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Project Outcomes

Project Outcomes

First integrated seismic imaging study of whole Antilles arc

1-page summary of main outcomes to date (last updated November 2019)

Project paper in EoS

  1. First images of the structure of slow-spread lithosphere away from the ridge shedding light on the distribution of hydration in this type of lithosphere (Davy et al., in prep).
  2. First images of the subducting Atlantic plate as it bends into the trench illustrating how further hydration occurs along bending faults similar to what has been seen in the Pacific, and how one of the ridges on the plate interacts with the upper plate as it subducts (Allen et al., in prep).
  3. New model of crustal structure below the whole arc from integration of seismic and petrological data which strongly improves on previous incomplete model from 1970s (Schlaphorst et al., Roy Soc. 2018; Melekhova et al., EPSL 2019)
  4. First images of the distribution and thickness of sediments and crust below the Grenada back-arc basin and new insights into how this was formed (Allen et al., Geology 2019; Chichester et al., subm. 2019
  5. First images of the mantle wedge from a range of seismic data showing strong variability along arc, with major anomalies behind the central islands, likely due to an enhanced contribution of fluid release and consequent melt production, explaining larger melt productivity of the central islands (Harmon et al., in prep; Hicks et al., in prep.; Bie et al., in prep.)
  6. Improved slab geometry (Bie et al., SRL 2020; Garth et al., in prep.)

New insights in seismicity

  1. Improved earthquake locations below the region including slab geometry below the arc based on widened network (Bie et al., SRL 2020)
  2. New 1-D velocity structure based on our improved coverage that can be used for routine earthquake locations (Bie et al., SRL 2020)
  3. New thermal models for the region using the updated slab geometry and ages, which are consistent with the variable depth of deep seismicity below the islands and the depths of fluid release indicated by the seismic images (Maunder et al., in prep.
  4. New moment tensor data for earthquakes recorded during our temporary deployment reflect slab deformation

New insights in magmatism and volcanism

  1. Comprehensive study of melt inclusions all along the arc, including fingerprinting for geochemical signatures of fluid release from the downgoing plate (Cooper et al., in revision)
  2. New insights in the magma storage system below St Eustatius from plutonic xenoliths (Cooper et al., Contr. Min. Pet. 2019)
  3. New isotopic analysis of the cumulates from several islands that sheds light on a 30 year old debate on whether these reflect crustal assimilation of variations in subduction input (Brown et al., in prep.).
  4. Two bathymetric surveys of Kick’em Jenny and consistent processing of previous data to reveal 30 years of history of this active underwater volcano (Allen et al., G3, 2018)

New tectonic framework

  1. New regional and Caribbean tectonic frameworks based on integration of our new results with existing data, including updated plate boundary (Allen et al., Geology 2019, Braszus et al., in prep)
  2. Improved image of slab structure throughout the upper mantle below the arc, and new insights in its relation to the tectonic history of the region (Braszus et al., in prep)
  3. New method for projecting subducting features onto the subducting slab (Harmon et al., GJI 2019)
  4. Our analyses settle the long-standing debate on where the North-South America boundary subducts below the arc (Braszus et al., in prep).
  5. Observation of deep decoupling depth below the LAA and model explaining decoupling depth variations (Maunder et al., in prep).