Study On Gold Mineralization Ore-Forming Rules And Prospecting Direction Of Guilaizhuang Gold Mine In Pingyi County In Shandong Province

In this paper, geological background, metallogenic geological conditions, characteristics and formation relationship of different types of gold deposits in Guilaizhuang ore field were studied, hydrothermal mineralization and origin of subvolcanos were studied, and ore-controlling factors and mineralization rule were summarized. By using already known geological information, metallogenic prediction was carried out, which will point out the prospecting direction.Tongshi complex was potassium-rich alkaline subvolcanic complex formed in early Yanshan period. Magmatic activity provided sufficient heat and hydrothermal for gold mineralization. Major structures with the trend of NNW, NW and EW were main ore controlling structures.subvolcanic dome, and associated ring and radial structures controlled the distribution of the ore bodies. Shancaoyu formation of Tai'shan group was the main source of ore in this area. The upper section of limestone in Cambrian Zhushadong formation was favorable strata for forming magnesium carbonate micro-disseminated gold deposit. Carbonate rocks in upper Cambrian-lower Ordovician were favorable country rocks of crypto-explosive breccia type gold deposits.Guilaizhuang gold ore field was a gold, copper (iron) ore-forming series which had close relation with Mesozoic intrusive rocks in western Shandong. According to geological conditions of ore-controlling, mineralization types and mineralization characteristics of various types of deposit, deposits can be divided into 5 types:crypto-explosive breccia type, magnesium carbonate micro-disseminated type, porphyry type, skarn superimposed type and fragmental altered type. Guilaizhuang gold deposit is the only large scale gold deposit in western Shandong by so far, while Zhuojiazhuang gold deposit was a rare selenium tellurium-rich gold mine in the world. Gold deposits in this area were quartz-fluorite-adularia-sericite-rich tellurium gold deposit associated with shallow epithermal in alkali subvolcanic magma. Forming temperature of gold deposits was mainly in 120℃～250℃, which belongs to low temperature epithermal deposits. Mineralization depth was about 1500m. Forming materials are mainly from Taishan group, and ore-forming fluid has the characteristics of multiple sources. They are mainly composed of magmatic water and meteoric water, accompanied with a small amount of metamorphic water. The forming period of this deposit was about 175～161Ma in middle Jurassic in early Yanshan period.On the basis of carrying out comprehensive gold deposit prediction information with the scale of 1:50000,7 target areas with A class and 3 target areas with B class target areas were chose. It is regarded that there has good prospecting and great exploration potentiality in this area.