A summary of the orogenies that affected the UK
THE CALEDONIAN OROGENY
Effects seen in Scotland, the Southern Uplands, the Lake District and Snowdonia
Effects seen in Pre-Cambrian, Ordovician and Silurian rocks
Occurred between 600 & 400Ma
Created the Caledonian fold belt
A result of the Laurentian continent (Greenland and Canada) colliding with Gondwanaland
(Scandanavia and Baltic continent)
Involved the closure of the Iapetus Ocean – between Scotland and England
Resulted in volcanics in Snowdonia (Mount Snowdon) and the Lake District (ScaFell Pike, Old
Man of Coniston etc.)
Main trend of fold axes = NE-SW
Associated with the Moine Thrust, the Highland Boundary Fault, the Great Glen Fault and
the Southern Uplands Fault – with NE-SW trends
Associated with major intrusions in Scotland eg. the Carrock Fell gabbro
THE VARISCAN OROGENY
Also known as the AMORICAN OROGENY
Also known as the HERCYNIAN OROGENY
Effects seen in Devon and Cornwall, South Wales, and northern England
Effects seen in Devonian & Carboniferous rocks
Occurred about 290Ma
Created the Variscan mountain belt
A result of southern Europe colliding with the Caledonian continent to from Pangaea supercontinent
Involved the closure of the Rheic Ocean – between South Wales and Devon and Cornwall
Resulted in intrusions and volcanics in Devon and Cornwall – including the Cornubian batholith
- granites
Resulted in intense folding such as that at Hartland Quay, Devon and Millook, Cornwall along
with folding of the South Wales coal fields
Main trend of fold axes = E – W
Associated with the formation of the Lizard Thrust, the Pennine Block faults and renewed
subsidence in the Scottish Rift valley
Associated with the intrusion of the Whin Sill
THE ALPINE OROGENY
Effects seen mainly in South East of England
Effects seen in Permian, Triassic, Jurassic, Cretaceous and Tertiary rocks.
Occurred about 25 - 30Ma
Created the Alpine mountain belt – the Alps
Created the Wealden Anticline
Created the Lulworth Crumple, Dorset
Main trend of fold axes = E-W
Re-activated many pre-existing fault lines
Was centred in Southern Europe and the UK only on the edge of the mountains formed
A result of northward movement of Africa colliding with Europe
The north Atlantic was opening up at the same time – producing the flood basalts seen in
Northern Ireland (Giants Causeway) and north-east Scotland (Staffa and Fingal’s Cave) and
dyke swarms across northern England and southern Scotland.