Abstract
Analogue experiments were carried out to get insights into the processes governing positive inversion during the foreland propagating thrust tectonics in the southern Serra do Espinhaço, a Brasiliano/Panafrican foldthrust belt in southeast Brazil. In particular, model listric half-grabens were inverted by applying contractional displacement to the footwall blocks. We investigated two different inversion conditions in listric half-grabens: (i) extensional and contractional detachments at the same level and (ii) at different positions. The models revealed that the development of a forward-breaking thrust system occurs in the basin synrift deposits, by contractional translation of the extensional footwall block when the extensional and contractional master faults do not coincide. Our experiments show the tectonic imbrication between basement and synrift sequences which characterizes the southern Serra do Espinhaço, and support the location in the eastern mountain range domain of the Espinhaço rift master fault system, which is not exposed at the surface.
Highlights
The southern Serra do Espinhaço, a north-south trending, nearly 300 km long mountain range, lies in the external portion of the Late Neoproterozoic Araçuaí belt, a Brasiliano/Panafrican orogenic belt that formed on the eastern margin of the São Francisco craton, in southeastern Brazil (Fig. 1)
In experiment III we investigate the contractional translation of the former extensional hanging wall, locating the two basal detachments at different positions
Our experiments demonstrate that in a positive inversion environment, when the contractional translation occurs along a basal detachment situated at a higher level with respect to the listric extensional one, the structural pattern greatly depart from the classic inversion pattern described until now in sandbox experiments
Summary
The southern Serra do Espinhaço, a north-south trending, nearly 300 km long mountain range, lies in the external portion of the Late Neoproterozoic Araçuaí belt, a Brasiliano/Panafrican orogenic belt that formed on the eastern margin of the São Francisco craton, in southeastern Brazil (Fig. 1). The Serra do Espinhaço is a west-verging thrust-fold belt originated by positive inversion of pre-existing extensional structures. Many sandbox experiments have been carried out to simulate crustal rifting and extensional fault systems (e.g. McClay and Ellis 1987, Allemand and Brun 1991, Higgins and Harris 1997) as well as positive inversion tectonics McClay 1989, Buchanan and McClay 1991, McClay and Buchanan 1992) These experiments show how structures progressively develop in the laboratory, providing coherent solutions and kinematic pathways that help unraveling the evolution of complex natural fault patterns
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
