Call to Participate: Expedition 502: Impact of Petit-Spot Magmatism on Subduction Zone Seismicity and the Global Geochemical Cycle
Call to Participate in IODP3 Expedition 502: Impact of Petit-Spot Magmatism on Subduction Zone Seismicity and the Global Geochemical Cycle now open!
International Ocean Drilling Programme (IODP3) Expedition 502 plans to explore the nature of the acoustic basement in the outer rise area of the NW Pacific subduction system, where layer-1 pelagic sediment of the subducting old (120–130 Ma) Pacific Plate is exceptionally thin. The hypothesis is that the acoustically thin sediment cover can be attributed to basalt sill intrusions or sheet lava extrusions in and on the pelagic sediment package by basalts fed by petit-spot magmatism. This hypothesis will be tested to see if petit-spot magmatism at the outer rise is more widely distributed than previously thought. The existence of widely-distributed petit-spots would strongly impact the subduction system, including rupture nucleation and slip propagation of plate boundary megathrust earthquakes, as well as effect changes to the geochemical cycle of arc magmatism and the global volatile cycle due to the differing materials associated with the subducted oceanic plate. Testing this hypothesis will shed light on the impacts of subduction inputs and help to determine the global role of petit-spot magmatism, both of which are important elements of the scientific objectives of the International Ocean Drilling Programme (IODP3).
For more information please read the full call on the PDF below. You can also read the Scientific Prospectus here.
A webinar was held on Monday 17th March 2025 to enable the community to find out more about Expedition 502. A recording of this webinar can be found below, closed captions are available, and can be toggled on and off using the CC button beneath the video (please note these captions are auto-generated).
Applications from scientists based in IODP3 Core and Associate Member nations must be submitted by Midnight GMT on Friday 28 March 2025 using the IODP3 Gateway system. The Gateway can be accessed via Apply to Participate on the IODP3 webpage, and more information on the content required for applications to this call is also available in the IODP3 Guide for Applicants.