Origin and Crustal Expression of Active Lithospheric Delamination in the Vrancea Zone, Romania

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Funds from the U. S. National Science Foundation are being used for acquisition and analysis of ~260 km of deep seismic reflection data to illuminate the origin, crustal structure, and three dimensional geodynamic setting of the Vrancea seismogenic zone of Romania. Project DRACULA (Deep Reflection Acquisition Constraining Unusual Lithospheric Activity), a collaboration between the University of South Carolina, the University of Bucharest, and the National Institute for Earth Physics in Romania, is employing deep seismic reflection techniques to (1) map the main structural detachment(s) of the Eastern Carpathians, and their westward continuation into the hinterland, (2) provide reliable constraints from the geometry of crustal reflectors on the postulated existence, position, and polarity of a Miocene-age subduction zone within the Transylvanian crust, (3) elucidate the geometric relationship between active faults in the Carpathian foreland and the seismogenic volume in the mantle, in order to (4) test the hypothesis of mechanical coupling of the foreland crust with Vrancea seismicity, and ultimately, (5) evaluate competing subduction/delamination geodynamic models for the origin of mantle seismicity in the Vrancea zone based on these results. With such data, the Vrancea zone may prove to be a unique setting in which to establish evidence for active continental lithospheric delamination.