Jurassic - Cretaceous boundary strata of the extreme Arctic (Peary Land,.North Greenland)

A fossiliferous Late Jurassic-Early Cretaceous sequence is described from the Wandel Sea Basin, eastern North Greenland. The area was transgressed in the Middle Oxfordian and a gradually shallowing marine regime prevailed until Early Valanginian time, when conditions became !ironic. Stratigraphic data based on dinoflagellate cysts, ammonites and Buchia species indicate the presence of strata of Middle and Late Oxfordian, Kimmeridgian, Middle and Late Volgian, Early and Late Ryazanian, and Early Valanginian ages. Both the dinoflagellate assemblages and the mollusc faunas show close similarity to assemblages from the Sverdrup Basin of the Canadian Arctic Archipelago, Svalbard and northern USSR. They are also linked to more southern Boreal and Sub-Boreal areas in East Greenland, England, the Russian Platform and to some extent, North America. An integrated dinoflagellate-ammonite-Buchia stratigra­phy shows that the Early Cretaceous dinoflagellate assemblage appeared later in the Wandel Sea Basin than further south. It is also seen that a discrete "Jurassic" dinoflagellate assemblage existed for some time in the Early Cretaceous unaffected by the general tum-over at the Jurassic-Cretaceous boundary. Dinoflagellate, ammonite and Buchia assemblages are briefly discussed and selected species figured.