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TTG; electron microprobe; xenotime; U–Th–Pb ages; Bundelkhand Craton; India.

Xenotime is a significant accessory mineral which is being extensively used for precise U–Th–Pb geochronology by Electron Microprobe Analysis (EPMA). This paper presents a protocol for high analytical precision (<3% uncertainties on the measured ages) developed for the accurate estimation of U–Th and Pb content in xenotime using SXFive EPMA at the Department of Geology, Banaras Hindu University, by deploying five spectrometers attached with TAP, LIF, LPET, LTAP and PET crystals. The protocol is applied to the xenotime grains of tonalite-trondhjemite-granodiorite-gneiss (TTG) rocks from the geochronologically well-constrained terrain of the Bundelkhand Craton, central India. The obtained xenotime age 2929$\pm$23 Ma of TTGs is in agreement with the earlier published Neoarchaen 2697$\pm$3 Ma Pb–Pb zircon ages from the same area which validates the authenticity of the analytical method developed at the BHU-EPMA facility.

$\bf{Highlights}$

$\bullet$ Analytical protocol for high precision U–Th–Pb chemical dating of xenotime by EPMA.

$\bullet$ High precision ages from TTG gneiss of the Bundelkhand Craton, Central India.

$\bullet$ Ages distinguishable from earlier reported ages from other techniques and samples.

$\bullet$ Validates the authenticity of the analytical method developed at the BHU-EPMA facility.

HIREDYA CHAUHAN¹ APARAJITA TRIPATHI¹ DINESH PANDIT¹ N V CHALAPATHI RAO¹ TALAT AHMAD²

1. Mantle Petrology Laboratory, Department of Geology, Centre of Advanced Study, Institute of Science, Banaras Hindu University, Varanasi 221 005, India.
2. University of Kashmir, Srinagar, India.

Published

14 October 2020

Manuscript received

10 May 2020

Manuscript revised

17 July 2020

Accepted

17 July 2020

Final version published online

14 October 2020