INTERREGIONAL CORRELATION OF THE MIDDLE FRASNIAN (UPPER DEVONOIAN) OF THE NORTH-WEST OF THE RUSSIAN PLATE AND THE EAST OF THE PECHORA PLATE: AN ECOGEOCHEMICAL ASPECT

The paper provides an example of the first stratigraphic application of ecogeochemical method based on the analysis of the carbon isotope values in conodont elements. The method is based on hypothesis of almost isochronic regime change (at least within the basin) in isotope fractionation of carbon i...

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Bibliographic Details
Published in:Georesursy
Main Authors: A. V. Zhuravlev, А. В. Журавлев
Other Authors: The work was done as a part of the state assignment theme FUUU-2022-0056., Работа выполнялась в рамках госзадания по теме FUUU-2022-0056.
Format: Article in Journal/Newspaper
Language:Russian
Published: Institute of the Earth's crust of the Russian Academy of Sciences, Siberian Branch 2022
Subjects:
стратиграфия
conodonts
Upper Devonian
stratigraphy
конодонты
верхний девон
Pechora
Online Access:https://www.gt-crust.ru/jour/article/view/1454
https://doi.org/10.5800/GT-2022-13-2s-0620
Description
Summary:The paper provides an example of the first stratigraphic application of ecogeochemical method based on the analysis of the carbon isotope values in conodont elements. The method is based on hypothesis of almost isochronic regime change (at least within the basin) in isotope fractionation of carbon in pelagic ecosystems which is reflected and kept in carbon isotope composition of conodont elements. This method has been used to compare between different facial Frasnian sequences of the northwestern Russian Plate (coastal marine facies) and eastern Pechora Plate (depression facies). There were traces of three isotope excursions: negative in the vicinity of the MN5 zone basement (domanic horizon basement), negative at the boundary between the MN5 and MN6 zones, and double positive excursion in the upper MN6 zone. The amplitude of excursions is usually much less in the deep-water facies. The similarity of variations in carbon isotope composition of conodont elements in geographically remote and facially different Fransnian sedimentary sequences of the northwestern Russian Plate and eastern Pechora Plate confirms the possibility of using this parameter for stratigraphic correlation. В статье рассмотрен первый пример применения экогеохимического метода в стратиграфии, основанного на анализе вариаций изотопного состава углерода конодонтовых элементов. В основу метода положена гипотеза о практической изохронности (как минимум в пределах бассейна) существенных изменений изотопного фракционирования углерода в пелагических экосистемах, которое отражается и сохраняется в изотопном составе углерода конодонтовых элементов. Этим методом сопоставлены разнофациальные франские последовательности северо-запада Русской плиты (прибрежно-морские фации) и востока Печорской плиты (депрессионные фации). Прослежены три изотопных экскурса: отрицательный вблизи подошвы зоны MN5 (подошва доманикового горизонта), отрицательный на границе зон MN5 и MN6 и двойной положительный экскурс в верхней части зоны MN6. В глубоководных фациях амплитуда ...

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