The Scourian orogeny was an
orogeny
Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An '' orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted ...
mountain building event 2.6 billion years ago during the
Archean
The Archean Eon ( , also spelled Archaean or Archæan) is the second of four eon (geology), geologic eons of History of Earth, Earth's history, representing the time from . The Archean was preceded by the Hadean Eon and followed by the Proterozo ...
before the beginning of the
Laxfordian orogeny
The Laxfordian orogeny was an orogenic (mountain building) event between 1.9 and 1 billion years ago. It primarily affected the North Atlantic Craton, in particular a section that cleaved off during the Mesozoic as the Scottish Shield Fragment, pa ...
(or potentially overlapping with the beginning of the Laxfordian.
The orogeny is marked by northwest-southeast trending folds south of
Laxford
Laxford is a remote area in the far Northwest Highlands of Scotland around the River Laxford which runs northwest from Loch Stack to Laxford Bay. This bay is an inlet of Loch Laxford, a sea loch and Special Area of Conservation. The river is w ...
in northwest Scotland. The event affected the
Lewisian gneiss
The Lewisian complex or Lewisian gneiss is a suite of Precambrian metamorphic rocks that outcrop in the northwestern part of Scotland, forming part of the Hebridean Terrane and the North Atlantic Craton. These rocks are of Archaean and Paleopro ...
.
Rubidium-strontium dating indicated Scourian metamorphism took place between 2.6 and 2.7 billion years ago
[{{cite book , year=1977, title= Precambrian of the Northern Hemisphere, url=https://archive.org/details/precambriannorth00salo, url-access=limited, publisher=Elsevier, ]
50
}
References
Archean orogenies
Geology of Scotland