1996-present
School of Environmental Sciences, University of East Anglia
Professor (since June 2009)
1989-1996
Department of Earth Sciences, University of Wales, Cardiff
Lecturer in Geology
1986-1989
Geology Department, University College, Cardiff
Lecturer in Applied Sedimentology
1983-1986
University of Leeds
Ph.D. Thesis title: "Sedimentary and Tectonic controls of alluvial faciesdistribution: Middle Jurassic, Yorkshire and North Sea Basins and Holocene, S.W. Montana, USA."
1980-1983
University of Bristol
BSc. Honours Geology 

 

• The Wollaston Fund of Geological Society of London 1997; Awarded to contributors to the Earth Sciences on the basis of noteworthy published research.
• The BP Exploration Prize 1991; A Partnership Trust award for innovation in teaching Geology and Geophysics in Higher Education.
• The Yorkshire Geological Society Fearnsides Prize 1986. 

CURRENT RESEARCH INTERESTS

My research interests and publications centre on understanding sediment movement in water currents and the nature of the resulting deposits. I am particularly interested in sediment dynamics in extreme or catastrophic flow events (subaerial or subaqueous).

Flash floods (including rainfall-triggered lahars) 

The runoff resulting from intense rainfall may generate flash floods and entrain large volumes of sediment directly as dissolved-, suspended- and bed-load and indirectly via slope failure. The high sediment flux adds greatly to the resulting hazard (both magnitude and variation in character). Better understanding and prediction of sediment movement and deposition could significantly improve risk mitigation. A multidisciplinary approach, integrating developments of in-situ flow monitoring, meteorology, hydrologic and hydraulic modelling, remote sensing and sedimentology is needed. I am involved in field, theoretical and laboratory studies addressing are range of aspects flash floods, including: a long-term study of the Belham Valley lahar system on Montserrat (with PhD student Janez Sušnik, Dr Jenni Barclay, Dr Richard Herd, Dr Adrian Matthews and others); studies of tropical cyclone induced flooding (see publications) and laboratory studies of sediment movement in rapidly changing conditions (flume lab web site).

Subaqueous sedimentary gravity currents

Subaqueous sedimentary gravity currents, and particularly turbidity currents, transport very large volumes of sediment into deep marine and deep lacustrine settings. The resulting deposits (notably turbidites) can form significant water, oil and gas reservoirs. My research in this area includes laboratory simulation and field observations. Recent work considers flow behaviour and deposit architecture at submarine channel mouths and within meandering channel (see publications). Currently PhD student James Hodson (jointly supervised by me, Dr A Kendall and Dr S Beavington-Penney of BG) is studying “Biogenic carbonate grain transport in gravity flows: sediment redistribution and the formation of calci-turbidite-hosted hydrocarbon reservoirs on carbonate platforms” (NERC Industrial CASE Studentship with BG Energy Holdings Limited).

Sedimentary transport mechanics

A sediment surface (e.g. river or sea bed) is a deformable boundary which may change in response to the flow conditions and may influence those flow conditions. Bedforms develop as a consequence of feedback between the flow and deformable bed, and sediment particles may move to and from the bed, into and out of bed and suspension load. I am involved in theoretical and laboratory studies on aspects of these complex interactions. My PhD student Robert Macdonald, together with his other supervisors Dr Mark Cooker (Maths School) and Dr John Bacon and myself, are studying the behaviour of sand and the bed under hydraulic jumps.

Jurassic fluvial rocks

I have a long standing interest in Jurassic sedimentary rocks and am currently reassessing some of the Middle Jurassic sequences of Yorkshire in the light of developments in the understanding of fluvial and shallow marine sedimentary processes.
 

TEACHING

Current teaching responsibilities include contributions to the following units at UEA:

ENV1A19 Environmental Sciences for International Development

ENV2A31 Volcanoes and Tectonics

ENV3A1Y Natural Hazards

ENV2A18 + ENV2AF18 Palaeoclimatology

ENV3A20 Global Environmental Change

 

CURRENT RESEARCH STUDENTS

James Hodson - Started Oct. 2005. Biogenic carbonate grain transport in gravity flows: sediment redistribution and the formation of calci-turbidite-hosted hydrocarbon reservoirs on carbonate platforms jointly supervised by me, Dr A Kendall and Dr S Beavington-Penney (BG). NERC Industrial CASE Studentship with BG Energy Holdings Limited.

Robert Macdonald - Started Oct. 2006. Sedimentary implications of hydraulic jumps. Jointly supervised by me, Dr Mark Cooker (MTH) and Dr John Bacon (ENV). NERC Studentship.

Janez Susnik - Started Oct. 2004. Catastrophic flood events incorporating volcanic sediments: the how and why on Montserrat. Jointly supervised by me, Dr J. Barclay and Dr Peter Talling (Bristol University). NERC Studentship.


HIGHLIGHTS OF PUBLICATION LIST

Alexander, J., Gray, T., McLelland, S., Vincent, C.E., Leeder, M.R. & Ellett, S. submitted. Channel mouth deposition from laboratory sustained turbidity currents. Sedimentology.

Mulder, T., Gaudin, M., Cirac, P., Bourillet, J.-F. & Alexander, J. submitted. Why terraces in submarine channels and canyons are not point bars. Submitted to Geology.

Barclay, J., Alexander, J. & Susnek, J., in press 2007. Rainfall induced lahars on Montserrat. Journal of the Geological Society of London.

Alexander, J. & Fielding, C.R.2006 Coarse-grained floodplain deposits in the seasonal tropics: towards a better facies model, Journal of Sedimentary Research 76, 539–556.

