The Eastern Pontides orogenic belt in the Black Sea region of Turkey offers a critical window to plate kinematics and subduction polarity during the closure of the Paleotethys. Here we provide a brief synthesis on rec...The Eastern Pontides orogenic belt in the Black Sea region of Turkey offers a critical window to plate kinematics and subduction polarity during the closure of the Paleotethys. Here we provide a brief synthesis on recent information from this belt. We infer a southward subduction for the origin of the Eastern Pontides orogenic belt and its associated late Mesozoic--Cenozoic magmatism based on clear spatial and temporal variations in Late Cretaceous and Cenozoic arc magmatism, together with the exis- tence of a prominent south-dipping reverse fault system along the entire southern coast of the Black Sea. Our model is at variance with some recent proposals favoring a northward subduction polarity, and illus- trates the importance of arc magmatism in evaluating the geodynamic milieu associated with convergent margin orocesses.展开更多
The Chinese Tianshan belt of the southern Altaids has undergone a complicated geological evolution. Different theories have been proposed to explain its evolution and these are still hotly debated. The major subductio...The Chinese Tianshan belt of the southern Altaids has undergone a complicated geological evolution. Different theories have been proposed to explain its evolution and these are still hotly debated. The major subduction polarity and the way of accretion are the main problems. Southward, northward subduction and multiple subduction models have been proposed. This study focuses on the structural geology of two of the main faults in the region, the South Tianshan Fault and the Nikolaev Line. The dip direction in the Muzhaerte valley is southward and lineations all point towards the NW. Two shear sense motions have been observed within both of these fault zones, a sinistral one, and a dextral one, the latter with an age of 236-251 Ma. Structural analyses on the fault zones show that subduction has been northward rather than southward. The two shear sense directions indicate that the Yili block was first dragged along towards the east due to the cloclkwise rotation of the Tarim block. After the Tarim block stopped rotating, the Yili block still kept going eastward, inducing the dextral shear senses within the fault zones.展开更多
基金The Scientific and Technological Research Council of Turkey(TUBITAK-Grant 108Y309)
文摘The Eastern Pontides orogenic belt in the Black Sea region of Turkey offers a critical window to plate kinematics and subduction polarity during the closure of the Paleotethys. Here we provide a brief synthesis on recent information from this belt. We infer a southward subduction for the origin of the Eastern Pontides orogenic belt and its associated late Mesozoic--Cenozoic magmatism based on clear spatial and temporal variations in Late Cretaceous and Cenozoic arc magmatism, together with the exis- tence of a prominent south-dipping reverse fault system along the entire southern coast of the Black Sea. Our model is at variance with some recent proposals favoring a northward subduction polarity, and illus- trates the importance of arc magmatism in evaluating the geodynamic milieu associated with convergent margin orocesses.
基金supported by the Chinese Major State Basic Research Program (Grants Nos.2009CB825007,2007CB411307)National Natural Science Foundation of China(Grant Nos.40730314,40821002, 41230207,41390441,41190075)the Molengraaff Fund to MCS
文摘The Chinese Tianshan belt of the southern Altaids has undergone a complicated geological evolution. Different theories have been proposed to explain its evolution and these are still hotly debated. The major subduction polarity and the way of accretion are the main problems. Southward, northward subduction and multiple subduction models have been proposed. This study focuses on the structural geology of two of the main faults in the region, the South Tianshan Fault and the Nikolaev Line. The dip direction in the Muzhaerte valley is southward and lineations all point towards the NW. Two shear sense motions have been observed within both of these fault zones, a sinistral one, and a dextral one, the latter with an age of 236-251 Ma. Structural analyses on the fault zones show that subduction has been northward rather than southward. The two shear sense directions indicate that the Yili block was first dragged along towards the east due to the cloclkwise rotation of the Tarim block. After the Tarim block stopped rotating, the Yili block still kept going eastward, inducing the dextral shear senses within the fault zones.
