Ground penetrating radar and shallow seismic - Stratigraphic and permafrost investigations of Lake Nikolay, Delta Lena, Arctic Siberia

The River Lena draining to the Siberian Arctic is considered to be the main sediment source for the Laptev Sea. Nevertheless, for the delta of River Lena occupying an area of 28000 km(2), there are many unsolved questions concerning the environmental and sedimentation history, genesis of deposits, permafrost distribution, and climatic records in the area especially for the second sandy terrace deposits in western Delta Lena. To survey the stratigraphic sequence of Lake Nikolay and its surrounding which is representative for the western Delta Lena area, radio-echo sounding (RES) with 25 MHz and 100 MHz antennae on the frozen lake and on land have been carried out in connection with drilling activities. RES measurements of the lake sediments are complemented by shallow seismic and reveal subsurface stratigraphy of the lake sediments and the bordering permafrost deposits.