Seismic images of the mantle beneath the active Changbai intraplate volcano in Northeast China determined by teleseismic travel time tomography are presented. The data are measured at a new seismic network consisting ...Seismic images of the mantle beneath the active Changbai intraplate volcano in Northeast China determined by teleseismic travel time tomography are presented. The data are measured at a new seismic network consisting of 19 portable stations and 3 permanent stations. The results show a columnar low-velocity (-3%) anomaly extending to 400 km depth under the Changbai volcano. High velocity anomalies are visible in the mantle transition zone, and deep earthquakes occur at depths of 500--600 km under the region,suggesting that the subducting Pacific slab is stagnant in the transition zone, as imaged clearly also by global tomography.These results suggest that the Changbai intraplate volcano is not a hotspot like Hawaii but a kind of back-arc volcano related to the upwelling of hot asthenospheric materials associated with the deep subduction and stagnancy of the Pacific slab under northeast Asia.展开更多
1研究背景。长白山天池火山坐落于延边朝鲜族自治州安图县境内,位于华北克拉通北部东缘,紧邻敦化—密山走滑深大断裂带东侧,属于欧亚板块与太平洋板块相互作用的活动大陆边缘构造环境,其火山喷发演化过程经历了造高原阶段、造盾阶段、...1研究背景。长白山天池火山坐落于延边朝鲜族自治州安图县境内,位于华北克拉通北部东缘,紧邻敦化—密山走滑深大断裂带东侧,属于欧亚板块与太平洋板块相互作用的活动大陆边缘构造环境,其火山喷发演化过程经历了造高原阶段、造盾阶段、造锥阶段和千年大喷发阶段(Xu et al,2023)。前人对长白山地区中酸性岩研究大多集中于千年大喷发产物的年代学和岩石地球化学研究,而对造锥期中更新世粗面岩的研究较少,且缺乏系统性,如岩相学、矿物学、成岩时代、岩石成因类型和成岩地球动力学等方面,一定程度上制约了人们对长白山天池火山造锥期中酸性岩浆喷溢作用的认识。展开更多
文摘Seismic images of the mantle beneath the active Changbai intraplate volcano in Northeast China determined by teleseismic travel time tomography are presented. The data are measured at a new seismic network consisting of 19 portable stations and 3 permanent stations. The results show a columnar low-velocity (-3%) anomaly extending to 400 km depth under the Changbai volcano. High velocity anomalies are visible in the mantle transition zone, and deep earthquakes occur at depths of 500--600 km under the region,suggesting that the subducting Pacific slab is stagnant in the transition zone, as imaged clearly also by global tomography.These results suggest that the Changbai intraplate volcano is not a hotspot like Hawaii but a kind of back-arc volcano related to the upwelling of hot asthenospheric materials associated with the deep subduction and stagnancy of the Pacific slab under northeast Asia.
文摘1研究背景。长白山天池火山坐落于延边朝鲜族自治州安图县境内,位于华北克拉通北部东缘,紧邻敦化—密山走滑深大断裂带东侧,属于欧亚板块与太平洋板块相互作用的活动大陆边缘构造环境,其火山喷发演化过程经历了造高原阶段、造盾阶段、造锥阶段和千年大喷发阶段(Xu et al,2023)。前人对长白山地区中酸性岩研究大多集中于千年大喷发产物的年代学和岩石地球化学研究,而对造锥期中更新世粗面岩的研究较少,且缺乏系统性,如岩相学、矿物学、成岩时代、岩石成因类型和成岩地球动力学等方面,一定程度上制约了人们对长白山天池火山造锥期中酸性岩浆喷溢作用的认识。
