Contents lists available at ScienceDirect Journal of Structural Geology journal homepage: www.elsevier.com/locate/jsg Analogue modeling of large-transport thrust faults in evaporites-floored basins: Example of the Chazuta Thrust in the Huallaga Basin, Peru Sandra Borderie a,* , Bruno C. Vendeville a , Fabien Graveleau a , César Witt a , Pierre Dubois a,1 , Patrice Baby b , Ysabel Calderon c a Univ. Lille, CNRS, Univ. Littoral Côte d’Opale, UMR CNRS 8187, LOG, Laboratoire d'Océanologie et de Géosciences, F 59 000, Lille, France b Géosciences Environnement Toulouse (GET), Université de Toulouse, CNRS UMR 5563 / UR 234 IRD / UPS Toulouse / CNES, 14 Avenue Edouard Belin, 31400 Toulouse, France c PERUPETRO S.A., Avenida Luis Aldana n 320, San Borja, Lima, 41, Peru ARTICLE INFO Keywords: Huallaga Basin Chazuta thrust Evaporitic décollement Analogue modeling Strain localization Surface processes ABSTRACT The Huallaga Basin is a deformed foreland basin located in North Peru. The basin comprises several syntectonic depocenters. The most significant is the Biabo Syncline located at the back of the Chazuta Thrust, a long, flat- floored thrust detaching on an evaporitic décollement, which has accommodated more than 40 km of horizontal displacement. The hangingwall of the Chazuta Thrust has remained remarkably intact with little or no internal deformation and has incorporated a large volume of evaporites at its base. In order to unravel the formation and evolution of this thrust, we conducted a series of physical experiments that tested the role of various parameters. The goal is to investigate a system in which most of the deformation is accommodated in the frontal part of the chain (Chazuta Thrust), whereas deformation of the thrust sheet itself remains minor. Results from our experimental investigations suggest that the three key parameters that have allowed for such a long-lived, large-slip frontal thrust to operate are (1) the wedge-shaped syn-kinematic sedimentation, (2) the presence of the Biabo Syncline, which acted as a bulldozer pushing the evaporites forward, forcing their distal inflation and (3) the erosion at the front that favored farther advance of the frontal thrust, dragging passively large volumes of evaporites along with it. 1. Introduction It has long been demonstrated that the dynamics of fold-and-thrust belts (FTBs) is notably controlled by the interaction between tectonic and climate surface processes (erosion and sedimentation) (e.g. Dahlen, 1990; Whipple, 2009; Willett et al., 1993). However, getting direct field evidence proving this has been challenging. Analogue and numerical modeling has greatly helped in better understanding the mechanisms by which both erosion and sedimentation can modify the mechanical equilibrium of such accretionary systems (see reviews by Buiter, 2012; Graveleau et al., 2012). Primarily, syntectonic sedimentation exerts a first-order control on the number and spacing of thrusts, with deposi- tion of thicker, wedge-shaped sediments favoring the formation of longer, somewhat “rigid” thrust sheets (e.g. Bonnet et al., 2008; Fillon et al., 2013; Mugnier et al., 1997; Wu and McClay, 2011). By reducing the average slope of the wedge, sedimentation reduces thrust advance in the outer parts of the belt. In order to maintain the critical wedge, older structures have to be reactivated at the hinterland (Huiqi et al., 1992; Boyer, 1995; Storti and McClay, 1995; Simpson, 2006; Stockmal et al., 2007; Wu and McClay, 2011). Similarly, erosion prevents de- formation from propagating towards the foreland and therefore reduces the length of the belts. It reduces the number of active thrusts and therefore increases their lifetime (Koyi et al., 2000; McClay and Whitehouse, 2004; Cruz et al., 2010). The term overthrust faulting was first used by Hubbert and Rubey (1959) on the basis of a former definition by Billings (1954) to describe flat, spectacular allochthonous geological features along which large masses of rock have been displaced along great distances. Large transport thrust faults (i.e. displacement greater than 10 km) have been reviewed using displacement-scale relationships (e.g. Bergen and Shaw, https://doi.org/10.1016/j.jsg.2019.03.002 Received 9 November 2018; Received in revised form 7 March 2019; Accepted 8 March 2019 * Corresponding author. Present address: University of Fribourg, Department of Geosciences, Chemin du Musée 6, 1700 Fribourg, Switzerland. E-mail addresses: sandra.borderie@unifr.ch (S. Borderie), bruno.vendeville@univ-lille.fr (B.C. Vendeville), fabien.graveleau@univ-lille.fr (F. Graveleau), cesar.witt@univ-lille.fr (C. Witt), duboispierre11@gmail.com (P. Dubois), patrice.baby@ird.fr (P. Baby), ycalderon@perupetro.com.pe (Y. Calderon). 1 Present address: Perenco – Oil and Gas, 8 Hanover Square, London W1S 1HQ, England.