A.V. Zhuravlev*, Ya.A. Vevel**
Geological Institute, Komi Scientific Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, 167000 Russia
E-mail: *micropalaeontology@gmail.com, **yadviga_vevel@mail.ru
Received December 20, 2016
Abstract
The paper considers the Lower-Middle Carboniferous boundary interval in the sections of the Pay-Khoy carbonate parautochthone (shallow-water facies) and the Kara slate allochthone (deep-water facies) with respect to the boundary tracing criteria. The boundary interval has been studied in the sections of the North-Eastern Pay-Khoy (Peschanaya River, Khardto Lake, Barents Sea shore near the Chaika Cape, and Lymbad”yakha River). The boundary recognition has been based on data for the conodonts and foraminifers. The boundary is not directly characterized by fauna in either deep- or shallow-water facies. The boundary interval has been recognized by the latest findings of the Early Carboniferous foraminifers and conodonts (Parastaffella cf. angulata, Gnathodus bollandensis), as well as the first findings of Declinognathodus noduliferus in the upper part of the Bolvanskiy Formation of the carbonate parautochthone. The transgression maximum has been detected in the boundary interval. In the sections of the slate allochthone, the boundary may coincide with the base of the Karasilova Formation. The lower part of the formation is characterized by condensed sequence (transgression maximum), and the first findings of the Middle Carboniferous conodonts (Rhachistognathus minutus) correspond to the upper part of the Syuransk Substage. The transgression maximum is considered as the reliable boundary marker. The traces of the transgression maximum have been detected in the upper part of the Bolvanskiy Formation and in the base of the Karasilova Formation.
Keywords: stratigraphy, Middle Carboniferous boundary, conodonts, foraminifers, correlation, Pay-Khoy
Figure Сaptions
Fig. 1. Locality map of the study sections: 1 – sections located on the shore of Barents Sea in the vicinity of the Chaika Cape and Lymbad”yakha River mouth. 2 – sections located in the Peschanaya River basin and the Khardto Lake.
Fig. 2. Correlation of the composite sections of the Lower-Middle Carboniferous boundary beds of the carbonate parautochthone and slate allochthone. Legend: 1 – detritic limestones with clayey layers; 2 – cherty limestones; 3 – stromatolithic limestones; 4 – detritic limestones; 5 – silicites; 6 – argillites; 7 – phosphatic concretions; 8 – siliceous concretions; 9 – regression acme; 10 – transgression acme.
Fig. 3. Images of some conodonts and foraminifers: 1, 2 – Declinognathodus noduliferus (Ellison et Graves), sample 2037/41, bed 3, Karasilova Formation, Middle Carboniferous, Bashkirian Stage; 3, 4 – Gnathodus bollandensis (Higgins et Bouckaert, sample 2037/37, bed 8, Kara Formation, Lower Carboniferous, Serpukhovian Stage; 5 – Adetognathus gigantus (Gunnell), sample 2700/58, bed 5, Bolvanskiy Formation, Middle Carboniferous, Bashkirian Stage; 6 – Declinognathodus noduliferus (Ellison et Graves), sample 2700/58, , bed 5, Bolvanskiy Formation, Middle Carboniferous, Bashkirian Stage; 7 – Endothyra sp., sample 2700/53, bed 2, Bolvanskiy Formation, Lower Carboniferous, Serpukhovian Stage; 8 – Parastaffella cf. angulata Rauser, sample 2700/53, bed 2, Bolvanskiy Formation, Lower Carboniferous, Serpukhovian Stage.
References
For citation: Zhuravlev A.V., Vevel Ya.A. The Middle Carboniferous boundary in the north of Pay-Khoy – correlation between the shallow- and deep-water sequences. Uchenye Zapiski Kazanskogo Universiteta. Seriya Estestvennye Nauki, 2017, vol. 159, no. 1, pp. 152–163. (In Russian)
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