TY - JOUR

T1 - Laser ablation (in situ) Lu-Hf geochronology of epidote group minerals

AU - Yu, Jie

AU - Glorie, Stijn

AU - Hand, Martin

AU - Simpson, Alexander

AU - Gilbert, Sarah

AU - Szilas, Kristoffer

AU - Roberts, Nick

AU - Pawley, Mark

AU - Cheng, Yanbo

N1 - Funding Information: The authors would like to thank the Mineral Exploration Cooperative Research Centre (MinEx CRC) and the Australian Research Council (ARC DP200101881) for funding this research. B. Wade and B. Cave are thanked for their technical support at Adelaide Microscopy. Dr X.F. He is thanked for collecting the monazite data from Yambah. Dr H. Zheng, Mr H.X. Zhang, and Mr X.Q. Yin are thanked for the sharing of allanite/epidote samples. Professor Daniela Rubatto is thanked for thorough and efficient handling of the manuscript during review. Professor St\u00E9phanie Duchene and Dr Lorraine Tual are thanked for constructive feedback during review. Publisher Copyright: © The Author(s) 2024.

PY - 2024

Y1 - 2024

N2 - Epidote group minerals, including allanite, clinozoisite and epidote are common in a range of metamorphic, igneous and hydrothermal systems, and are stable across a wide range of pressure–temperature (P–T) conditions. These minerals can incorporate substantial amounts of rare earth elements (REEs) during their crystallisation, making them potential candidates for Lu–Hf geochronology to provide age constraints on various geological processes. Here we report on a first exploration into the feasibility of in situ Lu–Hf geochronology for epidote group minerals from various geological settings and compare the results with age constraints from other geochronometers. Magmatic allanite samples from pegmatites and monzogranites in the Greenland anorthosite complex, Coompana Province and Qingling Orogen provided dates consistent with magmatic events spanning from c. 2660 to 1171 Ma. In the Qingling pegmatites, a younger phase of hydrothermal allanite was dated at c. 215 Ma, consistent with the timing of regional REE mineralisation. Allanite from the Yambah Shear Zone, Strangways Metamorphic Complex, yielded Lu–Hf age of c. 430 Ma. It predates the garnet and apatite growth at c. 380 Ma, suggesting the Lu–Hf system can be preserved in allanite during prograde amphibolite-facies metamorphism. Additionally, Lu–Hf dates for hydrothermal clinozoisite and epidote are consistent with the timing of hydrothermal alteration and mineralisation in a range of settings, demonstrating the utility of the technique for mineral exploration. Despite the current lack of matrix-matched reference materials, the successful application of laser ablation Lu–Hf geochronology to epidote group minerals offers valuable geochronological insights into various geological processes that can be difficult to access through other geochronometers.

AB - Epidote group minerals, including allanite, clinozoisite and epidote are common in a range of metamorphic, igneous and hydrothermal systems, and are stable across a wide range of pressure–temperature (P–T) conditions. These minerals can incorporate substantial amounts of rare earth elements (REEs) during their crystallisation, making them potential candidates for Lu–Hf geochronology to provide age constraints on various geological processes. Here we report on a first exploration into the feasibility of in situ Lu–Hf geochronology for epidote group minerals from various geological settings and compare the results with age constraints from other geochronometers. Magmatic allanite samples from pegmatites and monzogranites in the Greenland anorthosite complex, Coompana Province and Qingling Orogen provided dates consistent with magmatic events spanning from c. 2660 to 1171 Ma. In the Qingling pegmatites, a younger phase of hydrothermal allanite was dated at c. 215 Ma, consistent with the timing of regional REE mineralisation. Allanite from the Yambah Shear Zone, Strangways Metamorphic Complex, yielded Lu–Hf age of c. 430 Ma. It predates the garnet and apatite growth at c. 380 Ma, suggesting the Lu–Hf system can be preserved in allanite during prograde amphibolite-facies metamorphism. Additionally, Lu–Hf dates for hydrothermal clinozoisite and epidote are consistent with the timing of hydrothermal alteration and mineralisation in a range of settings, demonstrating the utility of the technique for mineral exploration. Despite the current lack of matrix-matched reference materials, the successful application of laser ablation Lu–Hf geochronology to epidote group minerals offers valuable geochronological insights into various geological processes that can be difficult to access through other geochronometers.

KW - Allanite

KW - Clinozoisite

KW - Epidote

KW - in situ geochronology

KW - Lutetium-hafnium

KW - Rare earth elements

U2 - 10.1007/s00410-024-02143-y

DO - 10.1007/s00410-024-02143-y

M3 - Journal article

AN - SCOPUS:85194587239

VL - 179

JO - Contributions to Mineralogy and Petrology

JF - Contributions to Mineralogy and Petrology

SN - 0010-7999

M1 - 62

ER -