Metamorphic chemical geodynamics of subduction zones

Magmatism, mantle evolution and geodynamics at the converging plate margins of Italy

“…Tatsumi et al 1986;Schmidt & Poli 2003;Manning 2004;Bebout 2007Bebout , 2013Gao et al 2007;Antignano & Manning 2008). Among C-O-H volatile species, water is the dominant component and a main element-transfer agent, and its behaviour determines the type and amount of element transfer to the mantle wedge and magma generation in subduction zones (e.g.…”

“…Tera et al 1986;Morris et al 1990;Hacker 2008). Sediments and upper continental crust are much more enriched in incompatible elements than MORB and, therefore, furnish the bulk of incompatible element budget to the mantle wedge (Hermann et al 2006;Bebout 2007Bebout , 2013Hermann & Rubatto 2009;Marschall & Schumacher 2012). They are also able to modify dramatically radiogenic isotopic signatures of mantle peridotite.…”

The geological characteristics of oceanic-type UHP metamorphic belts and their tectonic implications: Case studies from Southwest Tianshan and North Qaidam in NW China

“…However, recent study demonstrates that LILEs and LREEs in the eclogites subducted to 90 km depth are removed finitely, with a minor amount of variation and showing no dramatic change compared with their protolithes. Bebout [43] summarized and constructed some discrimination diagrams to show the variation of these elements with oceanic ridge metamorphism and subduction zone metamorphism.…”

Two types of the crust-mantle interaction in continental subduction zones

“…Fluids liberated from subducting oceanic crust metasomatize the overlying mantle wedge peridotite and trigger its partial melting to form oceanic arc basalts or continental arc andesites, which result in the growth of juvenile crust and even the accretion of continental crust (Ringwood, 1974;Tatsumi and Eggins, 1995); the residual slab material would continue to sink into the deep mantle to affect the mantle chemical compositions (Ringwood, 1982;Allegre and Turcotte, 1986;Hofmann, 1997;Anderson, 2006). Therefore, the oceanic crust entering the mantle by subduction either reacts with the mantle to generate the mantle sources of arc igneous rocks via fluid alteration and melt metasomatism (e.g., Gill, 1981;Allegre, 1982;Hofmann, 1997;Bebout, 2007Bebout, , 2014Spandler and Pirard, 2013), or those of continental basalts by melt-peridotite reaction (e.g., Zhang et al, 2009;Wang et al, 2011;Xu et al, 2012aXu et al, , 2014a.…”

“…The deep subduction of continental crust produces not only the UHP metamorphic rocks, but also brings about the crust-mantle interaction. Therefore, the continental crust can also be recycled into the mantle through deep subduction, and the crust-mantle interaction has now been expanded from oceanic subduction zones to continental subduction zones (Bebout, 2007;Zheng, 2012).…”