Research on the growth orientation of pyrite grains in the colloform textures in Baiyunpu Pb–Zn polymetallic deposit, Hunan, China

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• 作者：Shang Gao ; Fei Huang ; Xiangping Gu ; Zhenyu Chen ; Miaomiao Xing&#8230
• 关键词：Growth orientation ; Pyrite grains ; Colloform textures ; Baiyunpu ; Pb–Zn polymetallic deposit
• 刊名：Mineralogy and Petrology
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：111
• 期：1
• 页码：69-79
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Mineralogy; Inorganic Chemistry; Geochemistry;
• 出版者：Springer Vienna
• ISSN：1438-1168
• 卷排序：111

文摘

A large number of colloform-textured pyrites were found in Baiyunpu Pb–Zn ore bodies in Xinshao County, Hunan, China. This study investigates the growth orientation of the pyrite grains in these structures by field emission scanning electron microscopy (FE-SEM), in situ micro X-ray diffraction (μXRD) and electron backscatter diffraction (EBSD). The growth proceeded from micro-crystalline cores in the colloform textures. Moreover, the pyrite layers were discrete and separated by locally significant quantities of galena and calcite. The μXRD results suggested clear crystalline characteristics and weakly preferred orientations of the colloform textures. EBSD confirmed that the pyrite grains exist preferred orientations <100 > or <111 > in the layered zones. According to the crystal growth theory, the formation and variation of crystal preferred orientations (CPOs) in pyrite are mainly restricted by the internal crystal structure of the pyrite and depends on the external environment conditions, such as trace element concentrations and the supersaturation degree. We inferred the evolutionary regularity of lattice planes with different indices in the pyrite crystal structure from morphological, compositional and growth orientation information, which reflect the crystal growth history of the colloform pyrite. This study will advance our understanding of the growth processes of colloform pyrite and environmental evolution in the Baiyunpu Pb–Zn polymetallic deposits.