Interest in Alaskan tectonic studies has varied through time as different events have focused attention toward and away from this North American frontier. In 1964 the great Alaskan earthquake focused attention on Alaska, and was a major factor in the establishment of the concept of subduction in the early days of plate tectonics. In the 1980s, the northern Cordillera, including Alaska, was the subject of extensive study using the terrane analysis approach, which spawned a series of new tectonic syntheses. Topical studies continued in Alaska through the 1990s and into the early part of the first decade of the twenty-first century, but in smaller research groups primarily working on specific, focused studies. Larger multidisciplinary research projects were focused in Alaska at about the time of the 2002 Denali earthquake, which occurred while a large, collaborative research group was being assembled with a goal of understanding the general problems of the Neogene tectonics of Alaska associated with the collision of the Yakutat terrane. The St. Elias Erosion/tectonics Project (STEEP; http://www.ig.utexas.edu/steep/) arose in large part because of increasing evidence that erosion-tectonic interactions within mountain belts were poorly understood, and southern Alaska is in an ideal setting for examining the role of glacial erosional processes in this type of interaction. Although subsequent studies indicated that the original highest estimates of glacial erosion rates were overestimated, even these revised estimates indicated that fast moving, temperate ice was capable of removing rock at rates of centimeters per year. Since most of the world's moderate- to high-latitude mountain systems are either no longer active or are marginally active tectonically, and erosion rates are orders of magnitude lower, the southern Alaskan orogen represents a premier site for studies of the interactions between tectonic processes and glacial erosion. STEEP efforts, funded by the National Science Foundation (NSF) Continental Dynamics Program, together with other ongoing studies of Alaskan tectonics by the U.S. Geological Survey and other academic researchers, have focused attention back on Alaskan tectonics. The next decade promises to see even more profound changes in our level of knowledge of this last frontier for geologic studies in the United States. Research reported in this Geosphere themed issue was launched by members of the STEEP research group with the intent of showcasing some of the unusual data sets that were being assembled in this project.
- Received 8 January 2014.
- Revision received 1 February 2014.
- Accepted 5 March 2014.
- © Geological Society of America