Skip to Main Content
Book Chapter

Orogenic Evolution of the Peruvian Andes: The Andean Cycle

By
Víctor Benavides-Cáceres
Víctor Benavides-Cáceres
Carlos Graña Elizalde 137, San Isidro-Lima 27
, Peni
Search for other works by this author on:
Published:
January 01, 1999

Abstract

The Peruvian segment of the Andean Cordillera represents the paradigm of the Andean type of subduction, whereby the oceanic Nazca plate subducts the ensialic South American plate. This plate has developed along its western margin a considerable crustal thickening of as much as 70 km, leading to an attendant cordilleran uplift of nearly 4,000 meters above sea level (m.a.s.l.).

The Andean Cordillera is the result of three major geodynamic cycles: Precambrian, Paleozoic to Early Triassic, and Late Triassic to present. The last cycle commenced with the opening of the South Atlantic in the Triassic and includes a first phase of Late Triassic to Early Senonian, Mariana-type subduction, which was basically extensional and of crustal attenuation. During this phase, the cordilleran belt was the site of major shelf sedimentation, bordered on the west by island arc volcanism or a marginal volcanic rift.

In the Early Senonian, a profound geodynamic change led to the Andean-type of subduction, marine withdrawal, and emergence of the Cordillera. This phase was characterized by the recurrence of compressive pulses and the presence along the continental margin of a magmatic arc with intense plutonic and volcanic activity. During this phase, a sequence of compressive episodes: Peruvian (84-79 Ma), Incaic I (59-55 Ma), Incaic II (43-42 Ma), Incaic III (30-27 Ma), Incaic IV (22 Ma), Quechua I (17 Ma), Quechua II (8-7 Ma), Quechua III (5-4 Ma), and Quechua IV (early Pleistocene) formed three major, successive, and eastward-shifting fold and thrust belts: Peruvian (Campanian), Incaic (Paleocene-Eocene) and sub-Andean (Neogene). In general, the compressive pulses affected the entire mobile belt, but were particularly focused on the fold and thrust belts. They resulted in crustal thickening and uplift which was followed by periods of relative quiescence when well-developed erosional surfaces were formed, the most distinctive of which is the Puna surface, generated about 17 m.y. ago. The compressive pulses interrupted longer periods of extension during which the magmatic arc was particularly active, and which were also characterized by the development of fore-arc basins, intermontane grabens, and the great eastern foreland basin. All along this process, however, there were some persistent features, such as the continued presence of the magmatic arc, the Marañón arch, and the eastern foreland basin. The western margins of the Incaic and sub-Andean fold and thrust belts are considered to represent megafaults, deeply rooted into the ductile region, and along which the shortening experienced by the compression of the belt was absorbed.

You do not currently have access to this article.

Figures & Tables

Contents

Special Publications of the Society of Economic Geologists

Geology and Ore Deposits of the Central Andes

Brian J. Skinner
Brian J. Skinner
Search for other works by this author on:
Society of Economic Geologists
Volume
7
ISBN electronic:
9781629490311
Publication date:
January 01, 1999

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal