Paleoproterozoic geology of the Toumodi area, Ivory Coast, 1:100,000

Abstract

ABSTRACTField geological mapping of tropical West Africa is hampered by the variable development of deep regolith and tropical rainforest and this has impeded the progress of geological research. Nevertheless, there are areas in which field geological mapping can be effective. A 1:100,000 scale map of the Paleoproterozoic geology of the West African Craton in the Toumodi area of central Ivory Coast was developed on the basis of five months of independent field geological mapping carried out on foot, and with the aid of a motorised vehicle (Main Map). The field mapping was carried out in 1987 and 1988 using traditional field geological techniques and 1950s 1:50,000 and 1:200,000 topographic base maps published by the Institut Géographique National (Paris). Original field observations and the interpreted geological map were recently compiled using a geographic information system software, which was also used to confirm the positional accuracy of the field mapping using satellite imagery. The field geological mapping presented here provided the basis for recognition of discrete lithostratigraphic terranes exposing different crustal levels within the Paleoproterozoic Birimian domain of the West African Craton which are interpreted to have originated as juvenile crustal additions in a Paleoproterozoic accretionary orogen at an obliquely convergent plate boundary.