Abstract:

The distribution patterns of alkyl cyclohexane,alkylbenzene,carotane,sterene and terpane compounds in surficial sediments from the Bransfield strait,Antarctica are studied.The precursor of alkyl cyclohexane mainly derived from marine organism and mixed with terrestrial matter. The main peak of alkylbenzene is C 12 alkylbenzene in stations G 15 and G 32,carbon number ranging from C 11 to C 24 ;the predominance of C 21 alkylbenzene is present in station G 25,but C 17 and C 19-20 compounds are absent. The β carotane is the principal compound in carotane series and contains perhydro carotene.24 ethylcholest 5 en,steradiene and cholest 5 en are present in the sediments. The carbon number of bicyclic sesquiterpenes ranges from C 17 to C 21 . The lanostane compounds are C 30 8β(H),9α(H) lanostane,C 31 24 methyllanostane and C 32 24 ethyllanostane. The presence of biologicial conifugration of ββ type as C 29 17β(H),21β(H) 30 norhopane,C 30 17β(H),21β(H) hopane and C 31 17β(H),21β(H) homohopane indicate the low maturity of the sedimentary organic matter.