Uplift of the Bolivian orocline coastal areas based on geomorphologic evolution of marine terraces and abrasion surfaces: preliminary results

• Autores: Saillard, Marianne, Audin, Laurence, Herail, Gérard, Martinod, Joseph, Regard, Vincent, Macharé Ordoñez, José, Ortlieb, Luc, Hall, Sarah R., Farber, Daniel L., Bondoux, Francis
• Formato: tesis de grado
• Fecha de Publicación: 2006
• Institución: Instituto Geológico, Minero y Metalúrgico
• Repositorio: INGEMMET-Institucional
• Lenguaje: inglés
• OAI Identifier: oai:repositorio.ingemmet.gob.pe:20.500.12544/4130
• Enlace del recurso: https://hdl.handle.net/20.500.12544/4130
• Nivel de acceso: acceso abierto
• Materia: Tectónica; Antearco; Neógeno; Levantamiento; http://purl.org/pe-repo/ocde/ford#1.05.00; http://purl.org/pe-repo/ocde/ford#1.05.06

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 Nazca ridge; or in Chile, from Tongoy (30°15'S) to Los Vilos (31°55'S), situated above a flat subduction segment (Fig.1). We chose various sites from each branch of the Arica bend in order to sample possibly different time spans during the Neogene and different response of the continental plate to the subduction process. Various studies were already undertaken on such problems either in Peru or Chile but mainly leaded to the datation of the 5th isotopic stage. So, differential GPS and cosmogenic datations are pursued in order to propose robust ages on these sites and subtract the effects of eustatic sea-level changes from local curves, identifying tectonic uplifts.