Formation of cratonic mantle keels by arc accretion: Evidence from S receiver functions

Mantle flow deflected by interactions between subducted slabs and cratonic keels

Oceanic lithosphere is rapidly recycled into the mantle through subduction, an important part of the dynamic evolution of the Earth. Cratonic continental lithosphere, however, can exist for billions of years, moving coherently with the tectonic plates. At the Caribbean–South American Plate margin, a complex subduction system and continental transform fault is adjacent to the South American crat...

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...

Mapping the mantle transition zone beneath Hawaii from Ps receiver functions: Evidence for a hot plume and cold mantle downwellings

Hydrous origin of the continental cratonic mantle

We performed melting experiments of hydrous pyrolite at pressures from 3 to 8 GPa and temperatures from 1,100°C to 1,800°C to identify the origin of chemical variation in cratonic garnet peridotites with high contents of magnesian orthopyroxene. In hydrous conditions, the stability field of residual orthopyroxene expands relative to olivine above solidus, and the harzburgitic residue contains l...

Arc-parallel flow within the mantle wedge: Evidence from the accreted Talkeetna arc, south central Alaska

[1] Residual mantle exposures in the accreted Talkeetna arc, Alaska, provide the first rock analog for the arc-parallel flow that is inferred from seismic anisotropy at several modern arcs. The peridotites exposed at the base of the Jurassic Talkeetna arc have a Moho-parallel foliation and indicate dislocation creep of olivine at temperatures of 1000 to >1100 C. Slip occurred chiefly on the (00...