板块构造对海相钾盐矿床分布与成矿模式的控制  

Plate Tectonics Control on the Distribution and Formation of the Marine Potash Deposits

作　　者：刘成林[1,3] 赵艳军[1] 方小敏[2] 吕凤琳[1,3] 王立成[1] 颜茂都[2] 张华[1] 丁婷[3] 

机构地区：[1]中国地质科学院矿产资源研究所,成矿作用与资源评价重点实验室,北京100037 [2]中国科学院青藏高原研究所,北京100101 [3]中国地质大学(北京),北京100083

出　　处：《地质学报》2015年第11期1893-1907,共15页Acta Geologica Sinica

基　　金：国家“973”计划项目(编号:2011CB403007)资助

摘　　要：表生钾盐矿床主要沉积于陆壳板块上的陆表海盆地中,其沉积受制于全球板块运动,具体影响表现在板块的规模、边界特征、漂移历史与古纬度、古气候等的控制作用。在巨型稳定克拉通上,出现巨型陆表海盆,沉积分布广、厚度大的巨型钾盐矿床或矿集区,矿床沉积类型属于化学岩型即碳酸盐岩型钾盐矿;板块汇聚区域,如特提斯造山带,出现较多的小陆块并形成较小规模的海相及海陆交互相盆地,也形成了一些厚度大的巨型-超大型钾盐矿床或矿床群,沉积类型有化学岩型及碎屑岩型钾矿两类;而大陆板块边缘及其内部,出现裂谷盆地成钾,沉积环境可以从海相到非海相及过渡类型,钾盐沉积规模不等,也可出现超大型矿床,基本属于碎屑岩型钾矿;最后,在大陆板块内部出现典型陆相钾盐沉积。从时代上看,稳定巨型克拉通板块成钾,主要出现于古生代;而板块汇聚时期成钾,主要发生在中生代;裂谷成钾则主要出现在新生代,典型陆相钾盐矿床则出现在第四纪。由此可见,从古生代到新生代,地球表生成钾模式发生了重大转换。从成钾物质来源看,稳定克拉通海盆主要以海水补给为主,特提斯小陆块的海相盆地成钾物质,以海水补给为主,可能存在非海相(以火山活动带来深部物质等)的补给;而裂谷成钾物质补给,则是海相与非海相混合型,甚至一些盆地以非海相物质补给为主。从古生代到中生代,再到新生代,成钾盆地规模快速变小;所形成的钾盐资源量也呈相应递减变化规律。中国小陆块的漂移演化历史受控于全球主要板块的构造演化,其海相盆地成钾作用也应符合世界主要钾盐成矿的基本规律,因此,掌握全球板块对钾盐成矿基本约束规律,有助于研究中国小陆块海相成钾规律,指导中国海相找钾勘查突破。Supergene potash deposits mainly occur in epicontinental sea basins on the continental plates,and their formation is generally controlled by global plates including the scale,boundary characteristics,drift process,paleo-latitude position and paleoclimate of plates during different geological intervals.Huge potash deposits with a large area and great thickness during Paleozoic often occurred in giant epicontinental basins with background of giant stable craton and belong to chemical rock type that potash deposits were formed in chemical-depositional environment with carbonate. Mesozoic potash deposits were mostly concentrated within plate-convergent areas characterized by Tethys realm where huge to large-sized potash deposits or potash deposit groups were formed in smaller-scale marine and marine-terrestrial basins within small continental blocks,and belong to chemical rock type and clastic rock type that potash deposits were formed in clastic-depositional environment with carbonate.Cenozoic potash deposits were dominantly distributed in rift basins occurred along the margin or in interior of continental plates,and can be formed in marine,nonmarine environments or in transitional environment. Whereas,typical terrestrial potash deposits often occurred in interior of continental plates.From the perspective of the forming ages of potash deposits,the formation models of potash deposits had encountered a huge switch,that is,giant stable craton types formed during Paleozoic,plate-convergent（i.e.Tethys realm）types did during Mesozoic and plate rifting type did in Cenozoic,respectively,and aimed the Quaternary,almost all the potash deposits around the world were typically formed in terrestrial environments.Accordingly,the provenance for potash formation in basins also differed from Paleozoic to Quaternary.Seawater during Paleozoic was the main source for potash deposits in marine basin within stable cratons,and during Mesozoic the nonmarine materials（e.g.,deep fluids caused by volcanic activities）were probably ano

关 键 词：板块运动 小陆块 海相 钾盐矿床 成矿模式 

分 类 号：P619.211[天文地球—矿床学]