Cave on the Lunny ice cap, Alexandra Land Island, Franz Josef Land

The results of summer and winter surveys of a cave located in the marginal terrestrial part of the Lunny Ice Cap, the Alexandra Land, the westernmost island of the Franz Josef Land Archipelago, are presented. The cave on the Lunny Cap was partially surveyed in the summer of 2023. Due to the danger of collapses, the cave on the Lunny Cap was partially explored in the summer of 2023. The cave was completely crossed and mapped in April 2024. Difficulties in mapping the cave arose due to the strong magnetization of the rocks in the cave and the inability to use a compass. However, the recorded GPS track with low ice thickness above the cave channels made it possible to construct a plan of the cavity. The width and height were recorded at certain points of the track, which allowed to build a plan and a longitudinal profile of the cave. The length of the through channel of the cave was 250 m, the length of the passages was 380 m, the height difference between the entrances was 20 m, average width of the galleries was 9 m and average height was 3 m. The description of the cave is given. Sections with gallery widths up to 12 m characterized by stable arches. Ice collapses from the vaults were typical for sections of galleries of greater width. In winter, collapses stopped due to the frozen ice in the cavity. The cave has existed in any form for at least 18 years. The cave could result from subglacial movement of the channel under the warming effect of the water flow when the glacier bed slopes away from the ice edge. At the same time, the position of the subglacial channel is partially inherits the channel shape formed near the glacier edge during the period when the glacier was retreating.