Grampian Highlands, Shetland, County Antrim, County Tyrone, County Londonderry, Northern and Western Region
Country
Scotland, Northern Ireland, Republic of Ireland
Type section
Named for
Dál Riata (Dalriada)
Andalusite crystals in Dalradian (Southern Highland Group) metamorphic rock at Boyndie Bay, north-east Scotland
The Dalradian Supergroup (informally and traditionally the Dalradian) is a stratigraphic unit (a sequence of rock strata) in the lithostratigraphy of the Grampian Highlands of Scotland and in the north and west of Ireland. The diverse assemblage of rocks which constitute the supergroup extend across Scotland from Islay in the west to Fraserburgh in the east and are confined by the Great Glen Fault to the northwest and the Highland Boundary Fault to the southeast. Much of Shetland east of the Walls Boundary Fault is also formed from Dalradian rocks. Dalradian rocks extend across the north of Ireland from County Antrim in the north east to Clifden on the Atlantic coast, although obscured by younger Palaeogene lavas and tuffs or Carboniferous rocks in large sections.
The Dalradian Supergroup (informally and traditionally the Dalradian) is a stratigraphic unit (a sequence of rock strata) in the lithostratigraphy of the...
Paleozoic. The oldest Dalradian rocks (the Grampian Group) were deformed and metamorphosed around 750 Ma. The deposition of younger Dalradian sediments continued...
geology. The majority of the rocks within the National Park belong to the Dalradian Supergroup, a thick sequence of sands, muds and limestones that were deposited...
slates are some of its commercial uses. Phyllite is commonly found in the Dalradian metasediments of northwest Arran. In north Cornwall, there are Tredorn...
metamorphism during the Caledonian orogeny. These older rocks, assigned to the Dalradian Supergroup, lie to the northwest of the northeast – southwest aligned...
majority of the rocks within the Cairngorms National Park belong to the Dalradian Supergroup, a thick sequence of sands, muds and limestones that were deposited...
is thought to be unconformably overlain by the Cryogenian to Cambrian Dalradian Supergroup. The supergroup is subdivided into three groups. This group...
quartzite but with deposits of schists in the valleys (known as Connemara Dalradian rocks). "Ben" is an anglicized form of the Irish word binn, meaning "peak"...
onto the surrounding metamorphic/ igneous complexes formed during the Dalradian period (approximately 480–600 million years ago) with sporadic areas of...
psammites and pelites) which constitute the Southern Highland Group of the Dalradian. To its south are the conglomerates, sandstones, mudstones and siltstones...
sandstones in the west centre of the island are rich in feldspar and may be of Dalradian origin. Loch Indaal was formed along a branch of the Great Glen Fault...
outpost of the Caledonian orogeny, and there are outcrops of Lewisian, Dalradian and Moine metamorphic rocks with histories similar to their equivalents...
outpost of the Caledonian orogeny and there are outcrops of Lewisian, Dalradian and Moine metamorphic rocks with similar histories to their equivalents...
formed through the Cambrian period, some of which metamorphosed into the Dalradian series. The area which would become Scotland was at this time close to...
Complex have been interpreted as being in stratigraphic continuity with the Dalradian Supergroup, with the ophiolitic rocks (serpentinite, metagabbro, hornblende...
such as the Great Glen Fault which affected the Moine Supergroup and the Dalradian rocks in Scotland and the Shetland Islands through the Walls Boundary...
was intruded into the Late Proterozoic to Cambrian metasediments of the Dalradian Supergroup. Other Paleogene igneous rocks on Arran include extensive felsic...
from micaceous psammites of the Colla Firth Group - a suite of rocks which have been equated with the Dalradian succession of the Scottish Highlands...
northeast to southwest from Ardara to Fanad Head, and quartzo-feldspathic Dalradian rocks from the Precambrian era, which cover much of the rest of the county...
On Kerrera a conglomerate of andesite boulders rests unconformably on Dalradian black, pyritic slates (Easdale Slate) of the Easdale Subgroup. On Oban...
of Mull where it is seen to divide Moine rocks near Craignure from a Dalradian sequence at Loch Don. Though it is straight in its alignment on the Scottish...
assigned to the Trossachs Group, interpreted to be the youngest part of the Dalradian Supergroup, although this interpretation has been questioned. The Trossachs...
nearby are not usually included. The underlying geology of the islands is Dalradian slate, which was quarried widely until the mid-20th century. Quarry working...
geological composition beneath most of Dufftown is that of metamorphosed Dalradian sedimentary rocks with subsidiary volcanic rocks. The Isla Way is a 21-kilometre...
have been correlated with the Grampian Group, the oldest part of the Dalradian Supergroup. The sequences on Islay and Colonsay/Oronsay are not identical...
(million years ago), predating the deposition of the Cryogenian to Cambrian Dalradian Supergroup. It is named after Knoydart, one of the localities where the...
well as appearing in the north of Ireland. It is a subdivision of the Dalradian Supergroup and is itself divided into four units; from oldest to youngest...
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