In 1997, three ice cores were recovered from the Dasuopu glacier (28°23'N, 85°43'E) with the use of an electromechanical drill in dry holes. The first core (C1) was 159.9 m long and was drilled at 7000 m above sea level (a.s.l.) down the flow line from the top of the col, and two cores (C2 and C3), 149.2 and 167.7 m long, respectively, were drilled to bedrock 100 m apart on the col at 7200 m a.s.l. Visible stratigraphy showed no hiatus features in any of the cores. All cores were analyzed over their entire lengths for oxygen isotopic ratio (?18O ), chemical composition, and dust concentration.