“…Geochemical analyses indicate that synrift (Baden ian and Sarmatian) and postrift (lower Pannonian) shales and marls in the deeper parts of the Bekes basin and adjacent basins are the probable source of the natural gas and oil produced in the Bekes basin (Szalay, 1988;Clayton and Koncz, this volume;Clayton and others, this volume). These rocks contain predominantly type III (gas-prone) kerogen and it is not surprising, therefore, that chiefly natural gas is produced in the Bekes basin with only minimal amounts of oil.…”