Long-term crustal deformation in the Pamir: Tertiary continental subduction, crustal bucking, and orocline formation

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We aim to establish the Tertiary deformation of the Pamir–southern Tien Shan on a middle-upper crustal scale, including the first-order structural geometry of intra-continental subduction/crustal buckling, the kinematics of orocline formation, and the modes of tectonic denudation. Our hypothesis is that long-term deformation is concentrated in thick-skinned fold-thrust belts, tracing three continental subduction zones that were partly active contemporaneously; the subduction shortening produced basement domes that stretch across the Pamir and that were later accentuated by orocline formation and indenter rotation. We propose combined structural-geochronologic studies in: (1) the Tajik basin and the intra-montane Alai valley encompassing the southern Tien Shan and the Pamir frontal ranges; (2) the Yazgulem–Muskol–Sares basement domes of the central Pamir; and (3) the Shakhdara dome of the southern Pamir. We will use balanced cross section, stress-field, ductile flow, and kinematic studies together with U/Th/Pb, Ar/Ar, fission-track, and (U-Th)/He geochronology. This project is regionally and methodologically interwoven with the surface-process (CRP3, 5) and the crust/mantle-process aspects (CRP1, 4) of TIPAGE and collaborates with an associated US-project that will provide the petrologic (pressure-temperature) data for the Tertiary deformation history. Its data are pre-requisite to constrain and interpret the long-term geodynamic aspects of numeric modeling in TIPAGE.