Paleomagnetic evidence of earliest Paleocene deformation in Calama (∼22°S), northern Chile: Andean-type or ridge-collision tectonics?

Synorogenic foreland rifts and transtensional basins: A review of Andean imprints on the evolution of the San Jorge Gulf, Salta Group and Taubaté Basins

“…During the earliest Paleocene in the Andes of northern Chile, a regional angular unconformity attributed to a renewed orogenic reactivation constrained between aprox. 66 to 58 Ma has been broadly documented (seeSomoza et al, 2012 and references therein)(Fig. 8 and 10B).…”

New constraints on the chronology, magnitude, and distribution of deformation within the central Andean orocline

“…Existing paleomagnetic data extend from 10°S to 30°S and define the CARP (Figure b) [ Arriagada et al ., , ; Roperch et al ., , ; Somoza et al ., ]. Rotations range from 0° to 50° with the largest magnitude rotations in the forearc [ Arriagada et al ., ; Roperch et al ., ; Taylor et al ., ].…”

Tectonic rotations and internal structure of Eocene plutons in Chuquicamata, northern Chile

“…1b; see also Somoza et al, 2012). Thermally metamorphosed Cerro Empexa beds also dip westward at Cerro Negro, on the eastern side of the plutons (Fig.…”

“…1c). Although most of this structural attitude probably corresponds to deformation around the Cretaceous-Cenozoic boundary (K-T event; Cornejo et al, 2003;Somoza et al, 2012), we cannot rule out a priori the possibility of a superimposed tilting younger than the LPPC. However, there is no reason to assume that the Upper Cretaceous beds underwent a stronger westward tilt during the K-T event followed by a uniform eastward tilt between 43 Ma (LPPC age) and 39 Ma (FCP age).…”

“…South America began to episodically override the trench in the Late Cretaceous (Somoza and Zaffarana, 2008), leading to the first manifestations of Andean contractional deformation in Chile and Perú, which were expressed as uplift of arc massifs and tectonic inversion of the Jurassic-Early Cretaceous extensional basins (Callot et al, 2008;Charrier et al, 2007;Mamani et al, 2010;Mpodozis and Ramos, 1990). Slowdown of the westward continental motion in latest Cretaceous likely produced a renewed predominance of slab rollback over trench overriding (Somoza and Zaffarana, 2008), leading to the development of fault-bounded basins in northern Chile (Cornejo et al, 2003) which in turn were inverted around the Cretaceous-Cenozoic boundary as the product of a renewed contractional deformation (Cornejo et al, 2003;Somoza et al, 2012). Neutral to slightly extensional conditions continued through the Paleocene till the middle to late Eocene, when the widespread Incaic contractional phase occurred along a great extent of the Andean margin.…”