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The adjacent area of Yunnan, Guizhou, and Guangxi provinces, termed the “Golden Triangle”, is one of the world-famous Carlin-type gold ore concentration areas. Previous metallogenic research in this area mainly focuses on the mineralization at the edge of the carbonate platform. However, it rarely involves the interior of the carbonate platform, so the ore body emplacement factors and ore-controlling models are still unclear within the platform. The Longhuo gold deposit, a typical gold deposit located at the platform’s interior in the western Guangxi, was analyzed in detail; the ore-controlling structure and model were fundamentally constructed. The results show that the structures of Longhuo gold deposit can be divided into three periods. (1) The first period is Hercynian sedimentary, which forms the NE-trending F0 syngenetic fault and the platform-trench paleogeographic pattern with the thin-layer siliceous rock-mudstone-siltstone components; the lithology provides the stratigraphic conditions for the formation of the deposit. (2) The second period is Indosinian orogenic, which forms the Longhuo dome and NW-trending Mohao secondary anticline; the anticline provides favorable tectonic conditions for the mineralization. (3) The third period is Yanshan metallogenic characterized by the reactivation of fault F0, which is the main hydrothermal fluid migration channel in the mine area. A large number of parallel secondary normal faults and associated traction folds develop on its western side, and gradually weaken into joints and cleavage zones to the west. These secondary fault-joint-cleavage zones together form the ore-allocating tectonic system of the mine area, guiding the ore-forming fluids to replace and filling the siliciclastic-carbonaceous mudstones and tuffs of Lower Carboniferous Yingtang Formation in Mohao secondary anticline core to form bedded ore bodies. Therefore, the Longhuo gold ore body is jointly controlled by lithology and tectonics. According to the metallogenic model, combined with geophysics-geochemistry-remote sensing data, it is predicted that near the western side of the NE-trending fault F0, the secondary anticline core of the deep part of Longhuo gold deposit is the favorable prospecting target. The ore-bearing stratum is Lower Carboniferous Yingtang Formation. The intersection of fault F0 and the core of Longhuo dome is the favorable prospecting target for mineralization in the periphery of Lower Devonian Yujiang Formation, especially near the unconformity in contact with Cambrian. [ABSTRACT FROM AUTHOR]

The formation and dynamics of slope runoff as karst aquifer recharge process are rarely described specially for the karst area of South China. A spring which discharge epikarst in Yaji experimental site was selected as the research point. The hydrological and hydrochemical dynamic process under different precipitation conditions were obtained through multi-parameter monitoring for a hydrological year. Understanding the dynamic characteristics of runoff formation conditions as well as water source composition of slope flow were formed using hydrological and hydrochemical analyzes. According research there are strong seasonal changes which reflected on the hydrological processes for slope runoff. The total duration of low water level is half of the year, the continuous duration is more than 3 months, and more than 40 days are continuous dry-up throughout one hydrological period. All this indicates instability and variability in slope runoff, and it is necessary to apply certain measures in regulating this process. The hydrochemical dynamics controlled by carbonate dissolution show the merging of runoff from different geological formation. The oscillation of electrical conductivity as well as other indicators show that the runoff formed in bare rock surface plays vary important role. According to the geological structure of slope area regulation through three approaches is proposed: reducing runoff leakage in bare rock area; improving permeability of the epikarst zone; exploring karst conduits in dolines. These measures will help to increase the storage capacity of water tank and improve the utilization efficiency of runoff. [ABSTRACT FROM AUTHOR]

Aiming at the gas generation characteristics of coal measures source rock during the high evolution stage, which cannot be investigated by the common pyrolysis equipment, the TG-MS (thermogravimetry-mass spectrometry) equipment was employed to study the pyrolysis products characteristics of coal, and then hydrocarbon gases generation kinetic behaviors were investigated. The results show that the mass loss of coal can reach 40%, and can be divided into three stages; moisture and adsorbed gas loss, macromolecule bond cracking loss and the poly-condensation of the aromatic structure loss. Methane starts to generate at about 300 °C, and its generating rate reaches the highest value when the temperature reaches 480 °C. The termination temperature of methane is about 850 °C, which is higher than that of other hydrocarbon gases. The aromatic and aliphatic products are controlled by chemical reactions with the same functional groups, and the benzene evolution curve shows double peaks. Kinetic model parameters of hydrocarbon gases from coal degradation and the geological application results show that the generation activation energy increases with the decrease of gas molecular weight, and the lower molecular weight of hydrocarbon gas, the later of the generation time. The hydrocarbon gas generation history also shows that the gas generation time is long and no major generation period. [ABSTRACT FROM AUTHOR]