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 δ¹⁸O 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 km³. 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 δ¹⁸O 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.

在幼年的浮石玻璃碎片上获得的新的K-Ar年龄表明，厄瓜多尔弧的主要更新世特非拉标志物之一的Chalupas着火岩位在216±5 ka处。玻璃碎片的形态，主要和微量元素含量与深海岩心的灰分层相似，并且可以使大陆沉积物与海生特非拉层之间具有相关性。基于生物地层学和δ ^18个O数据，这些核心的时代型号支持我们的K-Ar年龄。查卢帕斯火山喷发柱的细灰已发现，距源火山口约1000公里，火成岩和共成岩沉积物的估计沉积量为200至265 km ^3。。这表明Chalupas事件可能已经足够强大到足以到达平流层并向两个半球注入大量SO ₂，可能影响了全球温度。此外，熔结凝灰岩在这里获得的Chalupas的年龄可为同位素级7的记录在以轨道调谐δ时代一个新的辐射约束¹⁸O深海核心。这项研究强调了将K-Ar定年应用于大块火成岩沉积物中的小玻璃碎片的相关性，以及它在改善不可能定年晶体的火山区评估风险方面的潜力。最后，深海岩心的详细年代年代学以及海洋火山灰层与大陆性火山岩沉积之间的相关性是研究活跃火山弧爆发历史的有力工具，该火山弧的近端产物已被年轻的沉积层侵蚀或深埋。