We therefore suggest that the tephra layers deposited at Aucayacu result from the eruptions of volcanoes along the Nazca and South American plate boundary which occurred during atypical (Westerly) wind conditions.
In an attempt to identify a source region and/or volcano for the AUC1 tephra we searched the Smithsonian Global Volcanism Database for volcanoes in Colombia, Ecuador or Peru, which had recorded eruptive activity around the time of the AUC1 tephra deposition.
Cryptotephra studies have focussed predominantly on northern latitudes of Europe, although cryptotephras have also been identified in many other regions for example China.
To the authors’ knowledge there have been no previous published studies of cryptotephra occurrence in the Amazon basin.
The presence of this tephra has important implications for dating and correlating very recent peats and lake sediments in western Amazonia, and provides unambiguous evidence that Amazonia has been affected by volcanic ash fall in the very recent past.
Aucayacu (“water of the natives” or “water of the warriors”) is a domed peatland in western Peru that currently operates as an ombrotrophic ‘raised bog’ system.
Our discovery 1) indicates that the Amazon basin has been subject to volcanic ash fallout during the recent past; 2) highlights the opportunities for using cryptotephras to date palaeoenvironmental records in the Amazon basin and 3) indicates that cryptotephra layers are preserved in a dynamic Amazonian peatland, suggesting that similar layers are likely to be present in other peat sequences that are important for palaeoenvironmental reconstruction.