Guyot Glacier originates at about 6,700 feet (2,042 m) on the eastern flank of Yaga Peak in the Robinson Mountains and flows east-southeast for 34 miles (55 km) to its terminus on the western shore of Icy Bay in Wrangell-Saint Elias National Park and Preserve, roughly 146 miles (235 km) east-southeast of Cordova and 76 miles (123 km) northwest of Yakutat, Alaska. The glacier was named in 1886 by Heywood W. Seton-Karr, during a New York Times-sponsored expedition to climb Mount Saint Elias, after Arnold H. Guyot of Princeton University. At the time, the glacier filled Icy Bay and was considered a western lobe of the Malaspina Glacier. Subsequent retreat has since separated that lobe into the Tsaa, Guyot, Yahtse, Tyndall, Agassiz, and several smaller glaciers. The southern Alaska coast here consists of seven tectonostratigraphic terranes that formed in the equatorial Pacific and rafted northward on oceanic plates, eventually accreting to the North American continent. Each terrane has a distinct stratigraphy, separated from its neighbors by major strike-slip or thrust faults. The most recent arrival is the Yakutat terrane; the bedrock now exposed in Icy Bay represents the Yakutaga Formation, comprising glacio-marine continental shelf deposits from the early Miocene (about 23 million to 5 million years ago); mudstone, siltstone, sandstone, and diamictite.

Rapid recession of the Icy Bay glacier system has uncovered extensive low-lying areas along the fjord margins, mantled with glacial drift from the last ice advance. Organic remains include subfossil tree trunks and root systems buried in glacial till. Peat deposits containing tree remains were the primary source of radiocarbon dates used to reconstruct the glacier’s advance and retreat over the last two millennia. The oldest samples, from the upper fjord, date to AD 8 and AD 131, indicating that forests occupied the fjord margin at least 22 miles (35 km) inland roughly 2,000 years ago. These forests were buried by successive ice advances culminating in the 9th century, after which the glacier retreated to positions similar to today’s. By the early 15th century, glaciers in Icy Bay advanced again during the Little Ice Age. An oral tradition of the Tlingit people at Yakutat—the Laa xaayík Kwáan—describes a major glacier advance that filled the bay and overwhelmed a village at the mouth of the fjord. In 1794, Captain George Vancouver surveyed the Alaskan coast near the present site of Icy Bay, recording not a bay but an ice cliff. In 1911 the US Coast and Geodetic Survey steamer McArthur, commanded by C.G. Quillian, found a new bay at the western edge of the Malaspina Glacier; the survey recorded a recession of about 9 miles (14.5 km) and a glacier terminus 200–250 feet (60–75 m) high. Subsequent mapping and aerial surveys have documented continued recession into the upper fjord and the separation of the glacier into retreating tributary ice streams.

Arnold Guyot was a Swiss-American geographer who became professor of physical geography and geology at Princeton University. He studied at the Collège de Neuchâtel and in Germany, where he began a lifelong friendship with Louis Agassiz, who later influenced his move to the United States. As early as 1838, at Agassiz’s suggestion, he undertook the study of glaciers and was the first to publish, in a paper submitted to the Geological Society of France, important observations on glacial motion and structure—noting, among other things, that ice flows faster at the center than at the sides, and faster at the surface than at the base. He described the laminated, ribboned structure of glacial ice and attributed glacial movement to gradual molecular displacement rather than the sliding of an ice mass, the prevailing view at the time. His extensive meteorological observations in America contributed to the establishment of the United States Weather Bureau. In 1945 Harry H. Hess, who had gathered data using echo-sounding equipment aboard a ship he commanded during the second world war, discovered that some undersea mountains had flat tops. He named these “guyots,” after Arnold Guyot. Read more here and here. Explore more of Guyot Glacier and Icy Bay here: