苏拉威西岛北部左旋走滑与俯冲后撤的动力学分析  

Dynamic analysis of sinistral strike slip and subduction roll-back in northern Sulawesi Island

作　　者：张健 董淼 姜程浩 方桂 褚伟 何雨蓓 ZHANG Jian;DONG Miao;JIANG Chenghao;FANG Gui;CHU Wei;HE Yubei(College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]中国科学院大学地球与行星科学学院,北京100049 [2]中国科学院地质与地球物理研究所,北京100029

出　　处：《地质学报》2023年第1期1-15,共15页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42176052);中国科学院战略性先导科技专项(编号XDB42020104);国家重点研发计划“变革性关键科学问题”重点专项(编号2021YFA0716002)联合资助的成果。

摘　　要：苏拉威西岛北部属于马鲁古海板块,其主体是北苏拉威西海沟俯冲带与帕卢-科洛左旋走滑断裂所围限的岛北支和岛东支。大约5 Ma前,苏拉群岛沿Sorong断层与苏拉威西岛东支碰撞,导致北苏拉威西海沟俯冲后撤,引起了岛北支顺时针旋转约20°~25°,同时,西侧的帕卢-科洛断层发生了约4 cm/a的左旋走滑。本文利用综合地球物理方法,计算了该区三维温度、速度、黏性特征,认为:苏拉威西岛北部在左旋走滑、俯冲后撤过程中,地壳以脆性变形为主,但由于北苏拉威西海沟俯冲带在地壳内形成南向倾斜的软弱层,Moho面和地形“镜像”区域内形成脆、韧变形共存的组合。地幔变形为韧性变形,深度约100 km的上地幔低速流变层是地幔韧性变形的主控层位。在周边板块边界不断移动的动力学背景中,苏拉威西岛北部在地壳尺度以收缩-伸展变形为主,在岩石圈尺度以旋转变形为主。The northern Sulawesi Island which main body is the North arm and East arm of the island surrounded by the North Sulawesi trench subduction zone and the Palu Kolo sinistral strike slip faul,belongs to the Molucca Sea Plate.Before 5 Ma,the Sula Islands collided with the east arm of Sulawesi Island along the Sorong fault,resulting in the subduction roll-back of the north Sulawesi Trench,causing the north arm of Sulawesi Island to rotate clockwise by about 20°~25°.Meanwhile,about 4 cm/a sinistral strike slip occurred on the Palu-Koro fault in the West.In this paper,the comprehensive geophysical method is used to calculate the three-dimensional temperature,velocity and viscosity characteristics in this area.It is considered that the crust in the northern Sulawesi Island is mainly brittle deformation in the process of sinistral strike slip and subduction retreat.As the subduction zone of the north arm forms a southward inclined weak layer in the crust,a combination of brittle and ductile deformation is formed in the Moho surface and the topographic“mirror image”area.The mantle deformation is ductile,and the upper mantle low vsor weak rheological layer with a depth of about 100 km is the main control layer of mantle ductile deformation.Under the dynamic background of the continuous movement of the surrounding plate boundary,the Northern Sulawesi Island is dominated by contraction or extension on the crustal scale and rotational deformation on the lithosphere scale.

关 键 词：苏拉威西岛北部 左旋走滑 俯冲后撤 地球物理计算分析 地壳与地幔变形 

分 类 号：P736[天文地球—海洋地质]