Biostratigraphy and lithostratigraphy of the Mid-Carboniferous boundary beds in the Muradymovo section (South Urals, Russia)

Abstract

The uninterrupted succession of the Mississippian–Pennsylvanian boundary beds in the Muradymovo section in the South Urals contains diverse fossils and has a high correlative potential. The Muradymovo section is located in the Zilair Megasynclinorium (ZM), which belongs to the West Uralian Subregion and displays carbonate-siliciclastic deep-water facies of the Bukharcha Formation, which is partly Serpukhovian (Kosogorian, Protvian and Yuldybaevian) and partly Bashkirian (Syuranian). In the southern ZM, the lower part of the formation contains argillaceous carbonates with beds of shale and siltstone, subordinate clastic limestones and limestone breccia, while the upper part is mostly limestone with cherty interbeds. In the north of the ZM, the formation mainly consists of limestone. The Muradymovo succession contains no identifiable gaps in the Mid-Carboniferous Boundary (MCB) portion and has a succession of foraminiferal, conodont, ammonoid and ostracod zones. The MCB in this section coincides with the base of the Bogdanovkian and is defined by the entry of Declinognathodus noduliferus. This level falls within the upper part of the foraminiferal Monotaxinoides transitorius Zone, is near the base of the ammonoid Homoceras–Hudsonoceras Genozone and can be correlated worldwide.

Ostracodes of the Lower – Middle Carboniferous Boundary Layers in the Muradymovo Section of the Southern Urals

“…Распространение остракод в пограничных отложениях нижнего -среднего карбона разреза Мурадымово. Стратиграфическая колонка по [Kulagina et al, 2014b] Известняки: 1 - мадстоун, пакстоун; 2 - грейнстоун; 3 - известняки с линзами кремней. Органические остатки: 4 - криноидеи; 5 - аммоноидеи; 6 - брахиоподы; 7 -мшанки.…”

Carboniferous conodont biostratigraphy of the Dianzishang section, Zhenning, Guizhou, South China

“…2004) and the Neognathodus askynensis – N. symmetricus Zone in South Urals, Russia (Nemirovska & Alekseev, 1994; Kulagina et al . 2009).…”

“…2011) and the Idiognathoides sulcatus parva Zone in Western Europe (Higgins, 1975, 1985), and it can be roughly correlated with the Idiognathodus sinuosus Ellison & Graves, 1941 Zone in Russia and North America (Lane & Straka, 1974; Nemirovska & Alekseev, 1994; Nemyrovska, 1999; Wang & Qi, 2003; Kulagina et al . 2009). It is also coeval with the previously established Idiognathoides sulcatus parva Zone in the Naqing section (Wang et al .…”

“…This zone is also recognized in the Naqing section, and can be roughly correlated with the Streptognathodus transtivus , Neognathodus bothrops , N. medadultimus and Streptognathodus concinus– Idiognathodus robustus zones in Russia (Kulagina et al . 2009), and with the N. bothrops Zone, N. caudatus Zone and the lower part of the N. asymmetricus Zone in North America (Barrick et al . 2004; Wang & Qi, 2003; Wang et al .…”

Evidence for a Stratigraphic Basis for the Anthropocene

“…The sections of this zone are the most stratigraphically significant, as they are composed of deep-water slope facies with foraminifers, ostracods, ammonoids, and conodonts. The most complete palaeontological characterization has been obtained from the Muradymovo section (Kulagina et al 2014). In this section, Declinognathodus inaequalis is found in association with ammonoids Proshumardites delepinei and foraminifers of the Monotaxinoides transitorius Zone.…”