Poster Number 209
See more from this Division: Topical Sessions
See more from this Session: Soil Geomorphology and Chronosequences (Posters)
Abstract:
For this study, we have used OSL to date the timing of deposition on alluvial fans in the LRR. Numerous surfaces from both glaciated and unglaciated basins have been sampled to assess the role of climate and glaciation on fan deposition. Complimentary dating of fan surface abandonment and stabilization will be obtained through U-series dating of pedogenic carbonate coats. U-series dating will also be applied to carbonate coats from inferred Pinedale and Bull Lake moraine surfaces.
Multiple geomorphic surfaces have been identified on the five fans included in this study. Preliminary OSL ages have been obtained from the Upper Cedar Creek Fan in the central portion of the LRR (10% glaciated). These results indicate that one of the higher Pleistocene surfaces is ~50 ka, and the lowest non-active surface is ~3-4 ka. Further age control will be obtained to determine the timing of sediment delivery to LRR fans and its relationship to regional climate and catchment glaciation.
See more from this Division: Topical Sessions
See more from this Session: Soil Geomorphology and Chronosequences (Posters)