Investigating the Dynamic Drivers Shaping Fold and Thrust Belts From Plate Margins to Intracontinental Settings

Abstract

This thesis employs a combination of fieldwork and numerical modelling to explore the formation and evolution of fold and thrust belts in both plate margin and intracontinental settings. It addresses four key research questions regarding gravitational forces, lithospheric rheology, structural and thermal inheritance, and the drivers behind intracratonic fold and thrust belt formation. The study comprises three manuscripts:

The first manuscript investigates how the interplay between tectonics and isostasy affect fold and thrust belt development. It shows that a ductile-flow-facilitated isostatic adjustment results in narrower, more complex fold-thrust belt architectures, while elastic flexure of the lithosphere leads to wider, structurally simpler fold-thrust belts. These findings are contrasted with the Bolivian and Peruvian Subandean zones.

The second manuscript compares the evolution of fold and thrust belts formed from wide and narrow rifts. It discusses how the Earth's geotherm influences the mode of continental rifting and how these modes, in turn, impact the structural development during rift inversion. Numerical experiments are compared with the Colombian Eastern Cordillera, the Centralian Superbasin, and the Araçuaì West-Congo Orogen.

The third manuscript presents a unique case of orogeny deep within the interior of a craton, examining the relationship between the Entia Dome and the Arltunga Nappe Complex. The research suggests that the Dome to Duplex tectonics in the Eastern Arunta region may have formed through contractional gravitational collapse of the Irindina Rift.

Overall, the thesis sheds light on the role of gravitational forces, lithospheric rheology, and rift inheritance in shaping fold and thrust belts. It introduces new perspectives on the tectonic processes in various geodynamic environments, including the first documented case of major contractional gravitational collapse.