The provenance of Middle Jurassic-Cretaceous sedimentary rocks deposited in the southern Peruvian Arequipa Basin has been investigated based on the measurement of 41 Sr-Sm-Nd isotopic compositions of sedimentary rocks, 993 U-Pb zircons ages, and 202 Lu-Hf zircon isotope data. The Middle Jurassic units are dominated by Brazilian/Pampean and Grenville/Sunsas and have juvenile to evolved Hf isotopic compositions of Permian zircons. These are consistent with an Eastern Cordillera (EC) provenance. In contrast, the Late Jurassic Labra Formation presents the first appearance of Triassic-Jurassic zircons and an increase in Famatinian zircons thus suggesting a mixed provenance from the EC and/or Altiplano and the Coastal Cordillera (CC). The Gramadal Formation shows older U-Pb zircon ages, which reflect a major contribution from Precambrian sources either from the Amazon craton or the EC thus implying a change in provenance. Another change in provenance is documented for the Hualhuani Formation with sources located both in the CC and EC. Finally, the Santonian Chilcane Formation is characterized by a large contribution of Cretaceous to Famatinian zircons indicating that it was mainly sourced from the CC. Our provenance dataset associated with the depositional setting of the Middle Jurassic to Early Cretaceous formations and the cumulative curves of zircon age distribution, indicate that the Arequipa Basin was not a back-arc setting but rather a rift-like setting. Contrary to the older formations, the Chilcane Formation is dominated by contributions from the CC in a retroarc foreland basin setting. This statement further implies that the Andean basin located eastward of the volcanic arc had evolved directly from a rift to a retroarc foreland basin and implies that the control of Andean subduction on these basins might be much younger than previously thought.
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We thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for granting a Master scholarship to the first author. We also thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and the Laboratório de Geocronologia of the Universidade de Brasília (University of Brasília, Brazil). We thank Sarah George and Carita Augustsson as well as the editor Sebastian Tappe for valuable reviews and helpful comments that improved this contribution.
We thank the Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) for granting a Master scholarship to the first author. We also thank the Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) and the Laborat?rio de Geocronologia of the Universidade de Bras?lia (University of Bras?lia, Brazil). We thank Sarah George and Carita Augustsson as well as the editor Sebastian Tappe for valuable reviews and helpful comments that improved this contribution. All geochronological and isotopic data including individual analyses of LA-MC-ICP-MS zircons (termed Table S3 to S19), Sr-Sm-Nd isotopic data (termed Table 2), and Lu-Hf isotopic data (termed Table S2), as well as cathodoluminescence images of dated zircons (termed Supplementary Fig. 1) and outcrop pictures (termed Supplementary Fig. 2), data information regarding analytical procedures used for LA-MC-ICP-MS dating (termed Table S2), characteristics of potential sources (termed Table 1) and percentages of U?Pb ages representing known orogenic events (termed Table S4) are uploaded into an online supplementary dataset associated with this paper Roddaz, Martin; Chavez, Cesar; Dantas, Elton Luiz; Ventura Santos, Roberto; Alvan, Aldo (2021), ?Supplementary dataset for Chavez et al ?Provenance of the Middle Jurassic-Cretaceous sedimentary rocks of the Arequipa Basin (South Peru) and implication for the geodynamic evolution of the Central Andes?, Mendeley Data, V2, doi: 10.17632/ksypv2smvp.2.
© 2021 International Association for Gondwana Research
- Arequipa basin
- Central Andes