The Mid-Carboniferous boundary in the eastern slope of the Southern and Middle Urals: carbon and oxygen isotopic composition in limestones

S A Dub,T I Stepanova,E I Kulagina,S V Nikolaeva,O L Petrov,G A Mizens,N A Kucheva,V N Kuleshov,O Yu Melnichuk

doi:10.24930/1681-9004-2020-20-3-305-327

S A Dub, T I Stepanova + Show 7 more

Open Access

https://doi.org/10.24930/1681-9004-2020-20-3-305-327

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Abstract

Research subject. Limestones of the Mid-Carboniferous boundary interval of the Urals eastern slope (“Khudo-laz”, “Khudolaz-gully” and “Bolshoy Kizil” sections at the Southern Urals, as well as “Iset quarry” and “Lugovaya” sections in the Middle Urals) are considered. Methods. Carbon and oxygen isotopic composition in bulk samples was analyzed. Results. The carbon and oxygen isotopic composition in carbonate deposits of the Serpukhovian-Bashkirian boundary interval in the sections of the Southern and Middle Urals eastern slope was studied. It is shown that the value of δ 13 C in the most complete sections varies from 1.5 to 3.8‰, while δ 18 O – from 23.1 to 30.7‰. Conclusions. Variations in the carbon and oxygen isotopic composition are associated with both global and local events. In the East Uralian basins (northern periphery of Paleotethys), the shift in carbon isotopic composition of carbonate sediments appeared in the Late Serpukhovian. In some cases, this trend correlates with the positive excursion of δ 18 O, which is most likely associated with the global short-term cooling (glaciation).

Highlights

Объектами исследования являлись известняки пограничного нижне-среднекаменноугольного интервала на восточном склоне Урала
It is shown that the value of δ13C in the most complete sections varies from 1.5 to 3.8‰, while δ18O – from 23.1 to 30.7‰
In the East Uralian basins, the shift in carbon isotopic composition of carbonate sediments appeared in the Late Serpukhovian

Summary

Introduction

Объектами исследования являлись известняки пограничного нижне-среднекаменноугольного интервала на восточном склоне Урала (разрезы “Худолаз”, “Худолаз-лог” и “Большой Кизил” на Южном Урале, “Исетский карьер” и “Луговая” – на Среднем). Получены первые результаты изучения изотопного состава углерода и кислорода карбонатных отложений серпуховско-башкирского интервала в разрезах восточного склона Южного и Среднего Урала. (2020) Граница нижнего и среднего карбона в разрезах восточного склона Южного и Среднего Урала: изотопный состав углерода и кислорода в известняках.

Results

Conclusion