长白山天池火山水热活动及气体释放特征

Volcanic Hydrothermal Activities and Gas-releasing Characteristics of the Tianchi Lake Region, Changbai Mountains

长白山天池火山属于新生代大型多成因复式火山 ,位于吉林省东部中 朝边境上。天池火山周围水热活动比较强烈 ,主要的水热活动区有天池北部的长白温泉群、天池湖滨温泉和天池西南的锦江泉群。长白聚龙泉群水温较高 ,一般为 70～ 83℃ ,湖滨温泉水温 2 0～ 4 0℃ ,锦江泉群水温为 5 8℃左右。长白聚龙泉群水热活动相对更为强烈。在水热活动区 ,地下气体活动也相当强烈 ,地下释放气体的主要成分是CO2 ,同时含有稀少气体He、Ar和微量气体H2 、CH4及少量O2 和N2 。长白和锦江两处泉群的地下释放气体中 ,其气体同位素地球化学特征表明 ,两处地下逸出气体均来源于地球深部 ,具有慢源气体特征。但是 ,长白聚龙泉地下逸出气体和地壳岩浆房有关 ,而锦江地下释放的气体则和地幔岩浆库及深大断裂有关。

Located in China-Korea border area, eastern Jilin Province, the volcano in Tianchi Lake region of Changbai Mountains is of Cenozoic large-size multi-genetic complex type. There exist rather strong hydrothermal activities around the Tianchi volcano, and the main hydrothermal areas include Changbai Julong hot spring group (70～83 ℃)and Tianchi Lakeshore hot spring (20～40 ℃)in northern Tianchi district as well as Jinjiang hot spring group (58 ℃ or so) in southwestern Tianchi district. Of these hot springs, the Changbai Julong hot spring group seem to display the strongest hydrothermal activities. Underground gaseous activities are also quite intense in these hydrothermal areas, and the gases released underground are mainly CO 2 together with rare gases He and Ar, minor gases H 2 and CH 4 and small amounts of O 2 and N 2. Isotopic geochemical studies of underground gases released from Changbai and Jinjiang show that these gases are all derived from the depth of the earth and have features of mantle-derived gases. Nevertheless, underground gases released from Changbai Julong hot spring group are related to the crustal magma chamber, whereas underground gases released from Jinjiang are associated with mantle magma chamber and deep faults.