Micromorphological and chemical complexities of a lateritic profile from basalt (Jos Plateau, Central Nigeria)

A ferricrete-capped lateritic profile developed on basaltic saprolite is described. Within both ferricrete and the immediately underlying soft laterite, two types of sesquioxidic cement are distinguished: the isopachous goethitic intergranular cement which is predominant and is interpreted as an indication of past phreatic conditions; and the Fe-stained meniscus cement which is interpreted as a sign of vadose conditions. The observed features are suggested to reflect changing drainage conditions related to morphological rejuvenation of the profile, in full accordance with previous hypotheses developed on the basis of geomorphological consideration. (C) 2000 Elsevier Science B.V. All rights reserved.