全吉微陆块基底古元古代变质表壳岩的成因和地壳演化研究

The Quanji continental block (QCB) is one of the micro-blocks in the southeastern margin of the Tarim Craton and is a cratonic remnant composed of metamorphic basement and unmetamorphic cover. The basement of the QCB consists of the early Paleoproterozoic (intrusive) Delingha Complex and metamorphic supracrustal rocks of the Dakendaban Group that can be further divided into upper and lower sub-groups. The upper Dakendaban sub-group has characteristics of the Khondalite and much progress on it has been made. On the contrary, the lower Dakendaban sub-group is relatively older and can play an important role in understanding the early crustal and tectonic evolution as well as the affinity of the QCB, however, less researches have been carried out for that sub-group. This project will perform, based on detailed geological survey, comprehensive studies of geology, petrography, geochronology and geochemistry on the lower sub-group to constrain the metamorphic lithological association, protolith formation, sedimentary ages, provenance of the sediments, components and tectonic environment of the source region as well as the tectonic setting of the sedimentary basin. Then, combined with these data, this project will try to make reconstruction of the crustal growth and reworking history, investigation of the early Paleoproterozoic to late Neoarchean crustal and tectonic evolution of the QCB and its relationship (affinity) with the other cratons in China, and provide important information to explore the Precambrian evolution of the three main cratons in China as well as the global supercontinent.

塔里木克拉通东南缘微陆块群中的全吉微陆块是一个由变质基底和未变质盖层组成的克拉通残块，其基底由古元古代德令哈（侵入）杂岩和变质表壳岩达肯大坂岩群组成。达肯大坂岩群分上、下两个亚岩群，上亚群具孔兹岩特征，研究程度较高；下亚群时代较早，是微陆块最早期的地壳和构造演化以及亲缘性的重要信息载体，但研究程度低。本项目以地质调查为基础，对达肯大坂岩群下亚岩群开展地质学、岩石学、年代学和地球化学等研究，查明变质岩建造（岩石共生组合）和原岩建造、形成时代、变沉积岩的碎屑源区和源区组成特征及构造环境、探讨沉积盆地的构造环境，然后综合上、下亚岩群的上述资料，重塑全吉微陆块的地壳生长与再造史，探讨古元古代早期-新太古代晚期的地壳演化、构造演化及其与中国大陆其它克拉通演化关系（亲缘性），为探索我国三大陆块之间的早前寒武纪和全球超大陆的演化关系提供更多资料。