The aeromagnetic data of the study area ware obtained from Tanzania Petroleum Development Corporation (TPDC). These data were part of a regional airborne dataset acquired by Geosurvey International in 1977 and 1980 along east-west flight line altitude of 120 m at 1 km line spacing and 10 km tie line spacing. Aeromagnetic data in Zambia were acquired by Geometrics Inc. for the Geological Survey Department of Zambia between 1973 and 1976 with a mean terrain clearance of 150 m and mean line spacing of 800 m–1000 m in the N-S direction (Sarafian et al.
, 2018). Aeromagnetic data in Malawi were acquired in 1984–1985, with 120 m flight elevation along NE-SW lines with spacing of 1 km and a tie-line spacing of 10 km (Kolawole et al., 2018). These datasets were merged together using GridKnit tool available in Oasis montaj software.The estimation of CPD from aeromagnetic data requires deep (long wavelength) magnetic anomalies/sources (Dolmaz et al., 2005). In order to attenuate shorter wavelength of the near surface anomalies and enhances the broad (longer wavelength) and deep seated magnetic anomalies derived from deeper causative sources, a low pass Butterworth filter with a cut-off wavelength of 3 (7 km) km was applied to aeromagnetic data (figure required).
This wavelength is based on the matched bandpass filter (Phillips, 2001) applied to aeromagnetic data. The Curie point depths were computed from the filtered aeromagnetic anomalies.