Project

Discipline

Lost City; Global carbon cycle; Serpentinization; Samail Ophiolite, Oman; Carbonate precipitation; Deep biosphere; ICDP continental drilling; IODP ocean drilling; Upper mantle rocks; Mid-Atlantic Ridge; CO2 sequestration; Abiotic and biotic carbon

Lead
Dieses Infrastruktur-Projekt läuft parallel zum Forschungsprojekt „Hydration and carbonation of mantle peridotite: Drilling the Atlantis Massif (MAR 30°N) and the Samail ophiolite (Oman)” (200021_163187) und unterstützt die Finanzierung der Bohrkampagne ICDP in Oman (siehe Unterprojekt C im Forschungsplan). Das Oman Drilling Project wird eine Reihe von Bohrungen in den Samail Ophiolith in Oman ausführen, vermessen und beaufsichtigen. Diese Ophiolith ist das grösste und beste Beispiel von Ozeankrusten und Mantelgesteinen, die am Land aufgeschlossen sind.
Lay summary
Im Zentrum der Untersuchungen stehen petrologische und geochemische Studien an den eroberten Kernen und an Gasen und Wasserproben, die direkt aus aktiven Serpentinisierung- resp. Karbonatisierungszonen entnommen werden. Bohrung, Vermessung und Beprobung werden in drei Phasen in 2016 und 2017 ablaufen. Im Winter der beiden Jahren werden die Bohrungen, Bohrlochvermessung und Versiegelungen der Bohrlöcher ausgeführt. In den darauffolgenden Sommer werden die Kerne an Bord des IODP-Forschungsschiffes JOIDES Resolution während der Trockendockzeit untersucht, beschrieben und beprobt. Im Herbst werden Gas- und Fluidproben aus den neuen Bohrlöchern entnommen. Durch dieses Projekt werden wir einen einzigartigen Zugang zu den Kernen, Fluiden, Vermessungsdaten erhalten, die einem PhD-Studierenden ermöglichen in einem internationalen Forscherteam Erkenntnisse über die Alteration, Karbonatisierung und die Mikrobiellen Prozesse in Mantelperidotiten zu sammeln und den natürlichen CO2 Aufnahmeprozess aus Oberflächenwasser und Atmosphäre zu untersuchen.

Direct link to Lay Summary

Last update: 19.10.2015

Active participation

Number	Title	Start	Funding scheme

We will take advantage of unique opportunities to participate in two exciting scientific drilling projects that target active hydration (serpentinization) and carbonation processes in upper mantle rocks: (1) IODP Expedition 357 to the Atlantis Massif at the Mid-Atlantic Ridge 30°N and (2) drilling on land in the Samail Ophiolite as part of the ICDP Oman Drilling Project. Altered upper mantle rocks (serpentinites), exposed on the ocean floor and in ophiolites on continents, constitute highly reactive chemical and thermal systems, in which interaction with water to produce serpentinite has major consequences for lithospheric cooling, geophysical properties, global geochemical cycles, CO2 sequestration, and microbial activity. Serpentinites are an important reservoir for carbon in the form of carbonate minerals as well as abiotically and biotically produced organic carbon, all of which can survive in ancient mantle domains for hundreds of millions of years. However, the source and distribution of carbon-bearing phases in altered mantle sequences and their contribution to the global carbon cycle remain poorly constrained. This project is parallel to the Research Project ““Hydration and carbonation of mantle peridotite: Drilling the Atlantis Massif (MAR 30°N) and the Samail ophiolite (Oman)” (200021_163187) and will provide infrastructure funds as Swiss member of ICDP to contribute to the costs of ICDP drilling in Oman (subproject C in the Research Plan). The Oman Drilling Project will drill, log and monitor a series of boreholes in the Samail ophiolite of Oman, which is the largest and best exposed slice of sub-aerially exposed ocean crust and upper mantle peridotite. We will focus on petrological and geochemical studies of the core, gas and water samples that will be drilled in 2016 and 2017 at sites where serpentinisation is actively occurring and leads to carbonate precipitation in and on the surface of peridotites. Drilling, logging and sampling are planned in three stages. Coring, downhole logging and sealing the boreholes will take place in the winter of both years. In the summer of each year, the cores will be logged, described and sampled onboard the IODP research vessel JOIDES Resolution while the ship is in port between expeditions. Gas and fluid samples will be taken from the new boreholes in the autumn after each coring campaign. Contribution to this project will allow us unique access to the cores, fluids and logging data and provides an important opportunity to participate in the international team to study present-day alteration, carbonation and microbial processes in mantle peridotites and to explore natural mechanisms of CO2 uptake from surface waters and the atmosphere. Our aim is to understand active low temperature processes of hydration and carbonation and the hydrology of the peridotite-hosted aquifer in the Samail Ophiolite. Combined petrological and fluid/gas geochemical analyses are aimed at understanding: how Ca-rich, high alkaline fluids develop, what minerals are deposited in the subsurface, the controls on H2 and CH4 production that is characteristic of fluids in these environments, the fluid flow paths, and the feedback mechanisms between reactions, cracks, and carbonate deposition.