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| Indexado |
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| DOI | 10.1029/2019TC005832 | ||||
| Año | 2020 | ||||
| Tipo | artículo de investigación |
Citas Totales
Autores Afiliación Chile
Instituciones Chile
% Participación
Internacional
Autores
Afiliación Extranjera
Instituciones
Extranjeras
An extensive system of NW striking faults constitutes a major tectonic feature of the Coastal Cordillera in northern Chile, but fundamental questions remain about timing and kinematics of these structures. We present new geologic mapping and geochronology that provide insight into the structural evolution and tectonic significance of the Taltal fault system (TFS). The TFS displaces the Early Cretaceous arc-parallel Atacama fault system (AFS) with similar to 10.6 km cumulative offset across a similar to 15 km wide zone. Brittle fault data demonstrate that the TFS is vertical to steeply NE dipping with an average sinistral slip vector plunging 11 degrees from the NW, compatible with E-W shortening. Two late Early Cretaceous dikes cut the AFS but are cut by TFS faults, and synkinematic calcite on a TFS strand yielded a U-Pb calcite date of 114.1 +/- 7.0 Ma. These data demonstrate that the AFS was abandoned and deformation (re) initiated on the TFS between similar to 114-107 Ma, with continued slip after intrusion of the Tropezon (similar to 110 Ma) and Librillo (106-101 Ma) plutonic complexes. Emplacement of a similar to 146 Ma rhyolite dike along the main Taltal fault and 141 +/- 11 Ma calcite mineralization in the fault core suggests that a precursor structure influenced magma emplacement and fluid flow in the Late Jurassic/Early Cretaceous, supporting the hypothesis that the TFS reactivated long-lived inherited crustal weaknesses. The Early Cretaceous shift from arc-parallel shear to slip on the TFS and E-W shortening shortly preceded migration of the magmatic arc and records a change in the Chilean margin subduction dynamics.
| Ord. | Autor | Género | Institución - País |
|---|---|---|---|
| 1 | Mavor, S. P. | - |
COLORADO STATE UNIV - Estados Unidos
Colorado State University - Estados Unidos |
| 2 | Singleton, J. S. | Hombre |
COLORADO STATE UNIV - Estados Unidos
Colorado State University - Estados Unidos |
| 3 | Gomila, Rodrigo | Hombre |
Pontificia Universidad Católica de Chile - Chile
|
| 4 | Heuser, G. | Hombre |
Pontificia Universidad Católica de Chile - Chile
|
| 5 | Seymour, N. M. | Mujer |
COLORADO STATE UNIV - Estados Unidos
Colorado State University - Estados Unidos |
| 6 | Williams, S. A. | - |
COLORADO STATE UNIV - Estados Unidos
Colorado State University - Estados Unidos |
| 7 | ARANCIBIA-HERNANDEZ, GLORIA CECILIA | Mujer |
Pontificia Universidad Católica de Chile - Chile
|
| 8 | Johnston, S. M. | - |
Calif Polytech State Univ San Luis Obispo - Estados Unidos
Cal Poly San Luis Obispo - Estados Unidos California Polytechnic State University, San Luis Obispo - Estados Unidos |
| 9 | Kylander-Clark, A. R. C. | - |
UNIV CALIF SANTA BARBARA - Estados Unidos
University of California, Santa Barbara - Estados Unidos |
| 10 | Stockli, Daniel F. | Hombre |
Univ Texas Austin - Estados Unidos
The University of Texas at Austin - Estados Unidos |
| Fuente |
|---|
| National Science Foundation |
| Geological Society of America |
| National Science Foundation grant |
| Geological Society of America Student Research Grant |
| Directorate for Geosciences |
| Agradecimiento |
|---|
| Analytical costs for this project were funded in part by the Geological Society of America student research grant to S. Mavor and by the National Science Foundation grant 1822064 to J. Singleton. We thank Micah Hernandez for field assistance and sample preparation and thank Gabriela Borquez G. for field assistance. Data for table S1 are on the Strabospot database of structural measurements here: https://www.strabospot.org/search/ Data for tables S2 and S3(zircon U-Pb and (UTh)/He) are here: https://www.geochron.org/dataset/html/geochron_ dataset_2020_01_26_XRJ5H Data for table S4 (Calcite U-Pb) are here: https://www.geochron.org/results.php?pkey= 28356 |
| Analytical costs for this project were funded in part by the Geological Society of America student research grant to S. Mavor and by the National Science Foundation grant 1822064 to J. Singleton. We thank Micah Hernandez for field assistance and sample preparation and thank Gabriela Bórquez G. for field assistance. Data for table S1 are on the Strabospot database of structural measurements here: https://www.strabospot.org/search/ Data for tables S2 and S3(zircon U-Pb and (U-Th)/He) are here: https://www.geochron.org/dataset/html/geochron_dataset_2020_01_26_XRJ5H Data for table S4 (Calcite U-Pb) are here: https://www.geochron.org/results.php?pkey=28356 |