Marine geology and geophysics: controlled source reflection and refraction seismology; coastal and ocean mapping with sidescan sonar and multibeam bathymetry.
Mantle plumes and continental breakup
A key question in the study of volcanic continental margins is whether their temporal-spatial pattern of magmatism is caused by mantle plumes (temperature and/or mantle composition anomalies) or by enhanced mantle flow. By developing a finite element model to account for mantle melting during breakup, we were able to show that, provided factors such as rift history are considered, thermal mantle plumes can explain the amount and properties of magmatism observed long the margins of the Indian and Atlantic Oceans. I am currently collaborating with industry (ION-GX) to use specialist data to further test these ideas and gauge their implications for hydrocarbon reserves.
The solid Earth water cycle
Subduction zones are the locations of the largest exchange of material from the surface to the deep Earth. However, currently we have little information on the passage of volatiles through this system, and have been unable to attempt any form of mass balance to estimate how much of it enters the deep interior. Over the past 18 months, we have been collecting field data in the Caribbean, with a year-long broad-band ocean-bottom seismic array, an active source experiment with 150 ocean-bottom seismometer deployments, and installation of seismometers along the island arc. My team will conduct a joint inversion of these data for velocity and attenuation structure, with the aim of establishing whether the along-strike pattern of water within the incoming plate controls the melting that forms the volcanic island arc. The results will be verified by considering how any spatial patterns would map into basalt chemistry.
Island Britain or “Brexit 1.0”
For much of our pre-history, a permanent land bridge existed between England and France at the Dover Strait. How or when it was removed, however, was until recently unknown. Following a grant for a suite of high-resolution sonar, I conducted the first ever multi-beam bathymetric survey of the UK continental shelf, which led to the discovery of a megaflood landscape carved into the floor of the English Channel. This feature could only be formed by a catastrophic failure of the rock ridge, resulting in the sudden isolation of Britain from continental Europe. This dramatic event significantly altered the pattern of human colonisation of Britain.
For further information on these and other projects see:
I am a member of the Geodynamics: Core to Surface research group
- Reader, Imperial College London, 2011-date
- Senior lecturer, Imperial College London 2002- 2011
- Lecturer, Imperial College London 1998-2002
- NERC Fellow, University of Cambridge 1996-98
- Lecturer, University of Leeds 1995-96
- Post-doctoral researcher, University of Oxford 1990-94
- PhD, University of Cambridge 1986-89
- MSc, University of Durham 1985-86
et al., 2017, Two-stage opening of the Dover Strait and the origin of island Britain, Nature Communications, Vol:8, ISSN:2041-1723
Collier J, 2017, A megaflood in the English Channel, Astronomy and Geophysics, Vol:58, ISSN:1366-8781, Pages:2.38-2.42
et al., 2017, Bathymetric mapping of the coastal and offshore geology and structure of the Jurassic Coast, Weymouth Bay, UK, Journal of the Geological Society, Vol:174, ISSN:0016-7649, Pages:498-508
et al., 2017, New constraints on the age and style of continental breakup in the South Atlantic from magnetic anomaly data, Earth and Planetary Science Letters, Vol:477, ISSN:0012-821X, Pages:27-40
Taposeea CA, Armitage JJ, Collier JS, 2016, Asthenosphere and lithosphere structure controls on early onset oceanic crust production in the southern South Atlantic, Tectonophysics, ISSN:0040-1951