What is "boelling-alleroed"

The Bølling-Allerød interstadial was a warm and moist interstadial period that occurred during the final stages of the last glacial period. This warm period ran from c. 14,700 to 12,700 years before the present. It began with the end of the cold period known as the Oldest Dryas, and ended abruptly with the onset of the Younger Dryas, a cold period that reduced temperatures back to near-glacial levels within a decade.

In some regions, a cold period known as the Older Dryas can be detected in the middle of the Bølling-Allerød interstadial. In these regions the period is divided into the Bølling oscillation, which peaked around 14,500 BCE, and the Allerød oscillation, which peaked closer to 13,000 BCE.