扬子克拉通太古宙至古元古代地壳演化过程研究

发布时间：2018-04-25 22:03

本文选题：扬子克拉通 + 太古宙　；参考：《中国地质大学》2016年博士论文

【摘要】：克拉通是大陆岩石圈古老而稳定的部分,经历了多期次大陆碰撞和裂解过程,保存有大量前寒武地壳演化信息。扬子克拉通零星出露有太古宙基底,主要分布在克拉通北缘。通过对扬子克拉通崆岭杂岩北部变沉积岩,以及崆岭杂岩南部片麻岩、斜长角闪岩、混合岩、变沉积岩进行矿物学、地球化学、年代学为主的综合研究,并结合区域已有研究成果,取得了以下研究进展：(1)北崆岭变沉积岩的源岩沉积时间为2.15-2.0 Ga,并且沉积事件与扬子克拉通2.2-2.1 Ga岛弧相关生长事件存在联系；2.2-2.1 Ga生长事件形成了后河花岗质组分并且为崆岭变沉积岩提供古元古代物质来源；古元古代2.4-1.85 Ga扬子克拉通经历了陆-弧-陆碰撞及裂解过程。(2)南崆岭经历了太古宙2.9 Ga、2.7-2.6 Ga,古元古代2.4 Ga、1.77 Ga,新元古代0.8 Ga地壳生长和再造过程,并保存有2.5 Ga、2.14 Ga、2.0 Ga锆石年龄记录；南、北崆岭具有高度相似的岩浆事件记录,南崆岭相当于经历了2.7-2.6 Ga再造过程的北崆岭西部。(3)在限定了扬子克拉通古元古代板块范围的基础上,依托地球物理资料、地球化学数据、地质年代学数据并结合陆-弧-陆地壳演化过程,划定近似南北方向的古元古碰撞带：沿着大别山黄土岭-北缘崆岭-中部宁乡-中南部四堡区域。(4)梳理扬子克拉通太古宙至古元古代地壳增生及再造过程；通过对具有相似演化过程的太古宙克拉通开展研究,探索扬子克拉通与其他克拉通之间的亲缘关系。本文综合现有研究成果,提出概念化模型：扬子克拉通在3.5-1.8 Ga时期参与了超级克拉通”Vaalbara"与”Zimgam"之间的裂解和再拼合过程。
[Abstract]:The craton is an ancient and stable part of the continental lithosphere, which has undergone many subcontinental collision and fragmentation processes and contains a large amount of information on the evolution of the Precambrian crust. Archean basement appeared sporadically in Yangtze craton, mainly distributed in the northern margin of craton. The mineralogy, geochemistry and geochronology of the metamorphic rocks in the northern part of the Yangtze Craton Kongling complex, as well as the gneiss, amphibolite, migmatite and metamorphic sedimentary rocks in the southern part of the Kongling complex, are studied. And combined with the existing research results in the region, The following research progress has been made: 1) the sedimentary time of the source rocks in the Beikongling variable sedimentary rocks is 2.15-2.0 Ga, and the sedimentary events are related to the Yangzi craton 2.2-2.1 Ga island-arc related growth events, resulting in the formation of Houhe granitic composition and association between the sedimentary events and the Yangzi craton 2.2-2.1 Ga island arc growth events. And provides Gu Yuan ancient material source for Kongling variable sedimentary rock; Paleoproterozoic 2.4-1.85 Ga Yangtze craton experienced a land-to-arc-land collision and pyrolysis process.) Nankongling experienced Archean 2.9 Ga 2.7-2.6 Ga, Paleoproterozoic 2.4 Ga 1.77 Ga, Neoproterozoic 0.8 Ga crustal growth and reconstruction process, and preserved 2.5 Ga2. 14 Ga 2.0 Ga zircon age records. The southern and northern Kongling have highly similar magmatic event records, and the southern Kongling is equivalent to the western Beikongling, which has undergone 2.7-2.6 Ga reengineering. On the basis of defining the range of the Gu Yuan plate in the Yangtze craton, the South Kongling relies on geophysical data. Geochemical data, geochronological data and the process of continental arc-land crust evolution, Delineation of the Gu Yuan paleo-collision zone in the north-south direction: along the Loess Ridge to the North margin of the Dabie Mountains, the Kongling in the North margin of the Dabie Mountains, Ningxiang in the Central China and Sibao area in the Central South) to sort out the process of crustal accretion and reconstruction from Archean to Gu Yuan in the Yangtze Craton; The phylogenetic relationship between the Yangtze craton and other cratons was explored by studying the Archean craton with similar evolution process. Based on the existing research results, a conceptual model is proposed in this paper: the Yangtze craton participated in the process of cracking and reassembling the super craton "Vaalbara" and "Zimgam" in the period of 3.5-1.8 Ga.
【学位授予单位】：中国地质大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P313

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