Lothar Friberg

RWTH Aachen University, Aachen, North Rhine-Westphalia, Germany

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Publications (2)4.52 Total impact

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    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 12/2005; 94(5):1023-1038. DOI:10.1007/s00531-005-0012-3 · 2.08 Impact Factor
  • Friberg L · Poelchau HS · Krooss B · Littke R
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    ABSTRACT: The Northeast German Basin (NEGB) is generally regarded as a long-lived intracontinental sedimentary basin. Deeply buried Carboniferous rocks are the main source rocks for hydrocarbon gases and nitrogen in the basin. For the northern part of the NEGB the thermal and burial history was reconstructed and simulated. Open system non-isothermal pyrolysis was used to determine the generation potential of methane and nitrogen and the corresponding kinetic parameters. These experimental data are used in a kinetic model to estimate timing and efficiency of gas generation in the NEGB and to assess, in a subsequent step, the gas migration pathways. Pyrolysis experiments of overmature Carboniferous samples and their corresponding kerogen concentrates indicate that a considerable amount of nitrogen comes from the inorganic matrix, probably ammonium illite. The simulation results reveal that the main methane generation took place during the rapid subsidence of Upper Rotliegend to Middle Triassic sediments. A residual gas potential exists only in the northern parts of the basin.
    Journal of Geochemical Exploration 06/2000; 69:263-267. DOI:10.1016/S0375-6742(00)00098-4 · 2.43 Impact Factor