Oman Drilling Project Field Study uri icon

DCO ID 11121/6759-3012-4242-6784-CC

open to journalists

  • Yes

description

  • The Samail ophiolite in Oman and the United Arab Emirates (UAE) is the world’s largest, best-exposed, and most-studied subaerial block of oceanic crust and upper mantle. In an ongoing dialogue between geological studies of the ophiolite and seagoing investigations along modern oceanic ridges, observations from Oman and the UAE are central to scientific understanding of oceanic plates formed at spreading centers. Observations of mantle peridotites overlying the subduction zone thrust, which carried the ophiolite onto the Arabian continental margin, reveal an unexpected reservoir of carbon, derived from subducted sediments and precipitated as carbonate minerals in the mantle wedge. This could form an important, hitherto unrecognized part of the global carbon cycle. And, following on ground-breaking work in the 1980’s, there has been a recent surge of interest in the Samail ophiolite as the ideal site for studies of weathering in mantle peridotite, together with the subsurface biosphere fueled by microbial catalysis of low temperature alteration reactions. Such studies will contribute to understanding of microbial ecosystems in extreme environments and the origin of life.  

    Following a successful workshop in September 2012, our international team of 38 investigators proposes a comprehensive drilling program in the Samail ophiolite in the Sultanate of Oman. Via observations on core, geophysical logging, fluid sampling, hydrological measurements, and microbiological sampling in a series of diamond- and rotary-drilled boreholes, we will address long-standing, unresolved questions regarding melt and solid transport in the mantle beneath oceanic spreading ridges, mass transfer between the oceans and the crust via hydrothermal alteration, and recycling of volatile components in subduction zones. We will undertake frontier exploration of subsurface weathering processes in mantle peridotite, natural mechanisms of carbon dioxide uptake from surface waters and the atmosphere via alteration and weathering, the process of reaction-driven cracking, and the nature of the subsurface biosphere in peridotite undergoing alteration and weathering. This aspect of the Oman Drilling Project is the one that is co-funded by the Sloan Foundation as part of the Integrative Field Studies for the Deep Carbon Observatory, Sloan Foundation Grant No: G-2014-3-01  Societally relevant aspects of our project include the involvement and training of university students in earth science research, including numerous students from Sultan Qaboos University in Oman. Studies of the natural system of mineral carbonation in peridotite will contribute to design of engineered systems for geological carbon dioxide capture and solid storage. More generally, our studies of alteration will contribute to fundamental understanding of the mechanisms of reaction-driven cracking: chemical reactions that cause subsurface cracking, enhancing permeability and reactive surface area, in a positive feedback mechanism. The results of these studies studies could enhance geothermal power generation and extraction of unconventional hydrocarbon resources.

     

    Scientific drilling of the Semail Ophiolite in the Sultanate of Oman, commencing in late 2015 and continuing into 2017, represents a unique opportunity to understand the activities and distributions of a deep continental microbial biosphere associated with serpentinization. The project will drill up to 400 m into the ophiolite complex and is our best opportunity to-date to understand spatiotemporal relationships between serpentinization and subsurface life. The major goal of the Oman Drilling Project is to understand the conditions leading to low-temperature serpentinization and their consequences for carbon cycling, including their impact upon subsurface microbial communities. The DLC community will (1) work closely with hydrogeologists studying fluid flow and fluid chemistry in the Semail Ophiolite, (2) support activities aimed at instrumenting excavated wells to facilitate future observatory studies, and (3) conduct fluorescently activated cell sorting for downstream single cell genomics analyses. These efforts will all enable the study of microbial biogeography and dispersal in the serpentinitehosted subsurface environment.


date/time interval

  • April 1, 2014 - March 31, 2017

participant