Skip to Main Content
Book Chapter

Pacific subduction coeval with the Karoo mantle plume: the Early Jurasssic Subcordilleran belt of northwestern Patagonia

By
C. W. Rapela
C. W. Rapela
1
Centro de Investigaciones Geológicas, Calle 1 No. 644, 1900 La Plata, Argentina (e-mail: crapela@cig.museo,unlp.edu.ar)
Search for other works by this author on:
R. J. Pankhurst
R. J. Pankhurst
2
NERC Isotope Geosciences Laboratory, Keyworth, Nottingham NG12 5GG, UK (e-mail: r.pankhurst@nigl.nerc.ac.uk)
Search for other works by this author on:
C. M. Fanning
C. M. Fanning
3
PRISE, Research School of Earth Sciences, The Australian National University, Mills Road, Canberra ACT 0200, Australia (e-mail: mark.fanning@anu.edu.au)
Search for other works by this author on:
F. Hervé
F. Hervé
4
Departamento de Geología, Universidad de Chile, Casilla 13518, Correo 21, Santiago, Chile (e-mail: fherve@cec.uchile.cl)
Search for other works by this author on:
Published:
January 01, 2005

Abstract

The Early Mesozoic magmatism of southwestern Gondwana is reviewed in the light of new U-Pb SHRIMP zircon ages (181 ± 2 Ma, 181 ± 3 Ma, 185 ± 2 Ma, and 182 ± 2 Ma) that establish an Early Jurassic age for the granites of the Subcordilleran plutonic belt in northwestern Argentine Patagonia. New geochemical and isotopic data confirm that this belt represents an early subduction-related magmatic arc along the proto-Pacific margin of Gondwana. Thus, subduction was synchronous with the initial phase of Chon Aike rhyolite volcanism ascribed to the thermal effects of the Karoo mantle plume and heralding rifting of this part of the supercontinent. Overall, there is clear evidence that successive episodes of calc-alkaline arc magmatism from Late Triassic times until establishment of the Andean Patagonian batholith in the Late Jurassic involved westerly migration and clockwise rotation of the arc. This indicates a changing geodynamic regime during Gondwana break-up and suggests differential rollback of the subducted slab, with accretion of new crustal material and/or asymmetrical ‘scissor-like’ opening of back-arc basins. This almost certainly entailed dextral displacement of continental domains in Patagonia.

You do not currently have access to this article.

Figures & Tables

Contents

Geological Society, London, Special Publications

Terrane Processes at the Margins of Gondwana

A. P. M. Vaughan
A. P. M. Vaughan
British Antarctic Survey, UK
Search for other works by this author on:
P. T. Leat
P. T. Leat
British Antarctic Survey, UK
Search for other works by this author on:
R. J. Pankhurst
R. J. Pankhurst
British Geological Survey, UK
Search for other works by this author on:
Geological Society of London
Volume
246
ISBN electronic:
9781862394940
Publication date:
January 01, 2005

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