Late Holocene tephrostratigraphy from Cajas National Park, southern Ecuador

Arcusa, Stephanie H.; Schneider, Tobias; Mosquera, Pablo V.; Vogel, Hendrik; Kaufman, Darrell; Szidat, Sönke; Grosjean, Martin (2020). Late Holocene tephrostratigraphy from Cajas National Park, southern Ecuador. Andean geology, 47(3), pp. 508-528. Servicio Nacional de Geología y Minería 10.5027/andgeoV47n3-3301

[img]
Preview
Text
Arcusa et al 2020 (Late Holocene tephrostratigraphy).pdf - Published Version
Available under License Creative Commons: Attribution (CC-BY).

Download (5MB) | Preview

Lakes located downwind of active volcanoes serve as a natural repository for volcanic ash (tephra) produced during eruptive events. In this study, sediment cores from four lakes in Cajas National Park, southern Ecuador, situated approximately 200 km downwind of active volcanoes in the Northern Andes Volcanic Zone, were analysed to document the regional history of tephra fall extending back around 3000 a cal BP. The ages of the lacustrine sedimentary sequences were constrained using a total of 20 AMS radiocarbon ages on plant remains. The tephra layers were correlated among the lakes based on their radiocarbon age, elemental composition, colour, and grain morphology. We found five unique tephra layers, each at least 0.2 cm thick, and further constrained their ages by combining the results from two age-depth modelling approaches (clam and rbacon). The tephra layers were deposited 3034 ± 621, 2027 ± 41, 1557 ± 177, 733 ± 112, and 450 ± 70 a cal BP. The ages of all but the youngest tephra layer overlap with those of known eruptions from Tungurahua. Some tephra layers are missing as macroscopic layers in several cores, with only two of the five tephra layers visible in the sediment of three lakes. Likewise, previous studies of lake sediment cores from the region are missing the four youngest tephra layers, further highlighting the need to sample multiple lakes to reconstruct a comprehensive history of fallout events. The newly documented stratigraphic marker layers will benefit future studies of lake sediments in Cajas National Park.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geography
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Departement of Chemistry and Biochemistry
08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Schneider, Tobias; Vogel, Hendrik; Szidat, Sönke and Grosjean, Martin

Subjects:

500 Science > 550 Earth sciences & geology
900 History > 910 Geography & travel
500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

ISSN:

0718-7106

Publisher:

Servicio Nacional de Geología y Minería

Language:

English

Submitter:

Andrea Stettler

Date Deposited:

01 Sep 2020 08:46

Last Modified:

12 Oct 2020 07:35

Publisher DOI:

10.5027/andgeoV47n3-3301

BORIS DOI:

10.7892/boris.146277

URI:

https://boris.unibe.ch/id/eprint/146277

Actions (login required)

Edit item Edit item
Provide Feedback