Old and recent processes in a warm and humid desert hypogene cave: ‘A’rak Na‘asane, Israel

Abstract

Recent environmental processes are studied in ʻA’rak Naʻasane Cave at the northern Judean Desert, Israel. The outer zone of the cave is heavily influenced by the outside environment through a large entrance, facilitating entry of air flow, fauna and humans, with minor cave-forming modifications. Conversely, the inner cave sustains humid and warm conditions, favoring modifications by condensation corrosion of convective air flow, associated with deposition of popcorn speleothems at the lower parts of dissolution pockets. The warm humid air of the inner cave may be associated with an underlying thermal water table. Active condensation corrosion is decreasing, possibly because of gradual change in the cave microclimate, associated with falling water table and ventilation. Increasing connection with the surface is indicated by high collapse domes, rare flood invasion, and a large Trident Leaf-nosed bat community which spends the winter within the innermost parts of the cave. Bat guano supports bedrock corrosion and a rich invertebrate fauna, but humans preferred the outer parts of the cave, particularly for refuge during the second Jewish revolt against the Romans. Rare occasions of ancient human entry into the inner cave support this scenario by the small number of artifacts compared with the outer cave. Enigmatic small cairns in the largest inner hall were probably erected during the Intermediate Bronze Age.

Keywords

• confined cave
• cave microclimate
• condensation corrosion
• bat guano
• popcorn speleothem