Coupling Between Lithosphere Removal and Mantle Flow in the Central Andes

Huilin Wang, Claire A. Currie, Peter G. DeCelles

Research output: Contribution to journalArticlepeer-review

Abstract

The central Andes is part of a Cordilleran orogen formed through continent-ocean convergence. In contrast to the thickened crust, the mantle lithosphere below much of the orogen is anomalously thin. Additionally, the surface is characterized by widespread backarc magmatism and transient ∼100-km-wide basins that developed the over last 30 million years, with basins located systematically seaward of major backarc ignimbrite centers and basin formation predating the late Miocene magma/ignimbrite flare-up. Using numerical models, we propose a novel mechanism whereby lithosphere removal is coupled with mantle flow. First, a small area of high-density eclogitized lower crust initiates a gravitational instability, causing a localized basin at the surface that subsides and then uplifts. Foundering crust and adjacent lithosphere are entrained by subduction-induced mantle flow, driving regional lithosphere removal and magmatism. The models demonstrate that mantle flow can amplify a local lithosphere instability to orogen-wide lithosphere removal, rapidly eliminating accumulated mass in the orogen.

Original languageEnglish (US)
Article numbere2021GL095075
JournalGeophysical Research Letters
Volume48
Issue number16
DOIs
StatePublished - Sep 16 2021

Keywords

  • Andean subduction
  • hinterland basins
  • ignimbrite magmatism
  • lithosphere removal
  • mantle flow

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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