Geological characteristics and genesis analysis of fluorite deposits in Harqin Banner area of Inner Mongolia
ZHANG Chengxin1, SHANG Pengqiang2, JIAO Sen2, WEI Longfei1, ZHAO Han1, JIANG Zhenning1, CAO Guangyuan2, DAI Xiaoguang1, WANG Yanchao1
1. Geology Institute of China Chemical Geology and Mine Bureau, Beijing 100101, China; 2. China Chemical Geology and Mine Bureau, Beijing 100013, China
Abstract:In order to further clarify the genesis of the fluorite deposit in Harqin Banner of Inner Mongolia, and to provide theoretical guidance for the exploration of regional fluorite deposits, the authors discussed the genesis and metallogenic source of fluorite deposits by analyzing the geochemical characters of trace and rare earth elements of fluorite ores and surrounding rocks in typical fluorite deposits, on the basis of systematically summing up the geological characteristics and distribution regulars of fluorite deposits. The content of Cu, Pb and Zn in fluorite is relatively low, and the light rare earth elements(LREEs) are slightly-enriched, with relatively low content of rare earth elements(REEs). It indicates that the fluorite ore-forming fluid in this area is less likely to be of post-magmatic hydrothermal origin. The chondrite-normalized REE distribution patterns of fluorite ores and ore-bearing surrounding rock are similar and synchronous. When the surrounding rock is biotite-monzonitic granite, the REE distribution curves of fluorite and surrounding rock ore in good agreement with these of biotite in South China, indicating that the REEs in fluorite may mainly come from the destroyed biotite. It indicates that this kind of fluorite ore-forming material mainly comes from leaching and extraction of surrounding rock by geothermal water fluid. Combining with the research results of H-O and S isotopes of fluorite deposits in Linxi area in the northern part of the study area, the authors think that the genetic type of fluorite deposits in Harqin Banner area is a hydrothermal vein filling type with atmospheric rainfall.