Pleistocene glaciations in Chukotka, Russia:: moraine mapping using satellite synthetic aperture radar (SAR) imagery

Abstract

Using satellite synthetic aperture radar (SAR) imagery we are able to identify many glacial features on the Russian landscape that were previously unobservable by scientists outside Russian institutes. Observations from SAR imagery provide information on glacial extent, moraine morphology, and non-sedimentary glacial features such as valley morphology and flow direction. Moraine sequences in several areas of Chukotka record multiple Pleistocene glacial events. Moraine position, along with several morphologic characteristics such as relative degradation and surface slope, can be determined from SAR imagery and used to estimate relative age of glacial features. By conducting comparative studies on moraines of known age in Alaska, we are able to estimate the ages of moraines in Russia and develop a framework for the correlation of glacial history across Bering Strait. Our study of these images suggests that the last major glaciation (Late Wisconsin) was much less extensive than older Pleistocene events, whose marks remain on the landscape beyond the younger moraines.