【作者】 刘福田； 徐佩芬； 刘劲松； 尹周勋； 秦建业； 张先康； 张成科； 赵金仁；

【Author】 LIU FUTIAN~1 XU PEIFEN~1 LIU JINSONG~1 YIN ZHOUXUN~1 CHUN KINYIP~2 ZHANG XIANKANG~3 ZHANG CHENGKE~3 ZHAO JINREN~3 1 Institute of Geology and Geophysics,Chinese Academy of Sciences,Beging 100029,China 2 Department of Physics,University of Toronto,Toronto Ontario,M5S 2J5,Canada 3 Research Center of Exploration Geophysics,CSB,Zhengzhou 450002,China

【机构】 中国科学院地质与地球物理研究所； 多伦多大学物理系； 中国地震局郑州地球物理勘探中心；

【摘要】 在安徽大别山(东大别)进行的深地震宽角反射/折射探测获得6条二维地壳速度结构剖面.结果显示,东大别造山带地壳为一高速穹隆构造,在其核部中、下地壳变质岩出露于地表,波速高达5.0km/s;在其翼部,上、中地壳发育速度约6.1km/s的壳内低速层(体).莫霍面的起伏变化较大,中心部位深达41km左右,周边地区则抬升到32～34km.在晓天—磨子潭断裂一线下方莫霍面垂向错断,断距约4km.东大别造山带具有大陆深俯冲-碰撞造山带地壳结构的典型式样.莫霍面错断与扬子陆块深俯冲有关,错断处表征扬子与华北陆块碰撞缝合的深部位置.高速穹隆构造可能是两陆块碰撞挤压的产物,穹隆翼部上、中地壳发育的低速滑脱带(面)可能在碰撞期之后的地壳伸展、超高压变质岩从中地壳抬升出露于地表过程中起到重要作用.更多还原

【Abstract】 Six two-dimensional crustal structure profiles in the eastern Dabie,Anhui Province,have been obtained by the wide-angle reflection/refraction.The results reveal that the crust of the eastern Dabie orogen presents a high-velocity dome,the velocity in the middle- and lower-crust’s metamorphic rocks exposed on the surface in the core of the dome approaches 5.0 km/s,the low velocity layers(body) with about 6.1 km/s has developed in upper-middle crust in it’s both sides wing,the Moho discontinuity relatively largely varies and ranges from～41km in the core to 32～34 km in both sides,and a 4 km Moho-offset is observed beneath along Xiaotian-Muzitan Fault.We recognize that the eastern Dabie orogen shows a velocity-pattern of typical continent-continent deep subduction/collision style.The Moho offset may be related with the deep subduction of the Yangtze Block,and represents the suture zone between the Yangtze/Sino-Korean Block collision.Therefore, the high-velocity dome may occur by collision/extrusion between the both continental Blocks and the low velocity layers(body) mentioned above may play an important role in the post-collisional crust extension and exhumation of the ultra-high press metamorphic rocks.更多还原