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, causin ...

Neoproterozoic The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago. It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is ...

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

s that outcrop across the

Central Highlands of Scotland The Grampian Mountains (''Am Monadh'' in Gaelic) is one of the three major mountain ranges in Scotland, that together occupy about half of Scotland. The other two ranges are the Northwest Highlands and the Southern Uplands. The Grampian rang ...

, east of the

Great Glen The Great Glen ( gd, An Gleann Mòr ), also known as Glen Albyn (from the Gaelic "Glen of Scotland" ) or Glen More (from the Gaelic ), is a glen in Scotland running for from Inverness on the edge of Moray Firth, in an approximately straight ...

. 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 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 Turbidites were ...

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, also called the Shetland Islands and formerly Zetland, is a subarctic archipelago in Scotland lying between Orkney, the Faroe Islands and Norway. It is the northernmost region of the United Kingdom. The islands lie about to the no ...

and

Islay Islay ( ; gd, Ìle, sco, Ila) is the southernmost island of the Inner Hebrides of Scotland. Known as "The Queen of the Hebrides", it lies in Argyll just south west of Jura, Scotland, Jura and around north of the Northern Irish coast. The isl ...

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