Dating a sedimentary manganese ore deposit using U-Pb geochronology of hausmannite (Mn3O4) by LA-ICP-MS: An example from Heqing Mn deposit, Yunnan Province, Southwestern China

• Published in: Ore geology reviews Vol. 183; p. 106711
• Main Authors: Li, Wen-Tian, Jiang, Shao-Yong, Su, Hui-Min, Huang, Qin, Pi, Dao-Hui, Wang, Wei, Xiao, Shugang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2025
• Subjects: LA-ICP-MS; Mn oxides; Sedimentary Mn deposits; U-Pb dating; LA-ICP-MS; Sedimentary Mn deposits; Mn oxides; U-Pb dating
• ISSN: 0169-1368
• DOI: 10.1016/j.oregeorev.2025.106711

[Display omitted] •We developed an in-situ U-Pb dating method for Mn oxides.•Heqing Mn deposit shows a hausmannite 207Pb-corrected age of 229 ± 4.5 Ma.•This method can be applied to investigate global sedimentary Mn deposits throughout geological history. Accurately dating sedimentary manganese (Mn) deposits remains challenging due to the scarcity of suitable geochronometers. Mn oxide minerals—which host relatively high uranium (U) and low lead (Pb) concentrations—offer significant potential as a viable geochronometric tool.In this study, we report the first accurate direct measurements of in-situ U-Pb ages of hausmannite (Mn3O4) from the Heqing sedimentary Mn deposit (Yunnan Province, Southwestern China), obtained via laser ablation-inductively coupled mass spectrometry (LA-ICP-MS). The U-Pb age of 229.5 ± 4.5 Ma for U-bearing hausmannite aligns remarkably with the 226 ± 3.4 Ma age of interbedded basalt in the Late Triassic Mn-bearing Songgui Formation, confirming a sedimentary-diagenetic origin for this deposit. This concordance validates Mn oxide U-Pb geochronology as a novel and reliable method for dating sedimentary Mn deposits. Furthermore, these ages provide direct support for the oxic ore genetic model, indicating primary deposition of Mn as oxides in sediments. By enabling direct dating of hausmannite and other Mn oxides, this research fills a critical gap in Mn mineralization chronology. Applied globally to sedimentary Mn deposits across geological time, and leveraging Mn’s redox sensitivity, this method promises new insights into Earth’s exogenic environmental evolution.