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The Donets Basin (Donbas) is one of the major late Paleozoic coal basins in the world. The Donbas Foldbelt is an inverted part of the Donets Basin characterized by WNW–ESE-trending folds and faults. The age of basin inversion is under discussion. Large parts of the Donets Basin host anthracite and meta-anthracite. Low-rank coals are restricted to the western and northern basin margins. Vitrinite reflectance patterns along the Gorlovka Anticline indicate syn-deformational coalification. Vitrinite reflectance isolines are displaced along thrusts, clear evidence that main coalification predates late faulting.1-D and 2-D numerical models were applied to elucidate the factors that control coalification in the western Donets Basin (Krasnoarmeisk Monocline, Kalmius–Torets Depression, South Syncline).The models indicate that the depth of the seams and the heat flow during maximum (Permian) burial are the most important parameters. The thickness of late Carboniferous and Permian rocks increased from the southwestern basin margin towards the basin center. Permian erosion along the Krasnoarmeisk Monocline and in the Kalmius–Torets Depression was on the order of 2–3 km. More rocks were eroded southeast of the Donetsk–Kadievka Fault Zone (4–5 km). Heat flow during maximum burial was in the range of 40–75 mW/m2. Heat flow in the Krasnoarmeisk Monocline and the Kalmius–Torets Depression increased in a northeastward direction from 40 to 55 mW/m2. Heat flow at the eastern edge of the Kalmius–Torets Depression and in the South Syncline was in the range of 60–75 mW/m2 and increased towards the southeast. The resulting coalification pattern in this area was overprinted by thermal events in the northern Krasnoarmeisk Monocline and the South Syncline. These are probably related to (Permian?) magmatic intrusions. Coked coal occurs at the contact to presumed Permian sills and dikes southwest of Donetsk. [Copyright &y& Elsevier]

Abstract: The main purpose of this contribution is to compare the ability of Carboniferous coals from the Donets Basin of the Ukraine and Cretaceous coal from the Sabinas Basin of the Mexico to generate hydrocarbon gases (C1–C5). Two bituminous coals from the Donets Basin (2c10YD and 1l1Dim; 0.55 and 0.65%R r respectively) and one bituminous coal from the Sabinas Basin (Olmos, 0.92%R r) were studied using heating experiments in a confined-pyrolysis system. The highest rank reached during the heating experiments corresponds to the anthracite stage (2.78 and 2.57%R r) for the 2c10YD and 1l1Dim coals and (2.65%R r) for the Olmos coal. The composition of the generated (C1–C5) gases was evaluated using a thermodesorption-multidimensional gas chromatography. The results show that the Carboniferous Donets coals produced more wet gas and methane during pyrolysis than the Cretaceous Olmos coal. This is probably due to their higher liptinite (6–20%) and collodetrinite content and to the loss of a major part of the petroleum potential of the Olmos coal during natural coalification. C2–C5 compounds are mainly derived from the cracking of liquid hydrocarbons. Ethane is the most stable compound and formed from the cracking of higher hydrocarbon component. Large amounts of methane (up to 81 mg/g coal for the Donets coals and 50 mg/g coal for the Sabinas coal) were formed at high temperatures by cracking of previously formed heavier hydrocarbons and by dealkylation of the coal matrix. A linear relationship was observed between methane generation and the maturity level of both coal types. [Copyright &y& Elsevier]