Chercheurs

Sciences de la Terre / MCKENZIE, DAN P.

Position

Professor at the Department of Earth Sciences, University of Cambridge, UK.

Thèmes de recherche

geophysics

Gravity fields of this and other planets continue to yield important information about the thickness of the elastic layer close to their surfaces, and about the convective circulation that controls heat loss from their interiors. Mr D. Barnett, Dr F. Nimmo and him have analysed the gravity data from Venus from cycles 5 and 6 of the Magellan Project, collected as the spacecraft was failing, and have confirmed that the elastic layer has a thickness of between 15 and 30 km. This work completes a long and successful project that has used our knowledge of the dynamics of the Earth to understand that of Venus. Dr F. Nimmo and him attempted to carry out a similar study of Mars with less success, because its topography is still too poorly known. However, what they did find is that some of the largest convective plumes in the Martian mantle are associated with huge dyke swarms. Some of the large canyon systems are produced by the extension associated with dyke intrusion.

His other major research interest is the generation and movement of basaltic melt. This year he has been working with two groups of geochemists in the US and France on the isotopic ratios of Sr, Nd and Hf in basalts from the Theistareykir region of NE Iceland. These show large variations within a single ridge segment, and even within a single flow. Mr J. Maclennan, Ms F. Hilton and him returned to Iceland this summer to collect 80 samples from Borgarhraun, one of the flows that shows the largest variations in composition, even though it was produced in a single eruption. These samples are now being analysed. Mr G. Walker and him have been carrying out numerical experiments using the equations that govern two phase flow, to understand the fluid dynamical processes involved. A surprising result is that solitary waves in such systems can lock together and move in phase, even when they are separated by several compaction lengths.

Prix et récompenses

2001 William Bowie Medal
Crafoord Prize 2002 "for fundamental contributions to the understanding of the Dynamics of the Lithosphere, particularly Plate Tectonics, Sedimentary Basin Formation and Mantle Melting".

Publications

Barnett, D. N. / Nimmo, F. / McKenzie, D. P.
Title: Flexure of Venusian lithosphere measured from residual topography and gravity
Journal title: Journal of Geophysical Research (In Press)

McKenzie, D. P.
Title: The oceanic tape recorder: Magnetic anomalies in the oceans
Book title: Seminal Nature (In Press)

Maclennan, J. / McKenzie, D. P. / Hilton, F. / Gronvöld, K. / Shimizu, N.
Title: Geochemical variability in a single flow from northern Iceland
Journal title: Journal of Geophysical Research (In Press)

Parke, J. R. / White, R. S. / McKenzie, D. P. / Minshull, T. A. / Bull, J. / Kuscu, I. / Gorur, N. / Sengör, A. M. C.
Title: The Sea of Marmara - a 2D seismic reflection profile data archive
Journal title: G3 Geochemistry Geophysics Geosystems (In Press)

Parke, J. R. / White, R. S. / McKenzie, D. P. / Minshull, T. A. / Kuscu, I. / Gorur, N. / Sengor, A. M. C.
Title: Active slumping and tectonics in the south-western Black Sea
Journal title: Journal of the Geological Society (In Press)

Priestley, K. F. / McKenzie, D. P.
Title: The structure of the Upper Mantle beneath Southern Africa
Journal title: Special Publication of the Geological Society of London (In Press)