Role of zooclasts in the kerogen type and hydrocarbon potential of the lower Paleozoic Alum Shale

This study investigates the role of zooclasts in bulk organic matter composition, kerogen type, and hydrocarbon generation potential lower Paleozoic marine Alum shale Baltoscandia, northwestern Europe. The results show that graptolite periderm is composed non-granular cuticles granular filling. cuticle non-fluorescing has a well-polishing measurable surface, while fraction semi-translucent brownish fluorescence, suggesting remaining potential. shows similar optical characteristics to fluorescing diagenetic solid bitumen. Both bitumen have low intensity yellow brown fluorescence contribute generative (Rock-Eval S2). sum semi-quantitative zooclastic (non-granular cuticle, chitinozoan vitrinite-like) content, obtained from maceral point-counting, correlates with non-generative carbon content. Enrichment samples displayed as enrichment inert carbon, hence geochemical type III. refractory carbon-rich represents autochthonous ‘refractory dilution’ will lead Hydrocarbon Index (HI) underestimation. Confined hydrous pyrolysis was used compare process cuticle-lean sample (0.2 vol%) cuticle-rich (1.6 sample. Results indicate there are four stages artificial maturation unconventional source rock Shale. higher more oil-prone than sample, which gas-prone generates CO 2 . difference attributed differences constituent composition. • influx primarily led dilution kerogen. zooclast-rich sedimentary rocks Ⅲ HI expected for graptolites variable oil