Quenching: An additional model for emplacement of the Iherzolite at Lers (French Pyrenees)

Abstract

Several of the metamorphic tectonite Iherzolites of the French Pyrenees have been emplaced as hot solid bodies at high crustal levels in carbonate sediments. On both sides of the contacts the rocks are brecciated, and the occurrence of kornerupine and sapphirine indicate extremely high temperatures at low pressure. We propose that the Iherzolites were quenched by the endothermic decomposition reaction of the carbonates. The large quantities of CO 2 that were generated caused the brecciation of both carbonates and Iherzolites, as well as the locally developed dynamothermal metamorphic aureole.