Using available information on the magnitude and age of tectonic shortening, as well as paleomagnetically determined tectonic rotations, we have run a series of 2‐D map view restorations of the central Andes. Neogene shortening in the foreland belt induced only slight orogenic curvature of the central Andes. The constraints on the ages of the large observed fore‐arc rotations (average of 37° counterclockwise in southern Peru and 29° clockwise in northern Chile) indicate that the Bolivian Orocline formed during the Eocene‐Oligocene as a consequence of differential shortening focused in the Eastern Cordillera. To minimize local block rotations along the fore arc, the restoration that best fits the central Andean rotation pattern requires about 400 km of total (Paleogene plus Neogene) shortening near the Arica bend. This value corresponds to the upper bound of estimates of maximum horizontal shortening for the central Andes. Along‐strike variations in horizontal shortening in the back arc induced bending of the continental margin, block rotations with fore‐arc along‐strike extension, and/or orogen‐parallel transport of upper crustal material toward the symmetry axis of the orocline.

The Salar de Atacama basin lies in the inner fore arc of northern Chile. Topographically and structurally, it is a first‐order feature of the central Andes. The sedimentary fill of the basin constrains the timing and extent of crustal deformation since the mid‐Cretaceous. We have studied good exposures along the western edge of the basin and have correlated them with seismic reflection sections and data from an exploration well. Throughout most of its history, the basin developed in a foreland setting, during periods of thin‐skinned and thick‐skinned thrusting. Growth strata provide evidence for coeval sedimentation and thrust motions during mid‐Cretaceous, Paleogene, and Neogene times. Pre‐Neogene deformation was significant in the basin and in surounding areas of the early central Andes. Models that attempt to explain the current thickness of the central Andes should consider Late Cretaceous and Paleogene shortening, as well as the more obvious Neogene and Quaternary shortening.

The results of a paleomagnetic study along the fore arc of southern Peru (15–18°S) and northern Chile (18–19°S) are reported from middle to late Miocene ignimbrites (7 sites), late Oligocene to early Miocene ignimbrites (72 sites), Paleogene sediments (20 sites), and Mesozoic and Paleocene volcanics and intrusions (31 sites). Comparison of locality‐mean directions with expected paleomagnetic directions indicates vertical axis rotations ranging from 5.2 ± 11.3° clockwise to 55.6 ± 7.0° counterclockwise. Spatially, the magnitude of counterclockwise rotations increases northward from ∼0° within the Chilean fore arc south of 18°30′S to >45° north of 16°30′S. In southern Peru, paleomagnetic rotations recorded in Paleogene red beds decrease from late Eocene to late Oligocene, whereas Miocene ignimbrites display no evidence of rotation. These new results confirm that the rotations recorded in the fore arc of southern Peru were acquired at least before ∼15 Ma, and probably before 25 Ma, and thus prior to the late Neogene shortening of the sub‐Andes. The onset of major Andean shortening in the Eastern Cordillera during the latest Eocene–earliest Oligocene is interpreted to have triggered the bending of the Peruvian fore arc. The region of the Peruvian fore arc with the largest rotations appears to be the fore‐arc counterpart of the Abancay deflection, a remarkable NE‐SW offset in the axis of the Eastern Cordillera induced by a major regional preorogenic structure. We underline that the Abancay deflection should be seen as the northwestern boundary, and therefore as a key element, of the Bolivian Orocline.

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