The earth’s ambient or reference magnetic field varies continuously. Short term (minutes to days) variations are accounted for and removed during acquisition and processing of magnetic surveys. Across the surface of the earth, the magnetic survey for G&G operations is measuring the distortion of the magnetic field caused by the geologic structure and lithology. This module will illustrate the changes the inclination of the ambient field will induce in the shape of a magnetic anomaly caused by a geologic feature such as an igneous intrusive.
After completing this unit, you’ll be able to:
- Describe what parameters are used to define the earth’s magnetic field and their general variation over the earth’s surface.
- Explain how an understanding of how magnetic anomaly shape varies with changing magnetic inclination of the earth’s field can benefit your exploration objective through improved delineation of geologic structure and lithology.