Facies distributions and lithostratigraphic correlation in the late Precambrian Ekkerøy Formation, east Finnmark, Norway

The late Precambrian Ekkerøy Formation of east Finnmark occurs at the top of the Vadsø Group and extends throughout the Tanafjorden-Varangerfjorden region. It consists of a uniform vertical and lateral facies pattern, in which four facies characteristically form part of a large-scale coarsening upward, marine- dominated regressive sequence. Lateral facies and thickness variations between inner Varangerhalvøya ( 12-190 m thick) and Varangerfjorden ( 15-35 m thick) are the product of both primary depositional thickness variations and a gentle, southerly dipping unconforrnity at the base of the overlying Grønnes Formation. The transgression at the base of the Grønnes Formation (basal Tanafjord Group) marked a major change in depositional conditions from the fluvially-dominated Vadsø Group below to the shallow marine-dominated Tanafjord Group above. This junction is the most distinctive lithostratigraphic horizon in an otherwise conformable 2,000 m thick, clastic-dominated succession.