Geochronothermobarometry - new methods for in situ dating of garnet.

PTt-talk 21: Geochronothermobarometry - new methods for in situ dating of garnet. Speaker: Kathryn Cutts (Geological Survey of Finland) Description: Garnet is known as the ultimate metamorphic mineral because it is found in almost all metamorphic rocks and its composition directly relates to the PT conditions that the rock has experienced. The only problem with garnet is the difficulty of getting an age from it. In the past garnet has been dated using the Sm-Nd and Lu-Hf systems by dissolution and column chemistry – this is not a simple process. In fact it is so difficult that trace element analysis of garnet and zircon and monazite is more routinely used to tie the ages of monazite and zircon (both very easy to date) to garnet growth. In the last few years two new methods have been developed for determining garnet age using in situ (laser ablation based) methods. In this presentation I will outline two of these methods (Lu-Hf and U-Pb), present some examples where these have been used and discuss the potential for the future. Hosts: Regiane Fumes, Paulo Augusto, Bruno Ribeiro e Mariana Madeira. Team Petrochronics: Mahyra Tedeschi, Mariana Madeira, Lucas Schiavetti, Hugo de Oliveira, Otávio Sant’Anna, Lucas Tesser, Regiane Fumes e Paulo Augusto.