Petrological vestiges of the Late Jurassic-Early Cretaceous transition from rift to back-arc basin in southernmost Chile: New age and geochemical data from the Capitán Aracena, Carlos III, and Tortuga ophiolitic complexes

M. Calderón, C. F. Prades, F. Hervé, V. Avendaño, C. M. Fanning, H. J. Massonne, T. Theye, A. Simonetti

Resultado de la investigación: Article

22 Citas (Scopus)

Resumen

The ophiolitic remnants of the Upper Mesozoic Rocas Verdes basin in southernmost South America were studied from the perspectives of petrography, chemistry of minerals, bulk-rock geochemistry, and U-Pb geochronology. The study aimed to unravel the tectonic, magmatic, and metamorphic evolution of a suprasubduction rift zone that underwent a transition to a back-arc basin. The rifting phase and bimodal magmatism within the Rocas Verdes basin started prior to or during the Late Jurassic, as indicated by a gabbro in contact with pillow basalts that dated at 154 Ma. In the Late Jurassic Capitán Aracena and Carlos III complexes, tholeiitic basalts are geochemically comparable to enriched mid-oceanic ridge basalts. Back-arc basin development continued for 35 myr until the Early Cretaceous, as suggested by the ages of detrital zircons in cherty layers within pillow basalts and metamorphic titanite that crystallized during seafloor metamorphism near the spreading/magmatic axis. In the Early Cretaceous Tortuga Complex, tholeiitic basalts are comparable to normal mid-oceanic ridge basalts. Non-deformative metamorphism converted the primary mineralogy of the ophiolites to low- to intermediate-grade metamorphic assemblages formed during ocean-floor type alteration in a suprasubduction setting. Fossilized bacteria, preserved as rounded aggregates of titanite microcrystals, were identified in the pillow basalts up to the Early Cretaceous. The Rocas Verdes basin closed during the Andean orogeny, which started during the Late Cretaceous, and ophiolites were tectonically juxtaposed and thrust over the sedimentary infill of the quasi-oceanic basin in which they developed. The tectonic emplacement of the ophiolitic complexes was complete before the latest Cretaceous, as indicated by crystallization ages of granites intruded into the ophiolitic complexes. Coyright

Idioma originalEnglish
Páginas (desde-hasta)201-217
Número de páginas17
PublicaciónGeochemical Journal
Volumen47
N.º2
DOI
EstadoPublished - 2013

Huella dactilar

Chile
basalt
arcs
Jurassic
Cretaceous
basin
tholeiitic basalt
titanite
mid-ocean ridges
metamorphism
seafloor
Andean orogeny
Tectonics
tectonics
infill
Geochronology
rift zone
basin evolution
petrography
Petrography

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

Citar esto

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title = "Petrological vestiges of the Late Jurassic-Early Cretaceous transition from rift to back-arc basin in southernmost Chile: New age and geochemical data from the Capit{\'a}n Aracena, Carlos III, and Tortuga ophiolitic complexes",
abstract = "The ophiolitic remnants of the Upper Mesozoic Rocas Verdes basin in southernmost South America were studied from the perspectives of petrography, chemistry of minerals, bulk-rock geochemistry, and U-Pb geochronology. The study aimed to unravel the tectonic, magmatic, and metamorphic evolution of a suprasubduction rift zone that underwent a transition to a back-arc basin. The rifting phase and bimodal magmatism within the Rocas Verdes basin started prior to or during the Late Jurassic, as indicated by a gabbro in contact with pillow basalts that dated at 154 Ma. In the Late Jurassic Capit{\'a}n Aracena and Carlos III complexes, tholeiitic basalts are geochemically comparable to enriched mid-oceanic ridge basalts. Back-arc basin development continued for 35 myr until the Early Cretaceous, as suggested by the ages of detrital zircons in cherty layers within pillow basalts and metamorphic titanite that crystallized during seafloor metamorphism near the spreading/magmatic axis. In the Early Cretaceous Tortuga Complex, tholeiitic basalts are comparable to normal mid-oceanic ridge basalts. Non-deformative metamorphism converted the primary mineralogy of the ophiolites to low- to intermediate-grade metamorphic assemblages formed during ocean-floor type alteration in a suprasubduction setting. Fossilized bacteria, preserved as rounded aggregates of titanite microcrystals, were identified in the pillow basalts up to the Early Cretaceous. The Rocas Verdes basin closed during the Andean orogeny, which started during the Late Cretaceous, and ophiolites were tectonically juxtaposed and thrust over the sedimentary infill of the quasi-oceanic basin in which they developed. The tectonic emplacement of the ophiolitic complexes was complete before the latest Cretaceous, as indicated by crystallization ages of granites intruded into the ophiolitic complexes. Coyright",
keywords = "Geochemistry, Microbes, Mineral chemistry, Rift to back-arc basin transition, Rocas verdes ophiolites, U-Pb dating",
author = "M. Calder{\'o}n and Prades, {C. F.} and F. Herv{\'e} and V. Avenda{\~n}o and Fanning, {C. M.} and Massonne, {H. J.} and T. Theye and A. Simonetti",
year = "2013",
doi = "10.2343/geochemj.2.0235",
language = "English",
volume = "47",
pages = "201--217",
journal = "Geochemical Journal",
issn = "0016-7002",
publisher = "The Physiological Society of Japan",
number = "2",

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TY - JOUR

T1 - Petrological vestiges of the Late Jurassic-Early Cretaceous transition from rift to back-arc basin in southernmost Chile

T2 - New age and geochemical data from the Capitán Aracena, Carlos III, and Tortuga ophiolitic complexes

AU - Calderón, M.

