The Structural Information Potential of Mapping Magnetic Responses Created in the Near-Surface Formations

John P. Land

Modern magnetic survey has the capacity to resolve magnetic anomalies created in the shallow sedimentary section as well as those created at or beneath the basement surface.

The detailed profile analysis of aeromagnetic data allows the resolution and mapping of detail less apt to be preserved through gridding and contouring processes, magnetic responses caused by the structural disturbance of the near-surface formations. When certain criteria are consistently applied to the mapping of these magnetic anomalies, in addition to defining magnetic prospect leads, linear features believed to represent tectonically-stressed subsurface zones are also resolved, information with the potential of adding another dimension to the magnetic surveymethod and contributing to more accurate integrations of multiple data sets.

Magnetic surveys in the Williston, Black Warrior and Val Verde basins and the Gulf of Mexico show linear near-surface based features coincident with deep-seated structure suggesting fracture zones created by the various mechanical and depositional processes associated with the lateral and vertical displacement of basement faults.

Small and large airborne magnetic surveys from the onshore and offshore are used to display the information gained through the mapping of magnetic responses created in the near-surface formations.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995