Field trip guide: Evolution of the Pampean flat-slab region over the shallowly subducting Nazca plate
Published:January 01, 2008
Víctor A. Ramos, 2008. "Field trip guide: Evolution of the Pampean flat-slab region over the shallowly subducting Nazca plate", Field Trip Guides to the Backbone of the Americas in the Southern and Central Andes: Ridge Collision, Shallow Subduction, and Plateau Uplift, Suzanne Mahlburg Kay, Víctor A. Ramos
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This field guide provides an opportunity to examine the central Andes between 31° and 32°S latitude in a segment characterized by flat-slab subduction. The field trip road was chosen to observe the westernmost contact between the basement uplift of Sierras Pampeanas and Precordillera, the early Paleozoic stratigraphy, and the Andean structure of the Precordillera, as well as a complete section of the Frontal and Principal Cordilleras in Argentina and Chile. The trip ends in the Coastal Cordillera along the Pacific margin. This road log discusses a complete early and late Paleozoic history of the central Andes with their typical Famatinian and Gondwanan orogenic rocks and the accretionary evolution of the Pacific margin at these latitudes. Superimposed on this framework, the structure of the Andes is viewed through the examination of the Precordillera and the Aconcagua fold-and-thrust belts, together with the observation of the Andean volcanic history, will allow reconstructing the shallowing of the subduction zone through the Neogene and the final formation of the Pampean flat-slab.
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Field Trip Guides to the Backbone of the Americas in the Southern and Central Andes: Ridge Collision, Shallow Subduction, and Plateau Uplift
The geologic field guides in this volume to the Andes of Argentina and Chile were written for the five field trips accompanying the 2006 Backbone of the Americas conference in Mendoza, Argentina, which was sponsored by the Geological Society of America and the Asociación Geológica Argentina. The meeting was organized around three processes influential in the evolution of the western margin and cordilleras of the Americas—ridge collision, shallowing and steepening subduction zones, and plateau and orogenic uplift. Designed for use in the office or the field, the field guides are to regions that highlight these themes and present up-to-date overviews with references. The trip in chapter 1 to southern Patagonia highlights the ridge-trench collision theme; the next three to different regions of the south-central Andes examine temporal and spatial issues related to shallowing subduction; and the trip in the last chapter to the central Andean Puna plateau highlights plateau uplift in the context of steepening subduction and lithospheric delamination.