Interpretation of Aeromagnetic Anomalies of Degema and Oloibiri area of Niger Delta, Nigeria, Using Qualitative Approach
C. C. Ofoha *
Department of physics, University of Port Harcourt, Choba, Rivers State, Nigeria.
G. Emujakporue
Department of physics, University of Port Harcourt, Choba, Rivers State, Nigeria.
A. S. Ekine
Department of physics, University of Port Harcourt, Choba, Rivers State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Qualitative interpretation of high resolution aeromagnetic data spanning Oloibiri and Degema area of Southern Niger Delta, Nigeria was undertaken in order to interpret anomalies that could (1) delineate structural features with low and high anomalous values within the area and (2) determine if there is any structural relationship between the offshore Niger Delta region and the onshore region. Regional-residual separation was applied to the digitized data covering Long. 6º0'0'' E - 7º0'0'' E and Lat. 4º30' N - 5º0i0ii N with a first order polynomial fitting using the X utility module of Oasis Montaj software. This filtering action gave rise to the regional and residual maps depicting anomalies relating to the low and high frequency components. The high frequency components/anomalies (or the residuals) emanate from shallow seated geologic bodies while the low frequency components/anomalies originate from the basement. The anomalies emanating from the deeply and shallow seated structural features have NE-SW, NW-SE, E-W and N-S directional trends.
Keywords: Anomalies, residuals, colour variations, qualitative approach, X Y channel, NE-SW, NW-SE.