Microfossils and Rb-Sr age of glauconite in the key section of the Upper Proterozoic of the northeastern part of the Russian plate (Keltmen-1 borehole)

Autor:	T. S. Zaitseva, E. G. Dovzhikova, E. Yu. Golubkova, A. V. Maslov, A. B. Kuznetsov
Rok vydání:	2015
Předmět:	Paleontology Riphean Section (archaeology) Clastic rock Earth and Planetary Sciences (miscellaneous) Borehole engineering General Earth and Planetary Sciences Hiatus engineering.material Glauconite Upper proterozoic Geology
Zdroj:	Doklady Earth Sciences. 462:547-551
ISSN:	1531-8354 1028-334X
DOI:	10.1134/s1028334x15060045
Popis:	Complex paleontological and isotope-geochronological study of clastic sediments of the Vychegda Depression (Mezen syneclise) has been carried out on samples retrieved from the Keltmen-1 borehole drilled in the junction zone of the Russian and Timan-Pechera plates. The stratigraphic structure of the clastic unit in the depth interval 1874–2910 m has been perfected. At the base of the unit, the new Okos Formation has been described: glauconite from it was dated by Rb-Sr to 807 ± 8 Ma. The obtained microphytologic characteristic of the upper part of the section is in agreement with lithological and geochemical data, allowing recognition of two Upper Vendian Formations: Ust-Pinega and Mezen. The stratigraphic hiatus between the Upper Riphean and Vendian deposits in the Keltmen-1 borehole reaches 200–250 M.y. For the first time Ediacaran acanthomorph microfossils of the genera Appendisphaera and Tanarium have been found in the high horizons of the Upper Vendian, proving their wider stratigraphic distribution.
Databáze:	OpenAIRE
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