Lithospheric Characterisation by Joint Interpretation of Potential Field and Thermal Modelling – Southwestern Barents Sea, Norway

Abstract

We characterise the basement structure and study the steady state thermal structure of the lithosphere integrating density and magnetic modelling. We present 2D models and a preliminary 3D model combining interpretation of gravity and magnetic fields of the Loppa High in the SW Barents Sea. The advantage of our modelling approach is to be able to distinguish features such as the basement characteristics, not visible when interpreting only the gravity field. Our models are constrained by seismic profiles, well logs, petrophysical measurements and core samples. Euler Deconvolution Solutions (EDS) (Reid et al., 1990) usually used to estimate the depth to magnetic sources, revealed two additional features. EDS plotted on a map allow to identify alignments of tilted blocks occurring in parallel bands. Along 2D profiles, the plotted EDS outline an intra-basement block near the Loppa High. The integration of 2D potential field models is a first step to a 3D lithospheric density and magnetic model. The interpretation of the magnetic models suggests different basement lithologies and allows providing a preliminary map of the basement units and their onshore-offshore links. To study the steady state thermal structure of the lithosphere we use a two dimensional algorithm that integrates thermal, gravity and local isostatic analyses (Zeyen and Fernandez, 1994; Zeyen et al., 2005).