NJG76-1-04
1996
Correlation of the late Precambrian Ekkerøya Formation (Vadsø Group; E. Finnmark) and the Brennelvfjord Interbedded Member (Porsangerfjord Group; W. Finnmark), N. Norwegian Caledonides
76
1
pp. 55-61
In the Caledonian Lower Allochthon, the 0-4 00 m thick Brennelvfjord Member at the base of the Porsangerfjord Group in W. Finnmark (correlated with the Tanafjorden Group in E. Finnmark) is similar to the <200 m thick Ekkerøya Formation at the top of the Vadsø Group in the Autochthon and Lower Allochthon in E. Finnmark. Both units are lithologically very variable, with basal conglomerates/sedimentary breccias, dark shales, grey quartzites with intraformational mud-flake conglomerates and rust-spotting, yellow-green to red sandstones and siltstones and compressed triradiate 'mud-cracks' in siltstones and fine-grained sandstones. Further, these successions underlie quartz pebble conglomerates and grits at the base of both the Grønneset Formation, which is the unconformable base of the Tanafjord Group in E. Finnmark, and its correlative, the Kikut Member, in W. Finnmark. Although the Brennelvfjord Member is essentially transgressive and the Ekkerøya Formation largely regressive, the two successions may be broadly chronostratigraphic (if not lithostratigraphic) correlatives. Such a correlation gives a greater continuity along the basin margin to the stratigraphic successions within the Lower Allochthon and Autochthon in Finnmark. An informal revision of the stratigraphic terminology is proposed in which the Ekkerøya Formation is renamed the Lille Molvik formation, the Brennelvfjord Member is upranked to the Brennelvfjorden formation and both these formations are combined into a new group, the Ekkerøya group.

A. H. N. Rice, Institut flir Geologie, Geozentrum, Universitiit Wien, Althanstrasse 14, Vienna, Austria;
C. Townsend, Den norske stats oljeselskap a.s., R&D Centre, Arkitekt Ebbellsveg 10, N-7005 Trondheim, Norway

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