Geological Characteristics and Origin of Manganese-silver Associated Deposits in China(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2017年第02期
- Page:
- 194-213
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Geological Characteristics and Origin of Manganese-silver Associated Deposits in China
- Author(s):
- LIANG Hou-peng; FU Yong; XU Zhi-gang; GE Zhi-hua; WEI Shuai-chao
- 1. College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, Guizhou, China; 2. Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China
- Keywords:
- manganese-silver associated deposit; geological characteristic; Yanshanian; formation age; material source; associated relation; metallogenic mechanism
- PACS:
- P618.32;P618.52
- DOI:
- -
- Abstract:
- Manganese-silver deposit, which is an important type of silver deposits with manganese-silver associated, has not been paid much attention. The main types, geological characteristics, mineralogenetic epoch and their relationships with volcanic activity and tectonic of manganese-silver associated deposits in China were introduced. On the basis of the intergrowth and associated combination, the manganese-silver associated deposits can be divided into four types: Mn-Ag, Mn-Ag-Pb-Zn, Fe-Mn-Ag-Pb-Zn and Pb-Zn-Ag-(Mn). Mn-Ag-type and Mn-Ag-Pb-Zn-type manganese-silver associated deposits are dominated; the scales of manganese deposits are often small and medium, while the scales of silver deposits are middle and large. The number of Fe-Mn-Ag-Pb-Zn-type manganese-silver associated deposits is less; the scales of manganese and silver deposits are middle or large in Houjiangqiao of Hunan. The Pb-Zn-Ag-(Mn)-type manganese-silver associated deposit is only Bajiazi; the scale of silver deposit is large, while the scale of manganese deposit is small. The formation ages of manganese-silver associated deposits in China are mainly in Jurassic-Early Cretaceous, which relates to intermediate-acidic intrusive and volcanic activities in Yanshanian; the deposits usually form near or in the volcanic rocks. The distribution of manganese-silver associated deposits is in some specific horizons under the control of Mn-rich and Ag-rich source beds; later magmatic water and meteoric water form a mixture of hydrothermal extraction of Mn and Ag ore-forming materials; these ore-forming hydrotherm migrates along fault, so that the Mn and Ag orebodies are obviously controlled by fault structure. According to the characteristics of S, Pb, H and O isotopes, the metallogenetic materials of manganese-silver associated deposits are from the mixture of hypomagma and shallow materials, and the hypomagma is dominated; the metallogenetic hydrotherm is also from the mixture of magmatic water and meteoric water, and just the ratios of the source materials are different for the deposits. In addition, the reason for Mn and Ag coexistence and the metallogenetic mechanism of manganese-silver associated deposit were discussed. The results show that Mn2+ is a significant reductant of the precipitation of Ag+, Mn2+ is oxidized to form MnO2, Ag+ is reduced to form Ag, which results in the precipitation of Mn and Ag at the same time; thus, manganese hat is a good marker indicating Ag mineralization.
Last Update: 2017-03-31