Red Vein
   HOME

TheInfoList



OR:

The Broad Vein Mudstone Formation (commonly known as the Broad Vein, historically known as the Red Vein and in Welsh as Y Faen Goch) is an
Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...
lithostratigraphic Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology. In general, strata are primarily igneous ...
group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic iden ...
(a sequence of
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 ...
) in
Mid Wales Mid Wales ( or simply ''Y Canolbarth'', meaning "the midlands"), or Central Wales, is a region of Wales, encompassing its midlands, in-between North Wales and South Wales. The Mid Wales Regional Committee of the Senedd covered the unitary autho ...
. The rock of the formation is silty
mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...
, intensely bioturbated in places. It varies in colour from a pale to a medium blue. This formation has been commercially quarried as
slate Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic ro ...
in several locations along its length. The formation is between and thick and runs from
Dinas Mawddwy Dinas Mawddwy (; ) is a town in the Community (Wales), 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 road, A470, and consequently many visitors pass the ...
south-west to
Cardigan Bay Cardigan Bay () 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 ha ...
at
Tywyn Tywyn (; ), formerly spelled Towyn, is a town, community, and seaside resort on the Cardigan Bay coast of southern Gwynedd, Wales. It was previously in the historic county of Merionethshire. It is famous as the location of the Cadfan Stone, a ...
.


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 quarries along its length.


Commercial quarrying

The Broad Vein is one of the two major slate veins in Mid Wales that were commercially quarried. Broad Vein rock is generally dense, with few natural joints, so most of the commercial use was for slab and products such as mantlepieces, cisterns and (later) electrical switchboards. Production of roofing slates was relatively rare in Broad Vein quarries. The Broad Vein was quarried in the following locations: *
Bryn Eglwys Bryn Eglwys quarry was a Slate industry in Wales, slate quarry and mine near Abergynolwyn, in Merionethshire (now part of Gwynedd), Wales. More than 300 men worked at the site, making it the principal employer in the area. Two veins of slate, k ...
where the Narrow Vein was also worked, connected to the
Talyllyn Railway The Talyllyn Railway () is a narrow-gauge railway in Wales running for from Tywyn on the Mid-Wales coast to Nant Gwernol railway station, Nant Gwernol near the village of Abergynolwyn. The line was opened in 1865Drummond 2015, page 17 to carr ...
* Abercwmeiddaw quarry, the most commercially successful of the quarries that only worked the Broad Vein. Connected to the Upper Corris Tramway * Cambergi quarry in
Cwm Hengae Cwm Hengae is a valley that runs roughly north-west from the village of Aberllefenni in Wales. The Afon Llefenni river runs along the valley and several slate quarries occupy the valley sides. The Roman road Sarn Helen ran along the valley, c ...
* Aberllefenni Quarry which worked from the 14th. century until 2002. Also worked the Narrow Vein. Connected to the
Corris Railway The Corris Railway () is a narrow gauge railway based in Corris on the border between Merionethshire (now Gwynedd) and Montgomeryshire (now Powys) in Mid-Wales. The line opened in 1859 as a horse tramway, running from quays on the River Dyfi ...
* Ratgoed quarry, which mainly worked the Narrow Vein, connected to the Ratgoed Tramway * Maes-y-gamfa quarry a smaller operation, connected to the
Hendre-Ddu Tramway The Hendre-Ddu Tramway was a narrow-gauge industrial railway built in 1874 in Mid-Wales to connect the Hendre-Ddu slate quarry to Aberangell station on the Mawddwy Railway. It consisted of a main line long and several branch lines and s ...
* Minllyn quarry, near
Dinas Mawddwy Dinas Mawddwy (; ) is a town in the Community (Wales), 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 road, A470, and consequently many visitors pass the ...
, connected to the
Mawddwy Railway The Mawddwy Railway was a rural line in the Dyfi Valley in mid-Wales that connected Dinas Mawddwy with a junction at railway station on the Newtown and Machynlleth Railway section of the Cambrian Railways. Despite being only 6 miles 63 cha ...


References

{{Reflist Ordovician System of Europe Upper Ordovician Series Rock formations of Wales Slate industry in Wales