Continental collision zones form extensive mountain ranges and high plateaus. They are associated with significant crustal recycling through magmatic, metamorphic, and erosional processes. The dramatic rise of mountain belts also influences global climate and ocean geochemistry, leading to long-term environmental changes and faunal extinctions. To understand these agents of global change, it is therefore important to constrain the timing and mechanisms of major mountain-growth episodes.
Although mountain belts are the crucible of our understanding of orogenesis, most mountain belts are only studied in one direction: parallel to the tectonic transport. This approach has revealed important across-strike variations from metamorphic hinterlands towards foreland thrust systems and led to ground-breaking advancements in orogenic models, but downplayed significant along-strike variations observed within most orogens. Equally underappreciated is the fact that inherited (pre-orogenic) structures influence the development of the orogenic architecture throughout the orogen’s cycle. To fully understand mountain building processes, it is therefore necessary to complement the understanding of the orogenic system with a clear depiction of the pre-orogenic configuration of the colliding plates. The Himalayan system is chosen as a natural laboratory because of its spectacular and unravelled preservation, recognized pre-Himalayan basement cross-structures, known tectonic plate configuration, convergence rates and recent evolution, and consequently limited tectonic overprinting enabling the distinction between Himalayan and pre-Himalayan deformation.
The long-term objective of my Himalayan research is to gain an understanding of the dynamics of continent-continent collision zones, with a focus on the structural and thermal evolution of the continental crust in collisional mountain belts, and the role old basement faults may have add in influencing the mountain belt’s evolution. My research aims to identify and analyse lateral variations in the Himalayan orogen, and to elucidate how such variations may be linked with the pre-collision internal configuration of the underthrusting plate. Specifically, my goal is a comprehensive understanding of the 3D temporal evolution of orogenic systems including the influence of pre-collision structural heterogeneities within the underthrusting plate.
These goals are achieved through several graduate student-led projects such as:
-3D reconstruction of the foreland fold-thrust belt using seismic data;
-Field and lab investigations to assess along-strike variation in strain, metamorphic peak conditions, and exhumation of the Himalayan metamorphic core;
-Numerical stress modelling linking present-day seismicity, stress trajectories, and cross-strike basement faults;
-Dynamically-scaled centrifuge analogue modelling of deformation.
My research program provides key dynamic links to understand basement cross-structures in the evolution of older mountain belts, such as the Appalachians, the Canadian Cordillera, and the Grenville orogen. Such lateral discontinuities have been interpreted to control earthquake ruptures, influence lateral sedimentary thickness variations and fold-thrust belt geometry, and may be related to deep-seated structures that can localize mineralizing fluids and control hydrocarbon migration through the foreland basin, such as what is observed in the Western Canadian sedimentary basin. In the case of the Himalayan system, such hidden geohazard controls can have tremendous repercussions for one of the most densely-populated regions on Earth. (Read more).