High-gradient, stepped fluvial tufa systems with dammed areas existed in the River Añamaza valley
(NW Iberian Ranges, Spain) during Quaternary times. Single deposits range from a few meters to about 70
m thick, in which prograding-aggrading wedges separated by erosional surfaces exist. Several episodes of
tufa formation have been distinguished by means of U-series, Amino-acid racemization and radiocarbon
techniques. These correlate to MIS 8, 7, 5 and 1. The presence of MIS 9 is uncertain, as chronological data
may also correspond to older stages. Most tufas in this area formed in MIS 5. Distinct tufa episodes can
also be distinguished in the Holocene. These are the first chronological data presented for one of the
northernmost Quaternary tufa systems in the Iberian Ranges