These results reveal the existence of a major and short-lived magmatic event in the Variscan belt of Brittany during the Devonian-Carboniferous transition, a feature further highlighted by field evidence.
Beyond the geological implications of these results, U-Pb LA-ICP-MS dating of apatite appears to represent an ideal tool to date small size mafic intrusions.
3) Data Acquisition Machine tuning and data acquisition is performed in the same way as zircon, although sample bracketing is done with a primary apatite standard (usually Madagascar, see below) with monitoring of machine performance done by ablating either a secondary apatite standard, NIST SRM 614 glass, or our in-house SL zircon standard.
Data are first corrected for background and any excess Pb values from ablating NIST SRM 614 glass are used to monitor and correct for ion counter gain, with an average value obtained from analyses at the beginning and end of each run compared to the known NIST SRM 614 Pb isotope composition of 17.842 [Baker et al., 2004].
Their emplacement ages were so far poorly constrained due to the difficulty to date these mafic rocks using either the Ar or the U-Pb methods on classical minerals like mica, plagioclase, or zircon.