High-precision U-Pb data and reference age for Emerald Lake apatite

Area of Science:

• Geochemistry
• Geochronology
• Isotope Geology

Background:

• Apatite is a common accessory mineral used in geochronology.
• Establishing reliable reference materials is crucial for accurate geochronological dating.

Purpose of the Study:

• To assess the suitability of Emerald Lake apatite as a reference material for U-Pb geochronology.
• To provide high-precision U-Pb age data for Emerald Lake apatite.

Main Methods:

• Isotope dilution thermal ionization mass spectrometry (ID-TIMS) was used for U-Pb dating.
• A three-dimensional U-Pb isochron was constructed to determine the age and initial lead composition.

Main Results:

• A precise U-Pb age of 95.2 ± 1.1 Ma was obtained for Emerald Lake apatite.
• Pb-corrected ²⁰⁶Pb/²³⁸U and ²⁰⁷Pb/²³⁵U dates yielded values of 95.18 ± 0.10 Ma and 95.20 ± 0.17 Ma, respectively.
• The initial lead isotopic composition was determined.

Conclusions:

• Emerald Lake apatite is a suitable reference material for U-Pb geochronology.
• The high-precision age data support its use in in situ U-Pb apatite geochronology.
• Samples are available for future research.