Impact of the Younger Dryas dry event on equatorial forest ecosystems: Insight from Lake Child, Manengouba crater, Cameroon

Abstract

This paper presents the pollen, microcharcoal and geochemical data generated by a sediment core extracted from Lake Child in the Manengouba massif of Cameroon (MAN-01: 5.02996 N, 9.822910E; 1948 m asl) covering the time interval between 15.4 and 9.6 ka. With an exceptional sedimentation rate of up to 13 cm per year, this record represents the highest resolution of the environmental changes that took place in the highlands of equatorial Atlantic Africa during the last deglaciation. Our study shows (1) that the Younger Dryas (YD) dry event consisted of two distinct phases: a dry phase between 12.8 and 11.7 ka followed by a wetter and colder phase between 11.7 and 11.3 ka; (2) that the Afromontane forest elements that were present during the last glacial period were replaced by sub-montane forest elements during the Holocene; (3) that vegetation and the hydrological environment have not always evolved in parallel: this was particularly the case at the YD/Holocene transition when the abrupt shift in hydrological conditions contrasted with the gradual spread of forests.