John P. Platt
The 2018 Stephan Mueller Medal is awarded to John P. Platt for his pioneering research in structural geology, which has fundamentally increased our understanding of deformation processes at plate margins through careful linking of field studies with mechanical and analytical analyses.
John Platt is an enthusiastic and outstanding structural geologist who combines careful observations of natural systems with mechanical analyses to understand how deformation occurs on scales spanning from the microscopic to that of lithospheric plates. He has made seminal contributions to our understanding of the dynamics of orogens, the exhumation and emplacement of high-pressure rocks and the importance of low-angle normal faults. His research brings together geology, microstructural analyses, geochronology, thermal modelling, palaeomagnetism, petrology and geophysics. His ideas are internally consistent, thought-provoking, and logical. They have stimulated many structural geologists to go out into the field to collect data to prove or disprove his conclusions. In this sense, his impact on modern structural geology and tectonics in a geophysical framework is exemplary.
His seminal paper on the dynamics of orogenic wedges, and uplift and exhumation of high-pressure metamorphic rocks, has been referenced almost a thousand times. This work is an excellent example of how Platt is able to marshal knowledge from continuum mechanics and rock rheology, combine this with detailed knowledge of field relationships in a wide variety of orogenic belts and tackle a fundamental problem in tectonics. The idea that large-scale extensional deformation may be important in active convergent margins and form a major cause of exhumation is original to this work. He was also one of the first to recognise the extensional nature of the major tectonic features in the Betic Cordillera of southern Spain. The early work of Platt in the European Alps showed, again as one of the first, how rock fabrics combined with petrological and age data can be used to constrain the kinematics of plate motions throughout the history of subduction and collision.
Over the past seven years, Platt’s research has focused on the western US Cordillera, especially on basin and range core complexes and their implications for rheology and strain localisation in the middle continental crust. This research has garnered much attention from the geophysics and rock mechanics communities. Very recently, he has ‘returned to his roots’, and is focusing on the Franciscan subduction complex in northern California and subduction zone mechanics.
In addition to his outstanding research achievements, Platt has also been highly successful in nurturing young researchers many of whom now work in industry and academia throughout the world. For all these reasons he is a worthy recipient for the 2018 Stephan Mueller Medal.