Detrital zircon U–Pb geochronology of the Murree Formation, western Himalaya, Pakistan: provenance and tectonic implications for Himalayan exhumation

The Murree Formation is the oldest continental sequence in the Himalayan foreland basin and holds significant information about the Himalayan exhumation following the India-Asia collision. This study explains the provenance of the Murree Formation using detrital zircon U-Pb geochronology supplemented with sandstone petrography to unravel the Himalayan exhumation in Pakistan. The sandstone provenance indicates the sediment was sourced from recycled orogen and suture belts, supporting a post-collisional origin. The source rocks, shown by the ternary plot (QpQnuQu), comprise plutonic and medium to high-rank metamorphic rocks prevalent in the Higher Himalaya (HH), Tethyan Himalayan (TH), and Lesser Himalaya (LH). The zircon ages are mainly ~ 1200–400 Ma, with two minor clusters (~1900–1400 Ma and ~ 2600–2300 Ma). This pattern is compatible with a Himalayan source mainly from the TH, HH, and partly from LH. Notably, the age populations默里组（Murree Formation）是喜马拉雅前陆盆地中最古老的陆相沉积序列，蕴藏着印-亚碰撞后喜马拉雅剥露作用的重要信息。本研究借助碎屑锆石U-Pb年代学，并辅以砂岩岩石学分析，阐释了默里组的物源特征，以揭示巴基斯坦境内的喜马拉雅剥露过程。砂岩物源分析表明，其沉积物来源于再造造山带与缝合带，支持碰撞后成因。通过三元图解（QpQnuQu）可知，源岩包括广泛分布于高喜马拉雅（HH）、特提斯喜马拉雅（TH）与小喜马拉雅（LH）的深成岩及中高级变质岩。锆石年龄主要集中于~1200–400 Ma，另有两个次要年龄簇（~1900–1400 Ma与~2600–2300 Ma）。该年龄分布模式与以特提斯喜马拉雅、高喜马拉雅为主要物源，且部分来源于小喜马拉雅的喜马拉雅物源体系相符。值得注意的是，年龄种群