Trench-parallel anisotropy produced by foundering of arc lower crust.

Supporting Online Material for Trench-Parallel Anisotropy Produced by Foundering of Arc Lower Crust

Constraints from Thorium/Lanthanum on Sediment Recycling at Subduction Zones and the Evolution of the Continents

Arc magmas and the continental crust share many chemical features, but a major question remains as to whether these features are created by subduction or are recycled from subducting sediment. This question is explored here using Th/La, which is low in oceanic basalts (<0 2), elevated in the continents (>0 25) and varies in arc basalts and marine sediments (0 09–0 34). Volcanic arcs form linear...

Differentiation of the continental crust by relamination

a r t i c l e i n f o Crust extracted from the mantle in arcs is refined into continental crust in subduction zones. During sediment subduction, subduction erosion, arc subduction, and continent subduction, mafic rocks become eclogite and may sink into the mantle, whereas more silica-rich rocks are transformed into felsic gneisses that are less dense than peridotite but more dense than the uppe...

Crust and upper mantle of Kamchatka from teleseismic receiver functions

Teleseismic receiver functions (RFs) from a yearlong broadband seismological experiment in Kamchatka reveal regional variations in the Moho, anisotropy in the supra-slab mantle wedge, and, along the eastern coast, Ps converted phases from the steeply dipping slab. We analyze both radialand transverse-component RFs in bin-averaged epicentral and backazimuthal sweeps, in order to detect Ps moveou...

Stability of arc lower crust: Insights from the Talkeetna arc section, south central Alaska, and the seismic structure of modern arcs

[1] One process for the formation of continental crust is the accretion of arc terranes at continental margins. A longstanding problem with this model is that although the composition of the continental crust is andesitic, the majority of arc lavas are basaltic. Moreover, those arc lavas that are andesitic tend to be evolved (lower Mg #) compared to the continental crust. Continental crust can ...