Abstract
Subduction along the western margin of South America has been active since the Jurassic, but Andean orogeny started in the middle Cretaceous and was preceded by backarc extension in the Jurassic-Early Cretaceous. The timing and sequence of these events has remained unexplained. Here I present a four-dimensional buoyancy-driven whole-mantle subduction model implying that the ~200 Myr geological evolution can be attributed to sinking of a wide slab into a layered mantle, where upper-mantle wide-slab subduction causes backarc extension, while whole-mantle (upper+lower) wide-slab subduction drives Andean orogeny. The model reproduces the maximum shortening and crustal thickness observed in the Central Andes and their progressive northward and southward decrease. The subduction evolution coincides with a 29° decrease in slab dip angle, explaining ~200 km of Jurassic-present eastward migration of the Central Andean magmatic arc. Such arc migration negates proposed long-term subduction erosion and continental destruction, but is consistent with long-term crustal growth.
| Original language | English |
|---|---|
| Article number | 2010 |
| Journal | Nature Communications |
| Volume | 8 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1 Dec 2017 |
Funding
Discussions with Zhihao Chen, Pieter Vroon, Gordon Lister, Joao Duarte, Vincent Strak, and Louis Moresi on subduction dynamics, Andean geology, mountain building, continental crustal growth and computational geodynamics are greatly appreciated. I would like to thank Louis Moresi, Mirko Velic, Julian Giordani, John Mansour, and Owen Kaluza for technical support with, and continuous development of, the Underworld code. I would also like to thank the reviewers Nadine McQuarrie, Laurent Husson, and Margarete Jadamec for their helpful comments. This work has been funded by a Vici Fellowship (016.VICI.170.110) from the Dutch National Science Foundation (NWO), and has been supported by computational resources from the NCI National Facility in Australia through the National Computational Merit Allocation Scheme (project ei8).
| Funders | Funder number |
|---|---|
| National Computational Infrastructure | |
| Nederlandse Organisatie voor Wetenschappelijk Onderzoek |
