Subducting volcaniclastic-rich upper crust supplies fluids for shallow megathrust and slow slip.

Autor: Gase AC; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA., Bangs NL; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA., Saffer DM; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA., Han S; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA., Miller PK; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA., Bell RE; Department of Earth Science and Engineering, Imperial College London, London, UK., Arai R; Research Institute for Marine Geodynamics, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan., Henrys SA; GNS Science, Lower Hutt, New Zealand., Kodaira S; Research Institute for Marine Geodynamics, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan., Davy R; Department of Earth Science and Engineering, Imperial College London, London, UK., Frahm L; Department of Earth Science and Engineering, Imperial College London, London, UK., Barker DHN; GNS Science, Lower Hutt, New Zealand.
Jazyk: angličtina
Zdroj: Science advances [Sci Adv] 2023 Aug 18; Vol. 9 (33), pp. eadh0150. Date of Electronic Publication: 2023 Aug 16.
DOI: 10.1126/sciadv.adh0150
Abstrakt: Recurring slow slip along near-trench megathrust faults occurs at many subduction zones, but for unknown reasons, this process is not universal. Fluid overpressures are implicated in encouraging slow slip; however, links between slow slip, fluid content, and hydrogeology remain poorly known in natural systems. Three-dimensional seismic imaging and ocean drilling at the Hikurangi margin reveal a widespread and previously unknown fluid reservoir within the extensively hydrated (up to 47 vol % H 2 O) volcanic upper crust of the subducting Hikurangi Plateau large igneous province. This ~1.5 km thick volcaniclastic upper crust readily dewaters with subduction but retains half of its fluid content upon reaching regions with well-characterized slow slip. We suggest that volcaniclastic-rich upper crust at volcanic plateaus and seamounts is a major source of water that contributes to the fluid budget in subduction zones and may drive fluid overpressures along the megathrust that give rise to frequent shallow slow slip.
Databáze: MEDLINE