Mineralogical Evidence for Hydrothermal Uranium Mineralization: Discovery and Genesis of the Uranyl Carbonate Minerals in the BLS U Deposit, SW Songliao Basin, Northeast China

Bo Ding; Hongxu Liu; Deru Xu; Linfei Qiu; Weihong Liu

doi:10.3390/min13030339

Minerals (Feb 2023)

Mineralogical Evidence for Hydrothermal Uranium Mineralization: Discovery and Genesis of the Uranyl Carbonate Minerals in the BLS U Deposit, SW Songliao Basin, Northeast China

Bo Ding,
Hongxu Liu,
Deru Xu,
Linfei Qiu,
Weihong Liu

Affiliations

Bo Ding: State Key Laboratory Breeding of Nuclear Resource and Environment, East China University of Technology, Nanchang 330013, China
Hongxu Liu: CNNC Key Laboratory of Uranium Resource Exploration and Evaluation Technology, China Beijing Research Institute of Uranium Geology, Beijing 100029, China
Deru Xu: State Key Laboratory Breeding of Nuclear Resource and Environment, East China University of Technology, Nanchang 330013, China
Linfei Qiu: State Key Laboratory Breeding of Nuclear Resource and Environment, East China University of Technology, Nanchang 330013, China
Weihong Liu: CNNC Key Laboratory of Uranium Resource Exploration and Evaluation Technology, China Beijing Research Institute of Uranium Geology, Beijing 100029, China

DOI: https://doi.org/10.3390/min13030339
Journal volume & issue: Vol. 13, no. 3
p. 339

Abstract

Read online

Diabase intrusions have been widely found in sandstone-type U deposits of the southwestern Songliao Basin, indicating diabase-related hydrothermal fluids might play an important role in this type of U mineralization. The first discovery of U-bearing carbonate minerals in the BLS U deposit provides an opportunity for understanding hydrothermal U mineralization and its relationship to diabase intrusions. U-bearing carbonate minerals occurred as thin shells generally ringing ankerite and then surrounded by colloidal pyrite through examination of scanning electron microscopy and energy dispersive spectroscopy. They can be interpreted as uranyl carbonate minerals, with the empirical formula of Ca2.7Fe0.9Mg0.4 (UO2) (CO3)5•9.6H2O, based on infrared absorption spectroscopy and electron microprobe. The formation of uranyl carbonate minerals is most likely related to the CO2-rich hydrothermal fluids from diabase intrusions according to its occurrence state, but the key factors are that the Ca-UO2-CO3 ternary complexes should have been produced in ore-forming hydrothermal fluids and adsorption of ankerite on ternary complexes. Thereby, a potential diabase-related hydrothermal U mineralization model for sandstone-type U deposits can be proposed. The ore-forming fluids that originated from diabase-related hydrothermal are formed through continuously extracting the adsorbed U6+ and dissolving the early U minerals. Then, U in the ore-forming hydrothermal fluids was migrated and transported probably either as uranyl carbonate ions or as Ca-UO2-CO3 ternary complexes. The former is easy to precipitate in the form of pitchblende dispersed in the fossil wood cells, ringing pyrite, and occurring along the edge of adsorbents at the site of reducing capacity change, while the latter will extremely inhibit the reduction of U6+, eventually leading to the precipitation of uranyl carbonate minerals ringing ankerite by adsorption. The above research results can provide mineralogical evidence for hydrothermal U mineralization in sandstone-type U deposits of the Songliao Basin.

Published in Minerals

ISSN: 2075-163X (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science: Geology: Mineralogy
Website: https://www.mdpi.com/journal/minerals

About the journal

Abstract

Keywords