Grapevine

Climate lessons from the fall of a Pacific chiefdom

A study reveals that new dates for an ancient site in the Pacific correlate with sea level rise and El Niño-Southern Oscillation (ENSO) variability.

Nan Madol is a monumental complex, built from stone and coral rubble on the Pacific Island of Pohnpei. Nan Madol was the administrative and cultural center of the Saudeleur Dynasty.

The exact dates of construction had been unclear, obscuring possible links between the history of the site and climactic changes.

Chuan-Chou Shen and colleagues used uranium–thorium dating for 167 coral samples and carbon dating for 18 charcoal samples to refine the site's chronology. The paper is published in the journal PNAS Nexus.

The dates reveal two major construction phases: the first from the 10th–12th centuries and the second from the late 12th to the early 15th century. These dates are centuries earlier than previous estimates.