A review of lateglacial pollen records from Ecuador and Peru with reference to the Younger Dryas event

Published biostratigraphic records from Ecuador spanning the Lateglacial period of approximately 13,000 to 10,000 BP lack radiocarbon dates delineating the Younger Dryas, and records with extrapolated dates do not exhibit evidence of a climatic reversal. For Peru, fossil pollen data from four sites suggest one and possibly two climatic oscillations in the Lateglacial, but only one site, Laguna Junin, has dates that delimit a short-term climatic change, and this occurs between 12,000 and 11,000 BP Pollen records from Laguna Baja and Rio Blanco pond give the strongest indication of a climatic reversal, but bracketing dates are not available. Other pollen records from Peru have tenuous dating or data and do not support a Lateglacial climatic reversal at the time of the Younger Dryas.