NEW INSIGHTS INTO THE SOURCES OF MAGNETIC ANOMALIES IN THE LEVANT
M. Rybakova, V. Goldshmidta, J.K. Hallb, Z. Ben-Avrahamc, and M. Lazard
aGeophysical Institute of Israel (retired), P.O. Box 182, Lod 71100, Israel
bGeological Survey of Israel (retired), 30 Malkhei Israel Street, Jerusalem, 95501, Israel
cDept. of Geophysics and Planetary Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
dThe Dr. Moses Strauss Department of Marine Geosciences, University of Haifa, Mount Carmel, Haifa, 31905, Israel
Keywords: Magnetic and gravity anomalies, ophiolites, volcanics, basic intrusion, eastern Mediterranean
Pages: 377-397
Abstract
The magmatic characteristics of the Levant were investigated by combining recompiled regional scale magnetic maps, revised petrophysical and gravity databases, and previous interpretations. In the study area, the inclination of the Earth's magnetic field vector is low and the total magnetic intensity map is, therefore, difficult to interpret for location and strike of magnetic bodies. Hence, a pole-reduced magnetic map was compiled. The integrated interpretation of magnetic and local gravity anomalies allowed for the estimation of depth and size of magmatic bodies and, in some cases, permitted identification of their composition. Reliability and accuracy of the results were approximated by forward modeling and by comparison with seismic reflection and drillhole data.
The study area was divided into five regions of consistent regional-scale magnetic patterns with more or less distinct boundaries. This was based not only on recognition of formal magnetic patterns but also on correlation with known (or expected) geology. The strong coincident magnetic and positive gravity anomalies probably correspond to ophiolite massifs in the northern part of the study area and basic magmatic intrusions in the southern part. Strong magnetic anomalies, which are not associated with positive gravity anomalies, most likely correspond to Mesozoic and Cenozoic volcanics located mainly in the central part of the region. The absence of magnetic anomalies in some areas suggests the lack of basic magmatic bodies (volcanic or plutonic) but provides no information on the presence of acid magmatics (granite, etc.).
|
