http://keck.wooster.edu/publications/eighteenthannual… 135 GLACIATION OF THE UGWI YAMMA VALLEY, KHARKHIRAA UUL, MONGOLIA MARTIN BEVIS AND ENKHBAYAR DANDAR Whitman College, Mongolia University of Science and Technology Sponsor: Bob Carson INTRODUCTION The Ugwi Yamma (UY) Valley is about 7 km long and 200 m deep; it is formed by the inner slope of Last Glacial Maximum (LGM) moraines (Figs. 1 and 2). A braided meltwater stream (the UY River) threads through small, probable LGM recessional moraines on the valley floor (Fig. 3). Though granitic drift mantles the valley, phyllite comprises the bedrock; the UY River cuts two gorges into the limited exposures. The top of the upper gorge is striated in places, and there are at least ten striated granitic boulders in the valley, indicating that the glacier was at least in part warm based. The maximum extent of Little Ice Age (LIA) glaciers is recorded by an 80-m-high ice-cored terminal moraine (ICTM) 3 km from the cirque headwall. The objectives of this research were to map glacial landforms, characterize the nature of glaciations in the UY Valley, determine the relative glacial chronology of the valley, and estimate extent of glaciations in the valley. Figure 2. Longitudinal section of the UY Valley showing past and present glaciation relative to the current topography. The LGM glacier surface is projected from the valley-forming LGM moraines. Figure 1. Annotated map of the UY Valley showing important features.