The Grampian Group is an estimated 9,000 m thick sequence of
metamorphosed
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...
Neoproterozoic
The Neoproterozoic Era is the last of the three geologic eras of the Proterozoic geologic eon, eon, spanning from 1 billion to 538.8 million years ago, and is the last era of the Precambrian "supereon". It is preceded by the Mesoproterozoic era an ...
sedimentary rock
Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...
s that outcrop across the
Central Highlands of Scotland, east of the
Great Glen
The Great Glen ( ), also known as Glen Albyn (from the Gaelic "Glen of Scotland" ) or Glen More (from the Gaelic "Big/Great Glen"), is a glen in Scotland running for from Inverness on the edge of the Moray Firth, in an approximately straig ...
. It forms a part of the
Dalradian Supergroup. The sequence thickness at any one place is limited to 5km.
Stratigraphy
The Glenshirra Subgroup is the lowermost (oldest) part of the succession. These rocks reflect deposition within shallow marine and fluvial environments. It is overlain by the thick sequence of proximal and distal
turbidite
A turbidite is the geologic Deposition (geology), deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean.
Sequencing
...
s of the Corrieyairack Subgroup which is in turn overlain by the Glen Spean Subgroup reflective of the infilling of the Corrieyairack, Strath Tummel and Cromdale
depositional basins. The
Bowmore Sandstone of the
Highland Border Complex is correlated with the Corrieyairack Subgroup. Rock successions in
Shetland
Shetland (until 1975 spelled Zetland), also called the Shetland Islands, is an archipelago in Scotland lying between Orkney, the Faroe Islands, and Norway, marking the northernmost region of the United Kingdom. The islands lie about to the ...
and
Islay
Islay ( ; , ) is the southernmost island of the Inner Hebrides of Scotland. Known as "The Queen of the Hebrides", it lies in Argyll and Bute just south west of Jura, Scotland, Jura and around north of the Northern Irish coast. The island's cap ...
may also be correlated with this succession.
[Strachan, R.A., Harris, A.L., Fettes, D.J. & Smith, M. 2002 The Highland and Grampian Terranes. ''In:'' Trewin, N.H. (ed) ''The Geology of Scotland.'' The Geological Society, London, pp. 96-99]
References
{{Reflist
Geology of Scotland