4 páginas

Active transpressive deformation has been occurring along the Andean hyperarid forearc for the last 3 Myrs but many of these faults are still not described even if able to produce large damaging earthquakes. Active faulting along the northern part of the Arica Bend can be recognized due to the presence of well-preserved and sharp fault scarps indicating recent surface slip. During the Mio-Pliocene, deposition within the forearc continental basins resulted in the formation of vast fan deposits and conglomerates of the Moquegua Formation, which can be considered as bedrock in this exposure study (~45-4 Ma; Tosdal et al., 1984; Sebrier et al., 1988a; Roperch et al., 2006). The typical vertical Purgatorio fault scarps offset both the Moquegua bedrock and several younger geomorphic features associated with <300kyrs climatic and 400 years old volcanic extreme events. This study focus on quanti...

The southern Pacific coast morphology and especially the presence of marine surfaces gives information on the dynamics of Andean forearc evolution from the Neogene. Along most of the Southern Peru and Northern Chilean coasts, discontinuous uplifts are recorded by marine terraces and marine abrasion surfaces; they have thus, preserved a record of eustatic sea level changes and the uplift history of the coastal area in the Andean forearc. One approach to study the tectonic history of the Andean forearc is to identify its effects in marine sedimentation or erosion patterns along the coastal area. To investigate these processes, the Neogene marine formations are studied in various coastal sections either in southern Peru, at Chala (15°50'S) and Ilo (17°32'S-17°48'S), situated above a steep subduction segment and at San Juan de Marcona (15°20'S), situated above the southern part of the Na...