AU - Prades, C. F.

AU - Hervé, F.

AU - Avendaño, V.

AU - Fanning, C. M.

AU - Massonne, H. J.

AU - Theye, T.

AU - Simonetti, A.

PY - 2013

Y1 - 2013

N2 - The ophiolitic remnants of the Upper Mesozoic Rocas Verdes basin in southernmost South America were studied from the perspectives of petrography, chemistry of minerals, bulk-rock geochemistry, and U-Pb geochronology. The study aimed to unravel the tectonic, magmatic, and metamorphic evolution of a suprasubduction rift zone that underwent a transition to a back-arc basin. The rifting phase and bimodal magmatism within the Rocas Verdes basin started prior to or during the Late Jurassic, as indicated by a gabbro in contact with pillow basalts that dated at 154 Ma. In the Late Jurassic Capitán Aracena and Carlos III complexes, tholeiitic basalts are geochemically comparable to enriched mid-oceanic ridge basalts. Back-arc basin development continued for 35 myr until the Early Cretaceous, as suggested by the ages of detrital zircons in cherty layers within pillow basalts and metamorphic titanite that crystallized during seafloor metamorphism near the spreading/magmatic axis. In the Early Cretaceous Tortuga Complex, tholeiitic basalts are comparable to normal mid-oceanic ridge basalts. Non-deformative metamorphism converted the primary mineralogy of the ophiolites to low- to intermediate-grade metamorphic assemblages formed during ocean-floor type alteration in a suprasubduction setting. Fossilized bacteria, preserved as rounded aggregates of titanite microcrystals, were identified in the pillow basalts up to the Early Cretaceous. The Rocas Verdes basin closed during the Andean orogeny, which started during the Late Cretaceous, and ophiolites were tectonically juxtaposed and thrust over the sedimentary infill of the quasi-oceanic basin in which they developed. The tectonic emplacement of the ophiolitic complexes was complete before the latest Cretaceous, as indicated by crystallization ages of granites intruded into the ophiolitic complexes. Coyright

AB - The ophiolitic remnants of the Upper Mesozoic Rocas Verdes basin in southernmost South America were studied from the perspectives of petrography, chemistry of minerals, bulk-rock geochemistry, and U-Pb geochronology. The study aimed to unravel the tectonic, magmatic, and metamorphic evolution of a suprasubduction rift zone that underwent a transition to a back-arc basin. The rifting phase and bimodal magmatism within the Rocas Verdes basin started prior to or during the Late Jurassic, as indicated by a gabbro in contact with pillow basalts that dated at 154 Ma. In the Late Jurassic Capitán Aracena and Carlos III complexes, tholeiitic basalts are geochemically comparable to enriched mid-oceanic ridge basalts. Back-arc basin development continued for 35 myr until the Early Cretaceous, as suggested by the ages of detrital zircons in cherty layers within pillow basalts and metamorphic titanite that crystallized during seafloor metamorphism near the spreading/magmatic axis. In the Early Cretaceous Tortuga Complex, tholeiitic basalts are comparable to normal mid-oceanic ridge basalts. Non-deformative metamorphism converted the primary mineralogy of the ophiolites to low- to intermediate-grade metamorphic assemblages formed during ocean-floor type alteration in a suprasubduction setting. Fossilized bacteria, preserved as rounded aggregates of titanite microcrystals, were identified in the pillow basalts up to the Early Cretaceous. The Rocas Verdes basin closed during the Andean orogeny, which started during the Late Cretaceous, and ophiolites were tectonically juxtaposed and thrust over the sedimentary infill of the quasi-oceanic basin in which they developed. The tectonic emplacement of the ophiolitic complexes was complete before the latest Cretaceous, as indicated by crystallization ages of granites intruded into the ophiolitic complexes. Coyright

KW - Geochemistry

KW - Microbes

KW - Mineral chemistry

KW - Rift to back-arc basin transition

KW - Rocas verdes ophiolites

KW - U-Pb dating

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U2 - 10.2343/geochemj.2.0235

DO - 10.2343/geochemj.2.0235

M3 - Article

AN - SCOPUS:84900301567

VL - 47

SP - 201

EP - 217

JO - Geochemical Journal

JF - Geochemical Journal

SN - 0016-7002

IS - 2

ER -