- journal_title：Geological Society of America Bulletin
- Contributor：KALERVO RANKAMA
- Publisher：Geological Society of America
- Date：1948-
- Format：text/html
- Language：en
- Identifier：10.1130/0016-7606(1948)59[389:NEOTOO]2.0.CO;2
- journal_abbrev：Geological Society of America Bulletin
- issn：0016-7606
- volume：59
- issue：5
- firstpage：389
An investigation was carried out concerning the origin of carbon in the following pre-Cambrian materials from Finland: graphite, carbon-bearing schists, carbonaceous accumulations in phyllites including the suggested fossil Corycium enigmaticum Sederholm; shungite from Karelo-Finnish S.S.R. Geological and petrological descriptions of the materials investigated are given. CuO, V<sub>2sub>O<sub>5sub>, and MoO<sub>3sub> contents of the samples and the isotope ratios C<sup>12sup>/C<sup>13sup> in carbon extracted from same are presented. Geological evidence and trace-element determinations make probable the division of carbon in these samples into organic and inorganic groups; the mass spectrometric C<sup>12sup>/C<sup>13sup> determinations furnish definite proof of this and also final proof of the organic nature of the Corycium which thus is a real fossil of the Late Archean time, the oldest ever recorded with definite certainty.