Geological Structure and Hydrocarbon Potential of the North of the Barents Sea

Sergey Pavlov

Main tectonic elements of the northern part of the Barents Sea are the Alexandrovskaya high zone located in the west, the North Barents depression - in the central part and the Prednovozemelskaya zone of folded dislocations - in the east, which are detected according to the thickness of the sedimentary cover and succession of its seismic geological sequences. There is no common opinion of the tectonics position of the North Barents depression. Many researchers define it as a part of the Barents shelf plate, others consider it as a part of the separate Barents-North-Kara megatrough. There is no clear understanding about the tectonics of the western and eastern parts of the upwarping of Franz Josef Land. Within the Alexandrovskaya high zone the basement occurs at the depths of 400-3000 m generally subsiding along the monocline towards the central part of the North Barents depression in concession to faults of the north-eastern strike. According to Nagurskaya-1 well data the basement is presented by strongly metamorphized Vendian – Riphean formations. Seismic data don’t allow to track the basement in the central part of the North Barents depression. Within the Prednovozemelskaya zone of folded dislocations the consolidated base is located at the depths from 6 to 17 km showing a graben-horst relief and the following rather gradual subsiding to the center of the North Barents depression. The sedimentary cover is divided into two structural – tectonic stages. The lower one consists of the Lower-Middle Paleozoic seismic geological sequence. Its thickness is caused by the block relief of the basement at the foot and considerably smoother forms of the regional surface of the Pre-Frasnian erosion III2 at the roof. The upper one is made of geological sequences from the Upper Devonian to the Upper Cretaceous deposits. The Cenozoic uplift is more brightly presented in the Alexandrovskaya high zone and in the Prednovozemelskaya zone of folded dislocations where the Jurassic – Cretaceous and, partly, the Triassic deposits are eroded and the erosion depth increases 2 km. The Triassic deposits had rather consistent thickness. The Triassic formations are broken by numerous magma bodies – dykes and sills. As for the formation mechanism of the North Barents depression there should be mentioned that rifting features are absent in the sedimentary cover of the Late Devonian – Cretaceous period.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013