Bablon M. auteur aut IRD Quidelleur X. auteur aut IRD Siani G. auteur aut IRD Samaniego Pablo auteur aut IRD Le Pennec Jean-Luc auteur aut IRD Nouet J. auteur aut IRD Liorzou C. auteur aut IRD Santamaria S. auteur aut IRD Hidalgo S. auteur aut IRD text journalArticle eng text/pdf born digital access New K-Ar ages obtained on juvenile pumice glass shards indicate that the Chalupas ignimbrite, one of the main Pleistocene tephra markers of the Ecuadorian arc, was emplaced at 216 +/- 5 ka. Morphology and major and trace element contents of the glass shards are similar to those of ash layers from deep-sea cores and allow correlation between continental deposits and marine tephra layers. Based on biostratigraphy and delta O-18 data, the age models of these cores support our K-Ar age. Fine ashes from the Chalupas eruption column have been found about 1000 km away from the source caldera, and the estimated deposit volume of both ignimbrite and co-ignimbrite deposits ranges from 200 to 265 km(3). This suggests that the Chalupas event could have been strong enough to reach the stratosphere and inject large amount of SO2 in both hemispheres, possibly impacting global temperatures. In addition, the age of the Chalupas ignimbrite obtained here could provide a new radiometric constraint for the age of isotope stage 7 recorded in orbitally-tuned delta O-18 deep-sea cores. This study highlights the relevance of K-Ar dating applied to small glass shards from massive ignimbrite deposits, and the potential that it represents to improve risk assessments in volcanic zones where dating crystals is not possible. Finally, detailed tephrochronology of deep-sea cores and correlation between marine ash-layers and continental volcanic deposits constitute a strong tool to investigate the eruptive history of an active volcanic arc whose proximal products have been eroded or deeply buried by younger deposit sequences. specialized K-Ar dating Glass shards Ecuador Chalupas Ignimbrite eruption EQUATEUR CHALUPAS VOLCAN 066 064 57 art. 101053 [12 p.] 2020 1871-1014 https://www.documentation.ird.fr/hor/fdi:010079019 10.1016/j.quageo.2020.101053 1871-1014 [F B010079019] https://www.documentation.ird.fr/hor/fdi:010079019 https://www.documentation.ird.fr/intranet/publi/2020/05/010079019.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2020-06-09 2025-02-24 fdi:010079019 fre