Plumbing the depths of magma crystallization using 176Lu/177Hf in zircon as a pressure proxy

Abstract Extensional tectonics are marked by shallow magma crystallization depths, whereas compressional associated with deeper depths. This implies that variations in depths can be used to track changes Earth’s dominant tectonic regimes through time. We therefore developed a new “pressure of crystallization” proxy based on the variation 176Lu/177Hf ratio zircon. is controlled zircon fractionation and residual garnet, it monitor evolution crystallizing ascending within crust. The secular characterized cyclical oscillations broadly tune δ18O record periods continental collision supercontinent amalgamation. apparent mean depth zircon-bearing igneous rocks has decreased time over last ~3.0 b.y. linked shallowing primary and/or effect time-integrated erosion geologic record. Prior ca. 3.0 Ga, maxima less clear, perhaps suggesting nature interactions was different Mesoarchean earlier.