Element recycling from subducting slabs to arc crust: A review

Spandler, Carl; Pirard, Cassian

doi:10.1016/j.lithos.2013.02.016

Cited by 486 publications

(244 citation statements)

References 162 publications

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“…During the subduction of crustal rocks, the aqueous solution is generated not only by the prograde breakdown of hydrous minerals such as amphibole, biotite, chlorite, lawsonite, muscovite, serpentine, and zoisite with increasing pressure and temperature (e.g., Schmidt and Poli 2003;Rupke et al 2004, Spandler andPirard 2013) but also by the exsolution of molecular water and structural hydroxyl from NAMs (Zheng 2009). While some of these hydrous minerals may be present in small amounts in HP to UHP eclogites, some UHP eclogites may contain neither of these hydrous minerals.…”

Section: Water In Subduction-zone Rocksmentioning

confidence: 99%

“…Fluids released from deeply subducting crustal rocks provide metasomatic agents for mass transfer at the slab-mantle interface in subduction channels (Figure 8a). Reaction of the fluids with the mantle wedge peridotite generates metasomatic mantle domains (metasomes) that are responsible for the enrichment of fluid-mobile incompatible trace elements in arc volcanics (Zheng 2012;Spandler and Pirard 2013;Adam et al 2014).…”

Section: Crust-mantle Interaction In Subduction Channelmentioning

confidence: 99%

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Geochemistry of continental subduction-zone fluids

2014

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The composition of continental subduction-zone fluids varies dramatically from dilute aqueous solutions at subsolidus conditions to hydrous silicate melts at supersolidus conditions, with variable concentrations of fluid-mobile incompatible trace elements. At ultrahigh-pressure (UHP) metamorphic conditions, supercritical fluids may occur with variable compositions. The water component of these fluids primarily derives from structural hydroxyl and molecular water in hydrous and nominally anhydrous minerals at UHP conditions. While the breakdown of hydrous minerals is the predominant water source for fluid activity in the subduction factory, water released from nominally anhydrous minerals provides an additional water source. These different sources of water may accumulate to induce partial melting of UHP metamorphic rocks on and above their wet solidii. Silica is the dominant solute in the deep fluids, followed by aluminum and alkalis. Trace element abundances are low in metamorphic fluids at subsolidus conditions, but become significantly elevated in anatectic melts at supersolidus conditions. The compositions of dissolved and residual minerals are a function of pressure-temperature and whole-rock composition, which exert a strong control on the trace element signature of liberated fluids. The trace element patterns of migmatic leucosomes in UHP rocks and multiphase solid inclusions in UHP minerals exhibit strong enrichment of large ion lithophile elements (LILE) and moderate enrichment of light rare earth elements (LREE) but depletion of high field strength elements (HFSE) and heavy rare earth elements (HREE), demonstrating their crystallization from anatectic melts of crustal protoliths. Interaction of the anatectic melts with the mantle wedge peridotite leads to modal metasomatism with the generation of new mineral phases as well as cryptic metasomatism that is only manifested by the enrichment of fluid-mobile incompatible trace elements in orogenic peridotites. Partial melting of the metasomatic mantle domains gives rise to a variety of mafic igneous rocks in collisional orogens and their adjacent active continental margins. The study of such metasomatic processes and products is of great importance to understanding of the mass transfer at the slab-mantle interface in subduction channels. Therefore, the property and behavior of subduction-zone fluids are a key for understanding of the crust-mantle interaction at convergent plate margins.

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Section: Water In Subduction-zone Rocksmentioning

confidence: 99%

Section: Crust-mantle Interaction In Subduction Channelmentioning

confidence: 99%

Geochemistry of continental subduction-zone fluids

2014

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“…Fluid flow is an agent of large-scale mass transfer in subduction zones and plays a key role in mantle metasomatism and arc magmatism (Peacock 1990;Bebout 1996Bebout , 2007aBebout , 2007bBebout , 2013Manning 2004;Klemd 2013;Spandler and Pirard 2013). At great depths in subduction zones (15 to 100 km), fluids (aqueous fluids in shallower levels and possibly silicate melts in deeper levels; cf.…”

Section: Introductionmentioning

confidence: 99%

Fluid-metapelite interaction in an ultramafic mélange: implications for mass transfer along the slab-mantle interface in subduction zones

2014

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The slab-mantle interface in subduction zones is a site of tectonic mixing of crustal and mantle rocks. It is the interface for fluid flow of slab-derived components into the mantle wedge. To assess the fluid-rock interaction along the slab-mantle interface, we studied the bleaching of pelitic schist in an ultramafic mélange. The Nishisonogi metamorphic rocks in Kyushu, Japan, comprise ultramafic mélanges intercalated with epidote-blueschist facies schists. The ultramafic mélange consists of tectonic blocks of various lithologies and a matrix of chlorite-actinolite schist and serpentinite. Along the contact with the mélange matrix, pelitic schist blocks are bleached mainly due to the modal increase of albite and the consumption of carbonaceous material. The bleaching is probably attributed to infiltration of Na-rich external fluid from the mélange matrix. Mass balance analysis indicates losses of C, Rb, K 2 O, Ba, Pb, and SiO 2 from the bleached pelitic schist, although Al 2 O 3 , TiO 2 , Sc, Y, Zr, Nb, La, Ce, and Nd remain immobile. This suggests fractionation of large-ion lithophile elements (LILE) and Pb from the high-field-strength elements and rare earth elements during the bleaching. If this ultramafic mélange is analogous to the slab-mantle interface, similar infiltration metasomatism will promote liberation of C, Si, LILE, and Pb from subducting metapelites and enhance metasomatism of the mantle wedge.

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“…Effective release of CO 2 is likely to require open-system decarbonation, flushing of carbonate-rich rocks by aqueous fluids (Zack and John, 2007) or dissolution of carbonates into slab melts or supercritical liquids (Frezzotti et al, 2011). The participation of fluids (CO 2 + H 2 O) derived from the devolatilization of subducting slabs would reduce the peridotite solidus and play critical roles in the fluxing melting of the mantle wedge and global geochemical cycles Spandler and Pirard, 2013).…”

Section: The Effects Of Slab-derived Comentioning

confidence: 99%