Formation of oxidized sulfur-rich magmas in Neoarchaean subduction zones
Formation of oxidized sulfur-rich magmas in Neoarchaean subduction zones
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DOI：
10.1038/s41561-022-01071-5
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发表时间：
2022-11
影响因子：
18.3
通讯作者：
Xuyang Meng;A. Simon;Jackie Kleinsasser;D. Mole;D. Kontak;P. Jugo;Jing-Qiao Mao;J. Richards
中科院分区：
文献类型：
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作者：
Xuyang Meng;A. Simon;Jackie Kleinsasser;D. Mole;D. Kontak;P. Jugo;Jing-Qiao Mao;J. Richards
富硫的氧化弧岩浆在现代俯冲带环境中普遍存在。这些岩浆被认为是在俯冲洋壳和上覆沉积物的俯冲变质作用期间释放的流体氧化和水化软流圈地幔时形成的。相比之下，大洋弧型岩浆被认为是相对减少和硫贫，由于海洋硫酸盐的浓度较低，并在缺氧的海洋有限的氧化性海底蚀变前的大氧化事件约24亿年前（Ga）。在这里，我们测量了总硫浓度和相对丰度的S6+，S4+和S2-在锆石托管磷灰石颗粒从钠质和钾质侵入岩从~2.7 Ga东南上级省，加拿大。我们发现，而不是减少和硫贫，新太古代岩浆的硫预算占主导地位的S6+和突然增加到浓度相当于中生代弧岩浆解释开始俯冲在约2.7 Ga，与第一个全球性的地壳生成脉冲。这些研究结果表明，氧化，富硫岩浆形成于俯冲带独立的海洋氧化还原状态，并可能影响海洋-大气和成矿演化的新太古代。
Oxidized, sulfur-rich arc magmas are ubiquitous in modern subduction-zone environments. These magmas are thought to form when the fluids released during prograde metamorphism of subducting oceanic crust and overlying sediments oxidize and hydrate the asthenospheric mantle. In contrast, Archaean arc-type magmas are thought to be relatively reduced and sulfur poor, owing to the lower concentrations of marine sulfate and limited oxidative seafloor alteration in the anoxic ocean before the Great Oxidation Event some 2.4 billion years ago (Ga). Here we measure the total sulfur concentration and relative abundances of S6+, S4+and S2−in zircon-hosted apatite grains from sodic and potassic intrusive rocks from the ~2.7 Ga southeastern Superior Province, Canada. We find that, rather than being reduced and sulfur poor, the sulfur budget of the Neoarchaean magmas was dominated by S6+and abruptly increased to concentrations comparable to Phanerozoic arc magmas following the interpreted onset of subduction at approximately 2.7 Ga, coincident with the first global pulse of crust generation. These findings indicate that oxidized, sulfur-rich magmas formed in subduction zones independent of ocean redox state and could have influenced oceanic–atmospheric and metallogenic evolution in the Neoarchaean.