The seismic mid-lithosphere discontinuity

Lithospheric low-velocity zones associated with a magmatic segment of the Tanzanian Rift, East Africa

“…Olugboji et al (2013) show that the reduction of velocity produced by EAGBS is recordable by P-receiver functions, depending on the sharpness of the velocity contrast created. This process has already been proposed to explain mid-lithospheric discontinuities (MLD Faul & Jackson 2005;Selway et al 2014) but gradually leads to diffusion creep processes with increasing temperature (Lee et al 2011). EAGBS is then usually restricted to uppermost mantle depth, even if the presence of a secondary phase of low viscosity (e.g.…”

Origins of cratonic mantle discontinuities: A view from petrology, geochemistry and thermodynamic models

“…4 Selway et al, 2015). It is clear, however, that the peculiarities of cratonic lithosphere composition and construction -cool geothermal gradients, compositional and rheological stratification, multiple metasomatic overprints in the course of their long existence -offer myriad possibilities for the generation, modification, translation and even obliteration of such discontinuities in ancient lithospheric keels.…”

“…In particular the presence of atypical phases in primitive mantle, such as amphibole, phlogopite, carbonates, Ti minerals and others ("modal metasomatism";Harte, 1983) attests to the former presence of fluids or melts that significantly affected the mantle lithosphere and possibly changed its thermophysical properties, such as density and seismic velocity (Afonso and Schutt, 2012;Selway et al, 2015;Rader et al, 2015). In addition, peridotite fabric generates anisotropy and therefore affects the seismic response of the mantle (Savage, 1999).…”

“…A plethora of papers has been published on the topic of both, with a focus on geophysical observables (e.g. Selway et al, 2015;Rader et al, 2015;Hopper and Fischer, 2015), and on petrologic-geochemical data (e.g. O'Reilly and Griffin, 2010).…”

Structure of the upper mantle in the north-western and central United States from USArray S-receiver functions

“…According to Yuan and Romanowicz (2010) the North American craton consists of two layers with different chemistry and anisotropy, with the upper layer reaching to about 100 km depth being the Archean lithosphere. Selway et al (2015) reviewed the mechanisms which could cause the MLD.…”