This study reports new data concerning the Holocene glaciation of Ameg
hino Glacier, an eastern outlet of the Southern Patagonia Icefield. Th
e lowest 7 km of the valley occupied by Ameghino Glacier is now ice-fr
ee, of which the upper 3.7 km is a moraine-dammed proglacial lake. Man
y glacial features are present in the Ameghino Valley. Across the vall
ey floor, four terminal moraines have been identified, each representi
ng a Neoglacial advance. Prominent vegetation trimlines are associated
with the youngest of these moraines (M IV) which dammed the proglacia
l lake. Samples for C-14 dating collected at the trimlines and from th
e valley floors indicate that the formation of M IV, the culmination o
f the recent maximum glaciation, occurred c. AD 1600-1700, and that de
position of the valley train occurred c. AD 1500. Large standing trees
which were buried and killed by this period of deposition have subseq
uently been exhumed by river erosion. The glacier may have remained at
the trimline level until around AD 1870-1880, the date obtained by Ni
chols and Miller (1951) from dendrochronological analyses. The number
of Neoglacial advances (4) identified in the Ameghino Valley is the sa
me as that recently identified at two other Patagonian glaciers, Upsal
a and Tyndall, and the date of the latest glacial episode, the 'Little
Ice Age', is found to be synchronous. However, the ages of the earlie
r three Neoglacial episodes remain unknown.