Petrological Characteristics Of The Lidongshan PD1 Profile In Huangbi Mine District, Yanshan County, Jiangxi Province

There are rare outcrops in the southeast of China, not to mention the fresh outcrop section which crosses several stratigraphic units. The Lidongshan PD1 tunnel in Huangbi Lead and Zinc Mine district, Qianshan, Jiangxi province provides such conditions. The Lidongshan PD1 tunnel, which is one of the best artificial outcrops in the study area at present, locates in the Shengmikeng Lead and Zinc mining section in Huangbi. The tectonic structure of Shengmikeng Lead and Zinc mining section is in the neighboring area of Yangtze plate and Cathaysian plate, also at the northern Wuyi uplift in the south side of Pingxiang - Guangfengshen fault zone; in the northwestern side of Haunggang volcanic basin which is in the east of Mesozoic volcanic rock belt. Shengmikeng lead-zinc deposit is hosted in the J3e volcanic rocks, and the discovery is of important exploration significance.In previous geological study, less has been done about Lidongshan PD1 tunnel, and controversial problems still exist on some important basic geological issues. In this paper, based on previous work, Lidongshan PD1 profile selected as the study object, I will use knowledge in the study of petrography, rock chemistry, geochemistry and isotopic dating to establish the rock types and stratigraphic contacts in this area, and a further study on the relationship of igneous rock and mineralization in the region will be done.Research shows that igneous rock in Huangbi district is made up of dacite, dacitic rhyolite, rhyolitic ignimbrite, rhyolitic crystal tuff debris rhyolitic lava and tuff breccia, cal-alkaline series are their main body. From the structural sense, the preliminary analysis shows that in the section of Lidongshan PD1, the sandstone is in the anticline area, with the gray-green rhyolitic tuff breccia in the syncline area, and the biotite plagioclase gneiss is thrust from the deep follow-up. U-Pb zircon dating indicates the formation age of Lidongshan PD1 profile rhyolitic ignimbrite is about 133Ma, the formation age of the pyroclastic breccia rock contained in Rhyolitic ignimbrite is about 147Ma, Speculated that there are two magmatic activity in the area at least. Related trace elements show that the tectonic setting of volcanic rocks in this area is the active continental margin, The rhyolitic rocks reflects its structure in parts of inland away from the trench.The rock in sandstone and volcanic which was used to think was the mafic dikes of rock, identified by the microscope, not dykes, but the altered rock, and no difference with the surrounding rock.It was chlorite and kaolin-based. Almost all fractures of the profiles are saw mineralization. At the Shengmikeng PD1, PD2 tunnel about 600m above Lidongshan PD2 tunnel, there is no silver mineralization was found in the original halo of the rock, but under the level department 600 meters , it is easy to see silverv mineralization . These phenomena show that it is advantageous for prospecting under the tunnel.