Upper Triassic to lower Cretaceous tectonostratigraphic development of the Barents Sea South East

Abstract

The aim of this study is to investigate the tectonic- and evolutionary differences between major structural elements of the Barents Sea South East (BSSE) during the uppermost Triassic to lower Cretaceous. The study area comprises the following structural elements: the Bjarmeland- and Finnmark platforms, the Nordkapp- and Tiddlybanken basins, the Signalhorn-, Haapet- and Veslekari domes and the Fedynsky High.

Interpretation of seismic 2D- and well-data from the exploration well 7435/12-1 have provided the stratigraphic framework on the uppermost Triassic to lower Cretaceous, represented by the Realgrunnen Subgroup (late Norian to Bajocian), the Fuglen Formation (Callovian to Oxfordian) and the Hekkingen Formation (late Oxfordian to Tithonian). Thickness variations, and seismic stratigraphy as reflection geometries and terminations were applied to identify structural events such as uplift, subsidence and periods of erosion.

Insight in the tectono-stratigraphic evolution of the Barents Sea South East have been provided by variations in the thickness and termination patterns of the uppermost Triassic to lower Cretaceous units. This study suggests a late Norian to Bajocian (represented by the Realgrunnen Subgroup) elevation of the Fedynsky High, Finnmark Platform, Veslekari- and Signalhorn domes. During the same period, a relatively stable platform configuration was valid for the Bjarmeland Platform and northern section of the Finnmark Platform, and concurrent basin configuration of the Nordkapp Basin, what today is the Haapet Dome and the area northeast of the dome structure. The structural trends valid for the late Norian to Bajocian continued into the Callovian to Oxfordian (represented by the Fuglen Formation), excluding the Haapet Dome, Bjarmeland Platform and north part of the Finnmark Platform in which the former experienced uplift and the two latter experienced subsidence during this period. The tectono-stratigraphic evolution of the Callovian to Oxfordian persisted through the late Oxfordian to Tithonian, accompanied by a rise in relative sea-level (represented by the Hekkingen Formation), in addition to subsidence of the Tiddlybanken Basin.

Late Norian to Tithonian structuring of the BSSE are suggested to be linked to the possible reactivation of deep lineaments by the final upthrusting of the Novaya Zemlya (Late Triassic – Early Jurassic) and also the tectonic events that influenced the NE Atlantic rifting (Late Jurassic – Early Cretaceous) and later opening