| During the Last Glacial Maximum (LGM) the Cordilleran Ice Sheet (CIS) advanced to the coast along southern Alaska, but not to Sitka Sound. Bathymetry, seismic reflection profiles, a piston core, and geologic map data collected in and around Sitka Sound reveal a lack of glacial features through the outer sound. The area has been assumed covered by the CIS. Instead, volcanic features produced by Mt. Edgecumbe and influenced by changes in global sea level during the LGM dominate. Glacial activity, however, occurred to the north and east of Sitka Sound, and Lisianski Inlet, 130 km to the NNW, is one example. It was covered by the CIS during the LGM and, on retreat, ice thinned and split, retreating in two directions---to the northwest and to the southeast. Current bathymetric features are being influenced by tidal activity and seasonal variations in marine productivity of sediment. |
