Deciphering the Late Cretaceous‐Cenozoic Structural Evolution of the North Peruvian Forearc System

Abstract

The link between plate tectonics and the evolution of active margins is still an ongoing task to challenge since the acceptance of plate tectonic paradigm. This paper aims at deciphering the structural architecture and uplift history of the North Peruvian forearc system to better understand the evolution and the mechanics that govern the Late Cretaceous‐Cenozoic building of this active margin. In this study, we report surface structural geology data, interpretation of seismic reflection profiles, apatite fission track data, and the construction of two offshore‐onshore crustal‐scale balanced cross sections. The structure of the North Peruvian forearc system is dominated by an accretionary style with northwestward propagation of thrust‐related structural highs involving continental/oceanic basement rocks and off‐scrapped sediments. The thrust systems bound thick thrust‐top forearc depocenters mainly deformed by crustal normal to strike‐slip faults and thin‐skinned gravitational instabilities. The sequential restoration of the margin calibrated with apatite fission track data suggests a correlation between uplift, shortening, and plate convergence velocity during Late Cretaceous and Miocene. Pliocene‐Quaternary shortening and uplift of the coastal zone is rather related to the subduction of asperities during convergence rate decrease. The development of crustal normal to strike‐slip faulting and subsidence zones might be the consequence of slab flexure, local basal erosion along subduction fault, and/or oblique subduction associated with sediment loading control. We conclude that the evolution of the North Peruvian forearc system was controlled by subduction dynamics, strong sediment accumulation, and recent ridge subduction, and it recorded the orogenic loading evolution of the Andes over the Cenozoic.

Cenozoic Stages of Forearc Evolution Following the Accretion of a Sliver From the Late Cretaceous‐Caribbean Large Igneous Province: SW Ecuador‐NW Peru

“…A movement that is possibly reflected in NW Peru by sequential trench retreats in both NW Peru and SW Ecuador. This is in agreement with trench retreat and seaward advance of the forearc depocenters proposed in NW Peru by Espurt et al ().…”

“…Chronostratigraphic chart of the SW Ecuador and NW Peru (modified after Benitez, ; Espurt et al, ; Fildani et al, ; Jaillard et al, ). The upper part of the chart displays the structural domains interpreted from this study and the location of the different stratigraphic columns.…”

“…The Lancones and Talara basins in NW Peru comprise a series of NE‐SW forearc depocenters bounded by thrust‐related structural highs with a sequential northwestward progradation (Figure , Espurt et al, ). Paleomagnetic results from the Lancones basin show clockwise rotations on the order of ~38° (Mitouard et al, ), indicating that the basin was affected by dextral movements that were probably coincident with the increased exhumation rates in the Amotape‐Tahuin massif at 75–65 Ma (Jaillard et al, ; Spikings et al, ).…”

“…The collision and accretion of the CLIP to the margin is well documented along the western Cordillera (Mamberti et al, 2003;Reynaud et al, 1999;Vallejo et al, 2009). However, the initial interaction between the trailing edge of the CLIP and the margin and its role into the further Cenozoic forearc basin development in SW Ecuador and NW Peru has not been discussed in detail (Benitez, 1995;Espurt et al, 2017;Fildani et al, 2008;Jaillard et al, 1995;Witt & Bourgois, 2010). Figure 1.…”

“…Black lines show the major structural lineaments of the study area. Geological units and major faults are compiled from previous studies (Bosch et al, 2002;Espurt et al, 2017;Fildani et al, 2008;Herms et al, 2012;Hungerbühler et al, 2002;Kerr et al, 2002;Mamberti et al, 2003;Reynaud et al, 1999;Spikings et al, 2005;Vallejo et al, 2009;Winter et al, 2010;Witt & Bourgois, 2010).…”