矿床地球化学国家重点实验室知识库

The multi-morphology sphalerite has been discovered in the Gengzhuang gold deposit in Shanxi province, China. The mechanism of sphalerite plays a significant role in identifying metallogenesis. Based on geological survey and modern testing, such as petrographic observation, Field Emission Scanning Electron Microscopy (FESEM) and Electron Probe Micro Analysis (EPMA), this research examines the occurrence and chemical composition of sphalerite, which is found in chalcopyrite. We discovered that sphalerite, which is mainly classified into two generations, occurs in the late middle mineralization stage. The second-generation sphalerite are short columnar, quadrangular starlike or dendritic crystal in chalcopyrite, and arrays along two orientations with an included angle of appr. 83 degrees. The fabric of chalcopyrite which contained sphalerite is determined by Electron Backscattered Diffraction (EBSD). We can observe that the crystal plane orientation of chalcopyrite is (112) surface. According to the relationship between surface broken bond properties and its surface energy, the smaller the density of surface broken bonds, the lower its surface energy, and the easier cleavage forms and absorbs species. We reached a conclusion that sphalerite in chalcopyrite resulted from the exsolution of primary chalcopyrite and intermediate solid solution, with the exsolution and growth of sphalerite happen on the (-112) and (332) surfaces of chalcopyrite.