Experimental modeling of rifting at craton margins
Por:
Corti G., Iandelli I., Cerca M.
Publicada:
1 feb 2013
Resumen:
Lithospheric-scale centrifuge models are used to investigate the process of continental rifting at the margins of cratonic areas. Models reproduce extension between a resistant cratonic lithosphere and an adjacent, weaker mobile belt and investigate the influence of the strength contrast between craton and belt and the presence or absence of an intervening weak zone (such as a suture) on the extensional deformation. Model results suggest that regardless of craton and belt strength contrast, the presence of the weak zone strongly localizes deformation, leading to the development of narrow, deep rift valleys corresponding at depth to marked lithospheric thinning. Depending on the pre-rift rheology (in particular depending on the presence of a significant decrease of the brittle-ductile transition depth in the belt domain), the resulting basin can be largely asymmetric, with a major border fault system on the craton side. When the weak zone is absent, deformation is typically more distributed and lithospheric thinning more homogeneous. In these conditions the strength contrast between craton and belt strongly controls deformation: when the contrast is minimal, no major faults form at the craton-belt boundary, and a roughly symmetric deformation affects a wide region inside the strong mobile belt after the initial stages of extension. Conversely, for high strength contrasts, more asymmetric deformation is localized on a major fault system at the craton margin at the beginning of extension; with progressive extension, minor faulting propagates inside the weak belt, widening the deformed zone. Comparison with different natural examples suggests that these results may be important and have relevance for the development of continental rifts at the margins of cratonic areas. © 2013 Geological Society of America.
Filiaciones:
Corti G.:
Consiglio Nazionale delle Ricerche (CNR), Istituto di Geoscienze e Georisorse, U.O. Firenze, Via G. La Pira 4, 50121 Florence, Italy
Iandelli I.:
Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via G. La Pira 4, 50121 Florence, Italy
Cerca M.:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Queretaro 76230, Mexico
Centro de Geociencias, Universidad Nacional Autónoma de México, Campus Juriquilla, Apartado Postal 1-742, Querétaro 76230, Mexico
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