# Kinematics of mountain-building of the Central Andes, from structural geology to analogue modeling

Martine Simoes, Robin Lacassin, Magali Riesner, Tania Habel, Benjamin Guillaume, Anne Replumaz, Daniel Carrizo, Audrey Margirier, Thomas Geffroy

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## ► To cite this version:

Martine Simoes, Robin Lacassin, Magali Riesner, Tania Habel, Benjamin Guillaume, et al.. Kinematics of mountain-building of the Central Andes, from structural geology to analogue modeling. 29 ème édition de la réunion des sciences de la Terre (RST 2025), Société Géologique de France (SGF), Oct 2025, Montpellier, France. pp.665654. insu-05379312

HAL Id: insu-05379312

https://insu.hal.science/insu-05379312v1

Submitted on 24 Nov 2025

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# Kinematics of mountain-building of the Central Andes, from structural geology to analogue modeling.

Martine Simoes*†<fnref n="1" />, Robin Lacassin<fnref n="2" />, Magali Riesner<fnref n="3" />,<fnref n="4" />, Tania Habel<fnref n="4" />, Benjamin Guillaume<fnref n="5" />, Anne Replumaz<fnref n="6" />, Daniel Carrizo<fnref n="7" />,<fnref n="8" />, Audrey Margirier<fnref n="9" />, and Thomas Geffroy<fnref n="10" />

## Résumé

The processes driving Andean mountain-building, along a subduction margin, have been largely questioned since the ~1970s but have remained relatively unclear, in particular within the western part of the belt where the geometry of structures is most often obliterated by active magmatism. The discovery of the active West Andean fold-and-thrust belt along the western Andean flank at the latitude of Santiago (Chili, ~33.5°S) (Armijo et al., 2010) has

<footnote n="1">¹CNRS - Institut de Physique du Globe de Paris – Université Paris Cité, Institut de physique du globe de Paris, CNRS, F-75005 Paris, France – France</footnote>

<footnote n="2">²Institut de Physique du Globe de Paris – Université Paris Cité, Institut de physique du globe de Paris, CNRS, F-75005 Paris, France – France</footnote>

<footnote n="3">³Centre européen de recherche et d'enseignement des géosciences de l'environnement – Institut de Recherche pour le Développement, Aix Marseille Université, Collège de France, Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Institut de Recherche pour le Développement :
UMR_D161, Aix Marseille Université : UMR34, CollègedeFrance :
UMR7330, CentreNationaldelaRechercheScientifique :
UMR7330, InstitutNationaldeRecherchepourl'Agriculture,l'Alimentationetl'Environnement :
UMR1410 – France</footnote>

<footnote n="4">⁴Institut de Physique du Globe de Paris – Université Paris Cité, Institut de physique du globe de Paris, CNRS, F-75005 Paris, France – France</footnote>

<footnote n="5">⁵Géosciences Rennes – Université de Rennes, Institut National des Sciences de l'Univers, Observatoire des Sciences de l'Univers de Rennes, Centre National de la Recherche Scientifique – France</footnote>

<footnote n="6">⁶Institut des Sciences de la Terre – Institut National des Sciences de l'Univers, Institut de recherche pour le développement [IRD] : UR219, Université Savoie Mont Blanc, Centre National de la Recherche Scientifique, Université Gustave Eiffel, Université Grenoble Alpes, Centre National de la Recherche Scientifique : UMR5275 – France</footnote>

<footnote n="7">⁷University of Chile, Advanced Mining Technology Center, Department of Geology – Chili</footnote>

<footnote n="8">⁸Geokun – Chili</footnote>

<footnote n="9">⁹Institute of Earth Surface Dynamics, University of Lausanne – Suisse</footnote>

<footnote n="10">¹⁰Géosciences Rennes – Université de Rennes, Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique – France</footnote>

<footnote>*Intervenant</footnote>

<footnote>†Auteur correspondant: simoes@ipgp.fr</footnote>
launched a vigorous debate on the relative contribution of the structures of the west Andean
flank to overall Andean mountain-building.

Here we review our most recent work on the structures and kinematics of deformation of the western Andes at two distant latitudes (−33.5 ◦S and −20.0◦S). Our approach is based on structural mapping, in the field and using satellite imagery, with particular emphasis on dated growth layers for the kinematic modeling of the investigated structures. Our results indicate that Andean mountain-building appears to have first been primarily sustained by west-vergent structures, synthetic to the subduction zone, at both investigated latitudes. Furthermore, in both cases, deformation evolved over time towards out-of-sequence thrusting and /or later east-vergent thrusting towards the South American continent. Such kinematics may possibly be found, to the first-order, all along the Andes and we question the idea that it could be characteristic of Andean mountain-building. From there, a first-order comparison of the evolution of this cordilleran orogen to that of collisional systems can be tentatively addressed.

To further investigate the processes driving Andean mountain-building, we recently set up
a series of analogue models of a subduction zone, exploiting an original experimental set-up
where plate kinematics is driven by the underlying mantle flow. We first explored the geo-
dynamic conditions that permit upper plate deformation in an oceanic subduction context.
Following on these achievements, future work will test and use a new analogue material ca-
pable of localizing deformation to tentatively reproduce the observed Andean kinematics of
deformation and unravel the parameters controlling it.

Mots-Clés: subduction orogen, structural geology, analog modeling