The influence of host-rock composition on the colour alteration of Namurian conodonts from Belgium

Abstract

The thermal alteration of Namurian conodonts of Belgium from existing stratigraphic collections has been examined and reviewed, their colour alteration indices (CAIs) being mapped. Comparisons with CAIs from Dinantian strata and with vitrinite reflectance data not only suggest little hydrocarbon potential for the Namurian in Belgium, but also indicate that the colour alteration of most Namurian conodonts has been influenced by their organic-rich host-sediments. Possible causes for this additional alteration, such as irradiation by natural radioactive decay of authigenic uranium, are discussed.