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Aberystwyth Grits Group
The Aberystwyth Grits Group is a Silurian lithostratigraphic group (a sequence of rock strata) in mid Wales. The name is derived from Aberystwyth in northern Ceredigion where the strata are well exposed in coastal cliffs. The Group comprises the Trefechan Formation and the underlying Mynydd Bach Formation. The rocks of the Aberystwyth Grits Group have also previously been known as the Aberystwyth Grits Formation Outcrops These rocks are exposed, along the Cardigan Bay coast both to the east and west of New Quay and northwards through Aberaeron and Aberystwyth to just short of Borth. They extend eastwards, though are usually obscured, in a belt of country between roughly 5 km and 10 km wide reaching from the coast. Much of the eastern boundary is defined by the Bronnant Fault. Lithology and stratigraphy The Group comprises several hundred metres thickness of mudstone and sandstone turbidites laid down in the marine Welsh Basin The Welsh Basin was a northeast-southwest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbidite
A turbidite is the geologic deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. Sequencing Turbidites were first properly described by Arnold H. Bouma (1962), who studied deepwater sediments and recognized particular "fining-up intervals" within deep water, fine-grained shales, which were anomalous because they started at pebble conglomerates and terminated in shales. This was anomalous because within the deep ocean it had historically been assumed that there was no mechanism by which tractional flow could carry and deposit coarse-grained sediments into the abyssal depths. Bouma cycles begin with an erosional contact of a coarse lower bed of pebble to granule conglomerate in a sandy matrix, and grade up through coarse then medium plane parallel sandstone; through cross-bedded sandstone; rippled cross-bedded sand/silty sand, and finally lami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceredigion
Ceredigion ( , , ) is a county in the west of Wales, corresponding to the historic county of Cardiganshire. During the second half of the first millennium Ceredigion was a minor kingdom. It has been administered as a county since 1282. Ceredigion is considered a centre of Welsh culture and just under half of the population can speak Welsh according to the 2011 Census. The county is mainly rural, with over of coastline and a mountainous hinterland. The numerous sandy beaches and the long-distance Ceredigion Coast Path provide views of Cardigan Bay. In the 18th and early 19th centuries, Cardiganshire had more industry than it does today; Cardigan was the commercial centre of the county; lead, silver and zinc were mined and Cardigan was the principal port of South Wales prior to the silting of its harbour. The economy became highly dependent on dairy farming and the rearing of livestock for the English market. During the 20th century, livestock farming became less profitable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian System Of Europe
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods (myriapods, arachnids and hexapods) became fully terrestrialized. A significant evolutionary milestone durin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welsh Basin
The Welsh Basin was a northeast-southwest aligned back-arc depositional basin during the Cambrian, Ordovician and Silurian periods during which a considerable thickness of marine sediments was laid down in the area. To the southeast lay the Midland Platform (a part of the micro-continent of Avalonia) and to the northwest, within the Iapetus Ocean, through what is now Ireland and the Lake District, was an island arc; a northeast-southwest aligned Irish Sea landmass which was associated with volcanic activity. Examination of the sediments and associated fossils allows the deeper centre of the basin to be distinguished from shallower 'platform' areas along its southeastern margins. From the middle Silurian onwards, collision of Avalonia with the more northerly continent of Laurentia occurred giving rise to the Caledonian Orogeny. The inversion of the basin occurred at that time i.e. its uplift and deformation. The southeastern limit of the Welsh Basin can be defined as the Welsh Bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronnant Fault
The Bronnant Fault is a geological fault affecting the lower Palaeozoic rocks of the counties of Ceredigion and Pembrokeshire in West Wales. The feature is mapped over part of its length as the Bronnant Fault Zone and is closely associated with the Glandyfi Lineament, a similarly aligned zone of faulting and folding. The rocks of the Aberystwyth Grits Group dating from the Llandovery epoch of the Silurian period thicken markedly to the west of the fault suggesting it was active at the time of their deposition. North of Lledrod its alignment is affected by cross-cutting east–west faults, including the Ystwyth Fault Zone. Its alignment is sub-parallel to the coast of Cardigan Bay thus curving from a north–south alignment in the north through a northeast–southwest alignment until it merges with broadly east–west aligned faults in northeast Pembrokeshire.British Geological Survey 2010 Fishguard. England and Wales sheet 210. Bedrock and superficial deposits. 1:50,000 (Keyworth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borth
