ANZIC is delighted to host Dr Marguerite Godard from Géosciences Montpellier at the Université de Montpellier, France in Canberra on 7 and 8 February. Dr Godard is in Australia for meetings about the New Caledonia Drilling Project (NCDP), an initiative to drill and sample the New Caledonia peridotites and associated lithologies on-land, in coastal waters, and beneath the deep oceanic sub-seafloor.
While in Canberra, Dr Godard will deliver two seminar, to be held at ANU Research School of Earth Sciences (4pm, Tuesday 7 February) and Geoscience Australia (11am, Wednesday 8 February), with both live-streamed for online access – see below for full details. ANZIC members are welcome to attend these hybrid seminars and learn more about this exciting research.
If you would like to meet with Dr Godard while she is visiting Canberra, please contact ANZIC Director Ron Hackney.
RSES Seminar: Linkages between Serpentinization and Carbon Trapping in the Semail Ophiolite (Oman)
4pm, Tuesday 7 February
Jaeger 1 Seminar Room (and online), ANU School of Earth Sciences, Acton ACT
The Semail Ophiolite preserves a section of Tethyian oceanic lithosphere obducted onto the Arabian peninsula. Its mantle section is variably serpentinized. It hosts several H2-rich alkaline springs suggesting that serpentinization is still active today and carbonate-rich areas that can be used as analogues to develop techniques for CO2 geological storage. At the field scale, the linkages between serpentinization and carbonate-forming reactions is evidenced in two key locations of the Semail Ophiolite: the Wadi Mansah area (OmanDP Hole BT1B) where fully-carbonated peridotite (listvenites) outcrop along the ophiolite basal thrust and in the Wadi Dima and Batin areas exposing carbonate-rich serpentinized harzburgite- and dunite-dominated basements, respectively.
By combining petrostructural, mineralogical, and geochemical approaches (elemental chemistry, C and O isotopes), we show that the ophiolite underwent widespread serpentinization induced by the ingress of seawater-derived fluids in Wadi Dima and Batin and by slab-derived fluids in Wadi Mansah. Carbonation reactions are closely associated with serpentinization, but show different reaction pathways producing Mg-carbonates (and quartz) in Wadi Mansah and Ca-carbonates and serpentinites in Wadi Dima and Batin. Preliminary results suggest a control by the composition of incoming fluids (salinity, pH, solute concentrations, …) and, in particular, by their CO2 concentrations (high in Wadi Mansah compared to Wadi Dima and Batin). Both reaction pathways are associated with the (possibly abiotic) formation of minor fractions of reduced-carbon species, but they are distinguished by elemental remobilization (Mn, Cr, Li, Pb,…) in Wadi Mansah and by evidences of H2-rich fluids in Wadi Dima and Batin. Investigations are still ongoing with a focus on the Batin site that hosts the first multi-borehole observatory (MBO) in an ultramafic basement, which was developed as part of OmanDP. Comparing the petro-structure and composition of drilled cores to downhole borehole physical and hydrodynamic measurements will provide a unique dataset to investigate reactive transport and the linkages between the basement structure, fluid flow, chemical fluxes and deep biosphere associated to serpentinization and their impact on H2 production and CO2 mineralization in natural environments.
Geoscience Australia Seminar: The New Caledonia Ophiolite Land-to-Sea Drilling Project (SW Pacific): Exploring, on-shore and off-shore, the structure, composition and resources of an exhumed mantle wedge section
11am, Wednesday 8 February
Raggatt Theatre (and online), Geoscience Australia, Symonston ACT
TheNew Caledonia Ophiolite Land-to-Sea Drilling Project (NCDP), submitted to the International Continental Scientific Program (ICDP) and the International Ocean Discovery Program (IODP), aims at sampling the the New Caledonia peridotites and associated lithologies on-land, in coastal waters, and the deep oceanic sub-seafloor. The project builds upon the expertise and results acquired thanks to the ICDP Oman Drilling Project (2017-2018; Semail Ophiolite). NCDP will allow (1) investigating the geodynamic, magmatic and hydrothermal processes driving, and resulting from, the formation and emplacement of the ophiolite and the possible interplays between obduction and climate over geological times in the still poorly known SW Pacific, and (2) developing borehole observatories to measure, in subaerial and marine settings, the hydrogeological and (bio-)geochemical processes that control, and are influenced by, low temperature serpentinization and H2-rich/CO2-capturing peridotite-hosted hydrothermal systems. NCDP will provide a unique dataset to address critical questions on the coupling between serpentinization, hydrogen production, carbon mineralization and metal remobilization over the different stages of obduction.
About Dr Marguerite Godard
Dr. Marguerite Godard is CNRS Senior Researcher (French National Centre for Scientific Research) at the Géosciences Montpellier laboratory (France). Her research combines petro-structural, mineral and geochemical studies of oceanic and ophiolite rock samples, mostly sampled by drilling, with experimental approaches to investigate reactive transport in mantle rocks, from magmatism to serpentinization.
She co-authored more than 100 publications in international scientific reviews and books (ORCID 0000-0003-3097-5135). M. Godard is one of the main proponents of the Oman Drilling Project of the International Continental Drilling Programme (2017-2018).