The curved Magallanes fold and thrust belt: tectonic insights from a paleomagnetic and anisotropy of magnetic susceptibility study
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Fecha
2014-12
Profesor/a Guía
Facultad/escuela
Idioma
en
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Título del volumen
Editor
Blackwell Publishing Ltd
Nombre de Curso
Licencia CC
Atribution 4.0 International (CC BY 4.0)
Licencia CC
https://creativecommons.org/licenses/by/4.0/deed.es
Resumen
The Magallanes fold and thrust belt (FTB) presents a large-scale curvature from N-S oriented
structures north of 52°S to nearly E-W in Tierra del Fuego Island. We present a paleomagnetic and anisotropy
of magnetic susceptibility (AMS) study from 85 sites sampled in Cretaceous to Miocene marine sediments.
Magnetic susceptibility is lower than 0.0005 SI for 76 sites and mainly controlled by paramagnetic minerals. AMS
results indicate that the sedimentary fabric is preserved in the undeformed areas of Tierra del Fuego and the
more external thrust sheets units, where an incipient lineation due to layer parallel shortening is recorded.
Prolate AMS ellipsoids, indicating a significant tectonic imprint in the AMS fabric, are observed in the internal
units of the belt. AMS results show a good correlation between the orientation of the magnetic lineation and
the fold axes. However, in Península Brunswick, the AMS lineations are at ~20° counterclockwise to the
strike of the fold axes. Pretectonic stable characteristic remanent magnetizations (ChRM) were determined in
seven sites. A counterclockwise rotation (21.2° ± 9.2°) is documented by ChRM data from four sites near the
hinge of the belt in Península Brunswick and near Canal Whiteside while there is no evidence of rotation near
the nearly E-W oriented Vicuña thrust within Tierra del Fuego. The curved shape of the Cenozoic Magallanes FTB
is not related to vertical axis rotation, and thus, the Magallanes FTB can be considered as a primary arc.
Notas
Indexación: Scopus.
Palabras clave
Paleomagnetism, Tectonics, Patagonia, Magallanes, Chile
Citación
Tectonics. Volume 33, Issue 12, Pages 2526 - 2551. December 2014
DOI
10.1002/2014TC003555