Raman spectroscopy study of the sedimentary organic material thermal alteration in the Paleoproterozoic Francevillian Basin, Gabon

Abstract

The aim of this master’s thesis was to discern the lateral and stratigraphic variability of thermal alteration in organic material and pyrobitumen (solidified petroleum) of the Franceville, Lastoursville and Okondja sub-basins of the Francevillian basin using Raman spectroscopy and reconstruct the extent of thermal overprint on preserved sedimentary organic material by diagenesis-metamorphism, later fluids and magmatism. Studied material was sampled from both drillcores and outcrops from the Franceville, Lastoursville and Okondja sub-basins. Spatial variation in temperature between the three sub-basins was detected with Franceville and Okondja having similar temperatures and Lastoursville having lower temperatures, though still over the threshold for biomarker preservation.