Investigation of pretertiary and tertiary surface sediments from Serbia: Organic geochemical interpretation

Samples of surface sediments originating from different localities in Serbia which contained more than 0.5 % organic matter were investigated in this paper. According to age, these samples were classified into two groups sediments of pretertiary age and sediments of tertiary age. Bulk and specific organic geochemical parameters were determined for their methylene chloride-methanol extracts, aimed at controling the relationship between the age of the sediment and the maturity of its organic substance. In this sense a general direct proportionality was observed. However, a better linear dependence of the bulk parameters was observed in the case of younger, tertiary sediments. That is to say, with samples of pretertiary age the organic matter maturity was approaching a definite limiting value contributing to an inferior linear dependence of their bulk maturation parameters. Nevertheless, the dependence was found to be preserved with specific maturation parameters (e.g., CPI; Fit/n-C18), the changes of which are generally more intensive at higher maturity degrees. U ovom radu ispitivani su uzorci povrsinskih sedimenata sa razlicitih lokaliteta Srbije i sadrzajem od preko 0,5% organske supstance, koji su se prema starosti mogli svrstati u dve grupe: sedimentne stene pretercijarne i sedimentne stene tercijarne starosti. U njihovim metilen-hlorid metanolskim ekstraktima odredjeni su grupni i specificni organsko-geohemijski maturacioni parametri da bi se proucilo da li postoji veza izmedju starosti sedimenata i maturisanosti njihove organske supstance. U tom smislu, utvrdjeno je da postoji opsta direktna propordonalnost. Medjutim, nadjeno je da grupni maturacioni parametri pokazuju bolju linearnu zavisnost kod mladjih, tercijarnih sedimenata. Naime, kod uzoraka pretercijarne starosti maturisanost organske supstance u vecoj meri se priblizavala odredjenoj granicnoj vrednosti sto je doprinosilo smanjenju ocekivane linearne zavisnosti njihovih grupnih maturacionih parametara. Ipak, ta zavisnost je sacuvana kod specificnih maturacionih parametara (na primer: CPI; Fit/n-C18) koji se izrazitije menjaju na visim stepenima maturisanosti.