Omar Bartoli

Abstract The debate on the origin of water in the Earth’s interior focuses on whether it originates from internal primordial sources or externally from the Earth’s surface via subduction-related processes. Here we report boron isotope data for Middle/Late Permian picrites and basalts from the Emeishan Large Igneous Province in South China. The observed heavy δ11B values (up to +27.6‰) fall outside the range of known mantle compositions, but similar to those of slab serpentinites.

1 Introduction The depth at which plutons and batholiths intrude depends on the interplay between the rheology of magmas, the rheology of the crust and the tectonic regime in a certain area. Constraining intrusion depths is fundamental for tectonic reconstructions of pre-intrusive crustal settings, syn-intrusive deformations and the post-intrusive evolution involving unroofing, exhumation and erosion (e.g., Hejl, Riedl, and Weingartner 2002; Zanchetta, Malusà, and Zanchi 2015; Lu et al. 2020).