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Hibernian Greensands Group
The Hibernian Greensands Group is a late Cretaceous lithostratigraphic group (a sequence of rock strata) in Northern Ireland. It is Cenomanian to Santonian in age. The name is derived from the characteristically coloured marls and sandstones which occur beneath the chalk particularly along the Antrim coast. The strata are exposed on or near to both the northern and eastern coasts of Antrim and also between Portrush and Dungiven within County Londonderry. Further outcrops occur between Belfast and Lurgan and between Dungannon and Magherafelt. It unconformably overlies a variety of units from the Metamorphic Precambrian Southern Highland Group to the Lower Jurassic Lias. The current names replace an earlier situation where the present group was considered to be a formation and each of the present formations was considered a 'member'. Several other stratigraphic naming schemes were in use during the nineteenth century and much of the twentieth century. Various units were ear ... [...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] |
Marl
Marl is an earthy material rich in carbonate minerals, clays, and silt. When hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. Marl makes up the lower part of the cliffs of Dover, and the Channel Tunnel follows these marl layers between France and the United Kingdom. Marl is also a common sediment in post-glacial lakes, such as the marl ponds of the northeastern United States. Marl has been used as a soil conditioner and neutralizing agent for acid soil and in the manufacture of cement. Description Marl or marlstone is a carbonate-rich mud or mudstone which contains variable amounts of clays and silt. The term was originally loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay and calcium carbonate, formed under freshwater conditions. These typically contain 35–65% clay and 65–35% carbonate. The te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unconformity
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record. The significance of angular unconformity (see below) was shown by James Hutton, who found examples of Hutton's Unconformity at Jedburgh in 1787 and at Siccar Point in 1788. The rocks above an unconformity are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents time during which no sediments were preserved in a region or were subsequently eroded before the next deposition. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area. The interval of geologic time not represented is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalk Group
The Chalk Group (often just called the Chalk) is the lithostratigraphic unit (a certain number of rock strata) which contains the Upper Cretaceous limestone succession in southern and eastern England. The same or similar rock sequences occur across the wider northwest European chalk 'province'. It is characterised by thick deposits of chalk, a soft porous white limestone, deposited in a marine environment. Chalk is a limestone that consists of coccolith biomicrite. A biomicrite is a limestone composed of fossil debris ("bio") and calcium carbonate mud ("micrite"). Most of the fossil debris in chalk consists of the microscopic plates, which are called coccoliths, of microscopic green algae known as coccolithophores. In addition to the coccoliths, the fossil debris includes a variable, but minor, percentage of the fragments of foraminifera, ostracods and mollusks. The coccolithophores lived in the upper part of the water column. When they died, the microscopic calcium carbonate p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lias Group
The Lias Group or Lias is a lithostratigraphic unit (a sequence of rock strata) found in a large area of western Europe, including the British Isles, the North Sea, the Low Countries and the north of Germany. It consists of marine limestones, shales, marls and clays. ''Lias'' is a Middle English term for hard limestone, used in this specific sense by geologists since 1833. In the past, geologists used ''Lias'' not only for the sequence of rock layers, but also for the timespan during which they were formed. It was thus an alternative name for the Early Jurassic epoch of the geologic timescale. It is now more specifically known that the Lias is Rhaetian to Toarcian in age (over a period of 20 million years between ) and thus also includes a part of the Triassic. The use of the name "Lias" for a unit of time is therefore slowly disappearing. Subdivisions In southern England, the Lias Group is often divided into Lower, Middle and Upper subgroups. In Southern England the Lias is d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Highland Group
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 Perthshire (locally: ; gd, Siorrachd Pheairt), officially the County of Perth, is a historic county and registration county in central Scotland. Geographically it extends from Strathmore in the east, to the Pass of Drumochter in the north, ... 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. References {{Reflist Geology of Scotland ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magherafelt
Magherafelt (, mˠaxəɾʲəˈfʲiːlt̪ˠə is a small town and civil parish in County Londonderry, Northern Ireland. It had a population of 8,805 at the 2011 Census. It is the biggest town in the south of the county and is the social, economic and political hub of the area. It is part of Mid-Ulster District. History Magherafelt has been documented as a town since 1425. An earlier name for the area was ''Teach Fíolta'' - ‘Fíolta’s (monastic) house’. This would suggest that there was a monastic settlement here under the leadership of Fíolta. The site of the medieval parish church may be marked by the ruins of a later church and graveyard at the bottom of Broad Street. The Salters Company of London was granted the surrounding lands in South Londonderry in the seventeenth century as part of the Plantation of Ulster. Subsequently, the town began to take on its current shape with a central diamond forming the heart of the town. During The Troubles in the late 20th c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dungannon
