T32C:
Shaping Slow and Ultraslow Spreading Seafloor with Faults, Magma, and Fluids I


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Session ID#: 57026

Session Description:
Crustal accretion at slow- and ultraslow spreading ridges is fundamentally different from that at faster spreading ridges, and accounts for vast areas of the Atlantic, Indian and Arctic Oceans.  Plate separation in these settings occurs in a thick brittle lithosphere and is accommodated by a combination of magmatic and tectonic extension, leading to deformation often dominated by large-offset detachment faults.  The ridge magma supply is highly variable in space and time, and the seafloor has a diverse range of morphologies including corrugated domes, non-corrugated massifs, back-tilted fault breakaways, and broad smooth hills.  Despite recent advances in seafloor observations and modeling techniques, the mechanics of this mode of seafloor spreading remain controversial.  We welcome contributions from a broad range of approaches, including geophysical and geological observations, geodynamic modeling, fluid chemistry, seismology, experimental rock mechanics and petrology.
Primary Convener:  Manon Bickert, Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Paris, France
Conveners:  Luc Lavier, University of Texas at Austin, Institute for Geophysics, Austin, TX, United States and Jean-Arthur L Olive, Ecole Normale Superieure Paris/CNRS, Laboratoire de geologie, Paris, France
Primary Liaison:  Manon Bickert, Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Paris, France
Chairs:  Manon Bickert, Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Paris, France, Jean-Arthur L Olive, WHOI, Woods Hole, United States and Luc Lavier, University of Texas at Austin, Institute for Geophysics, Austin, TX, United States
OSPA Liaison:  Jean-Arthur L Olive, WHOI, Woods Hole, United States

Cross-Listed:
  • OS - Ocean Sciences
  • V - Volcanology, Geochemistry and Petrology
Index Terms:

3035 Midocean ridge processes [MARINE GEOLOGY AND GEOPHYSICS]
8034 Rheology and friction of fault zones [STRUCTURAL GEOLOGY]
8135 Hydrothermal systems [TECTONOPHYSICS]
8178 Tectonics and magmatism [TECTONOPHYSICS]

Abstracts Submitted to this Session:

What’s rate got to do with it?: Oceanic core complex evolution and serpentinized mantle exhumation at the Mid-Cayman Spreading Center (Invited) (395112)
Nicholas W Hayman, Institute for Geophysics, Austin, TX, United States, Harm J Van Avendonk, University of Texas at Austin, Institute for Geophysics, Austin, TX, United States, Jennifer Harding, Rensselaer Polytechnic Institute, Crofton, United States, Christine Peirce, University of Durham, Durham, United Kingdom and Ingo Grevemeyer, GEOMAR, Kiel, Germany
Seafloor expression of oceanic detachment faulting reflects gradients in mid-ocean ridge magma supply (395143)
Mark D Behn, Boston College, Earth and Environmental Sciences, Chestnut Hill, MA, United States, Samuel M Howell, NASA Jet Propulsion Laboratory, Pasadena, CA, United States, Jean-Arthur L Olive, CNRS / Ecole Normale Superieure, Laboratoire de Geologie de l'ENS, Paris, France, Garrett Ito, University of Hawaii, Department of Earth Sciences, Honolulu, United States, Javier Escartin, Institut de Physique du Globe, Paris, France and Boris J P Kaus, University Mainz, Mainz, Germany
Surface Expressions of Deep Reactive Multi-Phase Flow Beneath the Longqi-1 Hydrothermal Field, Southwest Indian Ridge (412386)
Lars Rupke1, Zhikui Guo1, Falko Vehling1 and Chunhui Tao2,3, (1)GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany, (2)Second Institute of Oceanography, MNR, China, Hangzhou, China, (3)Second Institute of Oceanography, SOA, Hangzhou, China
Chaos at ultraslow and slow spreading ridges: effect of accretion style on basalt compositional variability (Invited) (353316)
Stephanie M Krein, Massachusetts Institute of Technology, Earth, Atmospheric and Planetary Sciences, Cambridge, MA, United States, Mark D Behn, Boston College, Earth and Environmental Sciences, Chestnut Hill, MA, United States, Jean-Arthur L Olive, CNRS / Ecole Normale Superieure, Laboratoire de Geologie de l'ENS, Paris, France and Timothy L Grove, Massachusetts Institute of Technology, Department of Earth, Atmospheric and Planetary Sciences, Cambridge, United States
Zircon Geochemistry at Atlantis Bank, Southwest Indian Ridge: Implications for Magmatic Accretion at Slow-Spreading Mid-Ocean Ridges (427305)
Christopher James Doorn1, Michael J Cheadle2, Barbara E John2, Matthew A Coble3, Matthew E Rioux4 and Joseph L Wooden5, (1)University of Wyoming, Laramie, WY, United States, (2)University of Wyoming, Geology & Geophysics, Laramie, United States, (3)Stanford University, Stanford, CA, United States, (4)University of California, Santa Barbara, CA, United States, (5)Oregon State University, Corvallis, OR, United States
Insights Into Crustal Structure Around the Chain Fracture Zone Using Ultra-long Offset Seismic Reflection Data (386093)
Milena Marjanovic1, Satish Chandra Singh2, Hanchao Jian1 and Pranav Audhkhasi1, (1)Institut de Physique du Globe de Paris, Paris, France, (2)Institut de Physique du Globe de Paris, Université Paris-Cité, Paris, France

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