白云鄂博洋板块地质与成矿作用初探  

Preliminary Study on Geology and Mineralization of the Bayan Obo Ocean Plate

作　　者：肖庆辉[1] 刘勇[1] 许立权[2] 丁孝忠[1] 张玉清[2] 程杨 李岩 范玉须 贺国奇 Xiao Qinghui;Liu Yong;Xu Liquan;Ding Xiaozhong;Zhang Yuqing;Cheng Yang;Li Yan;Fan Yuxu;He Guoqi(Institute of Geology,Chinese Academy of Geological Science,Beijing 10037,China;Inner Mongolia Geological Survey Institute,Huhhot 010020,China;Institute of Mineral Resources,China Metallurgical Geology Administrstion,Beijing 101300,China;General exploration and Research Institute of China Coal Geology administration,Beijing 100039,China;School of Earth Science and Resources,China University of Geosciences,Beijing 10083,China)

机构地区：[1]中国地质科学院,地质研究所,北京100037 [2]内蒙古自治区地质调查院,内蒙古呼和浩特010020 [3]中国冶金地质总局矿产资源研究院,北京101300 [4]中国煤炭地质总局勘查研究总院,北京100039 [5]中国地质大学地球科学与资源学院,北京100083

出　　处：《地球科学》2020年第7期2258-2278,共21页Earth Science

基　　金：地调"全国陆域及海区地质图件更新与共享"项目(No.DD20190370);内蒙古自治区地质矿产勘查基金(No.2017-YS01)。

摘　　要：提出全球规模最大的白云鄂博稀土矿受亚洲洋向华北克拉通北缘俯冲的洋板块地质演化控制.探讨了白云鄂博地区亚洲洋洋板块地质构造发育过程、亚洲洋向华北克拉通北缘俯冲过程中相继发育的新元古代,早、晚古生代俯冲增生杂岩带的地质构造特征.探讨了白云鄂博稀土矿成因,认为稀土矿成矿碳酸岩岩浆产在华北克拉通北缘的所谓特殊的远端弧后构造环境(far backarc settings),也有人称为远离弧后背景或者变形的大陆边缘环境(deformed continental margins),不在大洋俯冲过程中发育的岩浆弧环境中.相对于大陆边缘弧,远端弧后构造环境位于向克拉通或向弧后更远的位置,它是控制白云鄂博深部成矿物质向浅部地表运移聚集成大型矿床、矿集区的关键储运空间.远端弧后构造环境远离大洋汇聚带或俯冲带向大陆或向弧后位置的克拉通边缘上,即在华北克拉通北缘岩石圈与亚洲洋造山带的岩石圈分界上的伸展构造中,受大规模岩石圈不连续系统或深切岩石圈的断裂带系统控制.成矿碳酸岩岩浆可能来自携带大量铁与REE的亚洲洋洋壳沉积物,于晚元古-早古生代向华北克拉通俯冲消减到华北克拉通陆下岩石圈地幔SCLM深循环过程中,在深切华北克拉通边缘的岩石圈的不连续构造系统中出溶形成岩浆碳酸岩及其携带的REE矿床.This paper proposed that the world’s largest Bayan Obo rare earth elements(REE)deposit is controlled by the geological evolution of the oceanic plate which subducted from the Asian Ocean towards the northern margin of the North China Carton(NCC).And discussed the geological tectonic development of the Asian Ocean plate in the Bayan-Obo region,and the Neoproterozoic,Early and Late Paleozoic subduction-accretionary complex developed successively during the subduction of the Asian Ocean to the northern margin of the NCC.The origin of the Bayan Obo REE deposit is also discussed.It is believed that the REE-riched carbonatite magma is produced in the so-called special far backarc settings in the northern margin of NCC,which some people call it as far from the arc settings or deformed continental margins settings,instead of oceanic subduction settings(magma arc settings).Compared with the continental marginal arc,far backarc settings are located farther away from the carton or backarc,which is the key storage and transportation space that controls the migration and accumulation of deep ore-forming materials to shallow surface in Bayan Obo,and finally aggregates into large ore deposits and ore-concentrated area.The far backarc settings are far away from the oceanic subduction-convergence zone or subduction zone towards the carton or the carton edge behind the arc,that is,in the extension structure on the lithosphere boundary between the lithospheric boundary of the northern margin of the NCC and the Asian orogenic belt,it is controlled by a large-scale lithosphere discontinuous system or a deep-cut lithosphere fault zone system.The ore-forming carbonatite magma may come from the Asian oceanic crust sediments carrying a Large amount of Fe and REE.It subducted and subdued towards the SCLM deep circulation in the lower lithosphere of the NCC in the late Proterozoic-Early Paleozoic,then it dissolved to form magmatic carbonatites and the REE deposits in the discontinuous tectonic system which deep cutting the lithospheric e

关 键 词：洋板块地质兴蒙造山系 华北克拉通北缘 远端弧后构造环境、稀土矿成因 岩石圈的不连续构造 构造地质 

分 类 号：P548[天文地球—构造地质学]