Photo of Em P Nick Kusznir

Em P Nick Kusznir BSc, PhD

Emeritus Professor of Geophysics Earth, Ocean and Ecological Sciences

Research

Research Overview

"His early career research investigated the geophysical and geodynamic response of the Earth’s lithosphere to applied forces and the resulting deformation. His recent research has focussed on the structure and formation processes of rifted continental margins and global marine crustal thickness mapping using satellite gravity anomaly data. In 2019 he was awarded the Lyell Medal of the Geological Society of London for his scientific contributions to rifted continental margin research.

His current research includes:
(i) quantitative observations of the distribution and timing of lithosphere thinning and stretching at rifted continental margins and the investigation of ocean-continent transition structure and formation processes;
(ii) development of new models of continental breakup, sea-floor spreading initiation and rifted margin formation;
(iii) crustal thickness mapping at rifted continental margins, micro-continents and oceanic plateaux using satellite gravity anomaly data.

To date he has published over 125 paper in international journals (Citations = 8560, H-Index = 54) and has supervised over 60 PhD students, the majority of whom have gone into industry. His scientific contributions were spotlighted in the 2006 NERC (UKRC) report to UK Government.

His Key scientific contributions include:
(i) the prediction of upward stress transfer and amplification within continental and oceanic lithosphere and its thermo-rheological control of lithosphere strength;
(ii) the development of the flexural cantilever model of intra-continental rift basin formation and its application to quantitative structural and stratigraphic modelling;
(iii) the observation of lithosphere depth-dependent lithosphere stretching and thinning at rifted continental margins and its implications for rifted margin formation and evolution;
(iv) the development and successful testing of new models of continental lithosphere stretching and thinning leading to continental break-up and sea-floor spreading initiation;
(v) the development and application of new geophysical techniques for mapping crustal thickness and ocean-continent transition structure using satellite gravity inversion and the production of the first comprehensive crustal thickness maps for the Arctic and Antarctic polar regions.

In the last decade he has co-led a sequence of industry consortia research projects (iSIMM, MM2, MM3, MM4, M5) focussing on rifted continental margin structure and formation processes.
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Global Crustal Thickness Mapping Using Satellite Gravity Inversion

Until our development of a new geophysical technique to determine crustal thickness in oceanic regions using satellite gravity anomaly data, the measurement of crustal thickness in the oceans and continental shelves was limited to costly and spatially limited (2D) seismology techniques. The key innovation within the new gravity inversion is the incorporation of a self-consistent correction for the lithosphere thermal gravity anomaly component. This new technique together with the availability of high quality satellite derived free-air gravity anomaly data provides, for the first time, detailed 3D regional mapping of marine crustal thickness and has been applied globally. It has been used extensively to explore rifted continental margin structure and locate the continent-ocean boundary. In addition it has been applied to map and investigate micro-continents and oceanic plateaux. Using this new technique, we have produced the first comprehensive crustal thickness maps for the Arctic and Antarctic polar regions.




Determining Ocean-Continent Transition Structure and Composition

The transition from thicker continental crust to thin oceanic crust is complex and occurs in very deep-water often many hundreds of kilometres offshore. Understanding the structure and location of the ocean-continent transition is important for natural resource exploration and territorial claims under the law of the sea. We have developed an innovative set of geophysical and geodynamic analytical techniques to determine ocean-continent transition structure and composition at rifted continental margins. These quantitative techniques consist of gravity inversion to give Moho depth and crustal thickness, sediment corrected RDA analysis to give departures from oceanic water depth, flexural subsidence analysis to give lithosphere thinning and joint inversion of time seismic and gravity data to give lateral variations in basement density and seismic velocity. The integrated analysis of these techniques provides a powerful technique for determining the location and character of rifted margin proximal, necking zone, hyper-extension, exhumed mantle and oceanic domains which together comprise the ocean-continent transition.

The Geometry and Evolution of Extensional Faulting at Rifted Margins and the Resulting Structures and Stratigraphy

The geometry of active extensional faults during rifted continental margin formation, their evolution and the resulting structures and stratigraphy are poorly understood and contentious. In order to investigate these processes, we have developed a kinematic structural-stratigraphic forward model incorporating the flexural isostatic response to fault extension, crustal thinning, sedimentation, erosion and thermal loads during extreme stretching and thinning of continental lithosphere leading to rifted margin formation. We use this model to examine the geometry and evolution of extensional faults during the hyper-extension phase of rifted margin formation, the formation of crustal allochthon blocks and the transition between the hyper-extended and exhumed mantle domains.

Research Group Membership