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

Sylvain Fallourd (1) , Marc Poujol (2) , Philippe Boulvais (2) , Jean-Louis Paquette (3) , Michel de Saint Blanquat (4) , Philippe Remy

1 GR - Géosciences Rennes
2 Terre, Temps, Traçage
3 LMV - Laboratoire Magmas et Volcans
4 GET - Géosciences Environnement Toulouse

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.

Keywords: Na-Ca metasomatism; Albitization; Pyrenees; Titanite; LA-ICP-MS U-Pb dating

Domains: Earth Sciences

Sylvain Fallourd, Marc Poujol, Philippe Boulvais, Jean-Louis Paquette, Michel de Saint Blanquat, et al.. In situ LA‑ICP‑MS U-Pb titanite dating of Na-Ca metasomatism in orogenic belts: the North Pyrenean example. International Journal of Earth Sciences, 2014, 103 (3), pp.667-683. ⟨10.1007/s00531-013-0978-1⟩. ⟨insu-00965320⟩