Dungannon () is a town in County Tyrone, Northern Ireland. It is the second-largest town in the county (after Omagh) and had a population of 14,340 at the 2011 Census. The Dungannon and South Tyrone Borough Council had its headquarters in the town, though since 2015 it has been covered by Mid-Ulster District Council. For centuries, it was the 'capital' of the O'Neill dynasty of Tír Eoghain, who dominated most of Ulster and built a castle on the hill. After the O'Neills' defeat in the Nine Years' War, the English founded a plantation town on the site, which grew into what is now Dungannon. Dungannon has won Ulster in Bloom's Best Kept Town Award five times. It currently has the highest percentage of immigrants of any town in Northern Ireland. History For centuries, Dungannon's fortunes were closely tied to that of the O'Neill dynasty which ruled a large part of Ulster until the 17th century. Dungannon was the clan's main stronghold. The traditional site of inauguration f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lurgan
Lurgan () is a town in County Armagh, Northern Ireland, near the southern shore of Lough Neagh. Lurgan is about south-west of Belfast and is linked to the city by both the M1 motorway and the Belfast–Dublin railway line. It had a population of about 25,000 at the 2011 Census and is within the Armagh, Banbridge and Craigavon district. For some purposes, Lurgan is treated as part of the "Craigavon Urban Area" along with neighbouring Craigavon and Portadown. Lurgan is characteristic of many Plantation of Ulster settlements, with its straight, wide planned streets. It is the site of a number of historic listed buildings including Brownlow House and Lurgan Town Hall. Lurgan Park is the largest urban park in Northern Ireland. Historically the town was known as a major centre for the production of textiles (mainly linen) after the industrial revolution and it continued to be a major producer of textiles until that industry steadily declined in the late 20th century. The develop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belfast
Belfast ( , ; from ga, Béal Feirste , meaning 'mouth of the sand-bank ford') is the capital and largest city of Northern Ireland, standing on the banks of the River Lagan on the east coast. It is the 12th-largest city in the United Kingdom and the second-largest in Ireland. It had a population of 345,418 . By the early 19th century, Belfast was a major port. It played an important role in the Industrial Revolution in Ireland, briefly becoming the biggest linen-producer in the world, earning it the nickname "Linenopolis". By the time it was granted city status in 1888, it was a major centre of Irish linen production, tobacco-processing and rope-making. Shipbuilding was also a key industry; the Harland and Wolff shipyard, which built the , was the world's largest shipyard. Industrialisation, and the resulting inward migration, made Belfast one of Ireland's biggest cities. Following the partition of Ireland in 1921, Belfast became the seat of government for Northern Ireland ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
County Londonderry
County Londonderry ( Ulster-Scots: ''Coontie Lunnonderrie''), also known as County Derry ( ga, Contae Dhoire), is one of the six counties of Northern Ireland, one of the thirty two counties of Ireland and one of the nine counties of Ulster. Before the partition of Ireland, it was one of the counties of the Kingdom of Ireland from 1613 onward and then of the United Kingdom after the Acts of Union 1800. Adjoining the north-west shore of Lough Neagh, the county covers an area of and today has a population of about 247,132. Since 1972, the counties in Northern Ireland, including Londonderry, have no longer been used by the state as part of the local administration. Following further reforms in 2015, the area is now governed under three different districts; Derry and Strabane, Causeway Coast and Glens and Mid-Ulster. Despite no longer being used for local government and administrative purposes, it is sometimes used in a cultural context in All-Ireland sporting and cultural even ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dungiven
Dungiven () is a small town, townland and civil parish in County Londonderry, Northern Ireland. It is near the main A6 Belfast to Derry road, which bypasses the town. It lies where the rivers Roe, Owenreagh and Owenbeg meet at the foot of the Benbradagh. Nearby is the Glenshane Pass, where the road rises to over . It had a population of 3,288 people in the 2011 Census, an increase of 10% over the 2001 population of 2,993. It is within Causeway Coast and Glens district council area. History There is evidence of settlement in the area for at least 1000 years. There may have been an abbey in the area around 700AD. The Augustinian abbey of St Mary's was built in the 11th century. Its ruins contain the tomb of O'Cahan (Cooey na Gall O' Cahan), laid to rest in 1385. A thicket of thorn bushes hung with rags conceals a bullaun stone, visited for wart cures. Between the 12th and 17th centuries the area was ruled by the Ó Catháin clan, one of the most influential clans in Ulster The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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