Report Number: 105
Year: 2004

Preliminary Report on the Caves and Karst of Rota (Luta), CNMI

The island of Rota, Commonwealth of the Northern Mariana Islands, contains caves developed by most of the mechanisms previously documented for similar islands. Rota has a large number of flank margin caves, developed by mixing dissolution, under diffuse flow conditions, at the edge of the fresh water lens. Rota has a few caves developed along the contact with the underlying volcanic rock. Rota also has a few caves formed primarily by the physical erosion of ocean waves. Unlike the other islands in the Mariana Arc, Rota has a large number of mixing zone fracture caves. These mixing zone fracture caves apparently developed as fresh water discharging from the fractures mixed with sea water to create zones of enhanced dissolution in each fracture. These mixing zones are thought to have migrated headward as each fracture was widened by dissolution. The interaction between uplift, subsidence and glacio-eustasy has formed caves on Rota all elevations. Caves are documented from sea level to within a few meters of the summit of the island.

Thomas "Monty" M. Keel
John E. Mylroie
John W. Jenson