Northern Guam geospatial information server
The Barrigada Limestone is a monotonous expanse of friable and very porous foraminiferal white limestone. It was deposited in deep water and constitutes most of the bedrock mass on northern Guam (Tracey et al., 1964). It contains predominantly benthis foraminiferal fossils and, in some later shallow water deposits, corals, mollusks, and algae. The rocks can be classified as wackestones through grainstones and are chalky and friable. The Barrigada Limestone averages about 8 percent pore space (Schlanger, 1964) and represents the main aquifer rock of the Northern Guam Lens Aquifer (NGLA).