The review of studies of Divya cave: the longest cave in Perm region (Russia)

Abstract The work presented is a review of modern research conducted in Divya Cave—the longest cave in Perm Region, the first mention of which dates back to the 70’s of the eighteenth century. The cave provides the richest material for geologists, karstologists and speleologists, since it is a relic of an ancient aquifer, in which almost all types of secondary calcite formations found in caves are collected. The remote location of the cave from roads and settlements has never been an obstacle for explorers. The first plan of Divya cave was drawn up in 1949. Subsequently, a lot of speleologists kept exploring the cave, but not all passages were marked on the latest maps. Hydrogeological and hydrochemical research was done for the first time in 1948, 1956, 1962 and 1967. Numerous springs between the village of Divya and Divya cave were surveyed, water temperature and flow rates were measured and the hydrochemical indicators of water in the cave lakes were studied. Findings of cryogenic calcite in 1968 prompted further research related to the study of cave deposits, using isotopic analysis methods, taking into account their dating, to determine the migration of permafrost boundaries. From 2016 to 2020 the authors of this article conducted a number of studies in Divya cave itself and in the surrounding area, namely, they carried out instrumental and semi-instrumental topographic surveys of the cave and the surface, followed by the creation of a combined plan, and also determined the absolute marks of the earth’s surface, the entrance, the roof and the base of the cave and the new data on the length of the cave were obtained. For the first time, isotopic studies of atmospheric precipitation, surface channel runoff (the Kolva river) and groundwater emerging to the surface near Divya cave were carried out, and their relationship was determined. Data on the chemical composition of waters were supplemented. Samples of speleothems, including cryogenic calcite, were selected, their isotopic composition was studied and dating was carried out, which made it possible to obtain completely new information about interglacial periods. The modern data obtained allowed us to supplement previously known information about Divya cave.