First Estimates of Hydrothermal Helium Fluxes in Continental Collision Settings: Insights From the Southeast Tibetan Plateau Margin. Issue 11 (4th June 2022)

• Record Type: Journal Article
• Authors: Zhang, Maoliang; Liu, Wei; Guan, Lufeng; Takahata, Naoto; Sano, Yuji; Li, Ying; Zhou, Xiaocheng; Chen, Zhi; Cao, Chunhui; Zhang, Lihong; Lang, Yun‐Chao; Liu, Cong‐Qiang; Xu, Sheng
• Is Part Of: Geophysical research letters. Volume 49:Issue 11(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-04
• Subjects: mantle degassing -- helium isotopes -- helium fluxes -- magma recharge -- active tectonics -- Southeast Tibetan Plateau margin; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2022GL098228
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Continental regions are essential for the outgassing of deeply‐sourced helium in response to volcanic and tectonic processes. However, the helium fluxes remain largely unknown for continental collision settings such as the Tibetan Plateau. Here, we focus on hydrothermal helium degassing from the Simao block, Southeast Tibetan Plateau margin, and report flux estimates of (0.03 – 32) × 10 5 atoms m −2 s −1 for 3 He and (3.2 – 32) × 10 10 atoms m −2 s −1 for 4 He, with mantle fractions of helium fluxes up to 2−3 orders of magnitude greater than those of stable continents. Geologically recent magma recharge beneath Quaternary volcanoes is proposed to account for the high mantle helium fluxes and 3 He/ 4 He up to 7.24 Ra. Active tectonics driven by the India‐Asia continental collision possibly maintained efficient release of crustal helium over geological timescales. These findings present the first flux estimates for hydrothermal helium degassing controlled by volcanic and tectonic processes in continental collision settings. Plain Language Summary: Helium (including 3 He and 4 He isotopes) is an element mainly outgassing from Earth's interior to the atmosphere. The fluxes and isotopic compositions of helium are critical parameters for monitoring the hazardous volcanic eruptions and earthquakes, estimating the fluxes of other volatile species (e.g., CO2 and N2 ) from the solid Earth, and exploring the helium resources and geothermal energy. We conducted a quantitative study on the magnitude of helium outgassing from hot springs in the Simao block of the Southeast Tibetan Plateau margin, which is located in a region influenced by the India‐Asia continental collision. The results show that the mantle and crustal helium fluxes of the Simao block are comparable to those estimated for the representative continental regions worldwide. This observation can be explained by the intrusion and degassing of mantle‐derived magmas beneath Quaternary volcanoes and efficient release of crustal helium in response to regional active tectonics. We suggest that India‐Asia continental collision zone is an important natural laboratory for studying helium degassing from solid Earth. Key Points: We report the first estimates of hydrothermal helium fluxes for continental collision settings Geologically recent magma recharge is proposed to feed the mantle helium degassing Active tectonics driven by India‐Asia continental collision possibly maintained efficient release of crustal helium over geological timescales