Title
Controls on timing of exhumation and deformation in the northern Peruvian eastern Andean wedge as inferred from low-temperature thermochronology and balanced cross section
Date Issued
01 April 2015
Access level
open access
Resource Type
journal article
Author(s)
Eude A.
Roddaz M.
Brichau S.
Brusset S.
Baby P.
Soula J.C.
Université de Toulouse
Publisher(s)
Blackwell Publishing Ltd
Abstract
In northern Peru, a 500 km long regional balanced section has been constructed across the eastern Andean wedge, using fieldwork, industrial seismic sections, and wells. The structure is characterized by a thin-skinned thrust system involving the Eastern Cordillera (EC), the sub-Andean zone (SAZ), and the Marañõn foredeep. In the SAZ and the easternmost foredeep the development of the thrust system has been driven by the combination of two structural events. Permian thrust faults had been reactivated to form a basement duplex underlying the SAZ and the foredeep. At the same time a Triassic-Jurassic extensional basin has been transported as a crustal ramp anticline on to the duplex roof fault, giving rise to the EC. The impingement of the EC was responsible for the deformation of the SAZ and the propagation of the thrust wedge. The minimum shortening calculated is 142 km, representing a shortening strain of ∼ -28%. A sequential restoration calibrated by (U-Th)/He and Fission Track dating on apatites and vitrinite reflectance values shows that shortening rates vary from 7.1 mm yr-1 between 17 and 8 Ma to 3.6 mm yr-1 between 8 Ma and today and suggests that the thrust wedge commenced propagation between 30 and 24 Ma. When compared with other Andean thrust wedges, we suggest that the timing of the thrust wedge propagation is not a simple function of the distance to the hinge of the Bolivian orocline and the propagation is not controlled by the precipitation regime. We rather suggest that reactivated basement faults favored thrust wedge propagation.
Start page
715
End page
730
Volume
34
Issue
4
Language
English
OCDE Knowledge area
Paleontología Termodinámica
Scopus EID
2-s2.0-85027953423
Source
Tectonics
ISSN of the container
02787407
DOI of the container
10.1002/2014TC003641
Sources of information: Directorio de Producción Científica Scopus