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Graig Goch
Graig Goch is a 586m high hill in the Gwynedd area in Wales and lying within Snowdonia National Park. The hill falls within the communities of Llanfihangel-y-Pennant and Corris, the summit being located in the former. The hill takes the form of a NE-SW aligned ridge with a broad top which rise to subsidiary tops either side of the main summit. These are the 540m+ top of Mynydd Cedris (OS grid ref SH 707080) and the 504m top of Mynydd Rugog (OS grid ref SH 722092). The hill’s most notable feature is the large cliff which stretches the length of its northwestern face overlooking Tal-y-llyn, in part a major rock-slope failure. Geology The hill is formed from a succession of mudstones and siltstones laid down by turbidity currents during the Ordovician Period. The main ridge is developed in rocks of the Ceiswyn Formation assigned to the Ogwen Group and dating from around 457 to 454 million years ago. A near vertical cleavage is developed in the steeply southeasterly dipping ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welsh Language
Welsh ( or ) is a Celtic language family, Celtic language of the Brittonic languages, Brittonic subgroup that is native to the Welsh people. Welsh is spoken natively in Wales, by some in England, and in Y Wladfa (the Welsh colony in Chubut Province, Argentina). Historically, it has also been known in English as "British", "Cambrian", "Cambric" and "Cymric". The Welsh Language (Wales) Measure 2011 gave the Welsh language official status in Wales. Both the Welsh and English languages are ''de jure'' official languages of the Welsh Parliament, the Senedd. According to the 2021 United Kingdom census, 2021 census, the Welsh-speaking population of Wales aged three or older was 17.8% (538,300 people) and nearly three quarters of the population in Wales said they had no Welsh language skills. Other estimates suggest that 29.7% (899,500) of people aged three or older in Wales could speak Welsh in June 2022. Almost half of all Welsh speakers consider themselves fluent Welsh speakers ... [...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] |
Countryside And Rights Of Way Act 2000
The Countryside and Rights of Way Act 2000 (c. 37), known informally as the CRoW Act or "Right to Roam" Act is a United Kingdom Act of Parliament affecting England and Wales which came into force on 30 November 2000. Right to roam The Act implements the so-called "right to roam" (also known as ''jus spatiandi'') long sought by the Ramblers' Association and its predecessors, on certain upland and uncultivated areas of England and Wales. This element of the act was implemented in stages as conclusive maps of different regions were produced. The act refers to areas of 'mountain, moor, heath and down' in addition to registered common land; not all uncultivated land is covered. Rights of way A staged review of public rights of way, including limited rights to create new public footpaths where needed, is being conducted under the Act. Again, this is being conducted in a staged manner, which can produce anomalies – of the two administrative areas of the County of Gloucestershir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freedom To Roam
The freedom to roam, or "everyman's right", is the general public's right to access certain public or privately owned land, lakes, and rivers for recreation and exercise. The right is sometimes called the right of public access to the wilderness or the "right to roam". In Scotland, Finland, Iceland, Norway, Sweden, Estonia, Latvia, Lithuania, Belarus, Austria, Czech Republic and Switzerland, the freedom to roam takes the form of general public rights which are sometimes codified in law. The access is ancient in parts of Northern Europe and has been regarded as sufficiently basic that it was not formalised in law until modern times. However, the right usually does not include any substantial economic exploitation, such as hunting or logging, or disruptive activities, such as making fires and driving offroad vehicles. In countries without such general rights, there may be a network of rights of way, or some nature reserves with footpaths. Europe Nordic countries Ancient traces p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciation
A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate between glacial periods. The Last Glacial Period ended about 15,000 years ago. The Holocene is the current interglacial. A time with no glaciers on Earth is considered a greenhouse climate state. Quaternary Period Within the Quaternary, which started about 2.6 million years before present, there have been a number of glacials and interglacials. At least eight glacial cycles have occurred in the last 740,000 years alone. Penultimate Glacial Period The Penultimate Glacial Period (PGP) is the glacial period that occurred before the Last Glacial Period. It began about 194,000 years ago and ended 135,000 years ago, with the beginning of the Eemian interglacial. Last Glacial Period The last glacial period was the most recent glacial period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tal-y-llyn Lake
Tal-y-llyn Lake, ( cy, Llyn Mwyngil), also known as Talyllyn Lake and Llyn Myngul, is a large glacial ribbon lake in Gwynedd, North Wales. It is formed by a post-glacial massive landslip damming up the lake within the glaciated valley. The hamlet of Talyllyn lies at the west end of the lake. Name Tal-y-llyn Lake is named after the hamlet and historic parish of Tal-y-llyn. Tal-y-llyn itself is named after the lake and means 'the end of the lake' in Welsh. Literally, therefore, ''Tal-y-llyn Lake'' has the circular meaning of 'the lake at the end of the lake'. The Welsh name ''Llyn Myngul'' or ''Llyn Mwyngil'' probably derives from ''mŵn'' ('neck') and ''cul'' ('narrow'). Geography Tal-y-llyn Lake is situated to the north of Machynlleth, at the foot of Cadair Idris, in the Snowdonia mountain range of Gwynedd, Wales. The River Dysynni flows from the lake, through the village of Abergynolwyn, and discharges into the sea north of Tywyn. There is a route leading to the summit of C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scree
Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits. Talus deposits typically have a concave upwards form, where the maximum inclination corresponds to the angle of repose of the mean debris particle size. The exact definition of scree in the primary literature is somewhat relaxed, and it often overlaps with both ''talus'' and ''colluvium''. The term ''scree'' comes from the Old Norse term for landslide, ''skriða'', while the term ''talus'' is a French word meaning a slope or embankment. In high-altitude arctic and subarctic regions, scree slopes and talus deposits are typically adjacent to hills and river valleys. These steep slopes usually originate from late-Pleistocene periglacial processes. Notable scree sites in Eastern North America include the Ice Caves at White Rocks National Recreation Area in southern Ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cleavage (geology)
Cleavage, in structural geology and petrology, describes a type of planar rock feature that develops as a result of deformation and metamorphism. The degree of deformation and metamorphism along with rock type determines the kind of cleavage feature that develops. Generally, these structures are formed in fine grained rocks composed of minerals affected by pressure solution. Cleavage is a type of rock foliation, a fabric element that describes the way planar features develop in a rock. Foliation is separated into two groups: primary and secondary. Primary deals with igneous and sedimentary rocks, while secondary deals with rocks that undergo metamorphism as a result of deformation. Cleavage is a type of secondary foliation associated with fine grained rocks. For coarser grained rocks, schistosity is used to describe secondary foliation. There are a variety of definitions for cleavage, which may cause confusion and debate. The terminology used in this article is based largely on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ogwen Group
The Ogwen Group is an Ordovician lithostratigraphic group (a sequence of rock strata) in Gwynedd, north-west Wales. The name is derived from Ogwen Valley, a locality in Snowdonia where it outcrops. Outcrops The rocks occur throughout Llŷn and eastwards into Snowdonia within Gwynedd. Lithology and stratigraphy The Group consists of about 1000 m thickness (in the Pwllheli area) of mudstones and siltstones with some basal sandstones together with tuffs and oolitic ironstones laid down during the Arenig and Caradoc Caradoc Vreichvras (; Modern cy, Caradog Freichfras, ) was a semi-legendary ancestor to the kings of Gwent. He may have lived during the 5th or 6th century. He is remembered in the Matter of Britain as a Knight of the Round Table, under the na ... epochs of the Ordovician Period. The Nant Ffrancon subgroup alone exceeds 2km thickness in central Snowdonia. The subgroup as itself been classed as both a formation and a group at times. References {{Reflist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceiswyn Formation
The Ceiswyn Formation (also known as the Ceiswyn Beds) is an Ordovician lithostratigraphic group (a sequence of rock strata) in Mid Wales. The rock of the formation is made up of interleaved beds of silty mudstones and siltstones with some sandstones and tuffs also present in small amounts. The formation runs diagonally across Mid Wales from close by Bala Lake to Cardigan Bay near Tywyn. Outcrops The formation is exposed in a number of locations in Mid Wales where glacial valleys cut across it. It is especially visible in the cliffs of Graig Goch. Fossil content Harnagian-Soudleyan trilobites have been found in the rocks of the Ceiswyn Formation near Dinas Mawddwy Dinas Mawddwy () is a village in the community of Mawddwy in south-east Gwynedd, north Wales. It lies within the Snowdonia National Park, but just to the east of the main A470, and consequently many visitors pass the village by. Its population is .... References Geologic formations of Wales Ordovician Syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician
The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Celtic Britons, Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same Rock (geology), rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed Stratum, strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Union of Geological Sciences, Intern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siltstone
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, pp.381-382 Although its permeability and porosity is relatively low, siltstone is sometimes a tight gas reservoir rock, an unconventional reservoir for natural gas that requires hydraulic fracturing for economic gas production. Siltstone was prized in ancient Egypt for manufacturing statuary and cosmetic palettes. The siltstone quarried at Wadi Hammamat was a hard, fine-grained siltstone that resisted flaking and was almost ideal for such uses. Description There is not complete agreement on the definition of siltstone. One definition is that siltstone is mudrock ( clastic sedimentary rock containing at least 50% clay and silt) in which at least 2/3 of the clay and silt fraction is composed of silt-sized particles. Silt is defined a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
