Cause-effect relationship between volcanism and travertine-tufa deposition: the case study of Barranco de Azuaje, Gran Canaria, revisited

Abstract

The travertine and tufa of Barranco de Azuaje in Gran Canaria, Canary Islands, were revisited to analyze their relationship with volcanism. The carbonate deposits are geographically and stratigraphically related to the lava flows of the Montaña (Mt.) Doramas eruption. Nevertheless, this relationship remained controversial due to the incongruity of the previous ages of carbonate deposits and the underlying Mt. Doramas lava. We methodically collected and investigated nine charcoal samples related to the Mt. Doramas lava and 16 travertine and tufa samples for U-Th dating. Bayesian analysis indicated that the Mt. Doramas eruption occurred at 3107 [3164, 3068] cal BP (MAP, mode of the posterior distribution, and 95% highest posterior density (HPD) interval). Carbonate deposition began immediately after the Mt. Doramas eruption and spread over 865 [358, 1885] years, from 3095 [3143, 3158] to 2215 [2738, 1225] cal BP. The short time elapsed between the eruption and the carbonate deposition, together with evidence of direct deposition of travertine and tufa on the lava roof, or after a minimum accumulation of alluvial sediments between them, supports a genetic link between the eruption and the carbonate. Moreover, the duration of carbonate deposition is consistent with a one-time event, such as a volcanic eruption. The spatial distribution, stratigraphic relationships, and age compatibility presented here provide evidence for the cause-effect relationship between the eruption and the formation of carbonate deposits on this oceanic volcanic island.