HIGH RESOLUTION MAPPING OF HOLOCENE SEDIMENTS, CANANDAIGUA LAKE, NEW YORK

Contemporary topography of the Finger Lakes Basin in New York is largely due to the retreat of the Laurentide ice sheet over 14,000 years ago. The retreating glaciers carved out steep U-shaped valleys that are ideal for preserving sediment history. Since the Laurentide retreat the basin topography has altered, going through a series of different major lake evolution phases. The Finger Lakes started as streams or stream valleys; debris from the retreating glaciers blocked the southern most ends of the streams to create lakes. The large amounts of water from the melted glacier originally formed much larger ancestral lakes such as Lake Newberry and Lake Ithaca. As the water from glacial melting drained out, lake levels dropped leaving the contemporary Finger Lakes. Modern lakes of the basin are very different from the ancient proglacial lakes from which they evolved. The eight generally north-south trending lakes are now elongate troughs bounded on one end by glacial debris or moraines and having a maximum thickness of more than 90 m of sediment fill. They are shallower, and the width of the lakes has also decreased significantly since the time of the larger lakes such as Lake Ithaca.