Structural geology and glacier dynamics, Bering and Steller Glaciers, Alaska
Authors: Bruhn, R.L., Forster, R.R., Ford, A.L.J., Pavlis, T.L. and Vorkink, M.
Journal: Special Paper of the Geological Society of America
Volume: 462
Pages: 217-233
ISSN: 0072-1077
DOI: 10.1130/2010.2462(11)
Abstract:The Bering and Steller Glaciers of southern Alaska provide the opportunity to investigate relationships between climate and tectonics in a glaciated mountain belt. The glaciers profoundly impact the climate, ecology, and landscape of the northeastern Gulf of Alaska margin. The glaciers flow among and over deformed and eroded rocks of the Yakutat microplate, where geological structures impart topographic variations in the landscape that strongly affect glacier dynamics. The Bering Glacier flows along a tectonic boundary within the microplate that separates two regions of different structural style and history. East of the glacier, erosion of folded and thrust-faulted sedimentary strata creates E-W ridges and valleys oriented at high angle to ice flow. Farther west, second-phase folds and faults are superimposed on these structures, creating mountain blocks with complex structural geometry. Where the second-phase limbs have an E-W structural grain the glaciers flow around broad headlands, and meltwater streams discharge southward through narrow canyons. N to NE trending fold limbs are streamlined by glacial scouring parallel to folded bedding, and the elongated mountains are separated by narrow ice-and water-filled troughs, or flat-floored sediment-filled valleys. Measurements of ice motion and glacier surface topography are used in conjunction with geological mapping to constrain the location of the tectonic boundary beneath the Bering Glacier. The boundary is inferred to lie beneath the west-central terminus and extend up-glacier, passing west of the Grindle Hills and extending into the Khitrov Hills. The large volume of debris trapped in the Medial Moraine Band. © 2010 Geological Society of America.
Source: Scopus
Preferred by: Andrew Ford