摘要
喀斯特铝土矿是异地物源堆积在古喀斯特洼地经过强烈化学风化作用形成。华北晚石炭世形成超过50亿t喀斯特铝土矿产,是全球最大喀斯特铝土矿成矿带。本文系统梳理了华北喀斯特型铝土矿研究进展、存在问题及未来主要研究方向,协助完善全球同类型铝土矿成因理论体系。主要研究进展包括:(1)铝土矿规模和质量严格受控古岩溶地貌类型和矿床形成古环境条件,陆相宽广溶原是优质大规模铝土矿形成的理想场所;(2)成因母岩具有异地多来源特征,空间变化较大;北部铝土矿以白乃庙岛弧、华北克拉通北缘隆起及华北中部造山带中火成岩和变质岩为主;南部铝土矿以北秦岭造山带及华北中部造山带中火成岩和变质岩为主;中部铝土矿具有上述两者混合特征;(3)提出铁铝固溶体介导硬水铝石地表结晶成因机制,突破了传统地表风化+后期成岩变质作用的传统认识;(4)晚石炭世华北克拉通北缘大规模火山活动是促进华北克拉通短期大规模铝土矿形成的关键要素。存在的问题和研究方向:(1)巨量成矿源岩的复杂性;喀斯特型铝土矿来源在时空具有复杂多变特征,华北铝土矿源岩组成和供给情况尚需强化;(2)复杂的成矿环境条件与沉淀机制;喀斯特型铝土矿形成环境变化较大,可从陆相延伸至海相,从次氧化到还原条件,不同的环境条件中硬水铝石地表沉淀机制尚需对比研究,新提及的铁铝固溶体介导机制尚需通过实验手段进行验证;(3)共伴生资源综合利用;喀斯特型铝土矿中伴生大量的REE、Li、Ga、Sc等矿产资源,然其分布规律和赋存形式研究薄弱,制约矿石综合高效利用。
Karstic bauxite is formed from allochthonous materials that accumulated in paleokarst depressions and underwent intensive chemical weathering.The North China Craton(NCC)hosts over 5 billion tons of karstic bauxite deposits formed during the Late Carboniferous,making it the world's largest karstic bauxite metallogenic belt.This paper systematically reviews the research progress,existing problems,and main future research directions of karstic bauxite in the NCC,aiming to contribute to a global theoretical framework for the genesis of analogous deposits.Key research progress includes:①The scale and quality of bauxite are strictly controlled by the paleokarst landform and paleo-environmental conditions.Vast continental karst plains provide ideal sites for the formation of high-quality,large-scale bauxite.②The provenance of parent rocks exhibits allochthonous and multi-source characteristics with significant spatial variability.The bauxite deposits in the northern part of the NCC are derived mainly from igneous and metamorphic rocks of the Bainaimiao Arc Terrane,the uplift on the northern margin of the NCC,and the Central Orogenic Belt.The bauxite in the southern part of the NCC originates primarily from igneous and metamorphic rocks of the North Qinling Orogenic Belt and Central Orogenic Belt.The bauxite in the central part of the NCC has the characteristics of a mixed source of both.③A mechanism for the surface crystallization of diaspore mediated by iron-aluminum solid solutions has been proposed,challenging the traditional understanding of surface weathering and subsequent diagenetic modification.④Large-scale Late Carboniferous volcanic activity along the northern margin of the NCC was a key factor driving the short-term and large-scale formation of these bauxite deposits.Existing problems and research directions include:①The complexity of parent rocks for massive bauxite deposits.The provenance of karstic bauxite is temporally and spatially variable;thus,research on source rock composition and sediment supply dynamics in the NCC requires strengthening.②The complex metallogenic environments and sedimentation mechanisms of bauxite.Formation environments of karstic bauxite vary greatly,extending from continental to marine and from sub-oxic to reducing conditions.Comparative studies on the surface precipitation mechanism of diaspore under these varying conditions are needed,and the newly mentioned Fe-Al solid solution-mediated mechanism still needs to be verified through experimental means.③The comprehensive utilization of associated resources in bauxite.Karst bauxite is accompanied by a large amount of mineral resources,such as REE,Li,Ga,and Sc.However,the research on their distribution and occurrence in bauxite remains limited,which restricts the efficient utilization of these ores.
作者
赵利华
刘学飞
王庆飞
刘蕾
孙雪飞
赵军
杨淑娟
梁荣荣
张尚清
ZHAO Lihua;LIU Xuefei;WANG Qingfei;LIU Lei;SUN Xuefei;ZHAO Jun;YANG Shujuan;LIANG Rongrong;ZHANG Shangqing(Hebei Key Laboratory of Strategic Critical Mineral Resources,Hebei GEO University,Shijiazhuang,Hebei 052161,China;School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Key Laboratory of Bauxite Resources Exploration and Comprehensive Utilization of Shanxi Province,Jinzhong,Shanxi 030620,China;Shanxi Third Geological Engineering Investigation Institute Co.,LTD.,Jinzhong,Shanxi 030600,China;Shanxi Provincial Geological Survey Institute Co.,LTD.,Taiyuan,Shanxi 030006,China)
出处
《地质学报》
2026年第2期614-632,共19页
Acta Geologica Sinica
基金
国家重点研发课题(编号2022YFC2903402)
山西省铝土矿重点实验室项目(编号LTK202504)资助的成果。
关键词
铝土矿
成矿物源
表生成矿机制
成矿模式
成矿要素
华北
bauxite
provenance
supergene metallogenic mechanism
metallogenic model
metallogenic factors
North China
