d18O (LS03RUED): interpretation1_variable: 'Monsoon strength' has been replaced by 'circulationVariable'
d18O (LS03RUED): interpretation2_variable: 'P_E' has been replaced by 'effectivePrecipitation'
d18O (LS03RUED): interpretation3_variable: 'T_water' has been replaced by 'temperature'

d18O (LS03RUED): paleoData_longName: '' has been replaced by 'AD'
year (MAT1c8907d664): paleoData_units: 'AD' has been replaced by 'yr AD'
year (MAT1c8907d664): paleoData_longName: '' has been replaced by 'AD'
depth (MAT4e0b49cf47): paleoData_longName: '' has been replaced by 'AD'

Russell, J.M. , Johnson, T.C. , Talbot, M.R.

Russell, J. M., Johnson, T. C. and Talbot, M. R.: A 725 yr cycle in the climate of central Africa during the late Holocene, Geology, 31(8), 677, doi:10.1130/g19449.1, 2003.

A 725 yr cycle in the climate of central Africa during the late Holocene

the Holocene was sampled more intensively (every 0.5 cm), 4 cm intervals from 3000 cal. BP to the present, and at 1 cm intervals prior to 8200 cal. BP; Optically pure diatomite was obtained by oxidation (H2O2) to remove organics, an acid wash (10% HCl) to remove carbonates and gravity settling to remove small amounts of clay. The hydrous layer of the diatoms was stripped by outgassing during a prefluorination.

summer precipitation would impose a shift in the  isotopic composition of the lake water and ultimately  in the d18Odiatom record. More positive d18Odiatom values would suggest a greater contribution of summer rainfall from the Atlantic, bringing warmer temperatures. While more negative d18Odiatom suggests a greater contribution from the colder Arctic air mass.

The diatom blooms that provide the biogenic silica to the sediment occur in the summer months, June?  September, when the lake is ice-free, when temperatures  are highest and when rainfall is heaviest enabling  nutrients to be washed in from the catchment. The  d18Odiatom signal therefore reflects the climatic regime  during the summer months although there will be a  component of winter precipitation released from ice and snow in the catchment during the early summer thaw.; evaporative effects on the isotopic composition of the lake water are minimal.;comparison with  the pollen based temperature reconstruction indicates that the magnitude and direction of the isotope inferred temperature change is unrealistic.;