Phanerozoic rock magnetization in southern and central Israel

Magnetic susceptibility (κ) measurements were applied for the magnetic characterization of the Phanerozoic section in the central and, mainly, southern parts of Israel. Effective magnetization was also determined by correlation between the total magnetic field and the elevation of magnetic measurement points, and by measurements of oriented samples. The results confirm that igneous rocks within the Phanerozoic section cause most of the observed magnetic anomalies. Alkaline basaltoid flows in the Makhtesh Ramon are a have different patterns of κ variation and anisotropy in the tephrite, relative to the basanite flows. These results suggest that κ measurements can help to differentiate and characterize basic volcanic flows. Within the Phanerozoic sedimentary succession, only the metamorphic rocks of the Hatrurim Formation show a significant magnetic signature. The magnetization patterns of the Hatrurim Fm. rocks in the Hatrurim basin vary for different rock groups. The maximal κ values of high-grade metamorphic rocks exceed 5,600·10^-5 SI for calcium silicate pseudo-conglomerates and reach 1,500·10^-5 SI for calcium silicates. The magnetic susceptibility of the low-grade rocks reaches 1,100·10^-5 SI. Unaltered rocks of the Hatrurim Fm. and, sometimes, the underlying phosphorites or bituminous carbonates of the Mishash Fm. have κ values reaching (300-400)·10^-5 SI. Remanent magnetization (I_n) of the Hatrurim Fm. is greater than the induced magnetization (I_i.), while the I_n inclination is close to that of I_i. Slightly increased magnetization sometimes characterizes sediments that are fractured or contaminated by metallic elements, while lateritic crust is sometimes distinguished from the surrounding basic rocks by its decreased magnetization.