EMERGED PHOSPHATE ISLANDS IN MICRONESIA
Eight small emerged atolls or lagoonless coral islands in Micronesia have phosphate deposits: Minami Daito, Kita Daito, Okino Daito, Marcus, Angaur, Fais, Nauru, and Ocean. Two of these have exceptionally well-preserved rims, one lagoon evidences considerable filling, several are cliffed, seven lie in stable zones, and six have low-level abrasion benches. The islands range from the equatorial zone to the marginal zone. The presence of phosphate deposits, and paleontologic and geomorphic evidence indicate that the rims and uplands are pre-Wisconsin. While the low-level abrasion benches in the equatorial as well as in the marginal zone corroborate the Glacial Control theory, the fact that such small islands have survived truncation apparently attests to the inefficacy of wave abrasion.