Jason M. Dortch (e-mail: Dortchjm@uc.edu) and Lewis A. Owen (e-mail: firstname.lastname@example.org), Department of Geology, University of Cincinnati, Cincinnati, OH 45220, USA; Marc W. Caffee (e-mail: Mcaffee@purdue.edu), Department of Physics, Purdue University, West Lafayette, IN 47907, USA; Phil Brease (e-mail: Phil_Brease@nps.gov), Denali National Park and Preserve, P.O. Box 9, Denali Park, AK 99755, USA
Late Quaternary glaciation and equilibrium line altitude variations of the McKinley River region, central Alaska Range
Article first published online: 4 NOV 2009
© 2009 The Authors, Journal compilation © 2009 The Boreas Collegium
Volume 39, Issue 2, pages 233–246, April 2010
How to Cite
DORTCH, J. M., OWEN, L. A., CAFFEE, M. W. and BREASE, P. (2010), Late Quaternary glaciation and equilibrium line altitude variations of the McKinley River region, central Alaska Range. Boreas, 39: 233–246. doi: 10.1111/j.1502-3885.2009.00121.x
- Issue published online: 25 FEB 2010
- Article first published online: 4 NOV 2009
- received 2nd April 2009, accepted 27th August 2009.
Dortch, J. M., Owen, L. A., Caffee, M. W. & Brease, P. 2009: Late Quaternary glaciation and equilibrium line altitude variations of the McKinley River region, central Alaska Range. Boreas, 10.1111/j.1502-3885.2009.00121.x. ISSN 0300-9483
Glacial deposits and landforms produced by the Muldrow and Peters glaciers in the McKinley River region of Alaska were examined using geomorphic and 10Be terrestrial cosmogenic nuclide (TCN) surface exposure dating (SED) methods to assess the timing and nature of late Quaternary glaciation and moraine stabilization. In addition to the oldest glacial deposits (McLeod Creek Drift), a group of four late Pleistocene moraines (MP-I, II, III and IV) and three late Holocene till deposits (‘X’, ‘Y’ and ‘Z’ drifts) are present in the region, representing at least eight glacial advances. The 10Be TCN ages for the MP-I moraine ranged from 2.5 kyr to 146 kyr, which highlights the problems of defining the ages of late Quaternary moraines using SED methods in central Alaska. The Muldrow ‘X’ drift has a 10Be TCN age of ∼0.54 kyr, which is ∼1.3 kyr younger than the independent minimum lichen age of ∼1.8 kyr. This age difference probably represents the minimum time between formation and early stabilization of the moraine. Contemporary and former equilibrium line altitudes (ELAs) were determined. The ELA depressions for the Muldrow glacial system were 560, 400, 350 and 190 m and for the Peters glacial system 560, 360, 150 and 10 m, based on MP-I through MP-IV moraines, respectively. The difference between ELA depressions for the Muldrow and Peters glaciers likely reflects differences in supraglacial debris-cover, glacier hypsometry and topographic controls on glacier mass balance.