ORIGIN AND DIAGENESIS OF CARBOHYDRATES IN ANCIENT SEDIMENTS

Neutral saccharides were determined quantitatively in acid hydrolysate s of sediments ranging in age from Tertiary to Jurassic, derived from varying depositional environments and with different diagenetic histor ies. The present data show that intact saccharides can be identified a nd quantified in ancient sediments, and that an increase in temperatur e has a profound effect on the quantity and quality of the saccharides present. In diagenetically altered sediments < 0.1 wt% of the total o rganic carbon is attributable to carbohydrate carbon, with selective p reservation of glucose and mannose relative to the other sugars taking place, irrespective of whether the organic matter was predominantly m arine or terrestrial in composition. Saccharide data of Tertiary Deep Sea Drilling Project samples that have not been subjected to increased temperatures do not reveal any indicators of diagenesis. They show ab solute and relative sugar concentrations that are comparable with thos e of recent marine sediments. Analysis of a suite of samples from the Mahakam Delta and a suite of samples from the Paris Basin show that su gar concentrations in samples from the former do not indicate any tren d due to diagenesis, whilst the absolute sugar yields in samples from the latter decrease with increasing depth as a result of prolonged exp osure to temperatures of 80-90-degrees-C. This difference between resu lts of the Mahakam and Paris Basin samples might be attributable to a predominant origin from vascular plants of the organic material in the former, whilst the organic matter in the samples from Paris Basin is of a marine character.