216-6 Iron oxides in mineral deposits: critical age indicators?

Session: Geochronology of Critical Mineral Deposits with Special Reference to U-Th-Pb Dating of Common-Pb-Rich Minerals

Presenting Author:

Authors:

Abstract:

 Quantifying when and for how long ore and accessory minerals precipitate to form economic mineral deposits is key to enhancing orebody knowledge and is valuable in exploration targeting. The common iron oxide mineral hematite (α-Fe2O3) has been shown to incorporate significant concentrations of U into its crystal structure and retain radiogenic Pb and He over geological time. Therefore, within ore deposits where iron oxides are the dominant components (e.g., BIF hosted iron ore, IOCG, IOA), hematite is a critical geochronometer for constraining ore genesis from the Archean to recent across several environments.

Recent developments in the application of iron oxide U-Pb geochronology will be presented including the coupling of this method with both low temperature thermochronology and paleomagnetic studies, focusing on major unknowns in BIF-hosted iron ore deposits. We highlight several case studies and provide the first direct U-Pb dates for iron ore across several major deposits demonstrating the utility of iron oxides compared with other, more commonly dated accessory phases which should be considered ‘red herrings’ in ore deposit geochronology.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6637

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.