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| Titel |
Estimation of the total magnetization direction of approximately spherical bodies |
| VerfasserIn |
V. C. Oliveira, D. P. Sales, V. C. F. Barbosa, L. Uieda |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 22, no. 2 ; Nr. 22, no. 2 (2015-04-24), S.215-232 |
| Datensatznummer |
250120976
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| Publikation (Nr.) |
 copernicus.org/npg-22-215-2015.pdf |
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| Zusammenfassung |
| We have
developed a fast total-field anomaly inversion to estimate the magnetization
direction of multiple sources with approximately spherical shapes and known
centres. Our method is an overdetermined inverse problem that can be applied
to interpret multiple sources with different but homogeneous magnetization
directions. It requires neither the prior computation of any
transformation-like reduction to the pole nor the use of regularly spaced
data on a horizontal grid. The method contains flexibility to be implemented
as a linear or non-linear inverse problem, which results, respectively, in a
least-squares or robust estimate of the components of the magnetization
vector of the sources. Applications to synthetic data show the robustness of
our method against interfering anomalies and errors in the location of the
sources' centre. Besides, we show the feasibility of applying the upward
continuation to interpret non-spherical sources. Applications to field data
over the Goiás alkaline province (GAP), Brazil, show the good performance
of our method in estimating geologically meaningful magnetization directions.
The results obtained for a region of the GAP, near to the alkaline complex of
Diorama, suggest the presence of non-outcropping sources marked by strong
remanent magnetization with inclination and declination close to −70.35 and
−19.81°, respectively. This estimated magnetization direction leads
to predominantly positive reduced-to-the-pole anomalies, even for other
region of the GAP, in the alkaline complex of Montes Claros de Goiás.
These results show that the non-outcropping sources near to the alkaline
complex of Diorama have almost the same magnetization direction of those ones
in the alkaline complex of Montes Claros de Goiás, strongly suggesting
that these sources have been emplaced in the crust within almost the same
geological time interval. |
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