Nondestructive chemical dating of young monazite using XRF. 2. Context sensitive microanalysis and comparison with Th-Pb laser-ablation mass spectrometric data

Scherrer, Nadim; Engi, Martin; Berger, Alfons; Parrish, Randall R.; Cheburkin, Andriy (2002). Nondestructive chemical dating of young monazite using XRF. 2. Context sensitive microanalysis and comparison with Th-Pb laser-ablation mass spectrometric data Chemical Geology, 191(1-3), pp. 243-255. Elsevier 10.1016/S0009-2541(02)00159-6

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A newly developed XRF-microprobe at the Institute of Mineralogy and Petrology, University of Bern, Switzerland has been applied for precise chemical Th-U-Pb dating of individual monazite grains separated from Pb-free polished petrographic thin sections. The nondestructive nature of the XRF-measurement permitted a comparative study of dating methods by sequentially applying chemical dating by electron microprobe analysis (EMPA), chemical dating by XRF-microprobe analysis, and isotopic Pb-208/Th-232 dating by Laser Ablation Plasma Ionisation Multi-collector Mass Spectrometry (LA-PIMMS) analysis. As an example, the 2sigma precision achieved with the XRF-microprobe for well characterised reference material, monazite FC-1 (TIMS age 54.3 +/- 1 Ma; mu-XRF age 55.3 +/- 2.6 Ma), doubly polished to 30 mum in thickness, is below 5% after 90 min integration time (50 kV; 30 mA) at a spatial resolution of 90 mum. At 38-mum, spatial resolution, the uncertainty is 35% for the same integration time. The sample characteristics are 200-300 ppm of Pb (mu-XRF), 3.8-5.1 wt.% of Th (EMPA), and 0.4-1.4 wt.% U (EMPA). Combined with an electron microprobe and conventional optical microscopy, the XRF-microprobe is thus a competitive low-cost and nondestructive alternative to more costly isotopic methods. The XRF-microprobe is easy to use and maintain. (C) 2002 Elsevier Science B.V All rights reserved.

Item Type:	Journal Article (Original Article)
Division/Institute:	Bern Academy of the Arts Bern Academy of the Arts > Institute Materiality in Art and Culture
Name:	Scherrer, Nadim0000-0002-6576-885X; Engi, Martin; Berger, Alfons; Parrish, Randall R. and Cheburkin, Andriy
Subjects:	Q Science > QE Geology
ISSN:	0009-2541
Publisher:	Elsevier
Language:	English
Submitter:	Nadim Scherrer
Date Deposited:	09 Feb 2021 16:00
Last Modified:	20 Apr 2021 14:41
Publisher DOI:	10.1016/S0009-2541(02)00159-6
Related URLs:	Publisher
Web of Science ID:	000179511500015
Additional Information:	Notes: 620AW Times Cited:10 Cited References Count:22 Date: 2002
Uncontrolled Keywords:	monazite EMPA XRF-microprobe LA-PIMMS Th-U-Pb dating u-pb electron-microprobe age data metamorphism geochronology evolution petrology allanite xenotime gneiss
ARBOR DOI:	10.24451/arbor.13532
URI:	https://arbor.bfh.ch/id/eprint/13532