Sulfur loss from subducted altered oceanic crust and implications for mantle oxidation

Walters, Jesse B.; Cruz‐Uribe, Alicia M.; Marschall, Horst R.

doi:10.7185/geochemlet.2011

Cited by 46 publications

(30 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This would agree with previous estimates for slab fluid fO 2 above FMQ þ2 based on Mo isotope data of Raspas eclogites (Chen et al, 2019). More accurate constraints require experimental work, yet Se isotope data can already be attributed to more pronounced minimum redox variations than those required for stability of oxidised S and even Mo in the subducting slab, as supported by other studies arguing for variably pronounced oxidation potentials of fluids in subduction zones (e.g., Bénard et al, 2018;Chen et al, 2019;Piccoli et al, 2019;Li et al, 2020;Walters et al, 2020).…”

Section: Role Of Oxidised Slab Fluidssupporting

confidence: 89%

“…Likewise, different models for sulfate-and 34 S-enriched arc lavas involve either slab-derived sulfur flux into the overlying mantle wedge or crustal assimilation by ascending magma (e.g., Lee et al, 2012;Pons et al, 2016). Recent in situ S isotope investigations of sulfides from exhumed high pressure rocks reveal prograde subduction related mobilisation and reentrapment of S during (partial) sulfide breakdown and recrystallisation, resulting in differences in δ 34 S of almost 40 ‰ (Evans et al, 2014;Su et al, 2019;Li et al, 2020;Walters et al, 2020), with contrasting data for different localities suggesting either oxidised, SO 2 -and CO 2 -rich or reduced, H 2 S-rich fluid involvement (see also Piccoli et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Selenium isotope evidence for pulsed flow of oxidative slab fluids

Koenig¹,

Rosca²,

Kurzawa³

et al. 2021

Geochem. Persp. Let.

View full text Add to dashboard Cite

Isotope systematics of the redox sensitive and chalcophile element selenium (Se) were investigated on exhumed parts of subducted oceanic lithosphere to provide new constraints on slab dehydration conditions during subduction. The samples show increasing δ 82/76 Se NIST3149 with higher abundances of fluid mobile elements, comprising a larger range (−1.89 to þ0.48 ‰) than that of mantle (−0.13 ± 0.12 ‰) and altered ocean crust (−0.35 to −0.07 ‰). Our data point to pronounced, local scale redox variations within the subducting crust, wherein oxidative fluids dissolve sulfides and mobilise oxidised Se species. Subsequently recrystallising sulfides preferentially incorporate isotopically lighter, reduced Se, which shifts evolving fluids and late stage sulfides to higher δ 82/76 Se NIST3149. Redistribution of Se by repeated cycles of sulfide reworking within the subducted crust can be reconciled with episodes of oxidised fluid pulses from underlying slab mantle in modern subduction zones.

show abstract

Section: Role Of Oxidised Slab Fluidssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Selenium isotope evidence for pulsed flow of oxidative slab fluids

Koenig¹,

Rosca²,

Kurzawa³

et al. 2021

Geochem. Persp. Let.

View full text Add to dashboard Cite

show abstract

“…4). For instance, sulfatedominated fluids, derived from subducted oceanic crust at >100 km depth, have the ability to oxidise the sulfide-bearing mantle wedge (e.g., Evans, 2012;Walters et al, 2020), by producing partial melts that rise up further to the mantle-crust boundary (70-40 km depth) and experience multiple phenomena (e.g., Richards, 2003;Evans, 2012) as outlined in Figure 4. At higher crustal levels (5-15 km depth), mixing between sulfatebearing felsic and FeS-bearing mafic melts may lead to S-rich magmas and fluids that are the major source of Au, Cu and Mo in porphyry deposits (Audétat and Simon, 2012).…”

Section: Secondly Our Results Demonstrate That Both S •−mentioning

confidence: 99%

In situ determination of sulfur speciation and partitioning in aqueous fluid-silicate melt systems

Colin¹,

Schmidt²,

Pokrovski³

et al. 2020

Geochem. Persp. Let.

