GNGTS 2017 - 36° Convegno Nazionale

704 GNGTS 2017 S essione 3.3 In questa nota sono stati presentati teoria e applicazione del metodo nel caso di contrasti di proprietà fisica costanti, come si può assumere per il contrasto di densità in bacini poco profondi o nel caso magnetico. Come detto però, in casi reali la situazione è in genere più complessa, in particolare nel caso gravimetrico. Nell’ambito di questo metodo, primi test mostrano che la variazione del contrasto di densità con la profondità può essere gestita mediante l’uso di regressioni lineari multiple della relazione profondità vs. anomalie gravimetriche. Bibliografia Baranov, V. (1957). A new method for interpretation of aeromagnetic maps: pseudo-gravimetric anomalies . Geophysics, 22, 359–383 Barbosa, V. C. F., Silva J. B. C., and Medeiros W. E. (1997). Gravity inversion of basement relief using approximate equality constraints on depths . Geophysics, 62, 1745–1757 Bott, M. H. P. (1960). The use of Rapid Digital Computing Methods for Direct Gravity Interpretation of Sedimentary Basins . Geophysical Journal of the Royal Astronomical Society, 3(1), 63–67. Caratori Tontini, F., Cocchi, L., &Carmisciano, C. (2009). Rapid 3-D forward model of potential fields with application to the Palinuro Seamount magnetic anomaly (southern Tyrrhenian Sea, Italy) . Journal of Geophysical Research, 114(B2), B02103. Fedi, M. (1997). Estimation of density, magnetization, and depth to source: A nonlinear and noniterative 3-D potential field method . Geophysics, 62(3), 814–830. Hinze, W. J., von Frese, R. R. B., & Saad, A. H. (2013). Gravity and Magnetic Exploration - Principles, Practices, and Applications . Cambridge University Press. Litinsky, V. A. (1989). Concept of effective density: Key to gravity depth determinations for sedimentary basins . Geophysics, 54(11), 1474–1482. Parker, R. L. (1972). The rapid calculation of potential anomalies . Geophysical Journal of the Royal Astronomical Society, 31(4), 447–455. Rao, D. B. (1986). Modelling of sedimentary basins from gravity anomalies with variable density contrast. Geophysical Journal of the Royal Astronomical Society, 84(1), 207–212. Williams, S. E., Fairhead, J. D., & Flanagan, G. (2005). Comparison of grid Euler deconvolution with and without 2D constraints using a realistic 3D magnetic basement model . Geophysics, 70(3), L13–L21. Magnetization Vector Inversion of Magnetic Data and its Application IN mineral exploration OF China S. Liu 1,2 , M. Fedi 2 , J. Baniamerian 2 , X. Hu 1 1 Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan, China 2 Department of Earth, Environmental and Resources Science, University of Federico II, Naples, Italy Introduction. Remanent magnetization is one of the important physical property of rocks’ and ores’ magnetism, which changes the intensity and direction of total magnetization vector (Lelièvre and Oldenburg, 2009; Li et al. , 2010). The self-demagnetization effect for high-susceptibility (e.g., > 0.1 SI) source, producing an opposite magnetic field to external field, reduces the magnetization intensity and also alters the internal magnetization direction (Guo et al. , 2001; Lelièvre and Oldenburg, 2006). The magnetization vector inversion (MVI) recovering the total magnetization vector (TMV) distributions is an important method to solve the remanence and self-demagnetization problems. Wang et al. (2004) derived the magnetization vector inversion equations and recovered the horizontal and vertical magnetization components of a 2D theoretical model. Their approach was more applicable to determine the total magnetization of separated, homogeneous bodies. Lelièvre and Oldenburg (2009) improved their methods and calculated the three components of magnetization in Cartesian and spherical frameworks, which served more complicated scenarios and had widespread applicability in magnetic data inversion under the influences of significant remanent magnetization. However, magnetization vector inversion requires site-specific constraints (e.g., physical properties and