Application of magnetic methods to deep basin structures

Abstract

Although magnetic methods have long been used in basin studies the data are often underutilised since the formations of a relatively undeformed basin approximate sub-horizontal tabular sources except at basin edges. Horizontal sources are known to generate negligible anomalies. Very small angular deviations from tabularity, or horizontality, however, will generate very large responses at basin scale. This response is largely independent of source contrast, thickness, dip, or the orientation of either the source or the field but is very sensitive to small changes in dip differentials between upper and lower surfaces of the source. Classical rift sequence forms may account for many of the anomalies observed in basins and no presumption of basement sources is universally justified. Anomalies must be treated with basin perspective and scale and not as isolated elements.