| 海沟后退对地幔对流的影响 |
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| 引用本文： | 孙荀英,王其允.海沟后退对地幔对流的影响[J].地球物理学报,1994,37(6):738-748. |
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| 作者姓名： | 孙荀英 王其允 |
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| 作者单位： | 1. 北京大学地质系, 北京 100871;
2. 美国加州大学伯克利分校, CA 94720 |
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| 基金项目： | 国家自然科学基金,美国加州大学资助 |
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| 摘 要： | 本文分析了有海底扩张无海沟后退、有海沟后退无海底扩张以及海底扩张与海沟后退共存等３种情况下，俯冲板片运动与海沟迁移的关系．用幂律流体有限元方法计算海沟后退对地幔对流的影响．地幔有效粘度除依赖应力偏张量的第二不变量以外，尚与温度、压力（含流体静压力和流动压力）有关．计算表明，对流环、高流动负压区以及低粘区的个数和位置，均受控于海沟是否后退以及海底是否扩张；温度场与海沟后退无明显关系．流动压力对形成洋中脊和弧后火山、驱动地幔对流以及维持板片的倾斜角度都具有重要意义．
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| 关 键 词： | 海沟后退 地幔对流 幂律流体 流动压力 |
| 收稿时间： | 1992-02-25 |
THE INFLUENCE OF TRENCH RETROGRADATION ON MANTLE CONVECTION |
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| SUN XUN-YING,WANG REN.THE INFLUENCE OF TRENCH RETROGRADATION ON MANTLE CONVECTION[J].Chinese Journal of Geophysics,1994,37(6):738-748. |
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| Authors: | SUN XUN-YING WANG REN |
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| Institution: | 1. Dept.of Geology, peking Univ., Beijing 100871;
2. Dept.of Geology &; Geophysics, Univ.of California, Berkeley 94720, USA |
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| Abstract: | An analysis of the relation between the trench motion and the slab motion for three cases that:with the seafloor spreading without the trench retrogradation;with the trench retrogradation without the seafloor spreading;with both the seafloor spreading and the trench retrogradation have been carried out.A power law fluid whose rheological property depends on the temperature and total pressure which includs a static pressure and a kinematic pressure as well as on the 2nd invariant of deviatoric tensor of stress or strain rate have been used to investigate various fields of mantie flow either with or without the trench retrogradation by means of 2-D finite element method.The computing results show that there are remarkable influence of the trench retrogradation on me velocity field,the kinematic pressure field and the viscosity field but the small influence on the temperature field.The number and position of convection calls,lower viscosity areas and higher negative pressure areas are controlled by whether the trench retrogradation or not and whether the seafloor spreading or not. The kinematic pressure is significant for forming the oceanic ridge and the back-arc volcano,driving mantle convection. |
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| Keywords: | Trench retrogradation Mantle convection Power law fluid Kinematic pressure |
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