Between the cities of Dunedin and Oamaru on New Zealand’s South Island is Moeraki, a small coastal town home to famous rock formations. According to Maori legend, the Moeraki Boulders are gourds that washed ashore (on what is now Koekohe Beach) when the Araiteuru canoe was wrecked hundreds of years ago.
But every myth has a scientific explanation: The boulders are calcite concretions, formed over 60 million years ago in seafloor sediment. The spherical boulders formed in a pearl-like process that took as long as four million years (due to crystallization of calcium and carbonates), and the soft mud that contained the boulders surfaced due to wind and rain. The boulders vary in size—up to ten feet (three meters) in diameter—and can weigh several tons each.
Photos: Jeannette Kimmel
- Nat Geo Expeditions