那丹哈达地体及周缘中生代变形与增生造山过程

发布时间：2018-10-08 21:23

【摘要】：东亚陆缘中生代增生造山过程及变形响应一直以来都是中国区域地质研究的重大课题,也是东亚地质构造演化的一个难点和热点。其中一个最为关键的科学问题就是,古太平洋板块(Izanagi)何时开始启动俯冲?对中生代东亚大陆边缘产生何种影响?那丹哈达地体出露于中国东北,为一套构造混杂岩系,是中国境内由古太平洋板块俯冲-增生形成的唯一证据,为解决这一问题提供了可能。本文通过总结大量前人最新的岩石学、同位素年代学、沉积岩石组合、主干断裂、岩浆活动、古生物及古地磁等资料,试图厘定那丹哈达地体构造属性、增生过程、拼贴时间以及古太平洋板块开始俯冲的时间,并与周缘地体进行对比。结果表明:(1)那丹哈达增生杂岩分为饶河杂岩和跃进山杂岩,饶河杂岩具有洋岛玄武岩(OIB)的特征,不是前人认为的蛇绿岩,可称之为洋岛(海山)杂岩;跃进山杂岩具有洋中脊玄武岩(MORB)的特征,是典型的蛇绿岩,同时暗示古太平洋板块可能于晚三叠世开始启动俯冲,并在136~131 Ma期间就位于现今位置。(2)那丹哈达与日本丹波—美浓—尾足地体都是侏罗纪增生楔,在沉积岩石组合和年龄、放射虫类型及分布、地质构造等特征上都非常相似,在中新世日本海打开之前应是一个统一的超级地体。
[Abstract]:Mesozoic accretive orogenic process and deformation response in the continental margin of East Asia have long been a major subject of regional geological research in China, and are also a difficult and hot point in the evolution of geological structures in East Asia. One of the most critical scientific questions is, when does the paleo-Pacific plate (Izanagi) start subduction? What is the impact on the Mesozoic continental margin of East Asia? The Nadanhada terrane, which is a set of tectonic melange series, is the only evidence of subduction and accretion of paleo-Pacific plate in China, which provides the possibility to solve this problem. This paper attempts to determine the tectonic attributes and accretive processes of the Nathanhada terrane by summarizing a large number of recent data such as petrology, isotopic chronology, sedimentary rock assemblage, main faults, magmatic activity, paleontology and paleomagnetism, etc. The collage time and the time when the paleo-Pacific plate began subduction were compared with the surrounding terrane. The results are as follows: (1) Nadanhada accretive complex is divided into Raohe complex and Yuejin complex. The Raohe complex is characterized by oceanic island basalt (OIB) and is not ophiolite, which can be called the oceanic island (seamounts) complex. The Yuejin complex is typical ophiolite with the characteristics of mid-oceanic ridge basalt (MORB) and suggests that the paleo-Pacific plate may start subduction in the late Triassic. It was located in the present position during 136-131Ma. (2) the Natanhada and Danbo-Meinonon-caudopod terrane are both Jurassic accretive wedges, which are very similar in sedimentary rock assemblage and age, radiolarian type and distribution, geological structure, and so on. Before the Miocene Sea of Japan opened, it should be a unified super terrane.
【作者单位】：海底科学与探测技术教育部重点实验室中国海洋大学海洋地球科学学院;青岛海洋科学与技术国家实验室海洋地质功能实验室;江苏省电力设计院;
【基金】：国家自然科学基金杰出青年基金项目(41325009) 山东省泰山学者特聘教授项目鳌山卓越科学家计划(2015ASTP-0S10) 国家海洋局重大专项(GASI-GEOGE-01)
【分类号】：P542

【参考文献】