Abstract
The structure and geology of former rifted continental margins can exert significant influence on their subsequent incorporation into collisional orogens. While thinned continental crust attached to the subducting mantle lithosphere may be incorporated into subduction channels, the weakly rifted parts of the margin are likely to resist subduction and thus deform ahead of the main orogenic front. This expectation is corroborated by a case study from the external western Alps. The former Dauphinois basins have inverted to form external basement massifs. Much of the deformation was widely distributed, with few localized thrust structures. Existing models that invoke distinct deformation events separated in time by a major (late Eocene, “Nummulitic”) unconformity are abandoned here in favor of crustal shortening that was continuous in time. Integrated stratigraphic, paleothermal, and geochronological
data reveal that basin inversion was protracted over 6–10 m.y., coeval with deformation in the more internal parts of the chain. The notion of continuous, rather than episodic, deformation raises issues for the ways in which rates and tectonic activity may be evaluated within ancient orogens.
data reveal that basin inversion was protracted over 6–10 m.y., coeval with deformation in the more internal parts of the chain. The notion of continuous, rather than episodic, deformation raises issues for the ways in which rates and tectonic activity may be evaluated within ancient orogens.
Original language | English |
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Title of host publication | Linkages and Feedbacks in Orogenic Systems |
Editors | R. D. Law, J. R. Thigpen, A. J. Merschat, H. H. Stowell |
Publisher | Geological Society of America |
Pages | 55-74 |
Number of pages | 20 |
ISBN (Electronic) | 9780813712130 |
DOIs | |
Publication status | Published - 11 Sept 2017 |
Publication series
Name | GSA Memoirs |
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Publisher | The Geological Society of America |
Volume | 213 |
ISSN (Print) | 0072-1069 |
Bibliographical note
The account presented here is based on many years of Alpine research by the author and numerous discussions with individuals on Alpine and other tectonics. I especially thank Bill McCaffrey and others within the Leeds Turbidites Research Group for initiating me in the ways of deep-marine clastic sedimentology. Mark Cooper and Steve Matthews are thanked for their acute comments on an earlier draft of this manuscript. I also thank Editor Rick Law for his patience with this manuscript.Keywords
- tectonic inversion
- Alps
- foredeep
- basement deformation