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

Macpherson, C.G.

doi:10.1130/g24412a.1

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

Macpherson, C.G.

Authors

Professor Colin Macpherson colin.macpherson@durham.ac.uk
Professor

Abstract

The Philippine Trench marks a nascent plate margin where subduction initiation is propagating from north to south. Magma compositions in the East Philippine Arc record thinning of arc lithosphere as it is eroded from below. Lithosphere is thicker beneath the younger, southern part of the arc causing basaltic magma to stall and fractionate garnet at high pressure. In the mature, northern section basaltic magma differentiates at shallower levels, at pressures where garnet is not stable. Local variations in lithosphere thickness suggest that thinning is rapid and may be piecemeal. Fluctuations in arc lithosphere thickness throughout the history of this margin appear to control spatial and temporal variations in magma fluxes into the arc crust. Varying fractionation depths of hydrous basalt may help explain the andesitic composition of bulk continental crust.

Citation

Macpherson, C. (2008). Lithosphere erosion and crustal growth in subduction zones: Insights from initiation of the nascent East Philippine Arc. Geology, 36(4), 311-314. https://doi.org/10.1130/g24412a.1

Journal Article Type	Article
Acceptance Date	Dec 21, 2007
Publication Date	Apr 1, 2008
Deposit Date	Mar 19, 2015
Publicly Available Date	Mar 19, 2015
Journal	Geology
Print ISSN	0091-7613
Electronic ISSN	1943-2682
Publisher	Geological Society of America
Peer Reviewed	Peer Reviewed
Volume	36
Issue	4
Pages	311-314
DOI	https://doi.org/10.1130/g24412a.1
Keywords	Subduction initiation, Arc lithosphere erosion, Crust growth, Adakitic magmatism, High-Mg# andesite.