Late Quaternary Glacial Fluctuations in the Langtang Valley, Nepal Himalaya, Reconstructed by Relative Dating Methods

Abstract

Glacial fluctuations in the Langtang Himal are discussed on the basis of multiple relative dating (RD) methods in addition to the '4C method. The RD methods used for the classification of the moraine deposits include the Schmidt hammer rebound values, weathering rind thickness, percentage of clasts with oxidation stain, height of mineral projection, pit depth, percentage of weathered clasts, soil development, and soil color index. By using the RD data, we were able to divide the moraines into five stages (Gora Tabela, Langtang, Lirung, and Yala I and II); an older stage (Lama) is recognized only by the glacialtrough configuration extending down to an altitude of approximately 2600 m. The Gora Tabela Stage is defined by the deeply weathered Lower Till extending down to 3200 m a.s.l. The Langtang Stage (3650-3000 14C yr BP) probably corresponds to the greatest advance in the Holocene, followed by a series of smaller advances in the Lirung Stage (2800-550 '4C yr BP), and the two smaller Little Ice Age advances (Yala I and II Stages).