Exp. 357 Atlantis Massif

Theme

Serpentinization and life: Biogeochemical and tectono-magmatic processes in young mafic and ultramafic seafloor

Proposal #758-Full >>go to the full version

Scientific Prospectus; To be published

Schedule

Autumn – Winter 2015

Drilling Vessel

Mission Specific Platform (MSP)

 Ports (start/end)

TBD

 Drilling Sites

Scientific Objectives

IODP   Expedition   357   will address   two   exciting   discoveries   in   mid‐ocean   ridge research:   off axis, serpentinite hosted  hydrothermal  activity,  exemplified  by  the  Lost  City  Hydrothermal  Field  (LCHF) on the  Atlantis  Massif  oceanic  core  complex  (30°N,  Mid Atlantic  Ridge); and  the  significance  of  tectono magmatic   processes   in   forming   and   exposing   heterogeneous   mafic   and   variably   serpentinized ultramafic lithosphere   that   are   key   components   of   slow   and   ultraslow   spreading   ridges.

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. This  expedition  will  utilize  seabed  rock  drill  technology  (MeBo  and  BGS  Seafloor  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,  with  the  aim  to:

1. Explore the   extent   and   activity   of   the   subsurface   biosphere   in   young   ultramafic   and   maficseafloor
2. Assess how   abiotic   and   biotic processes   change   with   aging   of   the   lithosphere   and   with variations  in  rock  type
3. Quantify the   role   of   serpentinization   in   driving   hydrothermal   systems,   and   in   sustaining microbiological  communities,  and  in  the  sequestration  of carbon  in  ultramafic  rocks; and
4. Characterise tectono magmatic  processes  that  lead  to  lithospheric heterogeneities  and  the evolution  of  hydrothermal  activity  associated  with detachment  faulting

Go to the ECORD Science Operator Page