大洋岩石层拖曳窄条陆壳俯冲的极限尺度分析——以新西兰南岛和大别山超高压变质带为例  

ANALYSIS ON MAXIMUM SCALE OF CONTINENTAL CRUST SLIVER DRIVEN BY SUBDUCTING OCEANIC SLAB: A CASE STUDY OF SOUTH ISLAND OF NEW ZEALAND AND UHPM AT DABIE,CHINA

作　　者：石耀霖[1] 范桃园 

机构地区：[1]中国科学院中国科学技术大学研究生院,北京100039

出　　处：《地球物理学报》2001年第6期754-760,共7页Chinese Journal of Geophysics

基　　金：国家自然科学基金资助项目 ( 4 9774 2 36 )

摘　　要：超高压变质研究涉及的一个基本力学问题是为什么低密度的大陆地壳岩石能克服浮力俯冲到高密度地幔 1 0 0多公里的深度 .本文的三维有限单元法计算表明 :俯冲海洋板块可以拖曳侧面相邻宽度不超过 1 5 0km的一窄条大陆板块 ,俯冲到超高压变质深度 ,形成少见的大规模超高压变质带 .十几公里乃至几十公里尺度的陆壳块体 ,可能被俯冲地幔裹挟至超高压变质深度 ,在造山带内形成零星出露的超高压变质岩 .成熟的陆A basic question in mechanics of UHPM formation is why the density continental crust can overcome the buoyancy and subduct into the high density mantle more than 100km deep. In this study,3-D finite element computation shows that the subducting oceanic lithosphere can drag adjacent continental sliver with a width up to 150km to UHPM depth,and produce large scale UHPM belts rarely observed in the world. Smaller bodies of continental crust up to tens of kilometers in size can be wrapped to UHPM depth by subducting mantle,and concequently scattered UHPM can be formed in orogenic belts. Mature continental continental collision does not allow continental crust subduction to UHPM depth.

关 键 词：超高压变质带 大陆动力学 有限单元法 大别山 新西兰 陆壳俯冲 

分 类 号：P542[天文地球—构造地质学] P313[天文地球—地质学]