珍贝—黄岩海山链热-重力均衡动态调节机制

于磊 张健 陈石 董淼 徐长仪

于磊, 张健, 陈石, 董淼, 徐长仪. 2015: 珍贝—黄岩海山链热-重力均衡动态调节机制. 地震学报, 37(4): 565-574. doi: 10.11939/jass.2015.04.004
引用本文: 于磊, 张健, 陈石, 董淼, 徐长仪. 2015: 珍贝—黄岩海山链热-重力均衡动态调节机制. 地震学报, 37(4): 565-574. doi: 10.11939/jass.2015.04.004
Yu Lei, Zhang Jian, Chen Shi, Dong Miao, Xu Changyi. 2015: Thermal-gravity equilibrium adjustment mechanism of Zhenbei-Huangyan seamount chain. Acta Seismologica Sinica, 37(4): 565-574. doi: 10.11939/jass.2015.04.004
Citation: Yu Lei, Zhang Jian, Chen Shi, Dong Miao, Xu Changyi. 2015: Thermal-gravity equilibrium adjustment mechanism of Zhenbei-Huangyan seamount chain. Acta Seismologica Sinica, 37(4): 565-574. doi: 10.11939/jass.2015.04.004

珍贝—黄岩海山链热-重力均衡动态调节机制

doi: 10.11939/jass.2015.04.004
基金项目: 

国家自然科学基金项目 41174085

中国科学院创新团队项目 KZZD-EW-TZ-19

中国科学院战略性先导科技专项 XDA1103010102

国家自然科学基金重点项目 41430319

详细信息
    通讯作者:

    张健, e-mail: xjgaochaojun@163.com

  • 中图分类号: P314.2, P312.3

Thermal-gravity equilibrium adjustment mechanism of Zhenbei-Huangyan seamount chain

  • 摘要: 珍贝—黄岩海山链作为我国南海的残留扩张中心, 对其研究具有重要的科学意义. 本文运用均衡学方法, 通过重力异常数据反演了过珍贝—黄岩海山链剖面的地壳界面变化, 同时计算了岩石圈热结构状态, 在此基础上建立了珍贝—黄岩海山链的岩石圈地温结构模型. 通过均衡分析方法, 对剖面上测点的海底地形数据进行了热均衡和重力均衡分析, 得到了热均衡和重力均衡形变量. 结果表明, 在珍贝—黄岩海山链高热流区域, 热均衡作用可以产生最大约0.55 km的形变, 其重力均衡形变范围为0.77—1.89 km. 热均衡通过改变海底地形和地壳物质密度不断作用于重力均衡, 重力又反过来作用于热均衡, 形成了热均衡-重力均衡动态调节机制.

     

  • 图  1  研究区地质与地球物理特征图

    (a) 南海海底地形及热流q (单位: mW/m2)测点图, 黑色框为本文研究区域; (b) 珍贝—黄岩海 山链海底地形图, 图中AB为过珍贝—黄岩海山链的地震剖面; (c) 珍贝—黄岩海山链 自由空间重力异常图; (d) 珍贝—黄岩海山链布格重力异常图

    Figure  1.  Geological and geophysical characteristics of the research areas

    (a) Bathymetric chart and heat-flow q (in unit of mW/m2) observation point distribution, the black rectangle gives the studied area in this study; (b) Topography of the Zhenbei-Huangyan seamount chain, where AB is a seismic profile across Zhenbei-Huangyan seamount chain; (c) The free air gravity anomaly of the Zhenbei-Huangyan seamount chain; (d) The Bouguer gravity anomaly of the Zhenbei-Huangyan seamount chain

    图  2  海洋地壳组分均衡调整模式示意图(引自McKenzie等, 2005)

    图中LOC为补偿深度, MSL为平均海平面

    Figure  2.  Schematic diagram of parameters used in gravitational correction of the ocean area (after McKenzie et al, 2005)

    LOC is the compensation depth, MSL is the mean sea level

    图  3  热均衡计算结果

    (a) 给定地表热流值情况下岩石圈热结构图; (b) 热均衡产生的垂直形变量ΔεT随地表热流值q变化图

    Figure  3.  The computing result of the thermal equilibrium

    (a) Theory thermal structure of the lithosphere on the condition that a surface heat flow value is given; (b) Variation of vertical deformation ΔεT caused by thermal equilibrium with surface heat flow q

    图  4  过珍贝—黄岩海山链的三维地震速度剖面[根据丘学林等(2012)王建等(2014)修改]

    Figure  4.  D seismic section across Zhenbei-Huangyan seamount chain modified from Qiu et al (2012) and Wang et al (2014)

    图  5  重力均衡计算结果

    (a) 重力均衡形变量与海底地形高程对比图; (b) 热均衡形变量与重力均衡形变量之比与地壳厚度对比图

    Figure  5.  The computing result of the gravity equlibrium

    (a) Comparison between vertical deformation caused by gravity equlibrium (blue line) and the seabed terrain elevation (green line); (b) Comparison between the ratio of thermal equlibrium to gravity equlibrium (blue line) and crustal thickness (green line)

    表  1  热均衡模型的材料参数(引自张健和石耀霖, 2004

    Table  1.   Material parameters of the thermal equilibrium model (after Zhang and Shi, 2004)

    分层 生热率A/(μW·m-3) 比热容c/(J·(kg·℃)-1) 热导率k/(W·(m·℃)-1)
    大洋沉积层1.2809000.85
    洋壳层21.3009002.93
    洋壳层30.4009002.30
    岩石圈上地幔0.02410003.30
    下载: 导出CSV

    表  2  过珍贝—黄岩海山链的地震剖面上各观测点参数

    Table  2.   Model parameters of the observation points on the seicmic section across Zhenbei Huangyan seamount chain

    测点 海底地形高程/km 地壳厚度/km 平均地壳密度/(g·cm-3)
    2-4.28102.731
    3-4.0110.52.754
    4-1.3113.52.703
    5-2.0010.52.766
    6-2.55112.734
    7-3.8811.52.718
    8-4.0111.52.697
    9-4.3910.52.723
    10-3.06112.710
    11-1.1511.52.676
    下载: 导出CSV
  • 张训华. 1996. 地壳均衡与均衡重力异常[J]. 海洋地质动态, (8): 1-4.

    Zhang X H. 1996. The isostasy and isostatic gravity anomaly[J]. Marine Geology Letters, (8): 1-4 (in Chinese).
    Taylor B, Hayes D E. 1980. The tectonic evolution of the South China Sea basin[G]//The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands. New York: American Geophysical Union: 89-104.
    Taylor B, Hayes D E. 1983. Origin and history of the South China Sea basin[G]//The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands. New York: American Geophysical Union: 23-56.
    Turcotte D L, Schubert G. 2002. Geodynamics[M]. 2nd ed. Cambridge: Cambridge University Press: 1-456.
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出版历程
  • 收稿日期:  2014-11-20
  • 修回日期:  2015-01-26
  • 刊出日期:  2015-07-01

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