Fielding, C.R., Trueman, J. and Alexander J. 2006. Holocene depositional history of the Burdekin River Delta of Northeastern Australia: a model for a low-accommodation, highstand delta. Journal of Sedimentary Research 76, 411–428.

Gray, T. E., Alexander, J. & Leeder, M. R. 2006. Longitudinal flow evolution and turbulence structure of dynamically similar, sustained, saline density and turbidity currents. Journal of Geophysics Research 111, C08015, doi:10.1029/2005JC003089.

Gray, T.E, Alexander, J & Leeder, M.R. 2005. Quantifying velocity and turbulence structure in depositing sustained turbidity currents across breaks in slope. Sedimentology 52, 467-488.

Fielding, C.R., Trueman, J.D. & Alexander J. 2005. Sharp-based, flood-dominated mouth bar sands from the Burdekin River Delta of northeastern Australia: extending the spectrum of mouth bar facies, geometry and stacking patterns. Journal of Sedimentary Research 75, 55-66.

Fielding, C.R., Trueman, J.D. & Alexander, J. 2005. Sedimentology of the Modern and Holocene Burdekin River Delta of North Queensland, Australia – controlled by river output, not by waves and tides: Giosan, L. and Bhattacharya, J., eds., Deltas, New and Old: SEPM Special publication, 83, 467-496.

Leeder, M.R., Gray, T.E. and Alexander, J. 2005. Sediment suspension dynamics and a new criterion for the maintenance of turbulent suspensions, Sedimentology 52, 683-691.

Amos, K.J., Alexander, J., Horn, A., Pocock, G.D. & Fielding, C.R. 2004. Supply limited sediment transport in a high-discharge event of the tropical Burdekin River, North Queensland, Australia. Sedimentology 51, 145-162.

Moumani, K., Alexander, J. & Bateman, M. 2003. Sedimentology of the Late Quaternary Wadi Hasa Marl Formation of Central Jordan: a record of climate variability. Palaeogeography, Palaeoclimatology, Palaeoecology 191, 221-242.

Morris, S.A. & Alexander, J. 2003. Changes in flow direction at a point caused by obstacles during passage of a density current. Journal of Sedimentary Research 73, 621-629.

Alexander, J., Fielding, C.R., Wakefield, S.J., George, M.T., & Cottnam, C.F. 2002. Fluvial geochemistry through a short-duration, tropical-cyclone induced discharge event in the Burdekin River and Hann Creek, North Queensland, Australia, Aquatic Geochemistry 7, 275-293.

Nakayama, K. Fielding, C.R. & Alexander, J. 2002. Variation in character and preservation potential of vegetation-induced obstacle marks in the variable discharge Burdekin River of north Queensland, Australia. Sedimentary Geology 149, 199-218.

Alexander, J., Bridge, J.S., Cheel, R. & LeClair, S., 2001. Bedforms and associated sedimentary structures formed under supercritical water flows over aggrading sand beds. Sedimentology 48, 133-152.

Fielding, C. R. & Alexander, J., 2001. Fossil trees in ancient fluvial channel deposits: evidence of seasonal and longer-term climatic variability. Palaeogeogr. Palaeoclimat. Palaeoecol. 170, 59-80.

Mulder, T & Alexander, J. 2001a. The physical character of subaqueous sedimentary density currents and their deposits. Sedimentology 48, 269-299.

Mulder, T. & Alexander, J. 2001b. Abrupt change in slope causes variation in the deposit thickness of concentrated particle-driven density currents. Marine Geology 175, 221-235.

Alexander, J., Fielding, C.R. & Jenkins, G., 1999. Plant-material deposition in the tropical Burdekin River, Australia: implication for ancient fluvial sediments. Palaeogeography, Palaeoclimatology, Palaeoecology 153, 105-125.

Marriott, S. & Alexander, J. (editors) 1999. Floodplains: interdisciplinary approaches Geological Society of London, Special Publication, 163.

Bridge, J.S., Collier, R., Ll. & Alexander, J., 1998. Large-scale structure of Calamus River deposits (braid bars, point bars, and channel fills) revealed using ground-penetrating radar. Sedimentology 45, 977-986.

Alexander, J. & Fielding, C.R., 1997. Gravel antidunes in the tropical Burdekin Rivers, Queensland, Australia. Sedimentology 44, 327-337.

Fielding, C.R., Alexander, J. & Newman-Sutherland, E., 1997. Preservation of in situ vegetation in fluvial channel deposits - data from the modern Burdekin River of North Queensland, Australia. Submitted to Palaeogeography, Palaeoclimatology, Palaeoecology 135, 123-144.

Fielding, C.R. & Alexander, J., 1996. Sedimentology of the Upper Burdekin River of North Queensland, Australia - and example of a tropical, variable discharge river, Terra Nova 8, 447-457.

Bridge, J.S., Alexander, J, Collier, R.E.Ll., Gawthorpe, R.L. & Jarvis, J., 1995. Ground-penetrating radar and coring used to study the large-scale structure of point-bar deposits in 3 dimensions. Sedimentology 42, 839-852.

Alexander, J., Bridge, J.S., Gawthorpe, R.L., Leeder, M.R. & Collier, R.E.Ll., 1994.Holocene meander belt evolution in an extensional basin, SW Montana USA. Journal of Sedimentary Research 64B, 542-559.

Alexander, J., 1992. The nature and origin of a laterally extensive alluvial sandstone body in the Middle Jurassic Scalby Formation. Journal of the Geological Society, London, 149, 431-441.

Alexander, J. & Leeder, M.R., 1987. Active tectonic control of alluvial architecture. In: Ethridge, F.G., Flores, R.M. & Harvey, M.D. (eds.) Recent developments in fluvial sedimentology, SEPM (Society for Sedimentary Geology), Special Publication 39, 243-252.