标题：Volatile characteristics and fluxes of He-CO2 systematics in the southeastern Tibetan Plateau: Constraints on regional seismic activities

入藏号：WOS:000962956200001

中国科学院文献情报中心期刊分区：地球科学1区TOP（2023）

本校作者： 王迎春；周金林

来源出版物：JOURNAL OF HYDROLOGY  卷: 617  文献号: 129042

出版年：2023

第一地址：成都理工大学

关键词：He–CO2 systematics;Volatiles flux;Large fault zone;Tibetan Plateau;Geothermal system

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摘要：The spatial and temporal evolutionary mechanisms of volatile components at plate boundaries and their po-tential as earthquake precursors are not well understood. Based on observations of He-CO2 from 19 hot-spring gases in the Lancang River fault zone, Yunnan Province, the results show that the volatiles mainly come from the crust. The combined He isotope, He-CO2 relationships, and delta 13C-CO2 values of the hot-spring volatiles indicate that it is a mixture of mantle and crustal fluids. These are related to the radiogenic He production caused by crustal U and Th elements with <5% mantle-derived He, whereas C is mainly from the metamorphic decar-bonization of Tethyan marine carbonate rocks. Based on the He-CO2 isotopic relationship, crustal volatiles flux with a significant proportion were determined within a non-volcanic area, which was estimated to be 9-132 mol a-1, and CO2 degassing was estimated to be 2-120 x 109 mol a-1. These results are comparable to those of some volcanic areas and large seismically-active fault zones (such as the San Andreas Fault zone). The compressional stress field of the rigid crust near the study area leads to the low permeability of large faults and CO2 degassing from the hydrothermal system, resulting in chemical precipitation that further blocks the shallow crust conduits and deduced overpressure below the hydrothermal reservoir, which may be the cause of the presence of earthquakes with magnitudes greater than 7 in the Lancang River fault zone. The results are significant for el-ements cycling of converging plate boundaries and earthquake hazards monitoring.

文章链接地址: https://www.sciencedirect.com/science/article/pii/S0022169422016122?via%3Dihub