Lithostratigraphy and depositional history of Upper Ordovician - Silurian shelf carbonates in central and western North Greenland

Abstract

Field work in 1985 revealed that the Aleqatsiaq Fjord Formation (Ordovieian-Silurian) can be traced from Washington Land to westernmost Peary Land, and that a tripartite subdivision of the formation can be achieved throughout most of this area (units AFI-3). Five mapping units (WGI-5) were recognised within the overlying Washington Land Group of Silurian age between Hall Land and westernmost Peary Land. These are described and correlated with sequenees in Washington Land and elsewhere in Peary Land. Deposition was uniform in the lower part of the sequenee (units AFI-WG1) throughout the mapped area. Lateral lithologieal variation in the upper part (units WG2-5) refleets differential regional subsidenee, the presence of intrashelf mounds and the development of huge mound complexes along the shelf margin.