New Red Sandstone Supergroup | |
---|---|
Stratigraphic range: Permian-Triassic ~ | |
Type | Supergroup |
Sub-units | |
Underlies | Penarth Group |
Overlies | Unconformity with folded Devonian and Carboniferous rocks |
Thickness | up to 2,000 m (6,600 ft) |
Lithology | |
Primary | Sandstone |
Other | Arkose, conglomerate, breccio-conglomerate |
Location | |
Country | United Kingdom |
Extent | Originally in Scotland, range extended to all red-bed sequences of Permian and Triassic age in southwest England, and parts of northwest and northeast England. |
The New Red Sandstone, chiefly in British geology, is composed of beds of red sandstone and associated rocks laid down throughout the Permian (300 million years ago) to the end of the Triassic (about 200 million years ago), that underlie the Jurassic-Triassic age Penarth Group.[1] The name distinguishes it from the Old Red Sandstone which is largely Devonian in age, and with which it was originally confused due to their similar composition.
Its upper layers consist of mudstones, but most of the formation consists of reddish to yellowish sandstones, interbedded with rare evaporite minerals such as halite and gypsum. These indicate deposition within a hot and arid palaeo-environment, such as a desert or sabkha.[2]