Whole-rock chemistry and radiocarbon ages for tephras and lavas used to establish the eruption history over the past 15 kyr at Laguna del Maule volcanic field along the Chilean-Argentine border

The Laguna del Maule (LdM) volcanic field as mapped by Hildreth and others (2010) includes 36 postglacial rhyolite and rhyodacite coulees and domes that erupted from 24 separate vents that encircle the 54-km2 lake basin. Although recognizing that such effusive events commonly have accompanying explosive phases, pursuing downwind tephra studies into Argentina was not done then and the sequence and timing of much of the most recent LdM activity remained uncertain. In 2011, a new collaborative project among the Geological Surveys of the United States, Chile, and Argentina focused on the young tephra deposits with the goal of establishing a postglacial eruptive sequence at Laguna del Maule to better evaluate the frequency, timing, and scale of the eruptions. This study documented that >70 separate vents distributed over ~360 km2 produced >100 explosive and extrusive events over the past 17 ka. More than two-thirds of these have been silicic, with most being postglacial rhyolites (72–78% SiO2) concentrated near the eponymous lake, an extraordinary anomaly in the Quaternary Andes and unprecedented in this 1.5–Ma-old volcanic field as a whole. Of the >100 eruptive events, 55 are rhyolitic (73% –77% SiO2), 18 are rhyodacitic (68% –72% SiO2), 4 are dacitic (63% – 66% SiO2), 26 are intermediate (54 – 62% SiO2), and 2 are true basalts (50% – 53% SiO2). Most originated from single-vent domes, cones, or craters that erupted effusive and/or explosive products, each with relatively short lifespans. Some originated from multi-vent centers, the largest one being the Barrancas complex southeast of the lake, which has as many as 18 vents that erupted over as much as 10 kyr. The LdM basin itself is ringed by 13 separate silicic centers, many of which are also multi-vent and built over time by multiple explosive and extrusive events. These surround the lake, near the middle of which is the vent for the high-silica rhyolite Plinian eruption that produced the “Rhyolite of Laguna del Maule”, which was the first and largest silicic event from the postglacial field. Explosive and effusive products from all these events have been put in a time-stratigraphic framework supported by radiocarbon dating and chemical analyses to reconstruct the postglacial eruptive history. The geochemical data and radiocarbon ages that inform the stratigraphic framework are compiled in this data release. Correlations of pyroclastics to eruptive vents have provided a spatial-temporal framework that helps characterize the magmatic system beneath the LdM field.