Author(s)

Hélène Miche, Roland Simler, Pascal Affaton, Olivia Mickala, Florent Boudzoumou, Michel Mbina

Aix-Marseille Université, CNRS, IRD, CEREGE UM 34, Aix en Provence, France.
Département de Géologie, Faculté des Sciences et Techniques, Université Marien Ngouabi de Brazzaville, Brazzaville, République du Congo.
Département de Géologie, Université des Sciences et Techniques de Masuku, Franceville, Gabon.
Université d’Avignon et des pays du Vaucluse, INRA, EMMAH, UMR 1114, LHA, Avignon, France.

Post-sedimentary transformations have masked or completely obliterated the structures and textures of Precambrian carbonate rocks. Therefore, methods of classification of the carbonate rocks founded on the observation of primary structures or textural characteristics are ill-adapted. Consequently, only certain geochemical classification methods allow us to distinguish the various rock-types in the case of Neoproterozoic carbonates. After presenting the most suitable geochemical classifications, we propose a new classification into 14 groups based on a regular ternary diagram with computerized data input. For each sample of carbonate rock, analysis of calcium and magnesium contents allows us to calculate the input data for our diagram i.e. the percentages of Calcite, Dolomite and Insoluble Residue. To automate the application of this diagram, input parameters are created in a descriptive file “Roches.ternaires.txt” using an option called “Ternaires” in the “Diagrammes” software developed by Roland Simler. Thirty cap carbonates of Africa are used to validate this new method.

Carbonate Rock; Cap Carbonate; Ternary Diagram; Software; Calcite; Dolomite

Miche, H. , Simler, R. , Affaton, P. , Mickala, O. , Boudzoumou, F. and Mbina, M. (2013) New Computerized Method for the Geochemical Classification of Precambrian Carbonate Rocks: Case of a Set of African Cap Carbonates. International Journal of Geosciences, 4, 37-49. doi: 10.4236/ijg.2013.410A005.