Search

In the Godthabsfjord region of southern West Greenland a NE-SW-trending belt of rocks of very varied age and origin, here named the Akulleq terrane, is separated by major faults from more extensive blocks of typical high-grade Archaean rocks that, although they are superficially similar, have different ages and metamorphic histories. The continental crust that forms the block to the north-west, the Akia terrane, was accreted between ea. 3200 and 2980 Ma, and that forming the block to the south-east, the Tasiusarsuaq terrane, between 2920 and 2800 Ma. It is suggested that the Godthabsfjord belt is the result of collision of the two continental blocks between 2800 and 2650 Ma. The rocks of the Akulleq terrane are interpreted as fragments of different parts of the crust that originally separated the two continents. They include early Archaean continental crust, possible oceanic crust, and acid to intermediate rocks of intrusive and possibly also extrusive origin that may have been generated in a subduction-related environment.