The Krummedal supracrustal sequence around inner Nordvestfjord, Scoresby Sund, East Greenland

Abstract

The Krummedal supracrustal sequence is a lower to middle Proterozoic sedimentary succession widely represented in the Caledonian fold belt of the Scoresby Sund region. Around inner Nordvestfjord laterally variable sequences of pelitic, semipelitic and psammitic rocks occur. The sequences of different areas ranging from 2500 m to more than 8000 m in thickness are described but no formal subdivision is attempted. High amphibolite facies metamorphism, migmatisation, emplacement of granite intrusions and several phases of deformation appear to relate to an orogenic episode giving dates in the range 900-1200 m.y. Caledonian orogenesis is represented by a relatively weak retrogressive metamorphic phase, westward displacements on major thrusts and emplacement of granite intrusions.