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Is it possible to date baddeleyite (ZrO2) with the same precision as zircon (ZrSiO4) with CA-ID-TIMS?

Zircon (ZrSiO4) is the most used mineral in geochronology. Recent methods let to date zircon with precision of 1-2% error (Schaltegger et al., 2015) by SHRIMP/SIMS (high-resolution ion microprobe/secondary ion mass spectrometry) and LA-ICP-MS (laser ablation inductively coupled mass spectrometry) with a precision of 1-3.2% (Sundell et al., 2021). In comparison to other methods, CA-ID-TIMS (chemical abrasion isotope dilution thermal ionization mass spectrometry) enables to date zircons with very high precision of only 0.1% error (>10 times more precise than other methods). Zircon cannot be always used for dating, because not all rocks have zircon in their composition. For example, carbonatites do not always contain zircons, but they contain baddeleyite, which also can be applied as a geochronometer. SHRIMP/SIMS and LA-ICP-MS are fast and inexpensive methods used to date different minerals, including baddeleyite. However, the precision of these methods is not adequate to define a sequence of magmatic intrusions. CA-ID-TIMS dating uses a standard chemical abrasion procedure (CA), which was developed especially for zircon and cannot be applied for baddeleyite. Therefore, the CA method must be adjusted for baddeleyite before the dating is possible.

Rioux et al. (2010) designed numerous experiments to adjust chemical abrasion procedures for baddeleyite dating and achieved some positive results. However, the same effective method of treatment for baddeleyite as for zircon has not yet been developed. In this study, we present the first results of experiments with baddeleyite. We significantly reduced the effect of Pb-loss and increased measurement precision to the values of zircon (0.1%).

Details

Author
Daria Voropaeva1, Marion Tichomirowa1
Institutionen
1TU Bergakademie Freiberg, Germany
Veranstaltung
GeoMinKöln 2022
Datum
2022
DOI
10.48380/qkwb-hg78
Geolocation
Eastern Europe