Shayane P. Gonzalez, Valéria C. F. Barbosa and Vanderlei C. Oliveira Jr., (2022). Analyzing the Ambiguity of the Remanent-Magnetization Direction Separated Into Induced and Remanent Magnetic Sources. Journal of Geophysical Research: Solid Earth, 127(6), e2022JB024151. doi: 10.1029/2022JB024151
We developed a new ambiguity analysis method to investigate the remanence of a uniformly magnetized source. We wrote the unit vector of the total-magnetization direction as the weighted sum of the unit vectors of the induced- and remanent-magnetization directions. The unit vectors of the induced- and remanent-magnetization directions are weighted, respectively, by the ratio between the induced and total-magnetization intensities (λ), and by the multiplication of λ by the Koenigsberger ratio Q. We obtained analytical estimators for Q and the remanent magnetic inclination Ir and declination Dr. We constructed a family of ambiguity curves of Ir x Q, Dr x Q, and λ x Q for a fixed total-magnetization direction and for λ value. We estimated the total magnetic inclination It and declination Dt via the equivalent-layer technique constrained by an all-positive magnetic-moment distribution. We also used some total-magnetization directions associated with prespecified data-residual errors. We performed a systematic search for both It and Dt to obtain a discrete data-residual map on the plane It × Dt. We picked some It and Dt from the data-residual map associated with a percent of data-residual error and created some families of ambiguity curves of Ir, Dr, and λ versus Q. These ambiguity curves are quickly built up because we inverted the data only once. Tests with synthetic and field data from the Goiás Alkaline Province, Brazil, illustrated a wider perspective of the relationships between the remanent-magnetization direction and Q for different data-residual errors.
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