The study involves compositional analysis and source rock potential of samples from Posidonia and Wealden Shales of the Lower Saxony Basin, Germany. Focused ion beam, broad ion beam and scanning electron microscope imaging and point counting were used to study the compositions of these shale samples. Sufficiently large images at high resolution down to nm were studied and statistical representative areas were taken. Qualitative and quantitative descriptions were carried out using Jmicrovision v.1.27 computer software. Total organic carbon (TOC), Rock-eval pyrolysis and vitrinite reflectance were carried out to determine source rock properties (i.e. richness, quality and thermal maturity). In both of the shale units mineral phases and other compositions identified include: dominantly smectite, mixed smectite-illite and near equal proportions of calcite, quartz, mica, cubic and framboidal pyrite and organic matter with subordinate fossil fragments. Samples from both Posidonia and Wealden are kerogen type 1. TOC of 12.59 (Wt %) and 11.8 (Wt %) and vitrinite reflectance of 0.53% Ro and 0.74% Ro were recorded for Posidonia and Wealden samples respectively suggesting adequate organic carbon for petroleum generation but low maturity index.
