Ordnance Survey. Landranger 1:50000 Map Sheet 55 (Lochgilphead & Loch Awe)Ordnance Survey. Landranger 1:50000 Map Sheet 62 (North Kintyre & Tarbert) The name is derived from two Gaelic elements: ''Cnap'' meaning hill and ''Dall'' meaning field. Knapdale gives its name to the Knapdale National Scenic Area, one of the forty national scenic areas in Scotland, which are defined so as to identify areas of exceptional scenery and to ensure their protection from inappropriate development. The designated area covers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jura, Scotland
Jura ( ; gd, Diùra; sco, Jura) is an island in the Inner Hebrides of Scotland, adjacent to and northeast of Islay. With an area of , and 196 inhabitants recorded in the 2011 census, Jura is more sparsely populated than Islay, and is one of the least densely populated islands of Scotland: in a list of the islands of Scotland ranked by size, Jura comes eighth, whereas by population it comes 31st. The island is mountainous, bare and largely infertile, covered by extensive areas of blanket bog. The main settlement is the east coast village of Craighouse. The Jura distillery, producing Isle of Jura single malt whisky, is in the village, as is the island's rum distillery which opened in 2021. Craighouse also houses the island's shop, church, primary school, the Jura hotel and bar, a gallery, craft shop, tearoom and the community run petrol pumps. North of Craighouse are a number of other small settlements on or near the east coast: Keils, Knockrome, Ardfernal, Lagg, Tarbert, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcaniclastic
Volcaniclastics are geologic materials composed of broken fragments (clasts) of volcanic rock. These encompass all clastic volcanic materials, regardless of what process fragmented the rock, how it was subsequently transported, what environment it was deposited in, or whether nonvolcanic material is mingled with the volcanic clasts. The United States Geological Survey defines volcaniclastics somewhat more narrowly, to include only rock composed of volcanic rock fragments that have been transported some distance from their place of origin. In the broad sense of the term, volcaniclastics includes pyroclastic rocks such as the Bandelier Tuff; cinder cones and other tephra deposits; the basal and capping breccia that characterize ʻaʻā lava flows; and lahars and debris flows of volcanic origin.Vincent 2000, pp.27-28 Volcaniclastics make up more of the volume of many volcanoes than do lava flows. Volcaniclastics may have contributed as much as a third of all sedimentation in the geolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phyllite
Phyllite ( ) is a type of foliated metamorphic rock created from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation.Stephen Marshak ''Essentials of Geology'', 3rd ed. It is primarily composed of quartz, sericite mica, and chlorite. Phyllite has fine-grained mica flakes, whereas slate has extremely fine mica flakes, and schist has large mica flakes, all mica flakes of which have achieved a preferred orientation. Among foliated metamorphic rocks, it represents a gradation in the degree of metamorphism between slate and schist. The minute crystals of graphite, sericite, or chlorite, or the translucent fine-grained white mica, impart a silky, sometimes golden sheen to the surfaces of cleavage, called "phyllitic luster". The word comes from the Greek ''phyllon'', meaning "leaf". The protolith (or parent rock) for phyllite is shale or pelite, or slate, which in turn came from a shale protolith. Its constituent platy minerals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Craignish
Craignish (Scottish Gaelic, ''Creiginis'') is a peninsula in Argyll, on the west coast of Scotland. It lies around south of Oban, and north-west of Lochgilphead. The peninsula is around long, and is aligned along a north-east to south-west orientation, in common with much of the landform of coastal Argyll. To the south is Loch Craignish, which contains several small islands. To the north are the Slate Islands, with the island of Shuna closest. Jura is only west of Craignish Point, the southern tip of Craignish. There are two main settlements on Craignish, Ardfern on the south coast, and the modern village of Craobh Haven, established in 1983 as a holiday resort and marina, on the north. A single-track road, the B8002, runs along the south shore of the peninsula. Historic monuments There are a number of ruined duns on Craignish, as well as cup and ring marked rocks. One such site is Dunan Aula, a cist said to commemorate a Viking prince so-named, who fell in battle against ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conglomerate (geology)
Conglomerate () is a clastic sedimentary rock that is composed of a substantial fraction of rounded to subangular gravel-size clasts. A conglomerate typically contains a matrix of finer-grained sediments, such as sand, silt, or clay, which fills the interstices between the clasts. The clasts and matrix are typically cemented by calcium carbonate, iron oxide, silica, or hardened clay. Conglomerates form by the consolidation and lithification of gravel. They can be found in sedimentary rock sequences of all ages but probably make up less than 1 percent by weight of all sedimentary rocks. In terms of origin and depositional mechanisms, they are closely related to sandstones and exhibit many of the same types of sedimentary structures, e.g., tabular and trough cross-bedding and graded bedding.Boggs, S. (2006) ''Principles of Sedimentology and Stratigraphy.'', 2nd ed. Prentice Hall, New York. 662 pp. Friedman, G.M. (2003) ''Classification of sediments and sedimentary rocks.'' In G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scarba
Scarba ( gd, Sgarba) is an island, in Argyll and Bute, Scotland, just north of the much larger island of Jura. The island was owned by Richard Hill, 7th Baron Sandys, and has not been permanently inhabited since the 1960s. It is now covered in heather and used for grazing animals. Kilmory Lodge is used seasonally as a shooting lodge, the island having a flourishing herd of red deer. The island's name is from the Norse and may mean "sharp, stony, hilly terrain" or "cormorant island".Mac an Tàilleir (2003) p. 104 Description Scarba is not served by any public ferries, but access from Craobh Haven or Crinan Harbour is possible by arrangement with local boatmen. The rough summit ridge can be accessed from the harbour at the north end, from where a vehicle track leads up past Kilmory Lodge to a height of about 200 metres. After that, there are no paths or well defined routes, and the terrain becomes rough and boggy. The island rises steeply to a peak (Cruach Scarba) of . A c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ladder Hills
The Ladder Hills ( gd, Monadh an Fhàraidh) 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 , 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 hills are formed for the most part from late Precambrian age metamorphosed sandstones and mudstones; quartzites, psammites, pelites and semipelites which together form the Ladder Hills and Kymah Quartzite formations. These are placed within the Islay Subgroup of the Argyll Group, itself a division of the late Dalradian Supergroup. Parts of the range are formed from carbonate rich rocks. Metadolerite dykes intrude this sequence in places. The rock strata are intensely folded and typically dip steeply to the southeast or northwest. The range takes its name from the Ladder Road, a high pas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartzite
Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to grey, though quartzites often occur in various shades of pink and red due to varying amounts of hematite. Other colors, such as yellow, green, blue and orange, are due to other minerals. The term ''quartzite'' is also sometimes used for very hard but unmetamorphosed sandstones that are composed of quartz grains thoroughly cemented with additional quartz. Such sedimentary rock has come to be described as orthoquartzite to distinguish it from metamorphic quartzite, which is sometimes called metaquartzite to emphasize its metamorphic origins. Quartzite is very resistant to chemical weathering and often forms ridges and resistant hilltops. The nearly pure silica conte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
