South-American plate advance and forced Andean trench retreat as drivers for transient flat subduction episodes.
Nat Commun
; 8: 15249, 2017 05 16.
Article
em En
| MEDLINE
| ID: mdl-28508893
ABSTRACT
At two trench segments below the Andes, the Nazca Plate is subducting sub-horizontally over â¼200-300 km, thought to result from a combination of buoyant oceanic-plateau subduction and hydrodynamic mantle-wedge suction. Whether the actual conditions for both processes to work in concert existed is uncertain. Here we infer from a tectonic reconstruction of the Andes constructed in a mantle reference frame that the Nazca slab has retreated at â¼2 cm per year since â¼50 Ma. In the flat slab portions, no rollback has occurred since their formation at â¼12 Ma, generating 'horse-shoe' slab geometries. We propose that, in concert with other drivers, an overpressured sub-slab mantle supporting the weight of the slab in an advancing upper plate-motion setting can locally impede rollback and maintain flat slabs until slab tearing releases the overpressure. Tear subduction re-establishes a continuous slab and allows the process to recur, providing a mechanism for the transient character of flat slabs.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Nat Commun
Assunto da revista:
BIOLOGIA
/
CIENCIA
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Holanda