Timing of Quaternary volcanism and its relationship with tectonics in the central segment of the Ecuadorian Andes

The unusually high number of volcanoes in the Ecuadorian Arc, located in the deformation zone of the continental North Andean Sliver, coincides with the projection of the major oceanic structures observed in the Nazca Plate, such as the Carnegie Ridge and the Grijalva fracture zone. Although the relationship between this tectonic setting and volcanism has been widely discussed in the literature, their temporal relationship has not been thoroughly investigated due to the lack of geochronological data. We present here 20 new KAr and 2 40Ar/39Ar ages obtained for 7 volcanoes of the central segment of the Ecuadorian arc, which together with previous data show that volcanism in this area started at ∼1.3 Ma. A notable increase in volcanic activity occurred since ∼0.6 Ma, when the formation of a dozen volcanoes occurred in a relatively small area of the central segment. While this arrangement of volcanoes, here referred to as a “volcanic cluster”, appears to be controlled by crustal tectonic structures, the order of onset of these volcanoes and their eruptive activity does not show clear migration patterns over time. However, the presence of older volcanoes in the north of the central segment suggests a possible southward extension of volcanism between ∼1.3 and ∼ 0.6 Ma. Finally, based on the cumulative bulk volumes calculated for the volcanic edifices over time, we infer that the magmatic productivity rate has been roughly constant during the last ∼550 kyr in this area.

Keyword(s)

Ecuador, K-Ar dating, Quaternary, Eruptive history, Tectonics

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Publisher's official version
2127 Mo
Supplementary material 1. Thin sections of selected samples from volcanoes of the central segment of the Ecuadorian arc for K-Ar and 40Ar/39Ar dating.
59 Mo
Supplementary material 2. 40Ar/39Ar radiometric measurement data, interfering isotope corrections, constants, age calculations and other associated data.
-31 Ko
Supplementary material 3. Major and trace element composition of whole-rock samples collected from volcanoes of the central segment of the Ecuadorian arc.
-50 Ko
Supplementary material 4. Additional figures. Harker variation diagrams for D1) major and D2) trace elements. D3) 3D model of the north flank of the Corazon volcano. D4) Geochemical comparison...
4620 Ko
Author's final draft
566 Mo
How to cite
Santamaria Santiago, Quidelleur Xavier, Samaniego Pablo, Audin Laurence, Le Pennec Jean-Luc, Hidalgo Silvana, Liorzou Celine, Guillou Hervé (2023). Timing of Quaternary volcanism and its relationship with tectonics in the central segment of the Ecuadorian Andes. Journal Of Volcanology And Geothermal Research. 442. 107895 (21p.). https://doi.org/10.1016/j.jvolgeores.2023.107895, https://archimer.ifremer.fr/doc/00852/96419/

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