Lithosphere erosion and crustal growth in subduction zones: Insights from initiation of the nascent East Philippine Arc

Abstract

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Geochemistry, geochronology and Sr–Nd–Pb–Hf isotopic compositions of Middle to Late Jurassic syenite–granodiorites–dacite in South China: Petrogenesis and tectonic implications

“…In addition, plagioclase might have been another fractionated phase given the relatively low Eu/Eu* values of 0.77-0.80(Table 2), coupled with low Sr/Y ratios and Ba, Sr, Eu contents. The Dafengnao shoshonitic syenites have similar and limited variations in La/Yb (15-16) and Dy/Yb (2.0-2.1) with increasing SiO 2 , consistent with differentiation from a shoshonitic mafic melt by olivine, clinopyroxene and plagioclase dominated fractional crystallization(Macpherson, 2008) (Figs. 5i and 8).…”

Crust and upper mantle structure and its tectonic implications in the South China Sea and adjacent regions

“…It seems that there is a good spatial correlation between the thinned lithosphere and the subduction zone. One possibility is that the subduction-related lithospheric erosion in the mantle wedge causes thinned lithosphere (e.g., Macpherson, 2008). However, it is considered to be unreasonable because the uplift is not centered beneath the volcanic arcs.…”

A case for hornblende dominated fractionation of arc magmas: the Chelan Complex (Washington Cascades)

“…At intermediate pressure, amphibole is an important phase controlling the fractionation of hydrous basalt (Grove et al 2002;Sisson et al 2005). However, looking at arc mafic lavas reaching the surface, amphibole phenocrysts are often rare (Davidson et al 2007;Macpherson 2008), while geochemical arguments mainly based on trace elements point to an important role of amphibole fractionation in the volcanic suite (e.g., Cawthorn et al 1973;Arculus and Wills 1980;Davidson et al 2007;Ulmer 2007). Therefore, igneous amphibole should be present in large amounts and retained somewhere in plutonic roots of island arc crust (Larocque and Canil 2010;Jagoutz 2010).…”