DCO Project Summary

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Project Title
Diamonds and Mantle Geodynamics of Carbon (DMGC Organization)
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Natural diamonds are direct samples of carbon from Earth’s mantle and directly record the deep carbon cycle back through geologic time. We seek to establish a new international infrastructure for diamond research to advance studies of natural diamonds and experiments on diamond-forming fluids/melts for the understanding of carbon mobility in Earth’s mantle.
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Reporting Year 2014 Click to expand

  • RY2014-3 - submitted on Aug 31, 2014

    Update Details:

    3. Recent DMGC Activity: International Diamond Workshop, Bristol, UK (July 3-4, 2014)

    On July 3rd and 4th, 2014, the Diamonds and Geodynamics of Mantle Carbon Group (DMGC), supported by the Deep Carbon Observatory through funding from the Reservoirs and Fluxes directorate, held a two-day workshop in Bristol, U.K. The workshop included 34 delegates from 17 different institutions and 9 countries (see delegate list below). The purpose of the workshop was to bring together DMGC investigators and partners, as well as other leaders within the ‘diamond and carbon’ community to present recent research, to discuss the state-of-the-art in diamond research, and to foster communication and develop collaborations. The workshop program included three keynote lectures and twenty talks from delegates. The workshop included ample time for discussion, and included an evening reception and dinner.

    The workshop was notable in that it brought together many of the leaders in the field of diamond research. Nearly every speaker presented recent research, much of which was devoted to sharing and describing state-of-the art technical advances in analyzing diamonds and their mineral inclusions in novel and powerful new ways. This included synchrotron methods for 3-D tomographic mapping of inclusions and in situ analysis and mapping using fluorescence and absorption techniques, SIMS techniques for measuring the water content of inclusions, and crystallographic methods for determining the syn- or proto-genetic nature of inclusions. Several talks focused on new techniques and results on micro- and nano-inclusions in diamonds, which is a new frontier for understanding diamond growth media. Several talks concentrated on the isotopic compositions of diamonds and inclusions, and it is clear that subduction components are clearly important in superdeep diamond formation, and that deep recycling is a key feature recorded by diamonds and inclusions. The nature of carbon in the mantle and the chemistry of the fluids and melts from which diamonds grow were featured in several talks, and the important role of water is becoming more clear as both on the basis of experiment and from analysis of inclusions.  The composition of superdeep inclusions like majorite and magnesiowistite were shown to indicate a clear role for a deep geodynamic carbon cycle, possibly all the way to the core mantle boundary. Added to this were keynote speakers with expertise on kimberlites (Kjarsgaard) and the chemistry of mantle carbon (Hirschmann), who provided context for the diamond related talks.  Overall the quality and diversity of the talks were outstanding, and everyone came away learning new things and with new ideas for future research and collaboration.

    In the afternoon of the second day the DMGC committee met to discuss strategy for researching the new diamond collection purchased with DCO funding. A suite of 250 inclusion-bearing diamonds from Juina, plus a series of samples from Sierra Leone, Angola, Central African Republic (locations already listed in the DMGC site) was purchased by Shirey and Pearson on a recent trip to Juina, Brazil. Consensus was reached for first investigations to be made by in situ Raman to identify the diamond inclusion(s). In this respect, several Raman spectrometers are available among the different DMGC-groups that should allow a quick first survey. It is agreed that a first report, describing visual inspection (including cracks), and a list of the most promising inclusions will be made available and distributed immediately. 

    The upcoming International Diamond School to take place in January 2015 will take the place of a 2015 DMGC workshop. A 2016 workshop is being planned for 2016 in Alberta, Canada. 

    The overall cost of the workshop was ~$10,000, which included accommodation for all delegates, travel for keynote speakers, workshop facilities and workshop dinner. 


    Workshop Delegate List

    F. Brenker  (Frankfurt)

    R. Brooker  (Bristol)

    G. Bulanova  (Bristol)

    A. Burnham  (Bristol)

    P. Cartigny  (Paris)

    J. Coggan  (Munich)

    T. Elliott  (Bristol)

    D. Frost  (Bayreuth)

    B. Harte  (Edinburgh)

    M. Hirschmann  (Minnesota)

    D. Howell  (Canberra)

    A. Jones  (London)

    K, Kiseeva  (Oxford)

    B. Kjarsgaard  (Ontario)

    S. Kohn  (Bristol)

    A. Logvinova  (Novosibirsk)

    O. Lord  (Bristol)

    S. McMahon  (Bristol)

    S. Mikhail  (Bristol)

    O. Navon  (Tel Aviv)

    P. Nimis  (Padua)

    I. Parkinson  (Bristol)

    G. Pearson  (Edmonton)

    Rudloff  (Frankfurt)

    Schmitz  (Frankfurt)

    S. Shirey  (Washington D.C.)

    C. Smith  (Bristol)

    R. Southworth  (London)

    L. Speich  (Bristol)

    T. Stachel  (Edmonton)

    A. Thomson  (Bristol)

    M. Walter  (Bristol)

    H. Williams  (Durham)

    D. Zedgenizov  (Novosibirsk)


     Diamond and the Mantle Geodynamics of Carbon Workshop Programme 

    Thursday July 3

    Session 1

    09:30 Welcome

    09:40 Stachel - SIMS applications to diamond research

    10:20 Kohn - X-ray computed tomography of unmixed, polyphase inclusions in superdeep diamonds.

