The seward margin of Makatea, an uplifted carbonate island (Tuamotus, Central Pacific)

Abstract

Located at 148°15' West and 15°50' South, in the northwesternmost part of the Tuamotu archipelago (Central Pacific), Makatea island is isolated from its nearest neighbouring atolls, Rangiroa and Tikehau by about 80 km, and it is 245 km from its closest volcanic neighbour, Tahiti. This island rises at least 3,500 m above the sea floor. Like all Tuamotu islands, Makatea consists of biogenic deposits. But unlike the other islands which rise no more than a few metres above sea level and surround lagoons, Makatea reaches more than 100 m in elevation. Based on foraminiferal assemblages, age determination clearly indicated that the island frame was built up during Early Miocene (Montaggioni et al. 1985 a; Montaggioni, 1985).