Geochemical and Nd-Hf isotopic constraints on the origin of the ~ 1.74-Ga Damiao anorthosite complex, North China Craton

Abstract

The ~ 1.74-Ga Damiao complex in the North China Craton consists of anorthosite (85%), norite (10%), mangerite (4%) and minor troctolite ( 75%) would have been required to form the parental high-Al gabbroic magma from the lower crust. We propose that the crustal rocks were dragged into the upper mantle during amalgamation of the North China Craton, where the ambient temperature was high enough (> 1271 °C at 12 kbar) to cause extensive melting, producing a deep-seated magma chamber. The melt then evolved through polybaric crystallization, producing anorthositic magmas with abundant suspended plagioclase that were finally injected at mid-crustal depth to form the Damiao complex. © 2009 Elsevier B.V. All rights reserved.link_to_subscribed_fulltex