The opal phytolith inventory of soils in central Africa - quantities, shapes, classification, and spectra

Phytolith investigations of surface soil samples and of soil profiles from rain forest soils of northeastern and eastern D.R. Congo (former Zaire, tropical humid Africa) and from a grass-covered Bas-Fond of the Central African Republic, produced a preliminary phytolith classification scheme. The classification scheme was used in soil phytolith counting procedures to produce typical opal phytolith spectra for comparisons. The spectra proved suitable to describe and characterize rain forest and grassland vegetation. Temporal Variations in species composition of forests or grasslands were verifiable by phytoliths. Besides other characteristics, a high percentage of silt-sized spherical phytoliths were found to be typical for forests. Some specific, but not yet identified, opal phytoliths were shown to be widespread in central Africa. Phytolith content in tropical soils is presented in addition. The studies were carried out with the aim to improve the interpretation of fossil phytolith assemblages. Fossil opal phytoliths in soils or sediments can be used in the reconstruction of vegetation dynamics, palaeo-vegetation, and palaeo-climate. (C) 1999 Elsevier Science B.V. All rights reserved.