Coupling sulfur and oxygen isotope ratios in sediment melts across the Archean-Proterozoic transition
Coupling sulfur and oxygen isotope ratios in sediment melts across the Archean-Proterozoic transition
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DOI：
10.1016/j.gca.2021.05.045
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发表时间：
2021-05
影响因子：
5
通讯作者：
J. Liebmann;C. Spencer;C. Kirkland;C. Bucholz;X. Xia;L. Martin;N. Kitchen;L. Shumlyanskyy
中科院分区：
文献类型：
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作者：
J. Liebmann;C. Spencer;C. Kirkland;C. Bucholz;X. Xia;L. Martin;N. Kitchen;L. Shumlyanskyy
太古代-元古代的过渡标志着地球系统发生了根本的地质、生物和大气变化，包括大气的氧化作用（称为大氧化事件; GOE），以及海平面以上大陆的出现。GOE对地球表面环境的影响在地质记录中留下了印记，包括硫同位素的质量无关分馏（S-MIF）的消失。时间重叠的地质和地球化学观测（例如沉积物的氧同位素比的变化和陆上火山活动的增加）意味着大陆的广泛陆上出现与大气氧化是同时代的。在这里，我们提出了三重硫同位素比值的黄铁矿和氧同位素比值的石榴石和锆石在全球套件的太古代和元古代花岗岩类来自部分熔融的沉积原岩。这些地壳熔体记录了石榴石和锆石δ 18 O的平均值从2.3Ga前的7.2‰增加到2.3Ga后的10.0‰。前2.3 Ga花岗岩类显示出小的S-MIF特征，Δ 33 S变化范围为-0.29 ‰ ~ 0.13‰，而后2.3 Ga花岗岩类记录了S-MIF（即Δ 33 S = 0‰）。在同一样品中的硫和氧同位素的签名与锆石U-Pb地质年代学的组合提供了新的见解大陆的出现和古元古代大气氧化之间的潜在因果关系。
The Archean-Proterozoic transition marks a time of fundamental geologic, biologic, and atmospheric changes to the Earth system, including oxygenation of the atmosphere (termed the Great Oxygenation Event; GOE), and the emergence of continents above sea level. The impacts of the GOE on Earth’s surface environment are imprinted on the geologic record, including the disappearance of mass-independent fractionation of sulfur isotopes (S-MIF). Temporally overlapping geologic and geochemical observations (e.g. a change in oxygen isotope ratio of sediments and an increase in subaerial volcanism) imply the widespread subaerial emergence of continents was coeval with atmospheric oxygenation. Here we present triple sulfur isotope ratios in pyrite and oxygen isotope ratios in garnet and zircon in a global suite of Archean and Proterozoic granitoids derived from the partial melting of sedimentary protoliths. These crustal melts record an increase in average garnet and zircon δ18O from 7.2‰ before 2.3 Ga to 10.0‰ post-2.3 Ga. Pre-2.3 Ga granitoids show small S-MIF signatures with Δ33S ranging from −0.29‰ to 0.13‰, whereas post-2.3 Ga granitoids record S-MDF (i.e. Δ33S = 0‰). The combination of sulfur and oxygen isotope signatures in the same sample with zircon U-Pb geochronology provides new insights on a potential causal link between the emergence of continents and Paleoproterozoic atmospheric oxygenation.