黑龙江省东部新元古代—早侏罗世的洋-陆转换过程

Neoproterozoic-early jurassic ocean-land transformation in eastern Heilongjiang Province

针对东北微地块群拼贴位置及构造演化这一重要科学问题,运用洋-陆转换及大陆动力学等理论,结合最新研究成果,通过系统分析松嫩地块与佳木斯地块间晚二叠世—晚三叠世嘉荫-牡丹江俯冲增生杂岩(黑龙江杂岩)带的物质组成,甄别了俯冲增生杂岩带内蛇绿岩的类型。研究表明:晚二叠世—晚三叠世蛇绿岩类型主要包括SSZ型蛇绿岩-斜长角闪片岩,地幔柱型蛇绿岩-蓝片岩,洋中脊型蛇绿岩-蓝片岩、超镁铁质岩,与弧盆系演化相关的蛇绿岩超镁铁质岩、辉长岩组合;结合晚二叠世—晚三叠世嘉荫-牡丹江俯冲增生杂岩带和张广才岭杂岩物质组成和各期岩浆弧、区域磨拉石建造空间分布,总结了松嫩地块和佳木斯地块之间新元古代—早侏罗世洋-陆转换过程。

This paper is concerned with an important scientific issue which underlies collage location and tectonic evolution of micro-block groups in Northeast China.The targeted study offers the systematic analysis of material composition of the Jiayin-Mudanjiang subduction accretion complex(Heilongjiang complex)zone between the Songnen and Jiamusi blocks in the Late Permian-Late Triassic by applying the theories such as ocean-land conversion and continental dynamics,and combined with the latest research results;and the subsequent identification of the types of ophiolites in the subduction accretion complex zone.The results show that Late Permian-Late Triassic Ophiolite Types consist mainly of SSZ-type ophiolite-amphibolite schist;mantle plume ophiolite-blueschist;mid-ocean ridge ophiolite-blueschist and ultramafic rock,ophiolite-ultramafic rock and gabbro assemblages related to the evolution of arc basin system;and the combination of the material composition of the Jiayin-Mudanjiang subduction accretion complex belt and the Zhangguangcailing complex and the spatial distribution of magmatic arcs and regional molasses formations in different stages provides a new insight into the Neoproterozoic-Early Jurassic oceanic-continental transition between Songnen and Jiamusi blocks.