摘要
五大连池火山群北部的尾山火山形成于第四纪中更新世,具中心式火山喷发,距今(0.57~0.31)±0.05 Ma。同美国芬顿山干热岩项目所在地火山活动于1.40~1.10 Ma相比,其下方具备发育正在冷却中的岩浆囊的可能。重、磁法勘查结果表明,尾山地区基底以北宽河组(Pt3-∈1b)变质岩为主,放射状断裂和环形构造发育,外环影响直径12~13km,是地壳浅部火山穹窿构造的反映。天然地震背景噪声层析成像勘查结果表明,尾山下部火山岩浆囊顶界埋深6.5km,至8km深度面积扩展至约13km^2,至13km面积扩展至约35km^2,平面上呈北西—南东向展布西大东小的"蝌蚪状",可能构成了尾山地区干热岩体的热源。大地电磁测深(MT)勘查结果表明,该地区高导体/高温岩体主体顶界埋深5km,最浅达3km。MT单点勘查曲线及图解表明,尾山西侧(B点)在约2km深度,电阻率值降至2Ω·m以下,4~6km小于2Ω·m的低电阻率区域逐渐连成片,6km以下几乎整体小于2Ω·m。综合分析认为,五大连池尾山地区具较好的干热岩地热地质条件。
The Weishan volcano in the Wudalianchi volcanic group was formed in the Quaternary Medio- Pleistocene in 0.57~0.31 Ma ago. Compared to the hot dry rock project in the Fenton Hill where volcanic activity in 1.40~1.10 Ma, a cooling magma chamber may possibly exist in the crust beneath the Weishan volcano. The gravity and magnetic surveys suggest that the basement of Weishan volcano is mainly consisted of metamorphic rocks of Beikuanhe Group. It＇s also characterized as central volcanic eruption with annular structures and radial fractures. The impacted outer diameter can reach 12 ~ 13 km, suggesting a volcanic dome in the shallow crust. Based on the investigation of surface wave tomography with seismic ambient noise data and dense seismic array, a possible magma chamber is found beneath the Weishan volcano. The top interface for the possible magma chamber is about 6. 5 km in depth, and the areas increase to 13 km2 at 8 km depth and 35 km2 at 13 km depth. The lateral low shear-wave velocity anomaly beneath the Weishan volcano shows a shape of ＂tadpole＂, which may form the hot dry rock resources in this area. The MT survey suggest that the electric resistivity is decreased less than 2 Ω·m in the western area of the Weishan volcano （B point）. The areas with low electric resistivity （〈2 Ω·m） at 4 ~6 km depth are gradually combined together. For depth deeper than 6 km, the electric resistivity are mostly less than 2 Ω·m. The integrated analysis of geological, seismic and MT investigations suggest a good geothermal geology environment for the hot dry rock resources around the Weishan volcano, Wudalianchi region.
作者
张森琦
贾小丰
张杨
李胜涛
李志伟
田蒲源
明圆圆
张超
ZHANG Senqi JIA Xiaofeng ZHANG Yang LI Shengtao LI Zhiwei TIAN Puyuan MING Yuanyuan ZHANG Chao(Center for h ydrogeology and environmental geology survey, China Geological Survery , Baoding , 071051, China State Key Laboratory of Geodesy and Earth＇s Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan, 430077, China)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2017年第7期1506-1521,共16页
Acta Geologica Sinica
基金
国土资源部中国地质调查局项目(编号:12120114025001
12120115046201
DD20160192)资助的成果
关键词
五大连池火山群
第四纪火山
尾山
干热岩
岩浆囊
Wudalianchi volcanic group
Quaternary volcano
Weishan volcano
hot dry rock
magma chamber
