| Paper No. 21-2 | ||
| Presentation Time: 1:00 PM-5:00 PM | ||
| THE CHANGE IN PROVENANCE AND RECYCLING OF MESOPROTEROZOIC SEDIMENTARY ROCKS WITH TIME, SIBERIA | ||
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CULLERS, Robert, Kansas State Univ, 108 Thompson Hall, Manhattan, KS 66506-3201, rcullers@ksu.edu and PODKOVYROV, Victor, Inst. of Precambrian Geology and Geochronology, St Petersburg, Russia The mineralogy and elemental compositions of sedimentary rocks of Riphean age were determined. The sandstones are quartz-rich and range from wackes to arenites. Plots in A-CN-K diagrams suggest that samples of the Kerpyl Group have undergone K-metasomatism from a source with a high ratio of plagioclase to K-feldspar, but the other groups show no evidence of K-metasomatism. The ICV's of most samples are less than one so most samples are likely composed of recycled material; some samples have ICV's greater than one so some first cycle input may have occurred. The Eu/Eu* and (La/Lu)cn ratios of the shales decrease and the Th/Sc ratios increase with decreasing age. These results suggest that the average source for the shales changed from an initially more tonalite-rich source to gradually increasing amounts of granodiorite-granite. These chemical changes with time are similar to those in Proterozoic shales such as those exposed in the southeastern USA due to recycling of original tonalite-rich sources with periodic input of first cycle input of granites with time. | ||
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North-Central Section - 37th Annual Meeting (March 24–25, 2003)
General Information for this Meeting | ||
| Session No. 21--Booth# 10 Geochemistry, Petrology and Tectonics (Posters) Kansas City Airport Hilton: Shawnee A 1:00 PM-5:00 PM, Tuesday, March 25, 2003 | ||
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