Abstract

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Title:: Geotectonic Evolution of Longshoushan Metallogenic Belt in Gansu and Its Control Function on Uranium Mineralization

Author(s):: AN Guo-bao; XIN Cun-lin; YANG Tao; WANG Lu-han; QI Zheng-qiang; 1. No.282 Geological Team, Sichuan Bureau of Geology for Nuclear Industry, Deyang 618000, Sichuan, China; 2. College of Geography and Environment Science, Northwest Normal University, Lanzhou 730070, Gansu, China

Keywords:: tectonic evolution; uranium deposit; metallogenic regularity; control function; metallogenic belt; mineralization period; metallogenic model; Longshoushan 

Abstract:: The geotectonic evolution of Longshoushan metallogenic belt experiences three tectonic periods, including the initial stage and development of Proterozoic Longshoushan margin subsiding belt, and the active uplift of Paleozoic subsiding belt and partial collapse of continental margin belt, and the activity of Meso-Cenozoic fault block. Longshoushan metallogenic belt locates at the southwest margin of North China paleoland, and the paleoland and its margin are the most important uranium metallogenic zones. Uranium mineralization is controlled by geotectonic evolution; accordingly uranium-mineralized process is divided into three metallogenic periods, including Proterozoic, Paleozoic and Meso-Cenozoic. Corresponding with the three metallogenic periods, Longshoushan metallogenic belt form three metallogenic series of uranium mineralization, which are separately related to Lower Proterozoic metamorphic rocks, the crustal remelting granites in Qilian stage and the fault block uplift and sag in Meso-Cenozoic. The metallogenic model of Longshoushan metallogenic belt can be summarized as the pre-enrichment of Lower Proterozoic stratum, the preenrichment of (Luliang stage) pegmatoid alaskite (or the preenrichment of granitoids in Qilian stage), the pre-enrichment of (Tianshan stage) fault structure and hydrothermal alteration, and the industrial enrichment of (Indosinian, Sichuan stage and Himalayan) vein material superimposed.