檀玉娟^1,,
段永红^1,,,
林吉焱^1,2,3,
李玮²,
王高春^2,3,
李学民¹,
王国法¹,
邹长桥⁴,
赵延娜¹,
周铭¹
1. 中国地震局地球物理勘探中心, 郑州 450002
2. 中国科学院地质与地球物理研究所, 北京 100029
3. 中国科学院大学, 北京 100049
4. 南方科技大学 海洋科学与工程系, 深圳广东 518055

基金项目: 国家自然科学基金（41174052，41604048和42004080）联合资助


详细信息

作者简介: 檀玉娟, 女, 1983年生, 工程师, 现主要从事地震台阵探测和地壳精细结构成像相关研究.E-mail: tanyujuan@163.com

通讯作者: 段永红, 男, 1963年生, 研究员, 主要从事大陆动力学的地震学探测和研究.E-mail: yhduan123@126.com

中图分类号: P315

收稿日期:2021-02-03
修回日期:2021-05-11
上线日期:2021-09-10

Crustal composition of the eastern South China Block based on the seismological study

TAN YuJuan^1,,
DUAN YongHong^1,,,
LIN JiYan^1,2,3,
LI Wei²,
WANG GaoChun^2,3,
LI XueMin¹,
WANG GuoFa¹,
ZOU ChangQiao⁴,
ZHAO YanNa¹,
ZHOU Ming¹
1. Geophysical Exploration Center, China Earthquake Administration, Zhengzhou 450002, China
2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
3. University of Chinese Academy of Science, Beijing 100049, China
4. Southern University of Science and Technology, Department of Ocean Science and Engineering, Shenzhen Guangdong 518055, China


More Information

Corresponding author: DUAN YongHong,E-mail:yhduan123@126.com

MSC: P315

--> Received Date: 03 February 2021
Revised Date: 11 May 2021
Available Online: 10 September 2021


摘要
摘要:中生代晚期华南大陆东部发生了大规模的火成岩活动，对地壳物质组成属性有显著影响，地壳中SiO₂的平均含量是判别其属性的重要参数.基于华南大陆东部布设的宽频带地震台阵和固定台站数据，利用噪声成像获取高分辨率的面波频散，联合利用接收函数反演地壳的S波速度结构.由地壳的平均波速比和速度信息，通过与岩石物理实验数据对比，估测了华南大陆地壳平均的SiO₂含量的空间分布特征.结果发现，政和—大埔断裂以东的浙闽沿海碱性火成岩带具有相对高速的下地壳（V_S>3.9 km·s^-1），相对高的地壳平均波速比（V_P/V_S>1.77），估测地壳平均SiO₂含量相对较低（60~65wt%）；政和—大埔断裂以西的武夷带和江南造山带具有相对低速的下地壳（V_S < 3.8 km·s^-1），相对低的地壳平均波速比（V_P/V_S < 1.75），估测地壳平均SiO₂含量相对较高（65~75wt%）.政和—大埔断裂以东的地壳整体略偏基性，以西的地壳则偏长英质.推测古太平洋板块消减作用对华南大陆东部的影响主要为热扰动的形式，壳-幔物质交代作用仅限于政和—大埔断裂以东的区域.
关键词: 华南大陆东部/
地壳成份/
SiO₂含量/
联合成像

Abstract:In the late Mesozoic, extensive igneous activities occurred in the eastern South China Block (ESCB), which might change the crustal composition. The SiO₂ contents of the crust is an essential feature of its properties. Based on the data from the broadband seismic array and permanent stations deployed in the ESCB, we use ambient noise tomography to obtain high-resolution surface wave dispersions, and then we apply joint inversion of surface wave dispersions and receiver functions to construct the crustal S-wave velocity structure. Finally, based on the crustal average S-wave velocity and V_P/V_S ratio, we further estimate the spatial distribution of crustal SiO₂ contents referring to the petrophysical experiment data. The results show high lower crustal S-wave velocity (greater than 3.9 km·s^-1), relatively high V_P/V_S ratio (greater than 1.77), and intermediate composition with SiO₂ contents of 60~65 wt% in the southeast coastal region at where extensive alkaline igneous rocks emplaced. In contrast, the Wuyi orogenic belt and Jiangnan orogenic belt have relatively low S-wave velocity (lower than 3.8 km·s^-1), relatively high V_P/V_S ratio (lower than 1.75), and contains relatively felsic composition with SiO₂ contents of 65~70 wt%. The diverse crustal components across the Zhenghe-Dapu fault, as intermediate-mafic to the east while felsic to the west, indicate that the subduction of the paleo-Pacific plate has caused thermal erosion process beneath the ESCB, and the crust-mantle metasomatism is mainly limited to the east of the Zhenghe-Dapu fault.
Key words:Eastern South China Block/
Crustal composition/
wt% SiO₂/
Joint inversion



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