An early Holocene transitory arid phase in the central Sahara at the time of the 8.2 Ky BP climate anomaly

The beginning of the Holocene in the Sahara is marked by increased rainfall due to the expansion of the African monsoon over the North Africa. In the central Sahara springs were activated in the mountains and shallow lakes formed between dunes. An isotopic and geochronological approach to the study of spring and lake carbonates allowed defining the beginning of the Holocene humid period; moreover, data show its abrupt interruption at c. 8 Ky BP. The arid spell is attributed to the 8.2 Ky BP event and its significance is discussed in the frame of Holocene climate changes recorded in North Africa and in the Mediterranean.