TY - JOUR
T1 - Improved calibration procedures and new standards for U-Pb and Th-Pb dating of Phanerozoic xenotime by ion microprobe
AU - Fletcher, I.R.
AU - Mcnaughton, Neal
AU - Aleinikoff, J.A.
AU - Rasmussen, Birger
AU - Kamo, S.L.
PY - 2004
Y1 - 2004
N2 - 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 similar to1 % 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. (C) 2004 Elsevier B.V. All rights reserved.
AB - 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 similar to1 % 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. (C) 2004 Elsevier B.V. All rights reserved.
U2 - 10.1016/j.chemgeo.2004.06.015
DO - 10.1016/j.chemgeo.2004.06.015
M3 - Article
SN - 0009-2541
VL - 209
SP - 295
EP - 314
JO - Chemical Geology
JF - Chemical Geology
IS - 3-4
ER -