G. Florio et al., ANISOTROPIC MAGNETIC-SUSCEPTIBILITY IN THE CONTINENTAL LOWER CRUST AND ITS IMPLICATIONS FOR THE SHAPE OF MAGNETIC-ANOMALIES, Geophysical research letters, 20(23), 1993, pp. 2623-2626
Magnetic anisotropy measurements on samples from the lower continental
crust were made to test the hypothesis that anisotropy may cause defl
ection of the peak-to-trough axes of magnetic anomalies caused by mid-
to lower crustal sources. Average anisotropy (P') for these samples i
s 1.5 but can be as high as 3.4. Felsic granulite facies rocks show th
e highest anisotropy. Magnetic sources with P' equal to the maximum de
termined in this study can cause azimuthal rotations of magnetic anoma
lies by up to about 25-degrees, but P' lower than or equal to 1.5 caus
es no significant rotation. Comparison of the model results to the abn
ormal shape of some magnetic anomalies in southern Italy indicate that
these anomalies cannot be related easily to a strong and coherent AMS
of the source rocks. The most probable explanation of such shapes is
the existence of a strong remanent magnetization in subsequently rotat
ed source bodies.