CAVES: Stream Caves.

This article provides information on the stream caves in Guam. Stream caves are formed in the vadose zone by the action of free-surface underground streams, which are often continuations of surface streams. They can be permanent, ephemeral or abandoned. As aggressive water dissolves its way through limestone, its movement is often influenced by geologic structures, such as fractures and contacts with non-carbonate units. These can guide the development of caves. On Guam, stream caves usually develop along the contact between limestone and underlying impermeable volcanic rock, and tend to have long linear passages.