The Thermal History of the Carboniferous Source Rocks in the Moravian-Silesian Unit, Fore-sudetic Monocline, Poland

The burial and thermal history of the Carboniferous gas source rocks in the Moravian-Silesian Unit (eastern part of the Fore-Sudetic Monocline, SW Poland) has been reconstructed by 1-D maturity modelling. It allowed to establish the timing of gas generation and expulsion in the Fore-Sudetic Monocline. In the Carboniferous sediments in the study area maturity of the III type kerogen increases toward the SE part of Fore-Sudetic Monocline. The vitrinite reflectance values are from 1.0 to 5.0%. The results of the 1-D maturity modelling indicates clearly, that Carboniferous sediments in the northern part of the Moravian-Silesian Unit attained their thermal maturity prior to the Late Permian. The burial of the source rocks in the Late Carboniferous was probably very high (2-4 km), and the heat flow in the Late Carboniferous was also high (~90-120 mW/m2). It might have been caused by the migration of hot fluids related to the volcanic activity. The thermogenic gas generation and expulsion proceeded in pulses with variable intensity and the major stages of these processes took place in the Late Carboniferous in the eastern FSM, whilst in the Late Triassic-the Early Jurassic in the central part of the FSM.