Late Cenozoic structural and tectonic development of the western margin of the central Andean Plateau in southwest Peru

Abstract

Structural and thermochronologic studies of the western margin of the central Andean Plateau show changing styles of deformation through time that give insights into tectonic evolution. In southwest Peru, uplift of the plateau proceeded in several distinct phases. First, NW striking, NE dipping reverse faults accommodated uplift prior to ∼14–16 Ma. Subsequent uplift of the plateau relative to the piedmont (between the plateau and the Pacific Ocean) occurred between ∼14 and 2.2 Ma and was accommodated by NW striking, SW dipping normal faults and subparallel monoclinal folds. The youngest phase of uplift affected the piedmont region and the plateau margin as a coherent block. Although the uplift magnitude associated with phase 1 is unknown, phases 2 and 3 resulted in at least 2.4–3.0 km of uplift. Up to 1 km of this may have occurred during phase 3. Geodynamic processes occurring in both the continental interior and the subduction zone likely contributed to uplift.

Tectonic and climatic controls on the Chuquibamba landslide (western Andes, southern Peru)

“…Local reverse and normal apparent surface movements are known to occur along major strike-slip faults in the forearcs of northern Chile (Victor et al, 2004) and southern Peru (Hall et al, 2012). The present-day main sinistral strike-slip kinematics of the Incapuquio fault system demonstrated by the seismicity is compatible with normal apparent displacements as observed by Schildgen et al (2009) and Sébrier et al (1985Sébrier et al ( , 1988.…”

“…Some volcanosedimentary rocks were deposited on the coastal plains during the late Neogene. Starting at ∼ 9-10 Ma, these units were incised by 1-3 km deep canyons that strike perpendicular to NW-SE-striking range (Schildgen et al, 2007(Schildgen et al, , 2009Thouret et al, 2007;Gunnell et al, 2010). The Western Cordillera and Pacific piedmont are affected by Quaternary tectonic deformation mainly expressed in the Western Cordillera by an active fault system striking parallel to the range (Sébrier et al, 1985;Hall et al, 2008Hall et al, , 2012 (Fig.…”

“…Based on microtectonic studies, Sébrier et al (1985Sébrier et al ( , 1988 and Schildgen et al (2009) identified different kinematic episodes. Sébrier et al (1985Sébrier et al ( , 1988 defined major Tertiary and early Quaternary compressional phases and a minor late Quaternary episode of normal faulting.…”

“…Sébrier et al (1985Sébrier et al ( , 1988 defined major Tertiary and early Quaternary compressional phases and a minor late Quaternary episode of normal faulting. Schildgen et al (2009) proposed that a Tertiary episode of strike-slip and normal faulting occurred between 14 and 2.2 Ma. However, relocated microseismicity (Grange et al, 1984) and teleseismic data (Devlin et al, 2012) demonstrate present-day reverse and strike-slip components on the Lluta fault segment and more regionally for the Incapuquio fault system in the Arequipa region (Fig.…”

Seismic-stratigraphic architecture of the Oligocene-Pliocene Camaná Formation, southern Peruvian forearc (Province of Arequipa)

“…This is consistent with deposition of CamB; however, deposition of CamB reflects rapid uplift in the hinterland (Western Cordillera and/or Pacific Piedmont, e.g., Schildgen et al, 2009;Alván et al, 2015), and they have influenced sedimentation more than eustatic or climate-driven factors. Once established the stratigraphic sequence model, we proceed to extend the bounding surfaces of the Camaná Formation onto its offshore equivalents.…”