Postglacial drainage in the Mohawk River Valley with emphasis on paleodischarge and paleochannel development

During the final retreat of Laurentide ice from New York State, the Mohawk Valley played a major role in the routing of glacial meltwater. The Mohawk Valley contained the Iromohawk River, which drained Glacial Lake Iroquois, in the Ontario Basin, into Hudson Valley glacial lakes Albany II, Quaker Springs, Coveville and Fort Ann. Iromohawk drainage occurred for approximately 500 years while the St. Lawrence Lowland remained glaciated and the Mohawk Valley was ice free.; Iromohawk drainage developed a network of distributary channels across the Hudson-Mohawk Lowland, as well as carving the modern Mohawk channel between Schenectady and Cohoes. Progradation of these channels occurred as the Iromohawk drained toward lowering Hudson Valley glacial lake levels. Depositional and erosional surfaces associated with distributary and modern channels have been used to establish a chronology of channel development and usage relative to Hudson Valley glacial lakes. This chronology constrains the timing and duration of later Hudson Valley lake phases between {dollar}sim{dollar}12,500 and 12,000 years BP.; Sedimentologic evidence in the Scotia Gravel at Scotia, one of the principle Iromohawk deposits in the valley, indicates Iromohawk drainage was a long-term, high-discharge event with cyclic (probably seasonal) variation in flow. Estimates on the lower limit of maximum Iromohawk discharge of between 1 and 2 {dollar}times{dollar} 10{dollar}sp6{dollar} cubic feet per second (cfs) were obtained from Manning's equation and step-backwater modeling.; Possible effects of Iromohawk drainage on Hudson Valley morphology and global climate are discussed.