Isotope-geochemical composition of the massive ice of the Mordyakha and Seyakha (Mutnaya) Rivers interfluve, Central Yamal Peninsula

The objects of the study are massive ice bodies studied in the Mordyakha River valley and on the terrace of Seyakha River (Mutnaya) in the central part of Yamal Peninsula. The first site is located in the center of Yamal Peninsula (68°11ʹ18ʺ N, 68°51ʹ39ʺ E), at absolute elevation of 66-70 m, the second one is located 5 km to the north-west of the Bovanenkovo settlement (70°23.4 N, 68°19.4 E) at absolute elevation of 87 m near the Khanikosito lake. Stable isotope composition, ion composition, pollen and spores content were analyzed in detail. The main findings of the study are: a). The studied massive ice are of intra-ground type; b). One of the main sources of water, from which the massive ice was formed, were lake water and the water of the talik; c). During the formation of massive ice, there was a significant isotope fractionation, which led to the formation of layers with an isotope composition heavier than the original lake water.本研究的对象为亚马尔半岛中部莫尔迪亚哈河谷及谢亚哈河（穆特纳亚）阶地上的大型冰体。首个采样点位于亚马尔半岛中部（北纬68°11′18″，东经68°51′39″），绝对海拔66至70米；第二个采样点位于博瓦年科沃定居点西北5公里处，毗邻哈尼科西托湖，地理坐标为北纬70°23.4′、东经68°19.4′，绝对海拔87米。研究团队对冰体的稳定同位素组成、离子组成、花粉与孢子含量开展了详细分析。本研究的主要结论如下：a）所研究的大型冰体属于地下内生型；b）大型冰体形成的主要供水源之一为湖水与融区水；c）在大型冰体形成过程中发生了显著的同位素分馏作用，进而形成了同位素组成较原始湖水更重的冰层。