Publication Date:
2023-11-18
Description:
Deformed samples from the Yushu mélange, in the western Jinsha Suture, have been dated by 40Ar/39Ar isotopy on micas and/or amphibole. Rock samples were crushed using standard procedures. Individual grains were handpicked from the 0.5-1-millimeter fraction of the crushed samples. Samples were irradiated in three batches, IR24, IR26 and IR36, at McMaster Nuclear Reactor (Hamilton, Ontario, Canada - https://nuclear.mcmaster.ca/facilities-equipment/facility-list/mcmaster-nuclear-reactor/) in its 8E high neutron flux facility. IR24 IR26 and IR36 lasted 50.967h, 50h and 200.95h with global efficiencies (J/h) of 4.97 x 10-5, 8.25 x 10-5 h-1 and 1.03 x 10-4 h-1. The analytical procedure is described by Ruffet et al. (1991, 1995). The irradiation standard were sanidine TCRs (28.608 ± 0.033 Ma according to Renne et al., 2011) for irradiation IR24 and IR26 and amphibole Hb3gr (1081.0 ± 1.2 Ma according to Renne et al., 2011) for irradiation IR36. Blanks were performed routinely each first or third/fourth run, and are subtracted from the subsequent sample gas fractions. Errors of apparent ages are plotted at the 1σ level and do not include the errors on the 40Ar*/39ArK ratio and age of the monitor and decay constant. The errors on the 40Ar*/39ArK ratio and age of the monitor and decay constant are included in the final calculation of the error margins on the pseudo-plateau and plateau ages. 40Ar/39Ar ages are provided with 2σ errors. Analytical data and parameters used for calculations (e.g. isotopic ratios measured on pure K and Ca salts; mass discrimination; atmospheric argon ratios; J parameter; decay constants) and reference sources are available in Table "Parameters used for Ar-Ar data analysis".
Keywords:
40Ar/39Ar isotopy; Age, error; Age, mineral; Argon-36; Argon-36, error; Argon-37; Argon-37, error; Argon-39; Argon-39, error; Argon-40; Argon-40, error; Argon-40/Argon-39; Argon-40/Argon-39, error; Error, absolute; Event label; Jinsha Suture; Parameter; ROCK; Rock sample; Sample code/label; Step-heating and spot-fusion; Steps; Time in days; YU-14-62; YU-14-63B; YU-14-64; YU-14-68; YU-14-69; YU-15-05; YU-15-06; YU-15-07; YU-15-09; YU-15-11; YU-15-16; YU-15-17; YU-15-19; YU-15-20; Yushu mélange
Type:
Dataset
Format:
text/tab-separated-values, 5487 data points
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