Southern Nordkapp basin aeromagnetic survey 2006 (SNAS-06). Data acquistion and processing report

Abstract

The high-sensitivity Southern Nordkapp Basin Aeromagnetic Survey (SNAS-06) was carried out in an area of app. 4000 km2 in the Barents Sea, offshore Finnmark, northern Norway. Data processing comprised spike removal and data editing, IGRF correction, statistical levelling, floating differential median micro-levelling and directional cosine filtering (decorrugation). Three maps were produced for the survey area. One map shows the magnetic total field anomalies after correction for the IGRF of 2006. Another map shows residual magnetic values after application of a 20 km high-pass filter. A map showing magnetic analytic signal is also presented. The residual map after high-pass filtering delineates anomalies with amplitudes as low as 0.1-0.2 nT, representing shallow and weak magnetic sources in the sedimentary basin. Salt diapirs coincide clearly with negative magnetic anomalies. Small positive magnetic anomalies within the salt-related negative anomalies may reflect slivers of sedimentary rocks (e.g. claystones) within the diapirs.