Permian to Late Cenozoic Evolution of Northern Patagonia: Main Tectonic Events, Magmatic Activity, and Depositional Trends

  1. Garry D. Mckenzie
  1. M. A. Uliana1 and
  2. K. T. Biddle2

Published Online: 21 MAR 2013

DOI: 10.1029/GM040p0271

Gondwana Six: Structure, Tectonics, and Geophysics

Gondwana Six: Structure, Tectonics, and Geophysics

How to Cite

Uliana, M. A. and Biddle, K. T. (1987) Permian to Late Cenozoic Evolution of Northern Patagonia: Main Tectonic Events, Magmatic Activity, and Depositional Trends, in Gondwana Six: Structure, Tectonics, and Geophysics (ed G. D. Mckenzie), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM040p0271

Author Information

  1. 1

    Esso Exploration, Inc., Houston, Texas 77001

  2. 2

    Exxon Production Research Company, Houston, Texas 77001

Publication History

  1. Published Online: 21 MAR 2013
  2. Published Print: 1 JAN 1987

ISBN Information

Print ISBN: 9780875900643

Online ISBN: 9781118664483

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Keywords:

  • Gondwana(Geology)—Congresses;
  • Geology,Structural—Congresses

Summary

The late Paleozoic to late Cenozoic evolution of northern Patagonia was influenced significantly by events that occurred while the area was part of the South American sector of Gondwanaland. Late Paleozoic to Middle Triassic subduction along the edge of the supercontinent formed a broad convergent-margin system that is the underpinning of northern Patagonia. Deformation (Gondwanidian orogeny) associated with the subduction is recognized in both the forearc and the convergent backarc areas. Regional extension, accompanied by bimodal volcanism, began in the Late Triassic and led to the formation of a number of north-northwest trending rift basins in Patagonia, which generally followed the Gondwanidian basement grain. Continued extension in the Jurassic and Early Cretaceous led to the opening of the Rocas Verdes marginal basin in southern Chile and, ultimately, to the opening of the South Atlantic Ocean. Once oceanic crust began to form, faulting and volcanism declined in Patagonia. During the late Early Cretaceous to the Late Cretaceous, sags over the rift basins coalesced to form a broad backarc basin behind the volcanic arc to the west. These sags are suggestive of thermally driven subsidence. Subsidence of the evolving Atlantic margin allowed extensive marine transgressions to take place from the east. The stratigraphic record of northern Patagonia reflects these events. The upper Paleozoic to upper Mesozoic sedimentary sequences were deposited in basins directly associated with convergent activity along the margin of Gondwanaland or in rift basins created during its breakup. Even though the Tertiary evolution of Patagonia was dominated by events along the western margin of South America, the patterns of sediment transport, thickness, and general shoreline position were still influenced by the locations of the Mesozoic rifts formed during the breakup of Gondwanaland.