In situ LA-ICP-MS U–Pb titanite dating of Na–Ca metasomatism in orogenic belts: the North Pyrenean example

Abstract

In the Pyrenees, in association with the rotation of the Iberian plate around Europe during the Mid-Cretaceous, a Na–Ca metasomatism is recognized as a complementary record of the hydrothermal activity that led to Na-metasomatism (albitization) and talc–chlorite mineralization. It affected metasedimentary rocks as well as Hercynian granites. In situ laser ablation ICP-MS U–Pb analyses of titanite grains formed in albitites during metasomatism date the Na–Ca metasomatism between 110 and 92 Ma. The temperature of the Na–Ca metasomatism is estimated to be approximately 550 °C. Both the time constraints and temperature estimates suggest that the Na–Ca metasomatism is related to the low-P high-T North Pyrenean metamorphism.