Title: The geological features and metallogenic setting of the porphyry copper-molybdenum-gold deposits in Tongling ore district
Abstract: Tongling ore district is very famous in the world for its skarn deposits in large scale and quantity. As an important penetration of the ore prospecting in recent years,several porphyry deposits were successively discovered. In this paper,three porphyry deposits from Tongling ore district are chose to study. Based on the detailed field geology and indoor microscopic observation as well as systematical ore geological and geochemical studies,the geological features of the porphyry deposits and their metallogenic geological setting are recognized. It is suggested that the ore-bearing intrusions are high-K calc-alkaline association with high Al,Sr and LREE,which is similar to the geochemical signatures of adakite. The ore-bearing intrusions are fine-middle grained texture,seldom porphyritic texture,which implies the intrusions intruded in middle-shallow depth. The wall-rock of the ore-bearing intrusions are usually sandstone,sandshale or chert,show their dense texture is favorable to close the metallogenic fluids. The alteration types developed in the ore-bearing intrusions are mainly K-silicatization,beresitization( agillization) and propylitization,but they are different in three different deposits. These characteristics of the alteration assemblages and zoning are similar to those of the world typical porphyry deposits. The paragenetic relationship of three types of the fluid inclusions,liquid-rich phase,vapor-rich phase and daughter mineralbearing multiphase,indicate that the evolution of the metallogenic process may experience pressure dropping and fluid boiling. The oreforming temperatures and salinities of the ore deposits are characterized by the intrusion-related hypothermal system with high temperature. Combining with the discussion of the regional tectonic evolution,it is confirmed that the porphyry deposits in the Tongling ore district belong to continental environmental porphyry deposits,and the metallogeny happened under the dynamic background from compression transformed to tension in the intracontinental orogenic environment. The porphyry deposits,skarn deposits and vein deposits in the ore district are controlled by a unified magmatic hydrothermal system,and they constitute a complete relative metallogenic series.
Publication Year: 2016
Publication Date: 2016-01-01
Language: en
Type: article
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