Scidmore Bay, Gilbert Peninsula

Scidmore Bay, Gilbert Peninsula

by | Jan 12, 2022

Scidmore Bay is enclosed by the Gilbert Peninsula to the east and the Fairweather Mountains to the west, and is situated within Glacier Bay National Park and Preserve, about 119 miles (192 km) southeast of Yakutat and 43 miles (69 km) northwest of Gustavus, Alaska. Gilbert Island, now called Gilbert Peninsula since post-glacial rebound uplifted the connecting isthmus, was named in 1937 by William O. Field and William S. Cooper for Grove K. Gilbert, a geologist with U.S. Geological Survey who visited Glacier Bay in 1899 with the Harriman Expedition. Scidmore Glacier once flowed into the bay and all that presently remains is a small remnant ice field about 4 miles (6.5 km) up the Scidmore River valley at an elevation of 3,850 feet (1,174 m) on the eastern flank of a ridge bordering Reid Glacier to the west. Glaciologists, hydrographers, ecologists, and the general public have been fascinated with the ongoing disappearance of a once huge Glacier Bay Icefield since the visits of Captain George Vancouver in 1794, John Muir in 1879, Eliza Scidmore in 1883, and Grove K. Gilbert in 1899. This icefield extended more than 1,482,631 acres (600,000 ha) over the landscape and reached thicknesses of up to 4,921 feet (1,500 m) by the Little Ice Age maximum in about 1750 AD. Evidence for the glacial extent is etched clearly on the modern landscape. Adams Inlet was filled with ice and drained to the east through the Endicott Gap into Lynn Canal. Lakes were trapped along the glacier flanks, the largest of which flooded most of Beartrack Valley. Outwash sediments issued from large glacial rivers to create the Gustavus area fan. Scidmore Glacier streamed east from the Fairweather Mountains and merged with the main glaciers filling Glacier Bay leaving only the highest peaks of the Gilbert Peninsula exposed. The icefield projected well into Icy Strait creating a prominent submarine terminal moraine. The floating tidewater terminus began to destabilize and in the typical tidewater glacier cycle, such destabilization is generally followed by extensive calving and a rapid retreat of the glacier front. In 1794, Lieutenant Joseph Whidbey of the Vancouver expedition mapped the Glacier Bay icefield terminus when retreat from the terminal moraine had been underway for at least 40 years. Dramatic deglaciation of Glacier Bay over the last 250 years has been documented by numerous workers including Harry F. Reid in 1896, and Otto J. Klotz in 1899. In September 1899, an earthquake rocked the Alaskan coast and the Muir Glacier‘s terminus was shattered by the quake and within hours Glacier Bay was a mass of impenetrable floating ice. This put an end to vessel excursions for many years since ships could generally only get within about 5 miles (8 km) of the Muir Glacier ice front.

Scidmore Glacier is not noticed by most visitors today, but its name is a testament to one of the area’s more interesting and intrepid visitors. Eliza Ruhamah Scidmore (pronounced ‘Sid-more’) was an independent world traveler, writer, and diplomat. Scidmore was born in 1856 in Iowa and attended Oberlin College. Scidmore began her career as a newspaper correspondent writing society columns for newspapers. A milestone event occurred in the summer of 1883 when she purchased a ticket to Alaska. Scidmore traveled through Southeast Alaska on the steamship Idaho commanded by Captain James Carroll, and she and her fellow passengers made history as the first tourists to visit Glacier Bay. She wrote newspaper and magazine articles about her travels and in 1885 published the first Alaska travel guide called ‘Alaska, its Southern Coast and the Sitkan Archipelago‘, followed in 1890 by ‘Guide to Alaska and the Northwest Coast‘. Her articles and travel logs shared the grandeur and adventure of Alaska and opened Alaska to tourism. In the decades after her visit to Alaska, Scidmore worked on projects of lasting importance. In 1890, she joined the fledgling National Geographic Society and over the next 30 years, Scidmore contributed to the Society as a writer, editor, photographer, lecturer, and sat on the Board of Managers, the first woman to do so. Scidmore’s most visual legacy is the cherry trees in Washington, D.C. that resulted from a visit to Japan in 1885. Convinced that Japan’s cherry trees would beautify Washington, D.C., Scidmore worked with First Lady Helen Taft, the manager of Washington area parks, and representatives of Japan to plant hundreds of cherry trees. Scidmore Glacier was named in 1937 by William O. Field and William S. Cooper, and subsequently also Scidmore Bay, to commemorate the beauty she found in the world and described for others. See a short video about Scidmore here.

In 1966, the U.S. Geological Survey was requested by the National Park Service to investigate the mineral resource potential of, at that time, Glacier Bay National Monument for its use in planning future development. The chief metallic commodities of potential economic importance were copper, molybdenum, nickel, gold, silver, titanium, and iron. Geologists found a mineralization at the head of Scidmore Glacier at an elevation of about 4,000 feet (1,219 m) on the eastern headwall of a ridge in the Fairweather Range. The occurrence is about 1 mile (1.6 km) east of Reid Glacier at a point approximately 2.3 miles (3.7 km) southeast of the glacier terminus. The area is mainly underlain by a terrane intruded by granitic rocks of Cretaceous age containing small localized inliers of metamorphic schist, phyllite, and marble of Paleozoic age. In the area of the mineral occurrence, two conspicuously iron-stained zones as much as 25 feet (8 m) thick, cut through tightly folded metasedimentary rocks. Pyrite-bearing quartz veins 1-2 feet (0.3-0.6 m) thick, locally cut the iron-stained zones. Chalcopyrite was present and a float sample of quartz vein contained 1,000 ppm copper. A chip sample of a sulfided zone contained 300 ppm copper and 7 percent iron, but no gold or silver was detected. Today, mining in national parks is regulated by the Mining in the Parks Act of 1978. Any mining or mineral extraction-related activity in a park requires approval of a Plan of Operations, which includes an analysis of environmen­tal impacts. Although mining is regulated, the Alaska Mineral Resource Assessment Program, which was mandated by the Alaska National Interest Lands Conservation Act of 1980, assesses minerals in the entire state, including national park units. The program is headed by the U.S. Geological Survey and helps identify strategic and necessary mineral deposits for national security and the overall economic health of the United States. Read more here and here. Explore more of Scidmore Bay and Gilbert Peninsula here:

About the background graphic

This ‘warming stripe’ graphic is a visual representation of the change in global temperature from 1850 (top) to 2021 (bottom). Each stripe represents the average global temperature for one year. The average temperature from 1971-2000 is set as the boundary between blue and red. The color scale goes from -0.7°C to +0.7°C. The data are from the UK Met Office HadCRUT4.6 dataset. 

Credit: Professor Ed Hawkins (University of Reading). Click here for more information about the #warmingstripes.

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