Recently, Uzneftegazdobycha, a private company, designed an easier and cheaper method to explore hydrocarbons below the former Aral Sea seabed. The Uzbek government and the people in the region see this as an opportunity to earn additional revenue. But intensive development of oil and gas fields will further dry up the Aral Sea. The area earmarked for prospecting and drilling is located in the natural caverns that retain a part of the Aral Sea. The water in these caverns needs to be drained for this purpose, thus, furthering the disaster. What is the name of the rock in which this water and the caverns are located