Numerical Simulation of Temperature History in the Vøring Area, Offshore Mid Norway: The Effects of Palaeo Water Depth and Lower Crustal Body

Willy Fjeldskaar¹, Ivar Grunnaleite², and Janine Zweigel^3
1IRIS, Stavanger, Norway
²IRIS, Bergen, Norway
³Sintef Petroleum Research, Trondheim, Norway

The Vøring Basin, offshore mid Norway, is a large sedimentary basin province with grabens, sub-basins and structural highs. The basin is terminated to the west by the Vøring Escarpment, the eastern boundary of the Vøring Marginal High. The temperature history on a regional seismic profile across the Vøring Basin has been modelled using the BMT® software. The modelled profile runs from the Norwegian coast over the Trøndelag Platform and the Vøring Basin and ends close to the continent-ocean boundary. The profile is compiled from regional conventional seismic lines and deeper crustal structures obtained from OBS and ESP data.
A high-velocity and high-density layer is inferred below the crystalline basement of the Vøring Basin, and is often regarded as magmatic underplating. However, this hypothesis is questionable. There are several possible alternative hypotheses for the origin of the high-velocity lower crustal bodies. The temperature effects of the various possible hypotheses are tested here. In addition, we have studied the effects that palaeo waterdepth has on the calculated temperature history. The reason is that the uncertainty in palaeo water depth predictions over the deeper parts of the Vøring Basin are high. The modelling shows that palaeo water depth may have substantial effects on the calculated temperature history.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece