title: Carbon isotope composition of carbonaceous matter from the precambrian of the witwatersrand system.
abstract: Polymerized hydrocarbons occurring in the gold-uranium conglomerates of the Witwatersrand System (South Africa) show deltaC(13) values between -22.4 and -32.8 per mille, their isotopic composition thus falling into the range of sedimentary organic carbon. Accordingly, organic derivation of the material seems very probable. This conclusion is consistent with a model of the existence of organic evolution and biologic activity in times certainly older than 2.15 x 10(9) years.
authors.forename: J
authors.initials: J
authors.lastname: Hoefs
authors.forename: M
authors.initials: M
authors.lastname: Schidlowski