Abstract

Great Basin National Park (GBNP) is located in east central Nevada approximately 286 miles north of Las Vegas. The park includes much of the southern Snake Range rising to a maximum elevation of 3,982 meters at the summit of Wheeler Peak. The park is located in the Great Basin, a portion of the Basin and Range physiographic province that drains internally. Centered on the state of Nevada and extending from southern Oregon to western Texas, the Basin and Range Province is an immense region (~ 200,000 mi.2) of alternating, north-south trending, faulted mountains and flat valley floors. Topographically high regions like the Snake Range are found throughout the Great Basin and produce drastically different microclimates from the surrounding low lying valleys. For example, the high peaks of the Snake Range provide refuge for the only remaining active rock glacier in the interior Great Basin. Thus, the climate of GBNP is the closest modern analog we have for Late Quaternary climatic conditions.

It has long been recognized that the southern Snake Range in GBNP was glaciated during the last Ice Age. Early explorers (Gilbert, 1875; Simpson, 1876; and Russell, 1884) first described glacial features in the Snake Range and subsequent authors have continued to substantiate their reports (Weldon, 1956 and Kramer, 1962). However, little research had been conducted on the glacial history and paleoclimate of GBNP since this early reconnaissance work. There have been numerous studies on glaciation and paleoclimate throughout the Great Basin but to prior to this study, there had not been a formal investigation into the glacial geology and paleoclimate of the Snake Range and GBNP (Osborn and Bevis, 1997 and Osborn, 1988).

This study presents a preliminary map of glacial deposits and landforms in Great Basin National Park. The general surficial geology and glacial geomorphology has been mapped at a scale of 1:24,000 including the location and extent of cirques, moraines, and an active rock glacier. Relative age constraints have also been developed for prominent glacial deposits following the guidelines of Blackwelder, 1931; Sharpe, 1938; Birkeland, 1964, 1974; and Wayne, 1984.