Deep Earth Sampling Report for 2010
Chair – Benoit Ildefonse (CNRS, Univ. Montpellier 2, France)
After a rather active year in 2009, the Steering committee recommended that the DES WG should continue into 2010, to follow-up on the 2009 MMFL and INVEST workshops.
The Melting, Magma, Fluids and Life (MMFL) Workshop, held in July 2009 at the National Oceanography Centre, Southampton, UK, was co-sponsored by InterRidge, its goal was to discuss the scientific planning for scientific drilling in the ocean crust, in preparation for the IODP INVEST meeting in September 2009. The full workshop report is available online at http://www.interridge.org/WG/DeepEarthSampling/workshop2009, as well as the white paper prepared for the INVEST meeting.
The IODP New Ventures in Exploring Scientific Targets (INVEST) workshop was held in Bremen, Germany, in Sept. 2009 (http://www.marum.de/iodp-invest.html). INVEST was organized as a large, multidisciplinary, international community meeting, whose focus was to define the scientific research goals of a new ocean drilling program, expected to replace IODP late in 2013. The workshop was extremely well attended, with more than 550 participants, including most members of the Deep Earth Sampling Working Group. The meeting report is available online at http://www.iodp.org/weblinks/Featured-Publications-HOME-PAGE/INVEST/. Several key objectives that were outlined in the MMFL workshop report are also articulated in the INVEST report; they include:
• the MoHole, i.e., a full crustal penetration to the Moho and into the uppermost mantle,
• addressing crustal aging and lithosphere/hydrosphere exchanges through drilling transects,
• ultramafic seafloor, including serpentinite-hosted hydrothermal systems, and CO2 capture and storage through carbonation,
• subseafloor resources (including deep seafloor volcanogenic hosted massive sulfide deposits).
The Scientific Plan for the next phase of the scientific drilling program, to follow IODP in 2013, is currently being written by an international group of experts chaired by Michael Bickle (Cambridge University, UK).
In 2010, InterRidge co-funded the MoHole workshop organized in June in Kanazawa, Japan : http://earth.s.kanazawa-u.ac.jp/~Mohole/index.html. In continuation of the science planning discussions that took place in 2009 and during the earlier Mission Moho workshop in 2006 (http://www.iodp.org/mission-moho-workshop/), The 2010 MoHole workshop had two interconnected objectives, which have been discussed jointly between ocean lithosphere specialists, marine geophysicists, and engineers:
• to initiate a roadmap for technology development, and the project implementation plan, which are necessary to achieve the deep drilling objectives of the MoHole project,
• to identify potential MoHole sites in the Pacific (i.e., in fast-spread crust), where the scientific community will focus geophysical site survey efforts over the next few years. Selecting drilling sites is essential to identify the anticipated range of water depths, drilling target depths, and temperatures, and better define the technology required to be developed and implemented to drill, sample and geophysically log the MoHole.
This meeting was attended by ~65 people, and was very successful and productive. The full workshop report will soon be available on the IODP web site, and a report article is in press in Scientific Drilling.
In 2009, a motion was sent to the IODP Science Planning Committee (SPC) Chair to re-state the importance of returning to IODP Hole 1256D as a short-term community priority. The bottom of Hole 1256D currently resides in the vary-textured gabbros of the transition zone between the sheeted dyke complex and the underlying cumulate gabbros. The proposal to return to site 1256 and deepen further Hole 1256D was discussed for ranking at the August 2009 IODP Science Planning Committee meeting, forwarded to the IODP Operation Task Force, and the next expedition to Site 1256 is now scheduled in 2011 (April 14 to June 4; http://iodp.tamu.edu/scienceops/expeditions/superfast_rate_crust.html).
As a manifestation of the increased interest of the geomarine community for the ultramafic seafllor, aka "serpentinite sea", it is worth noting the recent submission in 2009 of a drilling proposal that presents a plan to drill and core the Atlantis Massif using a seabed, shallow drilling/coring device. Objectives of this proposal (IODP proposal #758, by G. Früh-Green et al.; http://www.iodp.org/index.php?option=com_docman&task=doc_download&gid=2837) are to:
• quantify the role of serpentinization in generating H2- and hydrocarbon-rich fluids, in driving hydrothermal systems, and in sustaining microbiological communities, and the potential for carbon sequestration in ultramafic rocks,
• understand the linkages among detachment faulting, abiotic and biotic processes, and hydrothermal circulation in young mafic and ultramafic seafloor, and determine how these change with age and rock type,
• and characterize tectono-magmatic processes that lead to lithospheric heterogeneities and the evolution of hydrothermal activity associated with detachment faulting.
The proposal currently resides in the Science Steering and Evaluation Panel of IODP, and has recently been sent for external reviews.
It is now time for the Steering Committee to consider whether the deep Earth Sampling Working Group should be disbanded after ~6 years of activity, or renewed with an updated mandate (and possibly a renewed membership?). In any case, continuous liaison with IODP (through mutual attendance of liaisons to science planning/Steering committee meetings) should be maintained in the future. It is essential to ensure a good, mutual understanding of the objectives of the two programs.
