GLACIATIONS OF NOVAYA ZEMLYA AND NORTH-EAST OF RUSSIA (SUNTAR-KHAYATA): DID THEY EXIST IN THE EPOCHS OF GLOBAL WARMING?

The paper presents results of glacio-climatic calculations for the Optimum Holocene and Eemean Interstadial based on general paleoclimatic scenarios which were adapted to the nival-glacial belt of the Novaya Zemlya ice sheet and Suntar-Khayata mountain glaciation. The method represents a reconstruction of glacier regime with the help of present glacio-climatic relationships. The chosen glaciations refer to the different by climate regions: Novaya Zemlya ice sheet is located in marine influence conditions of Arctic belt, Suntar-Khayata mountains are characterized by extremely continental climate of East Siberia. This difference defines their specifics of the glacier response on global warming. In Eemean on the Novaya Zemlya ice sheet until 800 m a.s.l., (maximal heights of the ice sheet) possible snow melting exceeded greatly snow accumulation. Taking into account the epoch duration, it is evident the preexisting glaciation had completely disappeared. For Suntar-Khayata our calculations cast some doubt on the glaciers existence in Eemian since the resulting values of the ELA are near the existing heights of topography. The two variants of the precipitation deviation +50 mm and +100 mm, inferred in the calculation, resulted in the ELA rise by 400 m,according to the 1st variant and by 300 m according to the 2nd. Deviations of the ablation-accumulation from the present would be 250 mm and 300 mm respectively. In Holocene optimum the calculated bottom boundary of hionosphere exceeded the ELA at 300-400 meters in Novaya Zemlya. It means that owing to the maximum altitudes of the present ice sheet and absence of tectonic uplifts in Holocene, the ice sheet could not emerge as well as survive since the LGM. However in the area of reticular glaciation in the most elevated Northern Island the bedrock rises higher 1000 m a.s.l. So in the corresponding relief forms glaciers could exist quite steadily and glacier development likely has not be terminated during the Holocene. For Suntar-Khayata we considered two variants of precipitation deviations: +25 mm and +50 mm. As follows from calculations, at different variants the ELA rise at the Holocene would be 50 to 90 m. Taking into account the position of the glacier upper boundary, it could persist through the Holocene warming.