The Badenoch Group is a 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 ...

Tonian The Tonian (from , meaning "stretch") is the first geologic period of the Neoproterozoic era (geology), Era. It lasted from to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined by the International Commissi ...

age

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 ...

. This rock sequence has formerly been referred to as the Central Highland Migmatite Complex and the Central Highland Division. Badenoch Group rocks extend across the Monadhliath Mountains and some surrounding areas largely between the Great Glen and Ericht-Laidon fault belts though their margins are hidden beneath younger strata;

Old Red Sandstone Old Red Sandstone, abbreviated ORS, is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the eastern seaboard of North America. It ...

to the north and west and Grampian Group rocks elsewhere. The succession is divided into two subgroups; the Dava Subgroup (previously referred to as the Dava Succession) and the Glen Banchor Subgroup. The former, named from the locality of Dava between

Inverness Inverness (; ; from the , meaning "Mouth of the River Ness") is a city in the Scottish Highlands, having been granted city status in 2000. It is the administrative centre for The Highland Council and is regarded as the capital of the Highland ...

and

Grantown-on-Spey Grantown-on-Spey () is a town in the Highland Council Area, Counties of Scotland, historically within the county of Moray. It is located on a low plateau at Freuchie beside the river Spey at the northern edge of the Cairngorms, Cairngorm mounta ...

includes the Slochd Psammite and Flichity Semipelite formations. The latter is named for Glen Banchor, west of

Newtonmore Newtonmore ( ) is a village of approximately 1100 inhabitants in Badenoch, within the Highland (council area), Highland council area of Scotland. The village is only a few miles from a location that is claimed to be the exact geographical centre ...

, the type area being from here to Laggan. The Glen Banchor sequence is believed to be between 1 and 1.5 km thick and unconformably overlain by rocks of the Grampian and Appin groups, though the boundary may be tectonic in nature. Long the subject of debate as to how they relate to surrounding rock sequences, some geologists placed the Badenoch Group within the

Moine Supergroup The Moinian or just the Moine, formerly the Moine Supergroup, is a sequence of Neoproterozoic metasediments that outcrop in the Northwest Highlands of Scotland between the Moine Thrust Belt to the northwest and the Great Glen Fault to the s ...

whilst others described them as simply ‘Moine-like’.

Detrital zircon geochronology Detrital zircon geochronology is the science of geochronology, analyzing the age of zircons deposited within a specific sedimentary rock, sedimentary unit by examining their inherent radioisotopes, most commonly the uranium–lead dating, uranium ...

has allowed the group to be correlated with the Glennfinnan and Loch Eil groups as they all contain zircons that are younger than 950 Ma (million years ago), showing that they postdate the

Renlandian Orogeny The Renlandian Orogeny is a Tonian (early Neoproterozoic) tectonic and metamorphic event that is found in East Greenland, on Svalbard, on Ellesmere Island and in Scotland. It takes its name from Renland in East Greenland, where the event was first ...

, a tectonic and thermal event that affected the

Morar Group The Morar Group is a sequence of Tonian (lower Neoproterozoic) sedimentary rocks that have been subjected to a series of tectonics, tectonic and metamorphism, metamorphic events since their deposition. Originally interpreted to be lowest (oldest) p ...

. The group has now been assigned to the Loch Ness Supergroup. The

lithologies The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lith ...

of these rocks suggest deposition in shallow marine conditions.British Geological Survey 2007. 1:625,000 scale Bedrock Geology UK North 5th edition (map)

References

{{Reflist Geology of Scotland