云南勐海地区离子吸附型稀土矿控矿因素及找矿前景

Ore Controlling Factors and Ore-Search Prospect of Rare-Earth Deposits of the Ion Adsorption Type in the Menghai Area,Yunnan Province

云南勐海地区地处临沧-勐海(岩浆弧)Fe-Pb-Zn-Au-Ag-Sn-Sb-Ge-REE矿带(Ⅳ9)南段,近年来该区发现多个离子吸附型稀土矿床。为查明勐海地区离子吸附型稀土矿床控矿因素,指导后续找矿工作,本文在野外地质调查和室内综合整理分析的基础上,对勐海地区离子吸附型稀土矿床的成矿地质背景和成矿特征进行了初步研究,探讨了本区离子吸附型稀土矿床控矿因素与找矿前景。研究表明,勐海地区离子吸附型稀土矿床是以轻稀土为主的稀土矿,其成矿母岩为晚三叠世临沧花岗岩,次生富集成矿于新生代以来;其矿床的形成不仅受成矿母岩、地球化学、构造等内在因素的影响,亦受地形地貌、气候和植被等外在因素的控制,在勐海回龙卡-帕宫苏胡一带形成一条北西-南东向的稀土矿富集带。结合1∶5万矿调工作成果,认为勐海地区成矿地质条件优越,具有很大的离子吸附型稀土矿找矿前景。

The Menghai area,Yunnan Province is located in the southern part of the Lincang-Menghai(magmatic arc)Fe-Pb-Zn-Au-Ag-Sn-Sb-Ge REE ore belt(Ⅳ9).In recent years,several rare-earth deposits of the ion adsorption type have been found in this area.The purpose of this work is to clarify the ore controlling factors of these deposits,guiding the follow-up prospecting work.On the basis of field geological surveys and indoor comprehensive analysis,a preliminary study was made on the metallogenic geological background and metallogenic characteristics of rare-earth deposits in the Menghai area,and their ore controlling factors and ore-search prospect were discussed.Research suggests that the deposits in the Menghai area are dominated by light rare-earth elements,their parent rocks are Late Triassic Lincang granite,and secondary enriched mineralization occurred since Cenozoic time.The formation of the deposits was not only affected by the internal factors such as ore-forming parent rock,geochemistry and structure,but also controlled by the external factors such as topography,climate and vegetation.A NW-SE-trending REE enrichment zone developed around the Huilongka-Pagongsuhu area of Menghai.Combined with the results of 1∶50000 ore survey,it is considered that the ore-forming geological conditions in the Menghai area are superior,and there is a good ore-search prospect for ion adsorption type rare-earth deposits.