ABSTRACT: Open-system non-isothermal pyrolysis up to 1,200°C in combination with elemental analysis was used to study the thermal liberation
of molecular nitrogen (N2) from sedimentary rocks and kerogen concentrates of Palaeozoic age from the Central European Basin system and an Eocene shale
(Liaohe Basin, China) with a high content (36%) of ammonium feldspar (buddingtonite). The N/Corg (atomic) ratios of the kerogen concentrates ranged from 0.005 to 0.014, which represents the range commonly observed for
coals. Bulk N/Corg ratios of the Palaeozoic shales extended from 0.035 to 0.108, indicating the presence of significant amounts of inorganic
nitrogen. Namurian A and A-B (CnA; CnA-B) samples typically exhibited the earliest onset of N2 generation with intense, characteristic peaks around 600°C. N2 liberation from the buddingtonite-rich sample occurred at higher temperatures, with a broad peak around 700°C. Pyrograms
of the kerogen concentrates showed no or strongly reduced N2 generation in the 500–700°C range. On-line isotope-specific analysis of the pyrolytically liberated N2 on one sample revealed a variability of ∼10‰ in the δ15N values and a steady increase in δ15N with temperature during the main phase of N2 generation.
International Journal of Earth Sciences 04/2012; 94(5):1023-1038. · 2.34 Impact Factor