柴达木盆地新近纪—第四纪陆相盐湖钾盐成矿机理OA

The Qaidam Basin,located on the northeastern margin of the Tibetan Plateau,is characterized by a"mountain-deep ba-sin"structural framework and Cenozoic sedimentary fill exceeding 10 km,which has given rise to China's largest continental saline-lake potash metallogenic belt,containing over 80％of the nation's proven reserves.Since the Neogene,the basin has experienced multiple phases of tectonic deformation.Under the combined influence of plateau uplift and extreme regional aridification,seconda-ry depressions such as Qarhan,Dalangtan-Heibei,Kunteyi,and Mahai have developed,forming a composite mineralization system dominated by brine-type deposits with the coexistence of solid-liquid mineralization.The potash-forming process is jointly controlled by four-dimensional factors:tectonics,climate,provenance,and sedimentation.Based on a systematic review of tectono-sedimen-tary evolution and paleoclimate changes,this study reconstructs the spatiotemporal distribution and controlling mechanisms of pot-ash mineralization.The results indicate that tectonic differentiation determined the framework of brine accumulation and storage,climate drove evaporation concentration and mineralization rhythms,while provenance supply promotes continuous potassium en-richment through a"deep-shallow coupling"binary mechanism.Combined with lithofacies-palaeogeographic differentiation,deposi-tional centers migrated multiple times during the Pleistocene,leading to progressive aridification and salinization in the northwest-ern Qaidam Basin.Based on the comprehensive analysis of metallogenic factors,the evolution of potash mineralization in the Qaid-am Basin can be divided into five stages:unified paleolake subsidence,multi-depression differentiation,extreme aridification and concentration,fault-controlled inheritance and metallogenic climax,and modern saline-lake cluster.Furthermore,three metallo-genic models are identified:central-sedimentary-center type,foreland thrust-belt-controlled type,and northwestern tectonically controlled type.This evolutionary sequence and model framework not only reveal the dynamic essence of saline-lake potash mineral-ization under the uplift of the Tibetan Plateau,but also provide a theoretical basis and practical guidance for deep brine exploration and the refinement of metallogenic models in China.