长白山天池火山地热系统——岩浆囊与隐伏高温地热资源  

Changbaishan Tianchi volcano geothermal system:Magma chamber and hidden high-temperature geothermal resources

作　　者：张健 范艳霞 褚伟 何雨蓓 Zhang Jian;Fan Yanxia;Chu Wei;He Yubei(College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院大学地球与行星科学学院,北京100049

出　　处：《地震学报》2024年第4期557-577,共21页Acta Seismologica Sinica

基　　金：国家重点研发计划“变革性关键科学问题”重点专项(2021YFA0716002);国家自然科学基金(42176052);中国科学院战略性先导科技专项(XDB42020104)共同资助.

摘　　要：长白山天池火山是晚新生代中心喷发式复合型层状火山,全新世以来发生过多次大规模喷发,与深部岩浆热扰动活动相关的构造地震、地表形变、温泉气体组份等均显示该火山仍可能再次喷发,是我国东部潜在的高温地热资源区。长白山天池火山周边地下水十分丰富,具有形成高温水热活动的岩浆囊热源。为探索地壳浅层隐伏的高温地热资源,本文在野外考察基础上,利用地热学方法,计算了该区地层结构与热状态,分析了地表下的火山地热系统。结果表明:长白山天池火山区地下2 km深处的温度在66—110℃之间,12 km深处的温度在313—417℃之间;该区居里面深度较浅,平均深度为12.7 km,居里点温度为375℃,其中长白山天池火山喷发中心和望天鹅火山喷发中心为居里面上隆区;在人工地震基底速度约束下,通过沉积地层重力反演发现,在约3.5—5.5 km深度处存在密度梯级高压带,该高压带与12 km深度处的岩浆囊之间的区域是形成隐伏高温地热资源的有利区域。The Changbaishan Tianchi volcano is a Late Cenozoic central eruptive composite layered volcano.It has experienced multiple large-scale eruptions since the Holocene,and there is still modern magmatic thermal disturbance in the depth.Therefore,it is a potential hightemperature geothermal resource area in China.The Changbaishan Tianchi volcano is an intraplate volcano which has undergone three forming stages of shield volcano,cinder cone and ignimbrite.The shield-forming stage:Late Pliocene-Early Pleistocene,basaltic magma erupted from Changbaishan Tianchi volcano and adjacent craters overflowed radially,forming a shield-shaped volcanic lava platform.The cone-forming stage:In the Mid-Late Pleistocene,the coarse rock lava formed by multiple eruptions overflowed from the centre of the Tianchi crater and accumulated on the volcanic shield basalt,forming the Tianchi volcanic cone.The ignimbrite-forming stage:In the Holocene,the activity of Tianchi volcanic reached a new peak,and an explosive eruption occurred at its centre.The pyroclastic flow accumulates and consolidates to form ignimbrite,which is covered on the volcanic cone in a sheet shape.Active magma chambers still exist beneath Changbaishan Tianchi volcano.The shallow crustal magma chambers provide sufficient heat for underground hydrothermal activity.The groundwater surrounding Tianchi volcano is primarily composed of pore and fissure water in the Late Pleistocene basalt,which is characterised by thick aquifers,good connectivity and an abundance of water.At the periphery of Tianchi volcano,the thickness of basalt thins towards the periphery,and groundwater runoff from the Tianchi volcanic cone to the periphery is impeded by the surrounding bedrock,forming a ringed groundwater overflow zone.The groundwater is heated by high-temperature magma gas(CO_(2))at depth and then rises along fractures under stratigraphic pressure to form hot springs at the surface.There are three thermal spring groups associated with modern volcanic activity around the Tianchi crater lake

关 键 词：长白山天池火山 浅层地热结构 沉积层密度梯级高压带 岩浆囊 高温地热资源 

分 类 号：P314.2[天文地球—固体地球物理学]