| Abstract: | Stable carbon isotope ratios measured in syngenetic graphite, epigenetic graphite, and graphitic marble suggests that syngenetic graphite forms only by the metamorphism of carbonaceous detritus. Metamorphism of calcareous rocks with carbonaceous detritus is accompanied by an exchange of carbon between the two, which may result in large changes in isotopic composition of the non-carbonate phase but does not affect the relative proportions of the two reactants in the rock. Epigenetic graphite forms only from carbonaceous material or preexisting graphite. The reactions involved are the water gas reaction (C + H2O ??? CO + H2) at 800-900??C, and the Boudouard reaction (2CO ??? C + CO2), which probably takes place at temperatures about 50-100??C lower. ?? 1982. |
| Genre: | Article |
| ProdID: | 70011719 |
| Citation Author: | Weis, P. L.; Friedman, I.; Gleason, J. P. |
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| Citation End Page: | 2332 |
| Citation Issue: | 12 |
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| Citation Language: | English |
| Citation Larger Work Title: | Geochimica et Cosmochimica Acta |
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| Citation Number Of Pages: | 8 |
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| Citation Search Results Text: | The origin of epigenetic graphite: evidence from isotopes; 1981; Article; Journal; Geochimica et Cosmochimica Acta; Weis, P. L.; Friedman, I.; Gleason, J. P. |
| Citation Start Page: | 2325 |
| Citation Volume: | 45 |
| Citation Year: | 1981 |
| Type: | citation/reference |
| Text: | The origin of epigenetic graphite: evidence from isotopes; 1981; Article; Journal; Geochimica et Cosmochimica Acta; Weis, P. L.; Friedman, I.; Gleason, J. P. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Thu, 1 Jan 1981 00:00 -0600 |
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