The subduction water cycle is a key process for understanding the long-term evolution of surface water, arc volcanism, continental growth, mantle hydration and convection. Much of our current understanding of volatile recycling comes from studies in the Pacific and Indian Oceans where fast-spread oceanic lithosphere is subducted. In this talk I will present results from project VoiLA– a NERC-funded large grant that targeted the Lesser Antilles subduction system in the slow-spread Atlantic. One of the project challenges was to estimate the incoming hydration and predict its spatial variability. To do this we collected a 380-km long, ridge-parallel active-source profile with closely-spaced ocean-bottom seismometers to give a high-quality dataset. We recorded sufficient converted S-waves to distinguish between hydrated serpentine and unhydrated lower crustal igneous rocks, allowing us to estimate the chemically bound water content for the first time. The pattern of hydration is highly variable and poorly correlated with fracture zones, as predicted by studies in the Pacific. On average the bound water content of the Atlantic crust is four times that of the Pacific crust. Implications for the Lesser Antilles arc will be discussed.
Further information can be found here:
Li, L., Collier, J.S. et al., (2025) “Estimating excess bound water content due to serpentinisation in mature slow-spread oceanic crust using P- and S-waves” Nat Comms. DOI: 10.1038/s41467-025-62052-x
Li, L., Collier, J.S., et al., (2024) “Downward continued ocean bottom seismometer data show
continued hydrothermal evolution of mature oceanic upper crust” Geology. DOI: 10.1130/g52329.1
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