| Popis: |
A succession of moraines and terraces in the Nenana River valley, Reindeer Hills, and the Monahan Flat in the central Alaska Range were dated using Terrestrial Cosmogenic Nuclides (TCN) and optically stimulated luminescence (OSL). Moraines date at >125 ka (Lignite Creek glacial stage), ~60 ka (Healy glacial stage), 22-30 ka (Riley Creek 1 glacial stage), ~22 ka (Riley Creek 2 glacial stage), and ~19 ka (Carlo glacial stage). These are minimum ages of deglaciation. Comparative examination of boulders shows that the position of boulders and condition/type of landforms are more influential of TCN ages than the condition of boulders. TCN ages on boulders from drumlins are more tightly clustered than morainal boulders. No correlation of boulder condition and accuracy of TCN ages was found. |
