STRATIGRAPHY AND INTERPRETATION OF DIAGENETIC IMPACT IN ORDOVICIAN SILICICLASTIC STRATA ON BELL ISLAND, NEWFOUNDLAND, CANADA

Clay minerals play a significant role for qualitative and quantitative identification of diagenesis. The clay mineral composition depends (I) on the original chemical composition of minerals that were delivered to the seafloor from the hinterland, and (II) on the diagenetic processes in sediments. Aside from biogeochemical reactions, burial temperatures and pressures impact the reactions leading to clay mineral development. Despite its economic and scientific importance, little is known about the processes of shallow marine diagenesis of terrestrial weathered material preceding the evolution of land plants. With this contribution we present preliminary results of a study on diagenesis within a shallow delta in the Ordovician on Bell Island, Newfoundland. Bell Island strata are subdivided into the Bell Island and the Wabana Group. The sediments of the siliciclastic succession are immature and consist mainly of detrital quartz, lithoclasts, feldspar, biotite, white mica, and diagenetic chlorite, illite and pyrite. Despite appearing to be a fine-grained succession it is sandstone-dominated, while the fine-grained appearance derives from diagenetic remineralization. The succession serves as an ideal archive for the study of early diagenetic impact on minerals, isotopic composition, and rock properties in general.