Title: Atlantis Massif Serpentinization and Life Expedition

Summary: Serpentinization is a fundamental process that controls rheology and geophysical properties of the oceanic lithosphere and has major consequences for heat flux, geochemical cycles and microbial activity in a wide variety of environments. However, we currently have no constraints on the nature and distribution of microbial communities in ultramafic subsurface environments, which are characterised by high hydrogen and methane concentrations but little available CO2. A major goal of the Atlantis Massif Serpentinization and Life expedition (based on IODP Proposal 758-Full2) is to better understand the role of serpentinization in driving hydrothermal systems, in sustaining microbiological communities, and in the sequestration of carbon in ultramafic rock. The offshore phase of this MSP expedition will use seabed rock drill technology (MeBo and BGS Rockdrill 2) to core a series of shallow (50-80 mbsf) holes along two profiles across the Atlantis Massif, where detachment faulting exposes both mafic and ultramafic lithologies on the seafloor. A spreading-parallel, E-W profile will target the serpentinite basement to explore the extent and activity of the subsurface biosphere and assess how abiotic and biotic processes change with aging of the lithosphere and with variations in rock type. A ridge-parallel, N-S profile into the gabbroic center of the massif will assess the role of differing rheologies in localising detachment faults and will examine how faulting and lithospheric heterogeneities influence hydrothermal alteration and the nature of the deep biosphere.

Sites: AM-01, AM-06, AM-11 as alternate. Upflow region associated with the Lost City Hydrothermal Field: recover sediments, hydrothermal deposits, fault surface & talc schist/serpentinite basement for petrological, chemical & microbiological analysis. Ideally, log and sample fluids.
AM-02, AM-03, AM-04, AM-05. Variations with age: recover sediments, fault surface & talc schist/ serpentinite basement for petrological, chemical & microbiological analysis.
AM-07, AM-08, AM-09, AM-10. Axis-parallel variations: recover sediments, fault surface & mafic basement for petrological, chemical & microbiological analysis.

Dates: 26th October - 11th December 2015

Port: Southampton, UK.

Co-Chief Scientists: Prof. Gretchen Früh-Green, Marine Geology and Geochemistry, ETH Zurich.
Dr. Beth Orcutt, Senior Research Scientist and Geomicrobiologist, Bigelow Laboratory for Ocean Sciences.

Expedition Project Manager: Sophie Green. Carol Cotterill (offshore EPM).

Petrophysics Contact: Sally Morgan

Expedition Participants: Please click here for details.

Drillship: RRS James Cook carrying the BGS Rockdrill 2 and the MARUM-MeBo seafloor drills.


Proposal #758
Scientific Prospectus
Expedition Flyer
Preliminary Report


Ship Reports


20th January to 5th February 2016. Please see general information about the OSP here.


Media Pack