Interpreting submarine structures for glacial retreat periodicity within Muchalat Inlet in Nootka Sound

Senior thesis written for Oceanography 445

[author abstract] At the end of the last glacial maximum a tidewater glacier, as part of the larger Cordilleran Ice Sheet, filled what is now Muchalat Inlet within Nootka Sound on Vancouver Island. As the glacier retreated it left distinct marks and features on the seafloor giving evidence as to what type, and how fast this retreat was. In this study we examined data collected with a Knudsen Chirp Echo Sounder 3260... to look at the seafloor structures present within the inlet. ...The overall pattern of structures such as sills along the comparably flatter seabed represents a distinct type of glacial retreat. Using the shape and size of the sills, their intermittent spacing within the inlet, and the location and extent of laminated sediments we can conclude, as shown by previous studies, that this glacier underwent episodic retreat.

University of Washington School of Oceanography