organisms, geologists employ a variety of techniques.
The age of apatite grains can be calculated by plotting their U-Pb isotopic composition to form a discordia line.
Apatite has a lower closure temperature than zircon, i.e., ~400 - 500°C, and so are more easily ‘reset’ by heating than zircons.
The laser ablation pit sizes ranged from 30 to 40 μm in diameter.
Laser-induced time-dependent fractionation is corrected by normalizing measured ratios in both standards and samples to the beginning of the analysis using the intercept method.
In this study we used LA-ICP-MS (laser ablation-inductively coupled plasma-mass spectrometry) to determine U-Pb ages of 5 zircon samples of known age (˜1800 Ma to ˜50 Ma) in order to determine the reproducibility, precision, and accuracy of this geochronologic technique.