A history of violence: magma incubation, timing and tephra distribution of the Los Chocoyos supereruption (Atitlán Caldera, Guatemala)

Schindlbeck‐Belo, Julie C.
Kutterolf, Steffen

Danišík, Martin

Schmitt, Axel K.

Freundt, Armin

Pérez, Wendy
Harvey, Janet C.
Wang, Kuo‐Lung
Lee, Hao‐Yang
DOI: https://doi.org/10.23689/fidgeo-4049
Kutterolf, Steffen; 2 GEOMAR Helmholtz Centre for Ocean Research Kiel SFB574, Wischhofstraße 1‐3 Kiel 24148 Germany
Danišík, Martin; 3 GeoHistory Facility, John de Laeter Centre, TIGeR Curtin University Perth WA 6845 Australia
Schmitt, Axel K.; 1 Institut für Geowissenschaften Universität Heidelberg, Im Neuenheimer Feld 234‐236 Germany
Freundt, Armin; 2 GEOMAR Helmholtz Centre for Ocean Research Kiel SFB574, Wischhofstraße 1‐3 Kiel 24148 Germany
Pérez, Wendy; 2 GEOMAR Helmholtz Centre for Ocean Research Kiel SFB574, Wischhofstraße 1‐3 Kiel 24148 Germany
Harvey, Janet C.; 1 Institut für Geowissenschaften Universität Heidelberg, Im Neuenheimer Feld 234‐236 Germany
Wang, Kuo‐Lung; 4 Institute of Earth Sciences, Academia Sinica Taipei 11529 Taiwan
Lee, Hao‐Yang; 4 Institute of Earth Sciences, Academia Sinica Taipei 11529 Taiwan
Abstract
The climactic Los Chocoyos (LCY) eruption from Atitlán caldera (Guatemala) is a key chronostratigraphic marker for the Quaternary period given the extensive distribution of its deposits that reached both the Pacific and Atlantic Oceans. Despite LCY tephra being an important marker horizon, a radioisotopic age for this eruption has remained elusive. Using zircon (U–Th)/He geochronology, we present the first radioisotopically determined eruption age for the LCY of 75 ± 2 ka. Additionally, the youngest zircon crystallization 238U–230Th rim ages in their respective samples constrain eruption age maxima for two other tephra units that erupted from Atitlán caldera, W‐Fall (130 +16/−14 ka) and I‐Fall eruptions (56 +8.2/−7.7 ka), which under‐ and overlie LCY tephra, respectively. Moreover, rim and interior zircon dating and glass chemistry suggest that before eruption silicic magma was stored for >80 kyr, with magma accumulation peaking within ca. 35 kyr before the LCY eruption during which the system may have developed into a vertically zoned magma chamber. Based on an updated distribution of LCY pyroclastic deposits, a new conservatively estimated volume of ~1220 ± 150 km3 is obtained (volcanic explosivity index VEI > 8), which confirms the LCY eruption as the first‐ever recognized supereruption in Central America.