Apatite is a common U-bearing accessory mineral with a U-Pb closure temperature of ∼500°C, making U-Pb dating of apatite a potentially valuable thermochronometer.

However, its low U concentration and tendency to incorporate common lead has limited widespread application to destructive isotope dilution methods, Laser ablation–multicollector–ICPMS can be used to overcome the limitations.

Apatite is also used for  Fission-track dating, for determining low-temperature thermal events, typically 0.1 Ma to 2000 Ma. Apatite, contain enough uranium to be useful in dating samples of relatively young age (Mesozoic and Cenozoic) and is mostly used for this technique.

If you know the age of the granitic rocks Proterozoic/ Archean...with reference to what new age/ data you want to do apatite dating.

Please have clarity what you want actually from your study before you proceed.

Thank you.

Dear Raphael,

Apatite, which is common in granitic rocks can be indeed used to put quite very different thermochronological contraints on the thermal history of the rocks you want to study.

Asoori Latha is fully right when she said that it depends on what you wanted to date.

To get high-medium-T contraint, then ICPMS U/Pb analyses will indeed give you the time ellapsed since the rocks cooled down ca. 500-550°C with may reflect the post-emplacement cooling or a subsequent thermal or fluids induced perburbation of the system.

Now, if you want to constraint the late stage of cooling you can used Fission-Track dating or even U-Th/He dating. During on the thermal history of your rocks you may record late exhumation (cooling) stages as low as 50°C.

In any case, i suggest to use combined zircon ages taht can be dated by the same means to give you other slightly differents contraints: almost the emplacement age with ICPMS U/Pb analyses and the age of the cooling below 250°C with the low temperature thermochronology.

Thank you so much Romain. Our intention is to use U/Pb by ICP-MS to get the high-medium-T constraint.