Cordilleran Benioff zones

Deep crustal anatexis, magma mixing, and the generation of epizonal plutons in the Southern Rocky Mountains, Colorado

“…The progression from early intermediate composition volcanism to later silicic ignimbrite deposition is similar to that observed through multiple cycles in the southern Rocky Mountain volcanic field in southern Colorado (Lipman 2007). The latter is generally considered to be the easternmost expression of the mid-Tertiary "ignimbrite flareup", a period of intense magmatic activity, primarily centered in the western USA, that took place ~25 to 40 Ma (Coney and Reynolds 1977;Armstrong and Ward 1991). The Never Summer igneous complex could represent a significantly smaller and shorter-lived manifestation of this same event.…”

Metasomatized lithosphere–asthenosphere interaction during slab roll-back: Evidence from Late Carboniferous gabbros in the Luotuogou area, Central Tianshan

“…Several distinct mantle components can contribute to continental basalts, such as subcontinental lithospheric mantle, plume-related OIB (oceanic island basalt)-type mantle sources, or depleted MORB (middle oceanic ridge basalt)-type asthenosphere mantle (Garfunkel, 2008;Saunders, 2005). Popular tectonic models for continental volcanism include decompressional melting as a result of lithospheric mantle removal (detachment) and upwelling asthenosphere mantle (Hoernle et al, 2006;Timm et al, 2009), lithosphere extension induced by continental rifting and breakup (McKenzie and Bickle, 1988), high temperature melting of mantle owing to elevated mantle temperature by deep-seated mantle plume head impinging on the lithosphere (Campbell and Griffiths, 1990), and the roll-back and/or foundering of flat-subducted oceanic plateaus or aseismic ridges (Coney and Reynolds, 1977;Li and Li, 2007). Identifying the primary magmas for continental basaltic magmas thus has the potential of deciphering their petrogenesis and related tectonic processes.…”

Middle Jurassic MORB-type gabbro, high-Mg diorite, calc-alkaline diorite and granodiorite in the Ando area, central Tibet: Evidence for a slab roll-back of the Bangong-Nujiang Ocean

“…These special rock types were generally generated under abnormal high temperature that was related to a slab roll-back environment, ridge subduction environment or slab break-off environment. In these environments, the upwelling of asthenosphere will heat the subducting slab (Ayabe et al, 2012;Sato et al, 2014) or subcontinential lithosphere mantle to form the MORB-type gabbros and high-Mg diorites (Coney and Reynolds, 1977;McKenzie and Bickle, 1988). The Zr saturation temperatures indicate that the Ando granodiorites were generated at high temperatures (793-836°C).…”