A Collaborative Proposal: Late Quaternary Glacial and Paleoclimate Record in the Southern Uinta Mountains, Northeastern Utah

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

ABSTRACT The Uinta Mountains contain a well-preserved record of alpine glacier extents and behavior during the latest Pleistocene. Yet, this record has not been studied in detail at the range-wide scale, and the timing of the Last GlacialMaximum (LGM) and subsequent deglaciation have not been determined. Documenting the spatial and temporal extent of late-Quaternary glaciation in the Uinta range is warranted for several reasons. First, the location of the range - central among well-dated alpine glacial localities and adjacent to the eastern edge of the Lake Bonneville basin - provides great potential for examining the regional effect of Lake Bonneville on paleoclimate and glaciation in northeastern Utah. Second, the orientation of the Uinta range provides a unique opportunity to study a record of large glaciers that flowed both north and south within a single mountain range. Finally, the excellent preservation of moraines and resistant lithology of erratic boulders provides ideal targets for cosmogenic surface-exposure dating. We propose to use a combination of conventional and advanced research methods to study the late-Quaternary glacial and paleoclimate record of the Uinta Mountains in pursuit of the following goals: 1) Determine the extent and timing of glaciation in the Uinta Mountains during and since the LGM. This effort will involve (1) detailed field and air photograph mapping of the surficial geology of the south flank of the Uinta Mountains (2) cosmogenic surface-exposure dating of moraines deposited during the LGM in the western, central, and eastern Uintas and (3) retrieval and study of lake sediment cores from lakes dammed by recessional moraines across the north and south slopes of the range. 2) Reconstruct the latest Pleistocene paleoclimate from glacial records across the Uinta Mountains. Because the extents of glaciers are a function of temperature and precipitation, glacial records are excellent proxies of climate change. We will use the geomorphic records of latest Pleistocene glaciers to validate numerical modeling experiments that simulate glacier growth based on climate input parameters; this will allow for a unique determination of LGM paleoclimate in the Uinta Mountains. Broader Impacts The research outlined in this proposal will yield benefits beyond pursuit of the core scientific objectives. First, it will further the ongoing relationship between the Ashley National Forest (ANF) and UW-Madison. Due to rising public use and more intensive management of National Forests, supervisors of the ANF have developed a greater interest in the geologic history of forest land and have supported graduate student research in the Uinta Mountains for the past 8 years (e.g., Douglass, 2000; Munroe, 2001; Carson, 2003) and continue to support current graduate research (B. Laabs, this study; see letter of support). Second, Ph.D. student B. Laabs will participate in the new NSF Center for the Integration of Research Teaching and Learning (CIRTL), an NSF-sponsored program that was launched at the UW-Madison to prepare the next generation of college science professors. He will participate in CIRTL courses and workshops focused on the effective use of research methods to disseminate scientific knowledge in the college classroom. Laabs will be among the first graduate students to receive a certificate acknowledging preparation for a career in academia and bring the fruits of this NSF-UW-Madison partnership into the U.S. higher education system. Finally, J. Munroe (Middlebury College) has built upon his graduate work in the Uintas and has begun including undergraduates in his current research on the late Quaternary history of the area. The proposed research provides the opportunity for three senior geology majors to pursue undergraduate theses on facets of the overall research objectives (see RUI impact statement for more information).