LIU Zhi-chen1,2,3, YANG Kun-guang3,4*, TANG Zi-chen1,3, GUO Yu1,3, CHEN Deng1,3, ZHONG Yue-li 1,3, ZHANG Xiao-dong1,3, FAN Bo1,3, CHEN Yun-ming1,3, DAI Di1,3
(1. The 102 Geological Team, Bureau of Geology and Mineral Resources of Exploration and Development of Guizhou Province, Zunyi 563003, China;
2. Faculty of Resources and Environmental Engineering, Guizhou University, Guiyang 550003, China;
3. Technical Innovation Center of Mineral Resources Exploration Engineering in Bedrock Area of the Ministry of Natural Resources, Guiyang 550003, China;
4. Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China)
Abstract: The northeastern Guizhou region is adjacent to the central Guizhou Uplift. Under the influence and control of the central Guizhou Uplift, this area had undergone influences of the Yunan, Duyun, Guangxi and Yanshanian movements since the Paleozoic Era. The NW-trending fissure developed in brittle limestones of the Early Paleozoic Ordovician Honghuayuan (O1h) and Tongzi (O1t) formations is the ore-bearing structure of fluorite deposits in the northeastern Guizhou, while the NE-trending fault is the ore-conducting structure. In this paper, the genetic relationship between the tectonic deformation and the genesis of fluorite deposits in the northeastern Guizhou has been studied through the study of regional structures, the analysis of typical structures in deposits, and the statistical analysis and eraplanation projection of foliations, lineations and joints. The results show that the Late Cambrian-Early Ordovician Yunan Movement and the Late Ordovician-Early Silurian Duyun Movement resulted in the formmation of ore-bearing and ore-conducting structures in the northeastern Guizhou. The Guangxi movement occurred at the end of the Early Paleozoic had resulted in the uplifting and exposing of the northeastern Guizhou for a long time (Carboniferous to Permian). During this period, normal fault associations were formed, and various fault associations, such as the horst, graben, staircase, radial and pinnate faults, were developed in the Lower Paleozoic strata. These faults were not developed in the overlying Upper Paleozoic strata. At the same time, the NW-trending faults cutting the Cambrian and Silurian strata were developed in the Lower Paleozoic strata, these NW-trending faults were not ore-controlling faults. On the basis of above researches, we have drawn up characteristics of the ore-controlling and not ore-controlling NW-trending faults in the area. The Yanshanian movement resulted in the formation of the trough-like fold association in the northeastern Guizhou. Most of the early formed faults were reversed or shifted during this period. Only a few reworked early faults by the inheriting reactivity had cut the overlying Permian-Triassic strata. In general, the fluorite mineralization in the northeastern Guizhou was only controlled by the early Paleozoic tectonic activities, and the fluorite deposits belongs to the hydrothermal filling type fluorite deposit. The Guangxi and Yanshanian movements only resulted in the transformation and destruction of the early formed deposits.
Key words: fluorite deposit; tectonic movement; structural analysis; the northeastern Guizhou
