Latest marine horizon north of Qomolangma (Mt Everest): implications for closure of Tethys seaway and collision tectonics

The newly discovered marine horizon at Zhepure Syncline, north of Qomolangma, revises timing of the closure of the eastern Neo-Tethys seaway in the central Himalayas. The marine Pengqu Formation conformably overlies a Lutetian shallow-water carbonate platform and comprises shales interbedded with sandstones deposited in a neritic shelf environment. The strata are dated by nannofossils and foraminifera as late early Lutetian to late Priabonian age (NP15-NP20, deposited approximate to 47-34 Ma), indicating that the final closure of the Tethys seaway in this region occurred at similar to 34 Ma. The newly discovered strata provide evidence about emplacement of a major thrust sheet south of southern Tibet prior to similar to 37 Ma, which affected the regional climate.