IODP Expedition 385: Guaymas Basin tectonics and Biosphere


Duration: 16 September to 16 November, 2019

Port Call at: San Diego, California


Guaymas Basin is a young marginal rift basin formed around ~5 Ma separating Baja California from the North America by San Andreas transform fault. The active seafloor spreading produces magma that intrudes into the organic rich thick sediments of the basin in the form of sills. The heat from the magma cooks/bakes the organic-rich sediments and releases hydrothermal fluids, carbon, sulphur, methane and  other gases, which then comes up to the ocean water and finally to the atmosphere. Therefore, the Guaymas becomes a highly productive ocean basin.

Expedition-385 targets to understand the physical, chemical and biological processes happening in the young ocean basin due to interaction of magma-sediment-water-microbes. It was back in 1978 that a team of scientists investigated the basin through DSDP Leg-64. After 41 years IODP is revisiting the site for in-depth study of the basin with a hope to reveal some of the exciting but unknown natural processes happening at the edge of pacific. This expedition targets to drill at 7 sites both on the axis and off-axis of spreading.

The Indian participant Mr. SKhogenkumar Singh from NCPOR, Goa is a petrologist by profession. His contribution in this science trip would be to hunt the source and nature of the magma for the sills because the basin has a dormant subduction zone in the west and mouth of the east pacific ridge to the south. It is a confluence of subduction zone and mid ocean ridge tectonic settings. His interest is to find out what happens to the magma factory in the lithosphere/asthenosphere when subduction and spreading meets at one point, through a combine study of geochemical, isotopic and mineral chemistry of the sills. This study will be helpful in understanding the mechanism in similar young ocean basins in Indian Ocean especially Andaman back arc basin.

This 60 day long expedition is led by Co-chiefs Andreas Teske(USA) and Daniel Lizarralde(USA) besides ~30 other scientists from different countries.