In‐situ U‐Pb dating of calcite slickenfibre constraints on Cenozoic multiple‐phase faulting along the eastern segment of Chengkou Fault, Dabashan Fold‐and‐Thrust Belt

Abstract

The Dabashan Fold‐and‐Thrust Belt is an important natural laboratory for exploring the Meso‐Cenozoic intracontinental orogenic evolution in China. Due to the severe lack of post‐Early Cretaceous strata, little attention has been paid to Cenozoic tectonic in the Dabashan. This study presents structural analysis, in‐situ U‐Pb dating of calcite in conjunction with petrographic and stable isotopic analyses along the eastern segment of the Chengkou Fault in the Dabashan. Structural analysis coupled with U‐Pb dating of syn‐kinematic calcite slickenfibres suggests two discrete S‐N compressional strike‐slip deformation events associated with localized E‐W extension along the eastern segment of the Chengkou Fault have occurred at the Early Eocene (~57–50 Ma) and Late Oligocene‐Early Miocene (~23–17 Ma), respectively. We tentatively related the Cenozoic deformation events in the study area to the clockwise rotation of the Sichuan Basin, resulting from the combined far‐field stress effects between the India, Eurasia and western Pacific plates.