Giant Quasi-Ring Mantle Structure in the African–Arabian Junction: Results Derived from the Geological–Geophysical Data Integration

Abstract

The tectonic-geodynamic characteristics of the North African-Arabian region are complicated by the interaction of numerous factors. To study this interaction, we primarily used satellite gravimetric data (retracked to the Earth's surface), which has been acknowledged as a powerful tool for tectonic-geodynamic zoning. The applied polynomial averaging of gravity data indicated the presence of a giant, deep quasi-ring structure in the Eastern Mediterranean, the center of which is located under the island of Cyprus. Simultaneously, the geometrical center of the revealed structure coincides with the Earth's critical latitude of 35°. A quantitative analysis of the obtained gravitational anomaly made it possible to estimate the depth of the upper edge of the anomalous body as 1650-1700 km. The GPS vector map coinciding with the gravitational trend indicates counterclockwise rotation of this structure. A review of paleomagnetic data on the projection of the discovered structure into the Earth's surface also confirms its counterclockwise rotation. Analysis of the geoid anomalies map and seismic tomography data commonly prove the presence of this deep anomaly. The structural and geodynamic characteristics of the region and paleobiogeographic data are consistent with the proposed physical-geological model. Comprehensive analysis of petrological, mineralogical, and tectonic data suggests a relationship between the discovered deep structure and near-surface processes. The deep structure also sheds light on specific anomalous effects in the upper layer of the crust, including the highintensity Cyprus gravitational anomaly, counterclockwise rotation of the Mesozoic terrane belt, configuration of the Sinai Plate, and asymmetry of sedimentary basins along continental faults.

Paleomagnetic-Radiometric Mapping of the Transition Zone from Ocean to the Continent: A Review

“…However, their initial application in the easternmost Mediterranean region was triggered by the work of Ben-Avraham et al [30]. The previous experience of our studies in this region [16,18,[31][32][33] indicates that paleomagnetic studies are effective in analyzing the geodynamic-tectonic features of the easternmost Mediterranean.…”

“…The data mentioned above join the deep-geophysical mechanisms of different levels -the mantle plumes from the deep mantle and the movements of the basement of the Earth's crust, which are sources of the shallow anomalies in the gravity and magnetic fields [16,91]. The Tuarkyr paleomagnetic zone, confined in this area to the Senonian, was developed in the form of the insignificant domains at the surface as scattered outcrops of the Bat Shelomo effusive rocks in the south of the Carmel Plateau, having a radiometric age of 82 Ma [89].…”

“…It was the first experience of such research in the transition areas from the ocean to the continent. In the context of the regional geological-geophysical studies of the African-Arabian region, paleomagnetic mapping of the area of the Sea of Galilee has been significantly expanded and detailed ( [16,23,32,52].…”

“…In such a manner, we nailed the mapping of the transition region from the ocean to the continent to the methods widely used in the paleomagnetic mapping of the marine areas [22], and optimally compiled with the geodynamic principles [25]. A novel variant of the paleomagnetic map of the Sea of Galilee and adjacent areas (Figure 5) includes an anomalous pull-apart basin, areas of development of the circular structures [16,22], the arc faults, and the rotational markers of the crustal block rotation identified from the structural and paleomagnetic data [93][94][95].…”

“…The deep structure is elicited from the regional tectonic constructions [15,32], results of seismic profiling [103,107,108], boreholes data [88,109], regional geological map [64], radiometric data [61,63,96,104,106]; and the results of the paleomagnetic zonation [16,18,19,22].…”