Pleistocene Accelerated Exhumation Within the Sumatran Fault: Implications for Late Cenozoic Evolution of Sumatra (Indonesia)

Abstract

AbstractThe 1,900‐km‐long Sumatran fault plays an important role in accommodating oblique plate motion between the Indo‐Australian and Sunda plates. Although fault geometry, kinematics, and seismic activity are well‐studied, the onset of dextral motion on the Sumatran fault and uplift of adjacent Barisan Mountains is unclear; this hinders an understanding of the late Cenozoic evolution of Sumatra and the forearc region. In this study, we use low‐temperature thermochronology to measure cooling histories of rocks within and outside of the Sumatran fault. An accelerated exhumation within the fault zone began at ∼2 Ma. The Barisan Mountains may have experienced uplift and associated river incision in the late Miocene to Pliocene. The fault systems in the forearc region were inferred to be kinematically linked to the Andaman Sea and Sunda Strait and accommodated early relative plate convergence, then relocated the strike‐slip component of deformation to the Sumatran fault at ∼2 Ma.