Sizing Up the Sub-Tommotian Unconformity in Siberia
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Kaufman, Alan J.
Semikhatov, Mikhail A.
Grotzinger, John P.
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CitationKnoll, Andrew H., Alan J. Kaufman, Mikhail A. Semikhatov, John P. Grotzinger, and William Adams. 1995. Sizing up the sub-Tommotian unconformity in Siberia. Geology 23, no. 12: 1139-1143.
AbstractSedimentary rocks in the western Anabar region, northwestern Siberia, preserve an exceptional record of evolution and biogeochemical events near the Proterozoic-Cambrian boundary. Carbon isotopic data on petrographically and geochemically screened samples collected at 1 to 2 m intervals support correlation of the lower Anabar succession (Staraya Reckha and lower Manykai Formations) with sub-Tommotian carbonates of the Ust'-Yu-doma Formation in southeastern Siberia, In contrast, the upper Manykai and most of the overlying Medvezhya Formation appear to preserve a sedimentary and paleontological record of an evolutionarily important time interval represented in southeastern Siberia only by the sub-Tommotian unconformity. Correlation of the Anabar section with other northern Siberian successions that contain well-dated volcanic rocks permits the estimate that the sub-Tommotian unconformity in southeastern Siberia spans approximately 3 to 6 m.y. Diverse small shelly fossils (but not archaeocyathans) previously thought to mark the base of the Tommotian Stage evolved sequentially throughout this earlier interval.
Citable link to this pagehttp://nrs.harvard.edu/urn-3:HUL.InstRepos:3119537
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