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Tajik Depression and Greater Pamir Neotectonics from InSAR Rate Maps
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  • Sabrina Metzger,
  • Łukasz Gągała,
  • Lothar Ratschbacher,
  • Milan Lazecky,
  • Yasser Maghsoudi,
  • Bernd Dieter Schurr
Sabrina Metzger
Helmholtz-Zentrum, Deutsches GeoForschungsZentrum Potsdam, Helmholtz-Zentrum, Deutsches GeoForschungsZentrum Potsdam

Corresponding Author:metzger@gfz-potsdam.de

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Łukasz Gągała
Technische Universität Bergakademie Freiberg, Technische Universität Bergakademie Freiberg
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Lothar Ratschbacher
Geologie, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany, Geologie, Technische Universität Bergakademie Freiberg, 09599 Freiberg, Germany
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Milan Lazecky
University of Leeds, University of Leeds
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Yasser Maghsoudi
University of Leeds, University of Leeds
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Bernd Dieter Schurr
Deutsches GeoForschungsZentrum GFZ, Deutsches GeoForschungsZentrum GFZ
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Abstract

Using E-W and vertical deformation-rate maps derived from radar interferometric time-series, we analyze the deformation field of an entire orogenic segment, i.e., the Tajik depression and its adjoining mountain belts, Tian Shan, Pamir, and Hindu Kush. The data-base consists of 900+ radar scenes acquired over 2.0–4.5 years and global navigation satellite system measurements. The recent, supra-regional kinematics is visualized in an unprecedented spatio-temporal resolution. We confirm the westward collapse of the Pamir-Plateau crust, inverting the Tajik basin into a fold-thrust belt with shortening rates decaying westward from ~15 to 2 mm/yr. Vertical rates in the Hindu Kush likely record slab-dynamic effects, i.e., the progressive break-off of the Hindu Kush slab. At least 10 mm/yr of each, uplift and westward motion occur along the western edge of the Pamir Plateau, outlining the crustal-scale ramp along which the Pamir Plateau overrides the Tajik depression. The latter shows a combination of basin-scale tectonics, halokinesis, and seasonal/weather-driven near-surface effects. Abrupt ~6 mm/yr horizontal-rate changes occur across the kinematically-linked dextral Ilyak strike-slip fault, bounding the Tajik fold-thrust belt to the north, and the Babatag backthrust, the major thrust of the fold-thrust belt, located far west in the belt. The sharp rate decay across the Ilyak fault indicates a locking depth of ≤1 km. The Hoja Mumin salt fountain is spreading laterally at ≤350 mm/yr. On the first-order, the modern 20–5 and fossil (since ~12 Ma) 12–8 mm/yr shortening rates across the fold-thrust belt correspond.