Study On The Genetic Mechanism Of The Ming Dynasty And Jigong Hot Springs In Chayu County,Tibet

In this paper,the characteristics of rock,tectonic features and hydrogeological features are obtained through field exploration combined with remote sensing geological interpretation in Chayu area.The intrinsic genetic relationship between regional deep faults and shallow active structures and hot springs is clarified.The water chemistry and gas isotope test analysis of 13 water samples in the area obtained data and correlations of water chemistry types,macroelements and trace elements,and clarified the process of migration,runoff,water-rock reaction and mixing of hot fluids.Combined with the water chemistry data,the optimal temperature standard for the temperature standard is used to select the most suitable water chemical temperature scale to calculate the thermal reservoir temperature.Finally,the comprehensive analysis of structure,heat source and water source,the genetic mechanism of hot springs was established and two different springs genesis models were established.Through the research,the following achievements and understandings have been made:?1?The Riga fault?F₁?is a deep fault that cuts to the crust and even the mantle.It intersects with the Dacha fault?F₂?in the deep part,and the neotectonic movement is strong.The fault develops in space to inherit the old fault,and the fault block is intermittent.The Dacha fault?F₂?,the Mingqi fault?F₃?,the Sangqu fault?F₄?,the Kaba fault?F₅?,and the yingxiongpo fault?F₆?are all Quaternary active faults and are still active.?2?The main faults of the Mingqi hot springs are the Riga fault,the Dacha fault,and the Mingqi fault;the main fault of the Yingxiongpo hot spring is the Sangqu fault and the Yingxiongpo fault;the main fault of the Jigong hot spring is the Sangqu fault and the Kaba fault.The faults show a tensile property in the modern tectonic activities,and the surface fissures develop,which provides good conditions for the migration and collection of hot springs.?3?The geothermal system water source in the study area is mainly atmospheric precipitation.There are deep magmatic water in the Mingqi Hot Spring and Yingxiongpo Hot Spring.The thermal reservoir type is mainly composed of banded fissure type thermal storage;the capping conditions are poor,and the hot spring is mixed during the upwelling process.Effect of the action;the heat transfer water guiding channel of the heat storage is mainly the part where the band-shaped crack or the fracture meets.?4?The water chemistry types of Mingqi Hot Spring and Yingxiongpo Hot Spring are HCO₃-Cl-Ca-Na type and HCO₃-Cl-Na type.These water chemistry types are derived from the deep-formed Cl-Na type.B,Li,Rb,Cs,Cl,and the isotope?¹³C in CO₂ in geot-hermal gases indicates that the fluids of the Mingqi Hot Spring and the Yingxiongpo Hot Spring have deep source components.?5?The empirical calculation formula of SiO₂ main mineral chalcedony temperature scale shows that the thermal reservoir temperature of the hot spring is between 99.5-111.72°C;the thermal reservoir temperature of Jigong Hot Spring is between 63.14-84.12°C;the thermal reservoir temperature of Yingpo is 121.03°C.?6?The regional tectonic faults in southern Tibet play an important role in controlling the distribution of hot springs.The regional deep faults and shallow active structures jointly control the distribution of hot springs.Therefore,the hot springs in southern Tibet are distributed along the fault zone and exposed.The intersection of the fracture and the secondary fracture.?7?The main heat sources of the Mingqi Hot Spring and Yingxiongpo Hot Springs are high regional thermal background,local melt and deep material flow carrying energy.The water source is atmospheric precipitation and deep magmatic water;the heat source of Jigong Hot Spring is high regional thermal background without additional heat source,the water source is atmospheric precipitation,and is a medium-low temperature convective system circulating in the granite fissure.