Researchers have found proof that people lived on islands in the Azores archipelago approximately 700 years earlier than prior evidence has shown. The paper was published in Proceedings of the National Academy of Sciences.
Researchers describe their study of sediment cores taken from lakes on some of the islands in the archipelago. Historians have believed that people first arrived in the Azores in 1427, due to the lack of evidence.
Analysis of the sediment cores showed an increase in 5-beta-stigmasterol in a core layer dated to a time between 700 CE and 850 CE, taken from Peixinho Lake. The compound is typically found in the feces of livestock, such as cows and sheep, neither of which lived in the Azores before the arrival of humans. The researchers found evidence in cores taken from Caldeirão Lake, which is on a different island, though it appeared approximately a century later.