Download One of the mysteries of the sea are the large number of seamounts

Project EARTH-14-ABW1: A geophysical study of the crustal and upper mantle
structure of the UAE/Oman mountains: Implications for foreland basin formation and
ophiolite emplacement
Supervisors: A. B. Watts and M. Y. Ali (Petroleum Institute, Abu Dhabi)
Seismic reflection and refraction profile data provide constraints on the structure, composition
and rheological properties of mountain belts, but little is known about the mechanism by
which the crust thickens in orogenic belts and the relative role of isostatic processes such as
thrust/fold loading compared to non-isostatic processes such as mantle convection. One
problem is the limited number of active source seismic transects of mountain belts. Arguably,
the best data has been acquired offshore of orogenic belts (e.g. BIRPS). One orogenic belt,
which is bounded on both its sides by water, but has not yet been explored, is located in the
Middle East, in UAE/Oman. This mountain belt comprises one of the world’s best known
ophiolites which were emplaced on the Arabian rifted continental margin during the Late
Cretaceous by obduction of oceanic crust and upper mantle formed on or near a ‘back-arc’
spreading centre. This studentship forms part of a joint project between the Petroleum
Institute and the University of Oxford to use land recording stations and a research vessel
equipped with a large-volume air-gun array, a long multichannel seismic streamer and ocean
bottom seismometers to constrain the deep structure of the UAE/Oman mountain belt. The
objective of the project is to determine the P-wave velocity structure and crustal thickness of
the mountain belt and use it, together with potential field data, to constrain geological
processes such as those associated with ophiolite emplacement, exhumation and foreland
basin and crustal ‘root’ formation. The student will participate in all aspects of the acquisition,
processing and interpretation of the seismic data which we anticipate will be collected during
field work in late 2014. The project will involve the manipulation of large seismic, receiver
function, gravity and magnetic and topography data sets and the analysis of these data using
GMT, Globe Claritas and in-house UNIX-based software. The student will be based in
Oxford, but there will opportunities to visit the Petroleum Institute in Abu Dhabi and to
collaborate with scientists there. The project should appeal to students interested in working
at the boundaries of geology and geophysics on a topic that is central to current efforts to
better understand the structure of mountain belts and the role played by plate mechanics and
mantle dynamics in their formation.
Selected references
Ali MY, Watts AB. 2009. Subsidence history, gravity anomalies and flexure of the United Arab Emirates (UAE)
foreland basin. GeoArabia 14: 17-44
Ali MY, Watts AB. 2013. Subsidence history, crustal structure and evolution of the Somaliland-Yemen conjugate
margin. J. Geophys. Res.