title: Volcanic-plutonic parity and the differentiation of the continental crust.
abstract: The continental crust is central to the biological and geological history of Earth. However, crustal heterogeneity has prevented a thorough geochemical comparison of its primary igneous building blocks-volcanic and plutonic rocks-and the processes by which they differentiate to felsic compositions. Our analysis of a comprehensive global data set of volcanic and plutonic whole-rock geochemistry shows that differentiation trends from primitive basaltic to felsic compositions for volcanic versus plutonic samples are generally indistinguishable in subduction-zone settings, but are divergent in continental rifts. Offsets in major- and trace-element differentiation patterns in rift settings suggest higher water content in plutonic magmas and reduced eruptibility of hydrous silicate magmas relative to dry rift volcanics. In both tectonic settings, our results indicate that fractional crystallization, rather than crustal melting, is predominantly responsible for the production of intermediate and felsic magmas, emphasizing the role of mafic cumulates as a residue of crustal differentiation.
authors.affiliation: Department of Geosciences, Guyot Hall, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: C Brenhin
authors.initials: CB
authors.lastname: Keller
authors.affiliation: Department of Geosciences, Guyot Hall, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Blair
authors.initials: B
authors.lastname: Schoene
authors.affiliation: 1] Department of Geosciences, Guyot Hall, Princeton University, Princeton, New Jersey 08544, USA [2] Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, California 90095-1567, USA.
authors.forename: Melanie
authors.initials: M
authors.lastname: Barboni
authors.affiliation: Department of Geosciences, Guyot Hall, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Kyle M
authors.initials: KM
authors.lastname: Samperton
authors.affiliation: 1] Department of Geosciences, Guyot Hall, Princeton University, Princeton, New Jersey 08544, USA [2] Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Jon M
authors.initials: JM
authors.lastname: Husson