The East Greenland Nagssugtoqidian mobile belt compared with the Lewisian complex

Summary The rocks, structures and geological history of the Lewisian complex are similar to those of the Nagssugtoqidian mobile belt in East Greenland. Both regions comprise a heterogeneous, mainly tonalitic, gneiss complex which formed 2900–2700 Ma. Both gneiss complexes were intruded by basic dykes and intensely deformed and metamorphosed during two major episodes. The first episode, called Inverian in Scotland, is broadly equivalent to the Nag. 1 episode in Greenland dominated by major dextral strike-slip shear zones about 2600–2300 Ma. The second episode, the Laxfordian of Scotland, is broadly equivalent to the Nag. 2 episode of Greenland associated with the southward translation of sheets of rock along northward-dipping thrusts and shear zones about 1900–1700 Ma. Both gneiss complexes were raised to a high crustal level by 1600–1400 Ma and extensively eroded.