Characteristics and Metallogenic Significance of Fe-Mn Carbonate Minerals in the Erdaokan Ag Deposit, Heilongjiang Province, Northeast China: Constraints from Sm-Nd Geochronology and Trace Elements

• Published in: Minerals (Basel) 2024-07, Vol.14 (7), p.655
• Main Authors: Yang, Yuanjiang, Li, Chenglu, Wang, Zeyu, Gu, Huajuan, Yang, Wenpeng, Yuan, Maowen, Fu, Anzong, Zheng, Bo, Cheng, Zhaoxun, Liu, Baoshan
• Format: Article
• Language: English
• Subjects: Aggregates; Carbonate minerals; Carbonates; Copper; Duobaoshan Cu-Mo-Au mineralization concentrated area; Earth mantle; Electron probe; Electron probe microanalysis; Erdaokan Ag deposit; Fe-Mn carbonate minerals; Geochronology; Geochronometry; Geology; Gold; Gold mines & mining; Information processing; Iron; Lava; Magma; Manganese; Metallogenesis; Mineral deposits; Mineralization; Minerals; Molybdenum; Neodymium; ore-forming fluid evolution; Pattern analysis; Quartz; Rare earth elements; Samarium; Scanning electron microscopy; Scientific imaging; Silver; Silver mines; Sm-Nd isotopes; Trace elements; Triassic; Upper mantle; Zirconium
• ISSN: 2075-163X; 2075-163X
• DOI: 10.3390/min14070655

Fe-Mn carbonate is the dominant mineral in the Erdaokan Ag deposit, which represents the first large independent silver deposit during the Late Triassic Period in the Duobaoshan Cu-Mo-Au mineralization concentrated area of Heilongjiang Province, NE China. The Fe-Mn carbonates in the deposit frequently co-exist with Ag minerals. Thus, the presence of Fe-Mn carbonates plays a crucial role in the ore-formation process, making their analysis essential for obtaining valuable metallogenic information about the Erdaokan deposit. Through microexamination, SEM and EDS analysis, a clear relationship between Fe-Mn carbonate minerals and Ag minerals was established. Furthermore, electron probe microanalysis, LA-ICP-MS, and Sr-Nd isotope tests were conducted to analyze Fe-Mn carbonates for significant metallogenic insights. The distribution pattern of trace elements and rare-earth elements in Fe-Mn carbonates is similar, characterized by Zr depletion (below 0.131 ppm), enrichment of light rare-earth elements, a noticeable deficit of Eu (δEu = 0.06–0.63), and an average Y/Ho value of 34.29, indicating the involvement of upper mantle-derived deep magma in the formation of ore-forming materials. The samples had a Sm-Nd isochron age of 233.7 ± 1.2 Ma, suggesting that the Erdaokan Ag deposit was formed during the Late Triassic Period. This study highlights the significance of Fe-Mn carbonate as a valuable mineral indicator for regional silver prospecting purposes, and confirms the Late Triassic Period as another important metallogenic stage in the Duobaoshan Cu-Mo-Au mineralization concentrated area.