First Estimates of Hydrothermal Helium Fluxes in Continental Collision Settings: Insights From the Southeast Tibetan Plateau Margin

Continental regions are essential for the outgassing of deeply-sourced helium in response to volcanic and tectonic processes. However, fluxes remain largely unknown continental collision settings such as Tibetan Plateau. Here, we focus on hydrothermal degassing from Simao block, Southeast Plateau margin, report flux estimates (0.03 – 32) × 105 atoms m?2 s?1 3He (3.2 1010 4He, with mantle fractions up 2?3 orders magnitude greater than those stable continents. Geologically recent magma recharge beneath Quaternary volcanoes is proposed account high 3He/4He 7.24 Ra. Active tectonics driven by India-Asia possibly maintained efficient release crustal over geological timescales. These findings present first controlled processes settings.