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兴蒙造山带诺敏河火山群地壳厚度与波速比研究
引用本文:谢振新,吴庆举,周仕勇,朱敏.兴蒙造山带诺敏河火山群地壳厚度与波速比研究[J].地球物理学报,2018,61(12):4805-4816.
作者姓名:谢振新  吴庆举  周仕勇  朱敏
作者单位:1. 中国地震局地球物理研究所, 北京 100081;2. 北京大学理论与应用地球物理研究所, 北京 100871;3. 中国地震局地震观测与地球物理成像重点实验室, 北京 100081
基金项目:国家自然科学基金项目(41474074)资助.
摘    要:利用布设于兴蒙造山带诺敏河火山群地区的宽频带流动地震台站资料,基于接收函数方法,获取了该地区的地壳厚度与波速比值.研究结果显示,该地区的地壳厚度介于32~38 km,莫霍面深度在空间上分布特征与五大连池为中心的火山带分布具有较好的一致性:沿着火山带延展方向地壳较薄.该地区的波速比介于1.74~1.84,波速比在空间上与地壳厚度变化具有一致性:高波速比主要集中于靠近五大连池火山带地区,向诺敏河火山和小古里河火山延展.研究认为:诺敏河火山与五大连池火山带可能具有相同的岩浆来源,可能与富钾岩石圈地幔拆沉作用造成的地幔热物质上涌有关.研究区地壳厚度与波速比呈现负相关关系,暗示该地区可能发生过岩浆底侵作用.

关 键 词:诺敏河火山群  接收函数  地壳厚度  波速比  
收稿时间:2018-04-03

Study of crustal thickness and VP/VS ratio beneath the Nuomin River volcanoes
XIE ZhenXin,WU QingJu,ZHOU ShiYong,ZHU Min.Study of crustal thickness and VP/VS ratio beneath the Nuomin River volcanoes[J].Chinese Journal of Geophysics,2018,61(12):4805-4816.
Authors:XIE ZhenXin  WU QingJu  ZHOU ShiYong  ZHU Min
Institution:1. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China;2. Institute of Theoretical and Applied Geophysics, Peking University, Beijing 100871, China;3. Key Laboratory of Seismic Observation and Geophysical Imaging, China Earthquake Administration, Beijing 100081, China
Abstract:We analyze thousands of receiver-function data recorded by 43 temporary seismic stations to reveal the crustal structure beneath the Nuomin River volcanoes in Northeast China. The H-κ method is applied to measure crustal depth and average VP/VS ratio. Results show that the crustal thickness of this area varies from 32 km to 38 km. The Moho depth is relatively larger in the west, decreasing significantly to~32 km beneath the volcanoes and adjacent areas, then increasing slowly to~35 km. The crust is thin in NNW direction, consistent with the trend of the volcanic belt centered at Wudalianchi. The region nearby Wudalianchi volcanoes has an average VP/VS ratio of 1.80, higher than in the west part of the study area, extending towards Nuomin River volcanoes and Xiaoguli River volcanoes. Research suggests that the delamination of K-rich lithosphere mantle triggered the upwelling of magma in Northeast China. Negative correlation between crustal thickness and Poisson's ratio is thought to result from simultaneous underplating of mafic magmas from upper mantle into crust which has likely modified crustal composition during Mesozoic-Cenozoic tectonic extension.
Keywords:Nuomin River volcanoes  Receiver functions  Crustal thickness  VP/VS ratio
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