Figure Caption: A debris-flow fan (~ 0.04 km2 in size) on the east side of Death Valley, California (upper panel) and optical microstratigraphies of rock varnish from the debris-flow fan deposits (lower panel). Seven debris-flow fan units (Df1-Df7) were identified on the basis of fan morphology and degree of rock varnish coverage. Varnish-based age estimates indicate that these debris-flow fan units were deposited around 12500 (Df1), 12500-11100 (Df2), 11100 (Df3), 10300 (Df4), 9400 (Df5), and 2800 (Df6) cal yr BP (Liu and Broecker, 2006). The dating results also indicate that the deposition of these fan units was more likely to have occurred during relatively wet periods of the Holocene.