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Improved calibration procedures and new standards for U - Pb and Th - Pb dating of Phanerozoic xenotime by ion microprobe

Chemical Geology

By:
, , , , and
DOI: 10.1016/j.chemgeo.2004.06.015

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Abstract

Xenotime is a widely occurring mineral that is amenable to U-Pb and Th-Pb dating but often is found as micrometre-sized crystals that can only be dated by in situ microanalytical techniques. Determining accurate ages for Phanerozoic samples, and assessing concordance in older samples, requires accurate determination of Pb/U and Pb/Th; however, ion microprobe data for these ratios are affected by the highly variable trace element composition of xenotime. We have identified calibration procedures, including matrix corrections for the effects of the dominant trace elements U, Th and REE, that provide an accuracy of ???1% for Pb/U and <2% for Pb/Th. Several new standard samples are available that cover a range of compositions, permitting better matching of samples with standards as well as giving control of the matrix effects. However, no chemically homogeneous samples have been identified. ?? 2004 Elsevier B.V. All rights reserved.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Improved calibration procedures and new standards for U - Pb and Th - Pb dating of Phanerozoic xenotime by ion microprobe
Series title:
Chemical Geology
DOI:
10.1016/j.chemgeo.2004.06.015
Volume
209
Issue:
3-4
Year Published:
2004
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Chemical Geology
First page:
295
Last page:
314
Number of Pages:
20