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DOI	10.1016/j.epsl.2020.116494
	Sulfur isotope behavior during metamorphism and anatexis of Archean sedimentary rocks: A case study from the Ghost Lake batholith, Ontario, Canada
	Bucholz C.E.; Biasi J.A.; Beaudry P.; Ono S.
发表日期	2020
ISSN	0012821X
卷号	549
英文摘要	Recycling of surface-derived sulfur into the deep earth can impart distinct sulfur isotope signatures to magmas. The details of sulfur transfer from sedimentary rocks to magmas (and ultimately igneous rocks) through metamorphism and devolatilization and/or partial melting, however, is difficult to trace. To understand this process in detail we studied multiple-sulfur isotope compositions of sulfides in the Archean (c. 2685 Ma) Ghost Lake batholith (GLB) and its surrounding host metasedimentary rocks of the Superior Craton (Ontario, Canada) by high spatial resolution secondary ion mass spectrometry, complemented by high-precision gas source isotope ratio mass spectrometry measurements. The GLB comprises strongly peraluminous biotite+cordierite, biotite+muscovite, and muscovite+garnet+tourmaline granites to leucogranites, which are thought to represent the partial melts of surrounding metagreywackes and metapelites. The metasedimentary rocks display a range of metamorphic grades increasing from biotite-chlorite (280-380 °C) at ∼5 km away from the GLB to sillimanite-K-feldspar grade (∼660 °C) immediately adjacent to the batholith, thus providing a natural experiment to understand sulfur isotope variations from low- to high-grade Archean sedimentary rocks, as well as granites representative of their partial melts. We find that metasedimentary sulfide δ34S values increase with progressive metamorphism at most 2-3‰ (from −1‰ up to +1 to +2‰). An increase in δ34S values in pyrrhotite during prograde metamorphism can be explained through Rayleigh fractionation during pyrite desulfidation reactions. Pyrite from all but one of the granite samples preserve δ34S values similar to that of the high-grade metasedimentary rocks, indicating that partial melting did not result in significant fractionation of δ34S. The exception to this is one granite sample from a part of the batholith characterized by abundant metasedimentary inclusions. This sample contains pyrite with heterogeneous and low δ34S values (down to −16‰) which likely resulted from incomplete homogenization of sulfur between the granitic melt and metasedimentary inclusions. Small (several tenths of a permil), mostly positive Δ33S are observed in both the metasedimentary rocks and granites. Our results suggest that Archean strongly peraluminous granites could be a high-fidelity archive to quantify the bulk sulfur isotope composition of the Archean siliciclastic sediments. Further, our findings indicate that subduction of reduced sulfur-bearing sediments in the Archean with δ34S at or near 0‰ should result in release of sulfur-bearing fluids in the mantle wedge with similar values (within a few permil). S-MIF (if initially present in Archean surface material) may be preserved during this process. However, the absence of S-MIF in igneous rocks does not preclude assimilation of Archean sedimentary material as either S-MIF may not be originally present in the Archean sedimentary sulfur and/or homogenization or dilution could obscure any S-MIF originally present in assimilated Archean sediments. © 2020 Elsevier B.V.
关键词	anatexis Archean granite metasedimentary rocks sulfur
英文关键词	Biotite; Feldspar; Granite; Isotopes; Lakes; Melting; Metamorphic rocks; Mica; Pyrites; Secondary ion mass spectrometry; Sedimentology; Sediments; Sulfur compounds; High spatial resolution; Isotope ratio mass spectrometry; Metasedimentary rocks; Multiple sulfur isotopes; Natural experiment; Rayleigh fractionation; Siliciclastic sediments; Surface materials; Sedimentary rocks; anatexis; Archean; batholith; granite; isotopic composition; metamorphism; partial melting; sediment chemistry; sedimentary rock; spatial resolution; sulfur isotope; Canada; Ontario [Canada]
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202515
作者单位	California Institute of Technology, Pasadena, CA 91125, United States; Massachusetts Institute of Technology, Cambridge, MA 02139, United States
推荐引用方式 GB/T 7714	Bucholz C.E.,Biasi J.A.,Beaudry P.,et al. Sulfur isotope behavior during metamorphism and anatexis of Archean sedimentary rocks: A case study from the Ghost Lake batholith, Ontario, Canada[J],2020,549.
APA	Bucholz C.E.,Biasi J.A.,Beaudry P.,&Ono S..(2020).Sulfur isotope behavior during metamorphism and anatexis of Archean sedimentary rocks: A case study from the Ghost Lake batholith, Ontario, Canada.Earth and Planetary Science Letters,549.
MLA	Bucholz C.E.,et al."Sulfur isotope behavior during metamorphism and anatexis of Archean sedimentary rocks: A case study from the Ghost Lake batholith, Ontario, Canada".Earth and Planetary Science Letters 549(2020).