Yuantong Mao, Liang Zhao, Marco G. Malusà, Stefano Solarino, Silvia Pondrelli, Baolu Sun, Coralie Aubert, Simone Salimbeni, Elena Eva, Stéphane Guillot
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引用次数: 0
Abstract
Fluids in subduction zones can have major effects on subduction dynamics. However, geophysical constraints on the scale and impact of fluid flow during continental subduction are still limited. Here we analyze the VP/VS ratios in the Western Alpine region, hosting one of the best-preserved fossil continental subduction zones worldwide, to investigate the impact of fluid flow during continental subduction. We found a belt of high VP/VS ratios >1.9 on the upper-plate side of the subduction zone, consistent with a partially serpentinized upper-plate mantle, and a belt of unusually low VP/VS ratios <1.7 on the lower-plate side, at depths shallower than 30 km. We propose that these low VP/VS ratios result from a widespread network of silica-rich veins, indicating past fluid flow along the continental subduction interface. Our results suggest that past fluid flow may have reduced the effective stress along the subduction interface thus favoring continental subduction.
期刊介绍:
Science China Earth Sciences, an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China, and published by Science China Press, is committed to publishing high-quality, original results in both basic and applied research.