Late Quaternary glaciation and equilibrium line altitude variations of the McKinley River region, central Alaska Range

• Main Authors: Jasonm Dortch, Jason M. Dortch (e-mail, Lewis A. Owen (e-mail, Department Of
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2009
• Subjects: Range; contains the type locations for Alaskan glacia; Ela; McKinley River; McLeod; alaska range; glaciers; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.508.281; http://webcentral.uc.edu/eProf/media/attachment/eprofmediafile_762.pdf

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 andmoraine 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 SEDmethods in central Alaska. TheMuldrow ‘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