The geology of the Australian Capital Territory includes rocks dating from the Ordovician around 480 million years ago, whilst most rocks are from the Silurian. During the Ordovician period the region—along with most of eastern Australia—was part of the ocean floor. The area contains the Pittman Formation consisting largely of Quartz-rich sandstone, siltstone and shale; the Adaminaby Beds and the Acton Shale.
Bryn Eglwys quarry was a slate quarry and mine near Abergynolwyn, in Merionethshire, Wales. More than 300 men worked at the site, making it the principal employer in the area. Two veins of slate, known as the Broad Vein and the Narrow Vein, were worked. The geology continues eastwards towards Corris and Dinas Mawddwy, and westwards towards Tywyn. It was one of many quarries that worked these veins.
Garneddwen is a hamlet in the south of the county of Gwynedd, Wales. It lies in the historic county of Merionethshire/Sir Feirionnydd, in the valley of the Afon Dulas.
The geology of Monmouthshire in southeast Wales largely consists of a thick series of sedimentary rocks of different types originating in the Silurian, Devonian, Carboniferous, Triassic and Jurassic periods.
The Folkeslunda Limestone is a thin limestone and mudstone geologic formation of Sweden. The formation crops out on the island of Öland to the east of Kalmar, where Folkeslunda is located. Other exposures of the formation are in Dalarna, Jämtland and Östergötland. The Folkeslunda Limestone was deposited in an open marine environment with an estimated water depth of 150 to 200 metres in a eustatically transgressive phase.
The geology of Ohio formed beginning more than one billion years ago in the Proterozoic eon of the Precambrian. The igneous and metamorphic crystalline basement rock is poorly understood except through deep boreholes and does not outcrop at the surface. The basement rock is divided between the Grenville Province and Superior Province. When the Grenville Province crust collided with Proto-North America, it launched the Grenville orogeny, a major mountain building event. The Grenville mountains eroded, filling in rift basins and Ohio was flooded and periodically exposed as dry land throughout the Paleozoic. In addition to marine carbonates such as limestone and dolomite, large deposits of shale and sandstone formed as subsequent mountain building events such as the Taconic orogeny and Acadian orogeny led to additional sediment deposition. Ohio transitioned to dryland conditions in the Pennsylvanian, forming large coal swamps and the region has been dryland ever since. Until the Pleistocene glaciations erased these features, the landscape was cut with deep stream valleys, which scoured away hundreds of meters of rock leaving little trace of geologic history in the Mesozoic and Cenozoic.
The Broad Vein Mudstone Formation is an Ordovician lithostratigraphic group in Mid Wales. The rock of the formation is silty mudstone, intensely bioturbated in places. It varies in colour from a pale to a medium blue. This formation has been commercially quarried as slate in several locations along its length. The formation is between 400 metres (1,300 ft) and 560 metres (1,840 ft) thick and runs from Dinas Mawddwy south-west to Cardigan Bay at Tywyn.
The Narrow Vein Mudstone Formation is an Ordovician lithostratigraphic group in Mid Wales. The rock of the formation is silty, homogeneous or finely-laminated mudstone. It generally a medium blue colour. This formation has been commercially quarried as slate in several locations along its length. The formation is between 400 metres (1,300 ft) and 560 metres (1,840 ft) thick and runs from Dinas Mawddwy south-west to Cardigan Bay at Tywyn.
The Ceiswyn Formation is an Ordovician lithostratigraphic group 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.
The Garnedd-Wen Formation is an Ordovician lithostratigraphic group in Mid Wales. The rock of the formation is a mixture of mudstones, siltstones, fine- to coarse-grained sandstones, greywackes and conglomerates. The formation extends from Dinas Mawddwy in the north-east to Tywyn in the south-west.
The Prince Llewellyn quarry was a slate quarry that stands on the west side of the Lledr Valley, ENE of Dolwyddelan. It was worked from around 1820 to 1934.
Chwarel Ddu quarry was the earliest slate quarry in the Lledr Valley. It was working before 1810, and continued in sporadic operation until the late 1920s. It is about 0.5 miles (0.80 km) west of Dolwyddelan, just beneath Dolwyddelan Castle.
Ty'n-y-bryn quarry was a slate quarry that was worked from the 1840s to about 1914. It stands on the south-east edge of Dolwyddelan.
Rhiw-goch quarry was a slate quarry that was worked from the 1860s to 1908. It stands on the north side of the Afon Lledr, on the opposite side of the valley from Pont-y-Pant railway station.
This article describes the geology of Dartmoor National Park in Devon, in south-west England. Dartmoor gained national park status in 1951 but the designated area of 954 km2 (368 sq mi) extends beyond the upland of Dartmoor itself to include much of the surrounding land, particularly in the northeast. The geology of the national park consists of a 625 km2 (241 sq mi) core of granite intruded during the early Permian period into a sequence of sedimentary rocks originating in the Devonian and Carboniferous periods. These rocks were faulted and folded, sometimes, intensely, during the Variscan orogeny. Thermal metamorphism has also taken place around the margins of the granite pluton altering the character of the sedimentary rocks whilst mineral veins were emplaced within the granite. A small outlier of Palaeogene sediments occurs on the eastern boundary of the national park.
This article describes the geology of the Brecon Beacons National Park in mid/south Wales. The area gained national park status in 1957 with the designated area of 1,344 km2 (519 sq mi) including mountain massifs to both the east and west of the Brecon Beacons proper. The geology of the national park consists of a thick succession of sedimentary rocks laid down from the late Ordovician through the Silurian and Devonian to the late Carboniferous period. The rock sequence most closely associated with the park is the Old Red Sandstone from which most of its mountains are formed. The older parts of the succession, in the northwest, were folded and faulted during the Caledonian orogeny. Further faulting and folding, particularly in the south of the park is associated with the Variscan orogeny.
Dolgoch slate quarry was a slate quarry in Mid Wales, approximately halfway between Bryn-crug and Abergynolwyn. The quarry was named after a nearby stream, the Nant Dolgoch. 'Dol goch' is Welsh for 'red meadow'.
The geology of Snowdonia National Park is dominated by sedimentary and volcanic rocks from the Cambrian and Ordovician periods with intrusions of Ordovician and Silurian age. There are Silurian and Cenozoic sedimentary rocks on the park's margins. The succession was intensely faulted and folded during the Caledonian Orogeny. The region was uplifted as the North Atlantic Ocean opened during the Cenozoic. The current mountainous landscape arises from repeated glaciations during the Quaternary period.
The bedrock geology of Ceredigion in west Wales consists wholly of a considerable thickness of Ordovician and Silurian age sedimentary rocks of marine origin. Unconsolidated deposits of Quaternary age include a widespread cover of glacial till, valley floor alluvium and scattered peat deposits in both upland and lowland settings.
The bedrock geology of Carmarthenshire in west Wales consists largely of Palaeozoic age sedimentary rocks. Unconsolidated deposits of Quaternary age in Carmarthenshire include a dissected cover of glacial till, valley floor alluvium and some scattered peat deposits in both upland and lowland settings. There are extensive beach and tidal flat deposits along the Carmarthenshire coast. The exploitation of the county's mineral riches, particularly coal and limestone, was a key part of the local economy through much of the nineteenth and twentieth centuries.
