TY - JOUR

T1 - Seismic structure of the crust and uppermost mantle beneath Caucasus based on regional earthquake tomography

AU - Zabelina, Irina

AU - Koulakov, Ivan

AU - Amanatashvili, Iason

AU - El Khrepy, Sami

AU - Al-Arifi, Nassir

PY - 2016/4/1

Y1 - 2016/4/1

N2 - We present a new seismic model of the crust beneath the Caucasus based on tomographic inversion of P and S arrival times from earthquakes occurred in the region recorded by regional seismic networks in the Caucasian republics. The resulting P and S velocity models clearly delineate major tectonic units of the study area. A high velocity anomaly in Transcaucasian separating the Great and Lesser Caucasus possibly represents a rigid crustal block corresponding to the remnant oceanic lithosphere of Tethys. Another high-velocity pattern coincides with the southern edge of the Scythian Plate. Strongly deformed areas of Great and Lesser Caucasus are mostly associated with low-velocity patterns representing thickened felsic part of the crust and strong fracturing of rocks. Most Cenozoic volcanic centers of Caucasus match to the low-velocity seismic anomalies in the crust. For example, the Kazbegi volcano group is located above an elongated low-velocity anomaly squeezed between high-velocity segments of Transcaucasian and Scythian Plate. We propose that mantle part of the Arabian and Eurasian Plates has been delaminated due to the continental collision in the Caucasus region. As a result, overheated asthenosphere appeared nearly the bottom of the crust and facilitated melting of the crustal material that caused the origin of recent volcanism in Great and Lesser Caucasus.

AB - We present a new seismic model of the crust beneath the Caucasus based on tomographic inversion of P and S arrival times from earthquakes occurred in the region recorded by regional seismic networks in the Caucasian republics. The resulting P and S velocity models clearly delineate major tectonic units of the study area. A high velocity anomaly in Transcaucasian separating the Great and Lesser Caucasus possibly represents a rigid crustal block corresponding to the remnant oceanic lithosphere of Tethys. Another high-velocity pattern coincides with the southern edge of the Scythian Plate. Strongly deformed areas of Great and Lesser Caucasus are mostly associated with low-velocity patterns representing thickened felsic part of the crust and strong fracturing of rocks. Most Cenozoic volcanic centers of Caucasus match to the low-velocity seismic anomalies in the crust. For example, the Kazbegi volcano group is located above an elongated low-velocity anomaly squeezed between high-velocity segments of Transcaucasian and Scythian Plate. We propose that mantle part of the Arabian and Eurasian Plates has been delaminated due to the continental collision in the Caucasus region. As a result, overheated asthenosphere appeared nearly the bottom of the crust and facilitated melting of the crustal material that caused the origin of recent volcanism in Great and Lesser Caucasus.

KW - Caucasus

KW - Collision

KW - Crust

KW - Mantle

KW - Seismic tomography

KW - Volcanism

UR - http://www.scopus.com/inward/record.url?scp=84955118655&partnerID=8YFLogxK

U2 - 10.1016/j.jseaes.2016.01.010

DO - 10.1016/j.jseaes.2016.01.010

M3 - Article

AN - SCOPUS:84955118655

VL - 119

SP - 87

EP - 99

JO - Journal of Asian Earth Sciences

JF - Journal of Asian Earth Sciences

SN - 1367-9120

ER -