Alaskan Uplift and Onset of Northern Hemisphere Glaciation
The topography of southern Alaska has been shown to have likely experienced rapid exhumation during the early Pliocene stating ~5-6 Ma. During the summers of 2013 and 2014 I collected samples from outcrops of tephra known in the interior of Alaska.
Tephra provide feldspars that weather into authigenic minerals quickly after time of deposition and "sample" the meteoric water of its age during the weathering process incorporating the isotopic signal of the ancient atmosphere into its mineral structure
Using δD measurements on the OH- groups of clay minerals, I constrain the change in paleometeoricwater isotopes from the Miocene-Holocene in the interior of Alaska as a proxy for the surface uplift history of Alaskan topography via its control on the δD signal of surface water. Results suggest that there was surface uplift between 3-5 Ma and will be published in EPSL.