LOCATING THE MAIN CENTRAL THRUST IN THE KAGHAN VALLEY, PAKISTAN: INSIGHTS FROM DETRITAL ZIRCON GEOCHRONOLOGY

Detrital zircon age spectra throughout the Himalayan orogen provide the means to distinguish between the Tethyan, Greater, and Lesser Himalayan tectonostratigraphic zones in the fold-thrust belt. In the Kaghan valley, northern Pakistan, debate exists over the existence and location of the Main Central thrust. Three new detrital zircon U/Pb ages from the footwall rocks of the Batal fault yield Meso- to Paleoproterozoic ages dominated by ca. 1.6-1.8 Ga peaks. Four new detrital zircon U/Pb ages from the hanging wall rocks are primarily Neoproterozoic and younger with strong ca. 800 Ma age components. Most samples exhibit Pb-loss from younger (<600 Ma) intrusive or metamorphic events. The detrital zircon age spectra from the footwall samples indicate that they are Lesser Himalayan rocks. Detrital zircon age spectra from the hanging wall samples indicate that they are either Tethyan or Greater Himalayan rocks, so future work will be needed to make this distinction. Regardless of the affinity of the hanging wall rocks, these data define the Batal fault as the Main Central thrust, resolving the stratigraphic framework of the Kaghan valley and linking it with that of NW India and the central Himalaya.