Tectonic modelling in the Bjørnøya West Basin of the Western Barents Sea 1

• Published in: Geophysical Prospecting
• Main Author: Liu, Guojiang
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1994
• Subjects: Barents Sea; Bjørnøya
• Online Access: http://dx.doi.org/10.1111/j.1365-2478.1994.tb00211.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2478.1994.tb00211.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2478.1994.tb00211.x

Abstract The Bjøirnøya West Basin lies between latitudes 73° and 74°, longitudes 16°E and 18°E, contains at least 8 km of sediments deposited from the Late Jurassic, and is of considerable interest for hydrocarbon exploration. The Cenozoic extensional tectonics in the basin can be clearly seen from seismic data with normal faulting and from subsidence curves with rapid subsidence. The extension occurred during the Late Palaeocene with active extension lasting about 6 million years (m.y.) followed by thermal cooling. The tectonic subsidence within the study area shows a three‐phase development: phase 1, synrift (58–52 Ma (million years before the present day)), is characterized by rapid subsidence; phase 2, postrift (52–5 Ma), by slow subsidence with occasional uplift; and phase 3 (5–0 Ma), by rapid subsidence. An adaptive finite‐element model, with consideration of the radiogenic heat production in the lithosphere, has been used to model the subsidence and heat flow. The modelling of subsidence shows the β‐factor distribution varying from 1.9 to 3.5 with an average of 2.4 for the uniform lithospheric extension. The heat‐flow modelling predicts a rapid increase of heat flow during the Early Palaeocene. The maximum heat flow at about 52 Ma, which could be as much as 3.0 hfu (10 −6 cal/cm 2 /s), was followed by a decrease in heat flow. A plate‐weakening model has been proposed to explain the rapid subsidence for the last 5 m.y. by flexure of the elastic lithosphere which is weakened by a decrease in elastic thickness caused by an increase of the temperature gradient in the lithosphere. The plate‐weakening model predicts a heat‐flow increase at 5 Ma of up to 2.0 hfu. Our study, using quantitative modelling of the tectonic subsidence, provides a partial (if not a full) understanding of the tectonic development and thermal evolution of the Bjønøya West Basin.