Fluid-rock interactions in the Ivrea Zone and the origin of high lower crustal conductivities

Abstract

The preservation of premetamorphic stable isotope heterogeneities in Ivrea Zone metasedimentary lithologies implies large amounts of pervasive fluid flow did not occur. Infiltration of externally derived fluid, in particular of mantle carbon bearing fluid, must have been limited. The quantities of fluid present during retrograde metamorphism in the Ivrea Zone are insufficient to explain the high lower crustal conductivities observed in many lower crustal regions. Petrological and stable isotopic data, from the Ivrea Zone and many other lower crustal terrains, suggest mechanisms of lower crustal conductivity other than conduction through a pore fluid. -from Author