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