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Published September 27, 2021 | Version Published
Book Section - Chapter Open

Sites U1547 and U1548

Creators

  • 1. ROR icon University of North Carolina at Chapel Hill
  • 2. ROR icon Woods Hole Oceanographic Institution
  • 3. ROR icon Forschungszentrum Jülich
  • 4. ROR icon Moss Landing Marine Laboratories
  • 5. ROR icon Rice University
  • 6. ROR icon University of Southern California
  • 7. ROR icon Chrono-Environment Laboratory
  • 8. ROR icon University of Bremen
  • 9. ROR icon Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques
  • 10. ROR icon Jinan University
  • 11. ROR icon International Ocean Discovery Program
  • 12. ROR icon National Institute of Oceanography
  • 13. ROR icon Korea Institute of Geoscience and Mineral Resources
  • 14. ROR icon Plymouth University
  • 15. ROR icon California State University, Northridge
  • 16. ROR icon Stanford University
  • 17. ROR icon Japan Agency for Marine-Earth Science and Technology
  • 18. ROR icon Center for Scientific Research and Higher Education at Ensenada
  • 19. ROR icon Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences
  • 20. ROR icon French Research Institute for Exploitation of the Sea
  • 21. ROR icon Autonomous University of Baja California
  • 22. ROR icon Second Institute of Oceanography
  • 23. ROR icon Laboratoire d'Océanologie et de Géosciences
  • 24. ROR icon Texas A&M University
  • 25. ROR icon California Institute of Technology
  • 26. ROR icon Hohai University
  • 27. ROR icon Tokyo University of Marine Science and Technology

Abstract

Sites U1547 and U1548 are located ~27 km northwest of the axial graben of the northern Guaymas Basin (Figure F1). Site U1547 lies within a circular, bowl-shaped hydrothermal mound called Ringvent that rises ~20 m above the seafloor and has a maximum diameter of ~800 m. Three holes at Site U1548 (U1548A–U1548C) lie at the periphery of Ringvent’s southeastern edge, and two holes (U1548D and U1548E) are situated ~600 m west-northwest of Ringvent (Figure F2). Seismic profiles across Ringvent show a prominent subseafloor mound feature at ~0.06 s two-way traveltime (TWT) that is characterized by brightly reflective strata within the central bowl-shaped region. A bright reflector underlying the base of the bowl (at ~0.18 s TWT) is interpreted to be a sill intrusion. It is hypothesized that this and previous similar intrusions provided the heat that formed Ringvent and keep it active today. Ringvent is the best-characterized active, sill-associated hydrothermal system at an off-axis site in Guaymas Basin, and the temperature of its vent fluids varies between 20° and 75°C (Teske et al., 2019). Site survey data suggest that the central portion of Ringvent may thus function as a hydrothermal recharge zone. Therefore, Sites U1547 and U1548 were intended to core sediments and sills to explore patterns of hydrothermal circulation at Ringvent, which were suspected to be different within (Site U1547) and outside of (Holes U1548A–U1548C) the ring structure. The comparatively hot sill intrusion setting at Ringvent represents a shallow-emplacement end-member. The primary objectives for Sites U1547 and U1548 were to characterize the physical, chemical, and biological processes driven and affected by this end-member type of sill–sediment system, with a particular focus on the response of microbial communities to the expected steep temperature gradients at these sites. Moreover, two additional holes in an area near Ringvent were added to Site U1548 during the expedition (Holes U1548D and U1548E), with the joint objective of characterizing the geochemical signature of the abrupt lateral change in seismic character observed in sediment strata between ~2.39 and 2.42 s TWT, which may be related to a diagenetic change caused by the proximity to the igneous intrusions at Ringvent.

Copyright and License

Attribution 4.0 International CC BY 4.0.

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Additional details

Funding

National Science Foundation
OCE-1326927
European Consortium for Ocean Research Drilling
Japan Agency for Marine-Earth Science and Technology

Caltech Custom Metadata

Caltech groups
Division of Geological and Planetary Sciences (GPS) , Seismological Laboratory
Publication Status
Published