Borth ( cy, Y Borth) is a village and seaside resort in Ceredigion, Mid Wales, 7 miles (11 km) north of Aberystwyth on the Ceredigion Coast Path. The community includes the settlement of Ynyslas. The population was 1,399 in 2011. From being largely Welsh-speaking, the village has become anglicised: over 54 per cent of its residents were born in England. According to both the 1991 and 2001 censuses, 43 per cent of the residents of Borth were primarily Welsh-speakers. Features and history Borth's sandy beach has helped to promote it as a seaside resort. There is a youth hostel in the village, and caravan and camping sites nearby. There is an ancient submerged forest visible at low tide along the beach, where stumps of oak, pine, birch, willow and hazel (preserved by the acid anaerobic conditions in the peat) can be seen. Radiocarbon dating suggests the trees date from about 1500 BCE. This submerged forest also ties in with the legend of Cantre'r Gwaelod. The stumps were e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aberaeron
Aberaeron, previously anglicised as Aberayron, is a town, community, and electoral ward between Aberystwyth and Cardigan, in Ceredigion, Wales. Ceredigion County Council offices are in Aberaeron. The name of the town is Welsh for ''mouth of the Aeron'', derived from the Middle Welsh ', "slaughter", which gave its name to Aeron, who is believed to have been a Welsh god of war. The population was 1,520 in 2001, and 1,422 in 2011. History and design In 1800, there was no significant coastal settlement here. The present town was planned and developed from 1805 by the Rev. Alban Thomas Jones Gwynne. He built a harbour which operated as a port and supported a shipbuilding industry in the 19th century. A group of workmen's houses and a school were built on the harbour's north side, but these were reclaimed by the sea. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Quay
New Quay ( cy, Cei Newydd) is a seaside town (and electoral ward) in Ceredigion, Wales, with a resident population of around 1,200 people, reducing to 1,082 at the 2011 census. Located south-west of Aberystwyth on Cardigan Bay with a harbour and large sandy beaches, it lies on the Ceredigion Coast Path. It remains a popular seaside resort and traditional fishing town, with strong family and literary associations with the poet Dylan Thomas, and his play, ''Under Milk Wood''. History Until the early 19th century, New Quay consisted of a few thatched cottages surrounded by agricultural land, the natural harbour providing a safe mooring for fishing boats and a few small trading vessels. The New Quay Harbour Act was passed in 1834 and a stone pier was constructed at a cost of £4,700. Trading activity increased and new houses were built as economic migrants arrived. Shipbuilding began to take place and the town increased in size with the construction of terraced housing up the slo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardigan Bay
Cardigan Bay ( cy, Bae Ceredigion) is a large inlet of the Irish Sea, indenting the west coast of Wales between Bardsey Island, Gwynedd in the north, and Strumble Head, Pembrokeshire at its southern end. It is the largest bay in Wales. Geography Cardigan Bay has numerous beaches, and marine life. Much of the coast surrounding the bay is fertile farmland, dotted with towns and seaside resorts such as Fishguard Fishguard ( cy, Abergwaun, meaning "Mouth of the River Gwaun") is a coastal town in Pembrokeshire, Wales, with a population of 3,419 in 2011; the community of Fishguard and Goodwick had a population of 5,407. Modern Fishguard consists of two p ..., New Quay, Aberaeron, Llanon, Aberystwyth, Borth, Aberdyfi, Tywyn, Barmouth, Porthmadog, Criccieth and Pwllheli on the Cambrian Coast. Smaller coastal villages include Cwmtydu, Nanternis and Llangrannog. Major rivers flowing into the bay include the Afon Glaslyn, Glaslyn, River Mawddach, Mawddach, River Dysynni, Dysynni, Ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratum
In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as either '' bedding surfaces'' or ''bedding planes''.Salvador, A. ed., 1994. ''International stratigraphic guide: a guide to stratigraphic classification, terminology, and procedure. 2nd ed.'' Boulder, Colorado, The Geological Society of America, Inc., 215 pp. . Prior to the publication of the International Stratigraphic Guide, older publications have defined a stratum as either being either equivalent to a single bed or composed of a number of beds; as a layer greater than 1 cm in thickness and constituting a part of a bed; or a general term that includes both ''bed'' and ''lamina''.Neuendorf, K.K.E., Mehl, Jr., J.P., and Jackson, J.A. , eds., 2005. ''Glossary of Geology'' 5th ed. Alexandria, Virginia, American Geological Institute. 779 pp. . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock Strata
In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as either '' bedding surfaces'' or ''bedding planes''.Salvador, A. ed., 1994. ''International stratigraphic guide: a guide to stratigraphic classification, terminology, and procedure. 2nd ed.'' Boulder, Colorado, The Geological Society of America, Inc., 215 pp. . Prior to the publication of the International Stratigraphic Guide, older publications have defined a stratum as either being either equivalent to a single bed or composed of a number of beds; as a layer greater than 1 cm in thickness and constituting a part of a bed; or a general term that includes both ''bed'' and ''lamina''.Neuendorf, K.K.E., Mehl, Jr., J.P., and Jackson, J.A. , eds., 2005. ''Glossary of Geology'' 5th ed. Alexandria, Virginia, American Geological Institute. 779 pp. . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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