Surficial geology, stratigraphy, and quaternary history of Granite Creek, Yukon

The Cordilleran Ice Sheet (CIS) affected Yukon multiple times during the Quaternary; understanding the interaction of alpine glaciers and the CIS is important for paleoclimate studies and placer exploration. In glaciated terrain, economic placer gold deposits can be in a range of glacial deposits and buried by tens of metres of sediment. We utilized placer mining exposures to interpret the sedimentology and stratigraphy of glacial and interstadial environments in Granite Creek, Yukon. Three glacial cycles were identified and include the first evidence of an MIS 4 alpine glaciation in central Yukon, dated using optically stimulated luminescence. We created a 1:20,000 surficial geology map with glacial limits, identified key placer-forming environments and gold-bearing units, and determined that, other that MIS 4, alpine glaciers were contemporaneous with the CIS. This study highlights complex glacial history not evident based on geomorphology, but resolved by utilizing mining excavations.