The Uplift of the Greater and Lesser Caucasus: Continental Collision to Subduction
Abstract
The Caucasus is a part of the orogenic belt which formed as the result of the closure of the Neo Tethys Ocean and the corresponding continental collision of Arabian and Eurasian plates. This region includes the southwestern part of the Caspian basin, the Kura basin, the Lesser and Greater Caucasus mountains, and the East Anatolian and North Iranian plateaus. A number of tomographic studies of both P and S wave velocities all show a broad low velocity zone beneath East Anatolian and North Iranian plateaus and most models show three high velocity zones located under the eastern part of the Greater Caucasus, the Talesh and Pontides. The low velocity zone is observed starting right at the moho down to 150 km, which suggests asthenospheric material underlying a very thin lithosphere of eastern Anatolia where widespread Late Miocene - Quaternary calc-alkaline volcanic products of mantle origin are reported. There appears to be a high velocity body beneath the eastern Greater Caucasus and Kura Basin at depths below the Moho down to 180 km, and apparently represents either a thick lithospheric mantle root or a shallow subducting slab associated with the South Caspian block. This high velocity model may extend to the eastern end of the Greater Caucasus. In addition to the seismological observations, recent geologic studies suggest that the uplift of the Greater Caucasus has occurred primarily over the past 5 Ma. . One of the critical questions related to earthquakes is the existence of deep earthquakes in the northeastern Greater Caucasus. Recent work by the Geophysical Survey of Russia has indicated that seismicity in this region extends to nearly 200 km depth. It is important to confirm these observations and to minimize uncertainties in the depths in order to understand the spatial patterns of these deep earthquakes. Having reliable locations of these events may indicate whether there is a previously undiscovered subduction zone beneath a portion of the Greater Caucasus. In order to image and thereby understand the uplift mechanism of the Caucasus we propose to establish a very ambitious multi-national seismic study of thethat would cross key parts of the Lesser and Greater Caucasus and help to test the models for intracontinenal orogenic uplift.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.S43J..06S
- Keywords:
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- 7208 SEISMOLOGY / Mantle;
- 7218 SEISMOLOGY / Lithosphere;
- 8108 TECTONOPHYSICS / Continental tectonics: compressional;
- 8123 TECTONOPHYSICS / Dynamics: seismotectonics