Geological development of the Northeast Greenland Shelf

Abstract

Seismic data from the East Greenland shelf show that the northern part of the shelf, north of 75°N, can be subdivided into five, roughly northeast-trending, major tectonic elements. From west to east they are: the Koldewey Platform, the Danmarkshavn Basin, the Danmarkshavn Ridge, the Thetis Basin and the Marginal High. A sixth tectonic element, the Shannon High, has been defined in the southern part of this area. The offshore areas between 72°30′N and 75°N are dominated by Tertiary plateau basalts, which obscure the acoustic signals from the deeper sedimentary succession. Seismic data from the area north of 75°N indicate the presence of a fairly complete succession of ? Devonian to Neogene age, exceeding the recorded interval (8 sec TWT – 13 km) in thickness in the deeper parts of the Danmarkshavn Basin. The succession has been subdivided into 15 seismic mega-sequences. In absence of well control, they have been dated by comparison to the onshore successions of East Greenland and eastern North Greenland, and the offshore successions in the southern Barents Sea and on the mid-Norwegian shelf. The Upper Palaeozoic succession is broadly similar to that of the southern Barents Sea, i.e. marine-dominated, with thick Upper Carboniferous–Lower Permian halite deposits in the northern Danmarkshavn Basin. The Mesozoic succession seems to show greater similarities to the onshore basins of East Greenland: rifting started during the mid-Jurassic and peaked near the Jurassic–Cretaceous boundary. The post-volcanic succession reflects deposition on a passive margin subjected to temporary uplift during the early Miocene and the latest Miocene to earliest Pliocene.