    10:40 Schmitz - Synchrotron techniques for in-situ analyses of inclusions

    11:00 Nimis - X-ray crystallography of inclusions in diamond. New results and perspectives

    11:20 Coffee

    11:40 Brenker - Coexisting high density fluid inclusion and fayalitic Ringwoodite found within a Sao Luiz diamond

    12:00 Navon - Microinclusions in Monocrystalline Diamonds

    12:20 Rudloff - Nano-inclusions in diamonds from Juina area, Brazil

    12:40 Logvinova - Multiphase assemblages of nanometer-sized inclusions in Siberian diamonds: new sense on diamond formation

    13:00 Lunch


    Session 2

    14:00 Kjarsgaard - Generation and evolution of kimberlite melts, from source to crust

    14:40 Frost - Diamond formation from H2O-CO2 bearing melts

    15:00 Thomson - An experimental study of superdeep diamond formation during reactions of slab-derived melts

    15:20 Howell - Diamonds in ophiolites: contamination or a new growth environment

    15:40 Coffee

    16:00 Cartigny - O and C isotope techniques

    16:20 Burnham - Coupled C and O isotopes of ultradeep diamonds and their inclusions

    17:00 Mikhail - Empirical and theoretical evidence for the isotopic and elemental decoupling of C and N during diamond-formation in the mantle

    17:20 Zedgenizov - Heterogeneous C reservoir in sublithospheric mantle: evidence from C isotope composition of diamonds from Sao-Luis (Brazil)

    17:40 end


    19:45 Drinks/Dinner Avon Gorge Hotel


    Friday July 4


    Session 3

    10:00 Hirschmann - Where is the carbon in the mantle?

    10:40 Pearson - The nature of the Transition Zone as revealed by ultra-deep diamonds

    11:00 Shirey - Water content of stishovite, majorite, and perovskite in Juina superdeep diamonds

    11:20 Coffee

    11:40 Kiseeva - Looking through diamond at garnet-bearing lithologies in the transition zone

    12:00 Smith - Diamonds from Machado River, Brazil, sourced from both upper and lower mantle

    12:20 Harte - Re-equilibration History of a Lower Mantle Magnesiowustite

    12:40 Walter - Stability of carbonate and hydrous phases in Earth's lower mantle

    13:00 Lunch

    End of workshop


    14:00 DMGC Group Meeting

  • RY2014-4 - submitted on Aug 31, 2014

    Update Details:

    2. Recent DMGC Activity: Diamond Procurement 

    John Betts, New York City

    Juina Field Procurement Trip

    GIA accession of specimens for KV Smit


    (This description is under construction.)

  • RY2014-1 - submitted on Aug 31, 2014

    Update Details:

    4. Upcoming DMGC Activity: International Diamond School, Brixen-Bressanone, Italy (Jan 27-31, 2015)

    Description of School:

    An international school on “The Nature of Diamonds and Their Use in Earth’s Study” is to be held from the 27th to the 31st of January, 2015, in the Italian Alps in the town of Bressanone-Brixen. It is being hosted by the University of Padua and co-organized by the University of Alberta and the Carnegie Institution of Washington under the auspices of the Diamonds and the Mantle Geodynamics of Carbon consortium (DMGC) of the Alfred P Sloan Foundation-sponsored Deep Carbon Observatory (DCO).

    The school will provide a general overview to an international group of students (MS and PhD level) of the most recent advances in diamond research as well as an introduction to modern techniques for diamond exploration. What will make this school successful is the blend of student and professional and cross disciplinary nature of the participants (experimentalists, petrologists, mineralogists, crystallographers, and isotope geochemists, diamond exploration industry experts). The committed speakers include the world’s leading scientists in the field as well as those actively involved in exploring for and evaluating diamond deposits. The lectures will provide theoretical and practical lectures and tutorial workshops concerning diamonds and their mineral inclusions.

    The planned general theoretical sessions will include these topics: diamonds in history, diamond formation and distribution in the Earth’s mantle, diamonds in mantle petrology and geochemistry, thermobarometry of diamonds, kimberlite volcanology, techniques for diamond exploration, methods for diamond deposit evaluation, and diamond morphology and its implications. 

    The workshops will be focused on optical observations of diamonds and their inclusions, direct microRaman spectroscopy, and the elasticity and equations of state of entrapped inclusions in diamonds. There will also be tutorials on dating diamonds and geo-thermobarometry.



    A highly successful first Diamond School was organized at the same venue and with a similar program model in 2011. It had over fifty students from all over the world and it was cost-effective, a superb blend of students and established diamond professionals. It was felt to be a highly successful educational experience for all the students involved. This school led directly to a number of successful PhD dissertations and spearhead the formation of the Diamonds and the Mantle Geodynamics of Carbon (DMGC) consortium and hence to the establishment of a collection of diamonds for coordinated open-access research. 


  • RY2014-2 - submitted on Aug 31, 2014

    Update Details:

    1. Current DMGC Projects (listed separately under the Reserviors and Fluxes Community)

    Diamond Oxygen Isotope Geochemistry

    DiamondDB: Community Data Infrastructure for Diamond Research within the Deep Carbon Observatory

    Diamonds at the Nanoscale - The initial growth stage

    Linking Diamond Fluids with Mantle Melts using Trace Elements and Isotopes

    Phase Relations of Silicate Inclusions in Superdeep Diamonds and Constraints on Mantle Geodynamics

    The Nature of Diamond Forming Liquids in the Mantle and Direct Estimates of Deep Mantle Stresses from Diamond Plasticity

    Water and Carbon Pathways in the Deep Mantle from Diamond Petrogenesis


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