Broad Vein Mudstone Formation facts for kids

Quick facts for kids Broad Vein Mudstone Formation Stratigraphic range: Hirnantian Age
The Abercwmeiddaw quarry in Corris Uchaf which quarried the Broad Vein
Type	Group
Unit of	Abercorris Group
Underlies	Narrow Vein Mudstone Formation
Overlies	Nod Glas Formation
Lithology
Primary	Mudstone
Other	Slate
Location
Coordinates	52°39′48″N 3°50′43″W / 52.6632°N 3.8453°W / 52.6632; -3.8453
Region	Mid Wales
Country	Wales

The Broad Vein Mudstone Formation is a special type of rock layer found in Mid Wales. People often call it the Broad Vein. Long ago, it was known as the Red Vein or Y Faen Goch in Welsh. This rock formed during the Ordovician period, a very long time ago when Earth looked quite different.

The Broad Vein is made mostly of silty mudstone. This means it's a type of rock formed from mud and silt. In some places, you can see signs of ancient creatures that burrowed through the mud, a process called bioturbation. The rock itself can be a pale blue or a medium blue color.

This rock formation is very important because it has been used for slate for many years. It is between 400 meters (about 1,300 feet) and 560 meters (about 1,800 feet) thick. The Broad Vein stretches from Dinas Mawddwy in the north-east all the way to Cardigan Bay at Tywyn in the south-west.

Where Can You See the Broad Vein?

The Broad Vein Mudstone Formation is visible in many places across Mid Wales. These spots are called "outcrops," which means places where the rock layers are exposed at the surface. You can especially see the Broad Vein in old quarries where people dug out the rock. These quarries are often found in glacial valleys that cut through the rock formation.

Why Was the Broad Vein Important for Quarrying?

The Broad Vein was one of two main types of slate rock that were dug up for money in Mid Wales. The rock from the Broad Vein is usually very strong and solid. It doesn't have many natural cracks or breaks. Because of this, it was mostly used to make large, flat pieces called "slabs."

These slabs were used for many different things. They became items like fireplace surrounds (mantlepieces) or large water tanks (cisterns). Later, they were even used to make electrical switchboards because slate doesn't conduct electricity well. It was not often used for roofing slates, which are thinner pieces, because of its dense nature.

Famous Quarries of the Broad Vein

The Broad Vein was quarried in several locations. Here are some of the most well-known:

• Bryn Eglwys: This quarry also worked with another rock type called the Narrow Vein. It was connected to the Talyllyn Railway.
• Abercwmeiddaw quarry: This was the most successful quarry that only worked with the Broad Vein. It was linked to the Upper Corris Tramway.
• Cambergi quarry: This quarry is located in Cwm Hengae.
• Aberllefenni Quarry: This quarry was active for a very long time, from the 14th century until 2002. It also worked the Narrow Vein and was connected to the Corris Railway.
• Ratgoed quarry: This quarry mainly worked the Narrow Vein but also used the Broad Vein. It was connected to the Ratgoed Tramway.
• Maes-y-gamfa quarry: This was a smaller quarry that was connected to the Hendre-Ddu Tramway.
• Minllyn quarry: Located near Dinas Mawddwy, this quarry was connected to the Mawddwy Railway.