PYROGENIC ORGANIC MATTER IN SEDIMENTS FROM LAKE BOSUMTWI AS A PROXY FOR HOLOCENE CLIMATE IN NORTHERN AFRICA

This study is an investigation into the Holocene paleoclimatic history of northern Africa, deconvolved using organic carbon (OC), black carbon (BC), and other chemical markers of pyrolysis in a sediment core from Lake Bosumtwi, Ghana, West Africa. The hypothesis tested with this research is that North Atlantic climate influenced historical wildfire occurrence in northern Africa throughout the Holocene. Downcore sedimentary OC and BC abundance were compared to records of regional precipitation. d¹³C_OC and d ¹³C_BC were quantified to understand the type of biomass burned. Sedimentary BC ranged from 0.72% to 34.60%. Similarly, OC was 0.11% to 14.3%. Stable isotope values of d¹³C_OC and d ¹³C_BC range from -19.00‰ to -29.06‰ and ~-28.35‰, respectively.

Collectively, the data suggest that a shift in vegetation/change in environment occurred in the west African region from a mix of C4 –C3 plants in the early Holocene to a C3 dominant system in the late Holocene. This investigation can help better understand coastal precipitation and draught patterns in response to climate change in Western Africa.