Old Red Sandstone

Sedimentology

The Old Red Sandstone describes a sandstone deposited after the Acadian Orogeny in the late Silurian, and before the Carboniferous.

The body of rock, or facies, is dominated by alluvial sediments and conglomerates at its base, and progresses to a combination of dunes, lakes and river sediments.

Its familiar red colour arises from the presence of iron oxide but not all the old red sandstone is red or sandstone - grey shales and conglomerates are common.

History of study

In the early 1800s, the paleontology of the formation was studied intensively by Hugh Miller, Henry Thomas De la Beche, Roderick Murchison, and Adam Sedgwick -- Sedgwick's interpretation was the one that placed it in the Devonian, and in fact it was he that coined that word. Many of the science of stratigraphy's early debates were about the Old Red Sandstone. Old Red Sandstone often occur in conjunction with conglomerate formations, one such noteworthy cliffside exposure being the Fowlsheugh Nature Reserve, Kincardineshire.

Common Building Stone

In regions where the formation is near the surface, many stone houses are built of the rocks quarried from it. Notable examples can be found in the area surrounding Stirling , Stonehaven , Perth , and Tayside. The inhabitants of Caithness at the northeastern tip of Scotland also used the stone to a considerable extent.

Note that in older geological works predating theories of plate tectonics, the United States' Catskill Delta formation is sometimes referred to as part of the Old Red Sandstone. In the modern day, however, it is recognized that the two are not stratigraphically continuous but are very similar due to being formed at approximately the same time by the same processes.

Notable buildings constructed of Old Red Sandstone

• Muchalls Castle, Scotland
• Stonehaven Tolbooth, Scotland
• Sweetheart Abbey, Scotland &
• Tintern Abbey, South Wales &
• Ross-on-Wye market hall, Herefordshire
• Shrewsbury Castle, Shropshire

See also

• New Red Sandstone
• Geology of the British Isles

External links

• Cawdor Castle which, despite being brown, is made of Old Red Sandstone
• Sweetheart Abbey