New optically stimulated luminescence ages provide evidence of MIS3 and MIS2 eolian activity on Black Mesa, northeastern Arizona, USA |
| |
Authors: | Amy L Ellwein Shannon A Mahan Leslie D McFadden |
| |
Institution: | a Western State College of Colorado, Department of Natural and Environmental Sciences, Gunnison, CO, USA;b US Geological Survey, Denver Federal Center, MS 974, Lakewood, CO, USA;c The University of New Mexico, Department of Earth and Planetary Sciences, Albuquerque, NM, USA |
| |
Abstract: | Eolian deposition on the semiarid southern Colorado Plateau has been attributed to episodic aridity during the Quaternary Period. However, OSL ages from three topographically controlled (e.g. falling) dunes on Black Mesa in northeastern Arizona indicate that eolian sediments there were deposited in deep tributary valleys as early as 35–30 ka, with most sand deposited before 20 ka. In contrast, the oldest OSL ages for sand sheets fall within the Pleistocene-Holocene climatic transition (~ 12–8 ka). Thus most eolian sediment accumulated on Black Mesa under climatic conditions that were in general cooler, moister, and more variable than today, not more arid, pointing to a considerable increase in sediment supply. |
| |
Keywords: | Soil stratigraphy Eolian geomorphology Falling dunes Linear dunes Sand ramps Black Mesa OSL geochronology |
本文献已被 ScienceDirect 等数据库收录! |
|