中亚造山带内微陆块的起源——以中国天山造山带研究为例

发布时间：2018-06-02 17:03

本文选题：伊犁地块 + 中天山地块　；参考：《矿物岩石地球化学通报》2017年05期

【摘要】：中亚造山带内分布有众多的具有前寒武纪基底的微陆块,其构造起源一直是中亚造山带地质演化研究的核心问题之一。中国天山造山带呈东西向展布于中亚造山带的南部,发育伊犁和中天山两个古老微陆块。已有成果认为,伊犁地块和中天山地块可能存在古元古代地壳物质,其古老陆核主要形成于中元古代(ca.1.4~1.3Ga),并在新元古代早期(0.97~0.85Ga)发生强烈的地壳改造作用而固结形成统一的结晶基底。笔者最新的碎屑锆石研究表明,伊犁地块在1.8~1.7Ga和1.6~1.3Ga期间发生同时期的地壳生长和改造作用,此后主要以地壳改造为主(1.0~0.78Ga)。基于最近的岩浆研究认为中天山地块在中元古代(1.6~1.3Ga)经历了一期地壳生长事件,随后在新元古代早期开始以地壳的改造作用为主。在中-新元古代时期,伊犁和中天山地块可能都处于大陆地壳伸展环境(0.76~0.71Ga)。与塔里木克拉通及周缘其他主要古老块体的综合对比研究揭示,伊犁地块和中天山地块在前寒武纪时期具有相似的地壳演化过程,但不同于塔里木克拉通及其他古老块体。由此认为,伊犁地块和中天山地块与塔里木克拉通不具有亲缘性,其构造起源于相邻的哈萨克斯坦地块。
[Abstract]:There are many microcontinental blocks with Precambrian basement in the Central Asian orogenic belt. Their tectonic origin has always been one of the core problems in the geological evolution of the Central Asian orogenic belt. The Tianshan orogenic belt in China distributes east-west in the south of the Central Asian orogenic belt with two ancient microcontinental blocks Yili and Middle Tianshan. It has been concluded that the ancient Gu Yuan crustal material may exist in the Yili and Middle Tianshan massifs. Its ancient continental nucleus was mainly formed in the Mesoproterozoic (1.41) 1.3Ga, and in the early Neoproterozoic (0.97 ~ 0.85Ga) was strongly reformed in the crust and consolidated to form a unified crystalline basement. The author's latest study of detrital zircon shows that the crust growth and transformation occurred in the same period during 1.8~1.7Ga and 1.6~1.3Ga in Yili block, and the crustal transformation mainly occurred after that time. Based on recent magmatic studies, it is believed that the Middle Tianshan block experienced a first crustal growth event in the Middle Proterozoic, and then began to take the role of crustal transformation in the early Neoproterozoic. In the Meso-Neoproterozoic period, both the Yili and the Middle Tianshan massifs may be located in the continental crustal extensional environment of 0.76 ~ 0.71 Ga ~ (-1). A comprehensive comparison with the Tarim craton and other major ancient blocks in the periphery reveals that the Yili block and the middle Tianshan block have similar crustal evolution processes during the Precambrian period, but are different from the Tarim craton and other ancient blocks. It is concluded that the Yili block and the middle Tianshan block are not related to the Tarim craton, and their structures originated from the adjacent Kazakstan block.
【作者单位】：西北大学地质系大陆动力学国家重点实验室;中国科学院广州地球化学研究所同位素地球化学国家重点实验室;
【基金】：国家自然科学基金项目(41522202,41603028,41373034) 国家重点基础研究发展计划项目(2014CB440801)
【分类号】：P542

【相似文献】