View full text Add to dashboard Cite

Current knowledge of sulfur behaviour in magmas is based exclusively on ex situ analyses. Here we report the first in situ measurement of sulfur speciation and partitioning between coexisting aqueous fluids and silicate melts. These data were acquired using Raman spectroscopy in a diamond anvil cell at 700°C, 0.3-1.5 GPa, and oxygen fugacity in the vicinity of the sulfide-sulfate transition, conditions relevant to subduction zone magmatism. Results show that sulfate and sulfide are dominant in the studied systems, together with the S •− 3 and S •− 2 radical ions that are absent in quenched fluid and silicate glass products. The derived fluid/melt partition coefficients for sulfide and sulfate are consistent with those from available ex situ data for shallow crust conditions (<10 km), but indicate stronger partitioning of these sulfur species into the silicate melt phase with increasing depth. In contrast, both radical ions partition at least 10 times more than sulfate and sulfide into the fluid phase. Thus, by enhancing the transfer of sulfur and associated chalcophile metals from melt into fluid upon magma degassing, S •− 3 and S •− 2 may be important players in the formation of economic metal resources within the redox window of the sulfate-sulfide transition in subduction zone settings.

show abstract

“…There is growing evidence for fluxes of sulphate in fluids during metamorphism both in and outside the subduction zone setting (e.g. Downloaded from https://academic.oup.com/petrology/advance-article/doi/10.1093/petrology/egab005/6122716 by CNRS -ISTO user on 16 February 2021 Pons et al, 2016;Connolly & Galvez, 2018;Walters et al, 2019Walters et al, , 2020. Such aqueous fluids have been described in inclusions trapped in metasomatic veins preserved in ultrahigh pressure eclogite (e.g.…”

Section: Rationalementioning

confidence: 99%

The Role of Sulphur on the Melting of Ca-Poor Sediment and on Trace Element Transfer in Subduction Zones: An Experimental Investigation

Pelleter

Prouteau

Scaillet

2021

Journal of Petrology

View full text Add to dashboard Cite

We performed phase equilibrium experiments on a natural Ca-poor pelite at 3 GPa, 750-1000 °C, under moderately oxidizing conditions, simulating the partial melting of such lithologies in subduction zones. Experiments investigated the effect of sulphur addition on phase equilibria and compositions, with S contents of up to ∼ 2.2 wt. %. Run products were characterized for their major and trace element contents, in order to shed light on the role of sulphur on the trace element patterns of melts produced by partial melting of oceanic Ca-poor sediments. Results show that sulphur addition leads to the replacement of phengite by biotite along with the progressive consumption of garnet, which is replaced by an orthopyroxene-kyanite assemblage at the highest sulphur content investigated. All Fe-Mg silicate phases produced with sulphur, including melt, have higher MgO/(MgO+FeO) ratios (relative to S-free/poor conditions), owing to Fe being primarily locked up by sulphide in the investigated redox range. Secular infiltration of the mantle wedge by such MgO and K2O-rich melts may have contributed to the Mg and K-rich character of the modern continental crust. Addition of sulphur does not affect significantly the stability of the main accessory phases controlling the behaviour of trace elements (monazite, rutile and zircon), although our results suggest that monazite solubility is sensitive to S content at the conditions investigated. The low temperature (∼ 800 °C) S-bearing and Ca-poor sediment sourced slab melts show Th and La abundances, Th/La systematics and HFSE signatures in agreement with the characteristics of sediment-rich arc magmas. Because high S contents diminish phengite and garnet stabilities, S-rich and Ca-poor sediment sourced slab melts have higher contents of Rb, B, Li (to a lesser extent), and HREE. The highest ratios of La/Yb are observed in sulphur-poor runs (with a high proportion of garnet, which retains HREE) and beyond the monazite out curve (which retains LREE). Sulphides appear to be relatively Pb-poor and impart high Pb/Ce ratio to coexisting melts, even at high S content. Overall, our results show that Phanerozoic arc magmas from high sediment flux margins owe their geochemical signature to the subduction of terrigenous, sometimes S-rich, sediments. In contrast, subduction of such lithologies during Archean appears unlikely or unrecorded.

show abstract

Sulfur loss from subducted altered oceanic crust and implications for mantle oxidation

Cited by 46 publications

References 1 publication

Selenium isotope evidence for pulsed flow of oxidative slab fluids

Selenium isotope evidence for pulsed flow of oxidative slab fluids

In situ determination of sulfur speciation and partitioning in aqueous fluid-silicate melt systems

The Role of Sulphur on the Melting of Ca-Poor Sediment and on Trace Element Transfer in Subduction Zones: An Experimental Investigation

Contact Info

Product

Resources

About