Burial and Exhumation History of Southern East Greenland after Opening of the NE Atlantic: Regional Tectonic Implications

Peter Japsen

The plateau lavas of southern East Greenland erupted onto a largely horizontal plain near sea level at breakup of the NE Atlantic at the Paleocene–Eocene transition, and the present-day margin with peaks reaching 3.7 km asl, is thus not a remnant of a rift shoulder, but the result of uplift after breakup. Synthesis of geological observations, stratigraphic landform analysis and apatite fission-track analysis, shows that three phases of uplift and exhumation subsequently shaped the present-day margin. A Late Eocene phase led to formation of a regional erosion surface near sea level (the Upper Planation Surface, UPS), a Late Miocene phase led to formation of the Lower Planation Surface (LPS) by incision below the uplifted UPS, and a final phase that most likely began in the Early Pliocene, caused incision below the uplifted LPS and to peaks reaching 3.7 km asl. Local uplift also affected the Kangerlussuaq area in the Early Eocene and in the Late Oligocene. Middle Miocene thermal activity heated rocks around the Kangerlussuaq Basin. The regional uplift phases are synchronous with phases in West Greenland, North America and Europe and the large-scale landscapes in both West and East Greenland, as well as NO are all characterized by elevated plateau at 1 km or more asl and by deeply incised valleys below the plateau. Given the similarity of the landscapes in East Greenland with those on the conjugate margin in Scandinavia, we also conclude that the mountains of NO were also formed long after Atlantic breakup. The synchronicity of the events that affected West and East Greenland is striking and in contrast to the histories of drifting adjacent to these margins that differed significantly. This indicates that the processes behind the epeirogenic movements are related to large-scale plate tectonic forces. Uplift at the Eocene–Oligocene transition coincided with the restart of Iceland plume activity and a major change in spreading directions in the NE Atlantic that was preceded by a drop in spreading rates. Late Miocene uplift and exhumation also affected the Barents Sea and the North American Cordillera. Early Pliocene uplift affected most margins in the NE Atlantic domain and was decisive for the extreme elevations around Kangerlussuaq where dynamic support from the Iceland plume reach a maximum for Greenland.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013