Yankuang ceshi (Sep 2022)
Mineral Distribution Characteristics of the Pengyang Uranium Deposit Based on Near Infrared Core Spectral Scanning Technology
Abstract
BACKGROUND As an epigenetic deposit dominated by supergene fluid, a sandstone type uranium deposit has many low-temperature minerals. In recent years, the Pengyang uranium deposit, a deep sandstone type uranium deposit, has been discovered in the southwest edge of the Ordos Basin, China. The deposit has the characteristics of large sand body scale, wide uranium mineralization area, large thickness and high grade. Many low-temperature altered minerals have developed, including calcite, gypsum, pyrite, and clay minerals. It is of great significance to study the spatial distribution characteristics of minerals and their relationship with uranium minerals to identify the main sources and properties of ore-forming fluids and their controlling on uranium mineralization. Near-infrared core spectral scanning technology can identify layered silicate minerals such as kaolinite, montmorillonite, sericite, and sulfate minerals such as gypsum and alunite, and carbonate minerals such as calcite and dolomite. OBJECTIVES To study the distribution characteristics of minerals and their relationship with uranium mineralization. METHODS Core samples were scanned by VNIR-SWIR spectroscopy core scanning system and analyzed by TSG 8.0. In addition, the microscopic occurrence characteristics of minerals related to uranium minerals were observed by scanning electron microscopy. RESULTS Minerals such as kaolinite, montmorillonite, illite, chlorite, carbonate, gypsum, and iron oxide were identified in the Luohe Formation. The mineral assemblage of uranium ore section was "illite+gypsum+carbonate", and minor kaolinite was present locally. CONCLUSIONS The uranium-bearing section of the Luohe Formation is mainly a set of alkaline environments in the sedimentary period. However, there is also an injection of reducing acid fluid in the metallogenic period.
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