A device for detecting and measuring magnetic field strength. Within down hole orientation cartridges three mutually perpendicular flux-gate magnetometers measure the Earth’s magnetic field relative to the tool axis, allowing orientation to the magnetic field, of known orientation, at that location. Cross-plots of three derived curves are important in the quality control of orientation curves.
We have observed that localised up-hole variations in the magnetic data can be used to help detect, discriminate and interpret intruded versus extruded basic (magnetite bearing) igneous rock bodies.
SHERIFF, R. E. 1973. Encyclopedic Dictionary of Exploration Geophysics. Society of Exploration Geophysicists, Tulsa, p266.