Seismic tomography of the Dead Sea region: Thinned crust, anomalous velocities and possible magmatic diapirism
Nitzan Rabinowitz, Yossi Mart, 1999. "Seismic tomography of the Dead Sea region: Thinned crust, anomalous velocities and possible magmatic diapirism", Salt, Shale and Igneous Diapirs in and around Europe, Bruno C. Vendeville, Yossi Mart, Jean-Louis Vigneresse
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Analysis of first arrivals of P waves from 113 earthquakes in the Dead Sea region and the calculation of a tomographic model indicates anomalous distribution of seismic velocities in the crust and the upper mantle. The seismic tomography model was applied to the lower and intermediate crust and the uppermost mantle there, at depths greater than the detection limits of seismic reflection surveys. At these depths the inversion shows two deep layers, at depths of 10–22 km and 22–32 km. The deeper layer shows average seismic velocity of 7.7 km s−1, and the shallower one 6.5 km s−1. The model suggests therefore that the Moho under the central Dead Sea is found at depth of 22 km, and the seismic velocity in the upper lithospheric mantle is anomalously low. The velocity of the layer overlying the Moho suggests a modelled layer of composite mineralogy, but high velocity anomalies were encountered in the 10–22 km layer under the boundary faults of the Dead Sea Rift, and a low velocity anomaly under the central Dead Sea is plausible. The probable interpretation of these anomalies is that the mantle under the central Dead Sea is shallow and anomalously hot, and that the lower and intermediate crust under the axial zone of the central and northern Dead Sea is also anomalously hot. Furthermore, it seems probable that magmatic diapirs ascend along the boundary faults of the rift into the intermediate crust. Structural similarity of the upper mantle and the lower crust between the Dead Sea and the northern Red Sea suggests an analogous tectonic regime for these two regions.
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The ten articles in this book describe the mode of emplacement of various types of intrusions (salt diapirs, mud volcanoes and magmatic bodies) by means of theoretical reasoning, analogue and analytical modelling, interpretation of seismic and field data, and geodetic surveying. All the articles emphasize the role of regional tectonics in driving or controlling the emplacement of the intrusions. The selection of articles includes examples from Spain, Romania, onshore and offshore Italy, the Eastern Mediterranean, Israel and iran.
Better understanding of the mode of emplacement of these intrusions has applications in hydrocarbon exploration (e.g., where salt structures or mud diapirs are present) and in the mining industry (where mineralization is related to the emplacement of batholiths).