The relationship between Caledonian nappe tectonics and Silurian turbidite deposition in North Greenland

Abstract

The relationship between the northern part of the Caledonian fold belt of East Greenland and the North Greenland fold belt is explored within the context of Silurian sedimentation and tectonics. A model is developed relating the Caledonian nappes of eastern North Greenland to major tectonic and sedimentological features of the Silurian of the remainder of North Greenland. The abrupt change from a thin succession of predominantly slowly deposited muds to a thick succession of rapidly deposited sandstone turbidites at the Ordovician/Silurian boundary, in the deep-water basin N of the carbonate platform in North Greenland, is directly related to uplift and westerly directed nappe emplacement in the eastern Caledonides. It is suggested that uplift to the E of North Greenland, which commenced in the late Ordovician or early Silurian, provided the main source of the Silurian turbidites of North Greenland. This is corroborated by the dominant westerly transport direction of the Silurian turbidites. Nappe emplacement during the latest Llandovery (Silurian), and foundering of the whole of the carbonate platform of eastern North Greenland E of the Victoria Fjord Arch (approximately 60 000 km 2 ), is marked by the replacement of shallow water carbonates by basin turbidites. These events were directly related to isostatic readjustments as the nappes advanced onto the eastern fringe of the platform.