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Directions of lithosphere interactions in the Pamir-Hindu Kush junction inferred from anisotropic tomography

Jamshed Aminov, Ivan Koulakov, Andrey Jakovlev, Zhao Junmeng, Sami El-Khrepy, Jovid Aminov, Nassir Al Arifi, Javhar Aminov and Yunus Mamadjanov
Directions of lithosphere interactions in the Pamir-Hindu Kush junction inferred from anisotropic tomography
Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre (May 2020) 57 (5): 601-616

Abstract

The Pamir and Hindu Kush are examples of a puzzling collision system where a complex junction of colliding lithospheric plates coexists with intermediate depth seismicity at 300 km. In this study, we constructed a new tomography model using travel time data from local events recorded by the TIPAGE (Tien Shan - Pamir Geodynamic program) network. In addition to the P- and S-wave velocities down to 200 km, we derived the azimuthal anisotropy. The velocity anomalies were consistent with the results of previous studies. In the crust, the velocity structure and anisotropy directions were mainly oriented along major suture zones. At depths of 80-120 km, a narrow low-velocity anomaly coinciding with the distribution of deep seismicity was interpreted as a trace of entrained crustal material by the dipping lithosphere. The anisotropy directions at these depths were mainly oriented northwest-southeast and were interpreted as indicating the direction of the motion of colliding plates. The difference in the magnitude of anisotropy south and north of the Pamir seismic zone suggests that the lithosphere coming from the south possesses less anisotropy than that of the Asian plate. The local tomography model was supplemented by previously computed regional tomography that expanded the area both laterally and axially. Beneath the Pamir, both continental plates coming from the north and south form a drop-shaped anomaly that will possibly delaminate in time. Beneath the Hindu Kush, we could clearly trace a continuous almost vertical subduction of the Katawaz block from the south. Thus, the continental collision beneath the Pamir and subduction beneath the Hindu Kush are separate processes with different rates and directions of plate movement.


ISSN: 0008-4077
EISSN: 1480-3313
Coden: CJESAP
Serial Title: Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre
Serial Volume: 57
Serial Issue: 5
Title: Directions of lithosphere interactions in the Pamir-Hindu Kush junction inferred from anisotropic tomography
Affiliation: Chinese Academy of Sciences, Institute of Tibetan Plateau Research, Laboratory of Continental Collision and Plateau Uplift, Beijing, China
Pages: 601-616
Published: 202005
Text Language: English
Summary Language: French
Publisher: National Research Council of Canada, Ottawa, ON, Canada
References: 70
Accession Number: 2020-083742
Categories: Solid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: 1 table, geol. sketch maps
N36°00'00" - N42°00'00", E70°00'00" - E76°00'00"
Secondary Affiliation: Russian Academy of Sciences, Trofimuk Institute of Petroleum Geology and Geophysics, RUS, Russian FederationKing Saud University, SAU, Saudi ArabiaUniversity of Chinese Academy of Sciences, CHN, ChinaAcademy of Sciences of the Republic of Tajikistan, Institute of Geology, Earthquake Engineering and Seismology, TJK, Tajikistan
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute. Reference includes data from Canadian Science Publishing, NRC Research Press, Ottawa, ON, Canada. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 2020
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