3.7.4. The Levant and the Eastern Mediterranean: Crustal Structure and Physiography
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| Fig. 70. Distribution of terranes with distinct crustal structure in the eastern Mediterranean and surrounding areas (Ben-Avraham and Ginzburg, 1990; Ben-Avraham et al., 2002; DTM: Hall, 2003). |
In the Levant and Eastern Mediterranean area the accretion of a number of small crustal units is expressed in the physiography and neotectonic activity of the region (Fig. 70).
The Levant-East-Mediterranean area underwent a long and complex evolution, involving different geological processes and repeated changes in its megatectonic setting, starting with the Early Paleozoic Pan-African Orogeny, followed by the Mesozoic break-up of Gondwana and opening of the Neotethys, its Late Mesozoic and Cenozoic partial closure and ultimately the Neogene separation of Arabia from Africa. Today the area includes a number of active plate boundaries that have repercussions on its deformation style and physiographic configuration (e.g. Cyprus arc, Dead Sea transform, Red Sea spreading axis).
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| Fig. 71. Distribution of earthquakes in the Levant and eastern Mediterranean area (1983-2003). Note the correlation between crustal unit boundaries and earthquake distribution (Geophysical Institute of Israel). |
Geophysical data, including seismic refraction and reflection profiles, gravity and magnetic measurements, seismicity, topographic and bathymetric maps, suggest that the eastern Mediterranean region can be divided into distinct crustal units which differ in their thickness and internal layering, such as the on-shore Negev, Judea-Samaria, Galilee-Lebanon and Jordan blocks and the offshore Levant Basin, Eratosthenes Seamount, Florence Rise, Hecateus Seamount and Cyprus (Fig. 70). Differentiation of the on-shore crustal domains probably dates back to Pan-African continental accretion processes. Analysis of the regional geology shows that this crustal differentiation is manifested in the structural style and deformation pattern of the upper few kilometres of the sedimentary section. The differences between the crustal units are also clearly exhibited in the seismicity and topography of the Levant and the bathymetry of the eastern Mediterranean (Fig. 71). Interestingly, the physiography of this region has played a strong role in the distribution and development of plants and birds and the dispersal of humans between Europe, Africa and Asia.
The topography of the region developed through several uplift phases that correlate with uplift phases of southern Europe. This suggests that similar mechanisms are responsible for the uplift of both regions.