TY - JOUR
T1 - Análisis estratigráfico y de proveniencia de unidades de rocas triásicas entre los 28-29° s, norte de Chile
T2 - Implicancias en la evolución tectónica y paleogeográfica del margen suroccidental de Gondwana
AU - Salazar, Esteban
AU - Vásquez, Paulina
AU - Vallejos, Daniela
AU - Creixell, Christian
AU - Oliveros, Verónica
AU - Ducea, Mihai N.
N1 - Funding Information:
This research was funded by the Plan Nacional de G ervicio Nacional de Geología y Minería (SERNAGEOMIN) and the Fondecyt grant 1120715. .F Coloma, M. Ortiz, R. Merino and I. Murillo are thanked for the fruitful discussions on the updated geological mapping in northern Chile. eW thank .F Poblete for faic il at it ng Gondwanean pael ogeographic reoc nitrucst ons and M. Padelfor his company and guidance on the field. M.N.D. acknowledges support from United States National Science Foundation grant EAR 1725002 and the Romanian Executive Agency for Higher Education, Research, Development and Innovation Funding project PN-III-P4-ID-PCCF-2016-0014. Finally we thank L. Giambiagi, E. Godoy and an anonymous reviewer for the constructive comments that led to a substantial improvement of the manuscript.
Funding Information:
This research was funded by the Plan Nacional de Geología of the Servicio Nacional de Geología y Minería (SERNAGEOMIN) and the Fondecyt grant 1120715. F. Coloma, M. Ortiz, R. Merino and I. Murillo are thanked for the fruitful discussions on the updated geological mapping in northern Chile. We thank F. Poblete for facilitating Gondwanean paleogeographic reconstructions and M. Padel for his company and guidance on the field. M.N.D. acknowledges support from United States National Science Foundation grant EAR 1725002 and the Romanian Executive Agency for Higher Education, Research, Development and Innovation Funding project PN-III-P4-ID-PCCF-2016-0014. Finally we thank L. Giambiagi, E. Godoy and an anonymous reviewer for the constructive comments that led to a substantial improvement of the manuscript.
Publisher Copyright:
© 2020, Servicio Nacional de Geologia y Mineria. All rights reserved.
PY - 2020/5
Y1 - 2020/5
N2 - Triassic rock units of northern Chile (28-29° S) record the transition, both in time and space, between two major orogenies that affected the southwestern margin of South America, the Gondwanian and Andean orogenies. The geodynamic configuration of the margin during this transition is still a matter of debate, particularly whether subduction was interrupted or continued under different parameters in between the orogenies. In order to evaluate these hypotheses by understanding the paleogeographic evolution of the margin, this work synthesizes recent stratigraphical, structural and geochronological data from northern Chile (28-29° S), along with detrital zircon analysis and detritus characterization of the two main siliciclastic Triassic basins present in the area. A detailed study of the evolution of the San Félix and the Canto del Agua basins, their source areas, and exhumation processes of the margin recognizes two stages of intra-arc/ forearc basins system development separated by a Carnian unconformity. The first stage (Lopingian-uppermost Middle Triassic) develops an eastern intra-arc basin, which is represented by the volcaniclastic rocks included in the Guanaco Sonso Formation and the roots of the volcanic arc represented by Chollay Plutonic Complex, bounded to the east by a Pennsylvanian-Cisuralian basement block. The forearc basin for this stage is constituted by two graben depocenter, separated by a topographic high, of marine to transitional depositional environment and proximal sediment sources. The eastern graben is filled by conglomerates and turbiditic rocks grouped in Members M1 to M4 of the San Félix Formation, and the western graben, by sedimentary and volcanic rocks of the lower section of the Canto del Agua Formation. The second stage (Norian-Rhaetian) involves an eastern intra-arc basin, represented by the volcanic rocks of the La Totora Formation that seals the exhumed roots of the magmatic arc developed in the previous stage, and a marine to transitional forearc basin to the west, represented by the sedimentary rocks of M5 member of the San Félix Formation and the upper section of the Canto del Agua Formation. These two successions show basal fluvial conglomerates unconformably overlying Anisian prodelta deposits of the first stage, recording a major base level drop of the forearc basin.
AB - Triassic rock units of northern Chile (28-29° S) record the transition, both in time and space, between two major orogenies that affected the southwestern margin of South America, the Gondwanian and Andean orogenies. The geodynamic configuration of the margin during this transition is still a matter of debate, particularly whether subduction was interrupted or continued under different parameters in between the orogenies. In order to evaluate these hypotheses by understanding the paleogeographic evolution of the margin, this work synthesizes recent stratigraphical, structural and geochronological data from northern Chile (28-29° S), along with detrital zircon analysis and detritus characterization of the two main siliciclastic Triassic basins present in the area. A detailed study of the evolution of the San Félix and the Canto del Agua basins, their source areas, and exhumation processes of the margin recognizes two stages of intra-arc/ forearc basins system development separated by a Carnian unconformity. The first stage (Lopingian-uppermost Middle Triassic) develops an eastern intra-arc basin, which is represented by the volcaniclastic rocks included in the Guanaco Sonso Formation and the roots of the volcanic arc represented by Chollay Plutonic Complex, bounded to the east by a Pennsylvanian-Cisuralian basement block. The forearc basin for this stage is constituted by two graben depocenter, separated by a topographic high, of marine to transitional depositional environment and proximal sediment sources. The eastern graben is filled by conglomerates and turbiditic rocks grouped in Members M1 to M4 of the San Félix Formation, and the western graben, by sedimentary and volcanic rocks of the lower section of the Canto del Agua Formation. The second stage (Norian-Rhaetian) involves an eastern intra-arc basin, represented by the volcanic rocks of the La Totora Formation that seals the exhumed roots of the magmatic arc developed in the previous stage, and a marine to transitional forearc basin to the west, represented by the sedimentary rocks of M5 member of the San Félix Formation and the upper section of the Canto del Agua Formation. These two successions show basal fluvial conglomerates unconformably overlying Anisian prodelta deposits of the first stage, recording a major base level drop of the forearc basin.
KW - Carnian unconformity
KW - Forearc basin
KW - Gondwana
KW - Intra-arc basin
KW - Paleogeography
KW - Triassic
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UR - http://www.scopus.com/inward/citedby.url?scp=85076363640&partnerID=8YFLogxK
U2 - 10.5027/andgeov47n2-3118
DO - 10.5027/andgeov47n2-3118
M3 - Article
AN - SCOPUS:85076363640
VL - 47
SP - 207
EP - 255
JO - Revista Geologica de Chile
JF - Revista Geologica de Chile
SN - 0718-7092
IS - 2
ER -