Late Quaternary glaciations of Ecuador

Abstract

Publisher Summary This chapter discusses the observations regarding the age control of the mapped glacial limits in Ecuador. Glacial sediments can be differentiated based on their altitude, morphology, tephrostratigraphy, degree of weathering, and radiocarbon as well as U/Th dating. Distinctive moraine systems in Ecuador date from the antepenultimate glaciation, the penultimate glaciation, the middle/early last glaciation, the last glacial maximum (LGM), the Late-glacial, the late Younger Dryas/early Holocene, and the Neoglacial. The chapter reviews that, because of weathering and radiocarbon dating, the massive moraines of the Ecuadorian Andes, commonly thought to be of LGM age, have been found to be older and were formed during the middle/early Last Glaciation and the penultimate glaciation. The chapter also reviews that the ecuadorian glacial chronology suffers from a lack of absolute dating; the only well-dated glacier advance being the late Younger Dryas/early Holocene advance. The exact ages of the LGM maximal glacier extent and of the Late-glacial ice advances are not yet known. The first phase of the LGM seems to have been more humid than the late LGM, as is documented by the ice-cored moraines and rock glaciers. It is still unclear when and why the LGM climate became more arid.