Field trip guide: Frontal and Main Andean Cordilleras near the southern boundary of the Pampean shallow subduction zone
Published:January 01, 2008
Víctor A. Ramos, 2008. "Field trip guide: Frontal and Main Andean Cordilleras near the southern boundary of the Pampean shallow subduction zone", 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 one-day field trip provides a sampling of the main components of the Andean deformation front in the Precordillera, and the Frontal and Main Cordilleras of the central Andes east of the drainage divide, which at these latitudes coincide with the political boundary of Argentina and Chile. The absence of Pliocene to Recent volcanic rocks in this transect over the southern hinge of the modern shallow subduction allows the older Andean rocks and their structures to be well seen. The structural consequences of shallow subduction are also well seen. The field trip stops provide a view of the Late Paleozoic sedimentary and magmatic rocks of the Frontal Cordillera, the Triassic volcanic and plutonic sequences and associated sedimentary rift sequences east of the Main Cordillera, the Mesozoic to Miocene arc magmatic and sedimentary basin sequences of the high Cordillera, and the Miocene foreland basin deposits to the east. The structure of the Triassic Cuyo rift and inverted normal faults is contrasted with both the Miocene thick-skinned contractional structures affecting the dominantly magmatic rocks of the Frontal Cordillera and the thin-skinned folds and thrusts of the Aconcagua belt affecting the Jurassic to Miocene sedimentary and volcanic rocks of the Principal Cordillera. Depending on climatic conditions, Cerro Aconcagua (6967 m above sea level), the highest peak in the Western and Southern hemispheres and the top of the Backbone of the Americas, can be viewed.
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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.