Research On The Fluorite Metallogenic Geological Conditions And Prognosis In Gannan Area

Gannan area, located in the compound position of Nanling Structure Belt and the north north east going Mt. Wuyi Structure Belt, whose geotectonic lying on the Huaxia Plate– the inner part of the subduction zone between Eurasia Plate and marginal Pacific Tectonic Domain, is a major fluorite metallogenic area in Jiangxi Province as well as Southeast China. However, research on the metallogenic regularity and metallogenic prognosis of this area have been done inadequately by now and thus there exists a bottleneck which checks the exploration of the mineral resources in this area.This article, guided by modern theories of mineralization and metallogenic prognosis, makes a comprehensive analysis on the information about the stratum, structure, magma rocks and characteristics of fluorite mineralization fluid of the Gannan fluorite metallogenic area. Combined with field investigation and the results of work on metallogenic regularity and metallogenic prognosis of the Gannan Fluorite ore, it delineates a prospect forecast area and provides guidance for the exploration work in this area.Studies on the metallogenic regularity of Gannan fluorite ore show that fluorite deposit have a lot to do with Yanshanian orogenic movement, especially with the geological activities in Late Yanshanian. Most of the deposit ages belong to Late Cretaceous. The Sinian System and Cretaceous System had a clear dominating control over the surrounding rocks of the fluorite deposit. The reason that the formation of the fluorite deposit in Gannan area is closely related to the Biotite Granite (mainly Granite in early Yanshanian) is that Yanshanian Granite, Biotite Granite in particular, is the major carrier of F. Obviously controlled by Fault Structure, most of the ore-bearing Faults in this area run north east or north north east. Judged by the nature of Faults, Compression and Scissor Fault is more favourable for mineralization because of its stability. The fluorite mineralization liquid came from the surface water (atmospheric precipitation), which formed ore-forming solution by changing into geothermal water and extracting minerals from the rocks, and eventually formed the deposit. Research on the mineral inclusion shows that the temperature varies between 102°C and 378°C. Among them the degrees between 130 and 190 appear most frequently and are the most favourable temperatures for fluorite metallization. Therefore, the deposit is classified as epithermal hydrothermal deposit formed in medium-low temperature.Through systematic research on the metallization controlling conditions and metallogenic regularity, this article focuses on the major ore-controlling factors and, with the mathematical statistics methods of integrated sorting and weighing, makes mineralization forecast on four major mineralization belts in Gannan area: the belt across three counties in southern Gannan, the Ruijin-Huichang belt, the Xinguo-Ningdu belt, and the Chongyi-Shangyu belt.