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Technical note: RA138 Calcite U-Pb LA-ICP-MS primary reference material.
- Source :
- Geochronology; 3/6/2024, p1-16, 16p
- Publication Year :
- 2024
-
Abstract
- A promising primary reference material for U-Pb LA-ICP-MS carbonate dating is analysed and reported here. The new RM is a botryoidal cement (C1) from sample RA138. The sample was collected in outcrop strata of mid-Carboniferous (Uppermost Mississippian, upper Serpukhovian) in northern Spain near La Robla, and multiple aliquots have been meticulously prepared for distribution. The RA138 is characterised by variable U/Pb ratios (from ~1 to ~19) and a relatively high and homogeneous U content (~4 ppm). This material exhibits a low age uncertainty (0.2 %, 2s; unanchored, ID-TIMS), allowing for the establishment of a well-defined isochron, particularly when anchored to the initial Pb ratio using LA-ICP-MS. ID-TIMS analyses of micro drilled C1 cement (17 sub-samples) produce a lower intercept age of 321.99 ± 0.65 Ma, an initial <superscript>207</superscript>Pb/<superscript>206</superscript>Pb ratio of 0.8495 ± 0.0065, and a Mean Square of Weighted Deviations (MSWD) of 5.1. The systematic uncertainty of 1.5 % observed in repeated LA-ICP-MS analyses challenges previous estimations of 2–2.5 % based on repeated analyses of ASH-15D and JT using WC-1 as primary reference material, underscoring the precision and reliability of RA138 for U-Pb dating applications. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 26283697
- Database :
- Complementary Index
- Journal :
- Geochronology
- Publication Type :
- Academic Journal
- Accession number :
- 175878851
- Full Text :
- https://doi.org/10.5194/gchron-2024-7