Hydrate formation from CH4 released during serpentinisation. How important it is on Earth?

Project Rationale:

Methane hydrate is an ice-like substance that forms at high pressures and low temperatures when sufficient methane is available in continental margins and deep ocean sediments. Serpentinisation is a low to intermediate temperature (100 to 700°C) metamorphic process that occurs when some mantle rock forming minerals such as olivine, come into contact with water. Vast zones of exhumed and serpentinised mantle are exposed at slow to ultraslow spreading ridges. Serpentinisation of olivine in the presence of carbon dioxide releases methane that can potentially be stored in hydrate form within the pores/fractures of the serpentinite or in the sedimentary overburden, if stable hydrate temperature and pressure conditions exist. Globally, most hydrate forming methane is produced by degradation of organic matter. However, abiotic methane from serpentinisation may be an important source of methane forming hydrates in slow to ultraslow spreading ocean basins, such as in areas below the Arctic Ocean, and also amagmatic continental margins. This project aims to understand, quantify and assess the contribution of abiotic methane to the formation of hydrate in all known slow to ultraslow spreading ocean basins on Earth. Insights from this work will also contribute to current theories about the possibility of abiotic methane forming hydrate in Mars.

Methodology:

The student will follow a set clearly defined stages:

(i) Collect geophysical (elastic and electrical properties) and petrophysical characteristics (pore size distribution and permeability) of serpentinised mantle from all known slow and ultraslow spreading ocean basins on Earth;
(ii) Laboratory experiments on serpentinite samples to further characterize the geophysical and petrophysical properties in (i), and assess their influence on methane flow and/or hydrate formation within and/or outside serpentinites;
(iii) Determination and assessment using numerical modelling of serpentinite bearing basins which currently have pressure and temperature conditions that allow methane hydrate stability;
(iv) Combination of petrophysical and geophysical data with thermal, hydrological and chemical modelling to understand and quantify the potential amount of hydrate that could exist in slow and ultraslow ocean basins from serpentinisation-derived methane.

Training:

The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at the National Oceanography Centre Southampton. Specific training will include:

(i) Laboratory petrophysical measurement techniques
(ii) Petrological analysis (e.g. thin section analysis)
(iii) Scientific computational skills that can be transferred easily to a range of fields after graduation;

The student will have the opportunity to present their results to academic, government-funded and industrial specialists, and will be thoroughly coached in the skilful delivery of their methods and results to these audiences in both verbal and written form. The student will be rigorously trained in the art of scientific communication in the form of academic papers for international journals. This will equip the student for future employment in the marine realm in both industry and academia/research.