Pinedale glacial history of the upper Arkansas River valley

Abstract

This field trip guidebook chapter outlines the glacial history of the upper Arkansas River valley, Colorado, and builds on a previous GSA field trip to the same area in 2010. The following will be presented: (1) new cosmogenic 10Be exposure ages of moraine boulders from the Pinedale and Bull Lake glaciations (Marine Isotope Stages 2 and 6, respectively) located adjacent to the Twin Lakes Reservoir, (2) numerical modeling of glaciers during the Pinedale glaciation in major tributaries draining into the upper Arkansas River, (3) discharge estimates for glacial-lake outburst floods in the upper Arkansas River valley, and (4) 10Be ages on flood boulders deposited downvalley from the moraine sequences. This research was stimulated by a new geologic map of the Granite 7.5’ quadrangle, in which the mapping of surficial deposits was revised based in part on the interpretation of newly acquired LiDAR data and field investigations. The new 10Be ages of the Pinedale terminal moraine at Twin Lakes average 21.8 ± 0.7 ka (n=14), which adds to nearby Pinedale terminal moraine ages of 23.6 ± 1.4 ka (n=5), 20.5 ± 0.2 ka (n=3) and 16.6 ± 1.0 ka, and downvalley outburst flood terraces that date to 20.9 ± 0.9 ka (n=4) and 19.0 ± 0.6 ka (n=4). This growing chronology leads to improved understanding of the controls and timing of glaciation in the western U.S., the modeling of glacial-lake outburst flooding, and the reconstruction of paleo-temperature through glacier modeling.

Local Knowledge Graph (Top 8 entities)

View in full graph →

Loading graph...

Related Works

Items connected by shared entities, co-authorship, citations, or semantic similarity.

Article

Climate in the southern Sawatch Range and Elk Mountains, Colroado, U.S.A., during the last glacial maximum: inferences using a simple degree-day model

2010Arctic, Antarctic, and Alpine Research1 shared authorcited

Article

Cosmogenic 10Be and 36Cl ages from late Pleistocene terminal moraine complexes in the Taylor River drainage basin, central Colorado, USA

2007Quaternary Science Reviews1 shared author

Dataset

Data associated with Quaternary Research manuscript Latest Pleistocene glacial chronology and paleoclimate reconstruction for the East River watershed, Colorado, USA

202470% similar

Dataset

Cosmogenic Nuclide Burial Isochron Data for the Central City Gravel, Malta Gravel, and Lava Creek B Ash Locations: Classic Locations of Early to Middle Pleistocene Deposits, South Platte and Arkansas Rivers, Central Colorado, USA

202568% similar

Dataset

Data release of OSL, 14C, and U-series age data supporting geologic mapping along the South Platte River corridor in northeastern Colorado

201867% similar

Article

Paleoglacier reconstruction and late Pleistocene equilibrium-line altitudes, southern Sawatch Range, Colorado

19981 shared author

Document

From Mesas and Mountains to Rocks and Rivers: A Quick Overview of the Geologic History of the Gunnison Basin

56% similar

Document

Colorado Geologic Highway Map

51% similar

Document

Field Excursion to Colorado and Utah, Western United States

50% similar

Cited 10 times

References (45)

1 in Knowledge Commons, 44 external

Publication

Climate in the southern Sawatch Range and Elk Mountains, Colroado, U.S.A., during the last glacial maximum: inferences using a simple degree-day model

2010Arctic, Antarctic, and Alpine ResearchDOI: 10.1657/1938-4246-42.2.164