Basement Structure of the Barents Platform

Abstract

The basement structure of the Barents Platform has been investigated to determine the control of structural inheritance and basement composition on basin development. The structural basement study was based on potential field data, published maps and cross sections, plate reconstructions, and wells. The resulting regional tectonic synthesis includes a depth-to-basement map, basement terranes basement contribution to heat flow, and fault events for key tectonic events. Gravity and magnetic data have been critical in the interpretation of basement terranes, event maps and 3D geometry of the basement surface. Basement age has been define by the age of the youngest significant tectonothermal event. For the Western Barents, this is the Scandian phase (Mid Silurian to Early Devonian) of the Caledonian Orogeny and in the Eastern Barents, this event is the Neoproterozoic Timanide Orogeny. It is considered unlikely that the Novaya Zemlya phase (Triassic to Early Jurassic) of the Uralian Orogeny generated new basement. The structure of the Barents Platform can be divided into four main structural styles. The NW Barents is dominated by interconnected N-S strike-slip fault systems introduced during the Late Silurian Caledonian Orogeny and Late Devonian Svalbardian Orogeny. Steps in these strike-slip systems introduce constraining and releasing bends that produce pop-up structures or pull-apart basins depending on the sense of displacement during reactivation. In the SW Barents, basement structure is dominated by NE-trending Caledonian-age strike-slip and reverse faults that reactivate to produce depocentres in pull-apart or oblique-extension basins with arcuate fault boundaries linked by NE to NNE trending strike-slip faults. Late Caledonian and younger N-S and NW-trending faults offset the dominant NE trend. The Central Barents is transected by a conjugate set of NNW and NNE vertical strike-slip faults that acted as conduits for volcanics during Cretaceous time. The structure of the eastern part of the central Barents remains enigmatic. The Eastern Barents is underlain by Timanian basement that has undergone extreme subsidence due to (mainly Triassic) sediment loading and, presumably (retorarc?) extension, related to the Uralian Orogeny. Overall, there is a very strong basement control on basin development, and major structures mapped in seismic data mimic the underlying basement topography.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015