Apatite u pb dating

By continuing to use this site, you consent to the use of cookies.We use cookies to offer you a better experience, personalize content, tailor advertising, provide social media features, and better understand the use of our services.Consequently, the U-Pb dates obtained on apatite can be interpreted as the emplacement ages for these mafic intrusions.

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.

Although the closure temperature of apatite is lower than the emplacement temperature of the magma, physical models show that the time needed to solidify and cool these mafic dikes and sills below the apatite closure temperature is basically of the order of 100 years or less.5.1) Mc Clure Mountain apatite fractionation standard (MMap) The Cambrian Mc Clure Mountain syenite of Colorado is well known as the source of the widely used Ar hornblende standard MMhb and apatite from this rock has a published U-Pb TIMS age of 523.5 Ma.Typical self-normalized concordia age uncertainty for 10-12 spots during a typical sample run is between 1.2-2.0% at the 2 sigma level.We use cookies to make interactions with our website easy and meaningful, to better understand the use of our services, and to tailor advertising.For further information, including about cookie settings, please read our Cookie Policy . 1) Challenges to reliable U-Pb dating of apatite U-Pb dating of apatite is made difficult by its generally low U concentrations and hence limited production of measurable concentrations of radiogenic Pb), as well its tendency to incorporate high amounts of common lead during formation and/or recrystallization.