Geological perspectives of the -East Greenland continental margin

The East Greenland continental margin can be divided into a northern area showing evidence for plate separation and suturing of Hudsonian, Grenvillian and Caledonian ages followed by post-Late Caledonian molasse sedimentation and Mesozoic rifting, and a southern area which apparently formed a cratonic block from the Early Proterozoic to the Middle Cretaceous. The whole margin was finally separated from the NW European margin by sea floor spreading in the latest Paleocene to earliest Eocene and now forms a rifted passive margin. The Tertiary consists of thin pre-drift sediments overlain by 1-7 km of Late Paleocene basaltic lavas extruded immediately prior to active spreading. Subsequent subsidence of the shelf led to accumulation of 2--8 km of post-basaltic sediments offshore whereas the land area was uplifted 1-2 km. Initiation of spreading along the Kolbeinsey Ridge during the late Oligocene was accompanied by renewed tectonism within the middle part of the margin. Finally the shelf was characterized by strong progradation during the Miocene. Backwards rotation of the inferred ocean-to-continent transition, through the total pole of opening, favours a slightly modified Talwani and Eldholm pole which provides a pre-drift fit of the two margins with no major overlap or gaps between the southern tip of Greenland and the Greenland-Senja Fracture Zone. Comparison of the Greenland margin and the V0ring Plateau implies a genesis for the latter, different from that proposed by Talwani and Eldholm. Minor revisions of the spreading history are presented including repeated westward displacement of the southernmost part of Mohns Ridge between anomaly 24 and 21, commencement of spreading around Kolbeinsey Ridge not later than anomaly 6 and associated activation of the recent active part of Jan Mayen Fracture Zone (JMFZ), to the north of the previous active part. The area between the fossil part of JMFZ and the recent active part including the northern part of Jan Mayen Ridge is suggested to have formed around a southern extension of Mohns Ridge active until about anomaly 6 and the predicted position of the extinct axis correlates well with bathymetry.