Thermokinematic Modeling of Frontal Thrusts in the Kyllakh Tectonic Zone of the Verkhoyansk Fold-and-Thrust Belt

This study addresses the timing of formation of the frontal thrusts of the Kyllakh Tectonic Zone (South Verkhoyansk sector of the Verkhoyansk fold-and-thrust belt), which is crucial for understanding the final stages of the Mesozoic collision in the region. An integrated approach, comprising apatite fission-track (AFT) dating, thermal history (t-T) modeling, and thermokinematic modeling, was employed to reconstruct the tectonic deformation and exhumation history of the Siberian Platform margin thrusts in the Ebeike-Khayata and Kyllakh ridges area. New and previously published AFT ages (~62–86 Ma) point to a Late Cretaceous cooling episode. Modeling indicates that this signal corresponds to a phase of thrusting with ~16 km of shortening between 75 and 62 Ma. The results demonstrate that the main phase of frontal thrust activity in the region occurred during the Late Cretaceous–Paleocene, which is consistent with the terminal evolutionary stages of the Verkhoyansk–Kolyma orogen.