Eastern Mediterranean sapropels: chemical structure, deposition and relation to oil-shales

Ten sapropels, deposited in three different basins of the eastern Mediterranean since the Miocene and selected from cores of the Deep Sea Drilling Programme have been characterised by elemental analysis; fluorescence, infra-red and NMR spectrometry, by pyrolysis-gas chromatography/mass spectrometry and by catalytic hydrogenation at moderately high pressure. The sapropels are Types I–II kerogens, which have been oxidised, probably by a front experienced, since their deposition. Only one, from the Cretan basin, contained structures from lignin. The others, typical of a marine deposition, possessed aromaticities of about 0.2. Their detailed organic structures are described.