The upper Viséan–Serpukhovian in the type area for the Serpukhovian Stage (Moscow Basin, Russia): Part 1. Sequences, disconformities, and biostratigraphic summary

Abstract

The upper Viséan–Serpukhovian strata in the type region for the Serpukhovian Stage is an epeiric‐sea succession ca. 90 m in thickness. The predominantly Viséan Oka Group (comprising the Aleksin, Mikhailov, and Venev formations) is dominated by photozoan packstones with fluvial siliciclastic wedges developed from the west. The Lower Serpukhovian Zaborie Group is composed of the Tarusa and Gurovo formations. The latter is a new name for the shale‐dominated unit of Steshevian Substage age in the studied area. The Zaborie Group is composed of limestones and marls in its lower (Tarusa and basal Gurovo) part and black smectitic to grey palygorskitic shales in the main part of the Gurovo Formation. The Gurovo Formation is capped by a thin limestone with oncoids and a palygorskitic–calcretic palaeosol. The Upper Serpukhovian is composed of a thin (3–12 m) Protva Limestone heavily karstified during a mid‐Carboniferous lowstand. The succession shows a number of unusual sedimentary features, such as a lack of high‐energy facies, shallow‐subtidal marine sediments penetrated by Stigmaria, the inferred atidal to microtidal regime, and palustrine beds composed of saponitic marls. The succession contains many subaerial disconformities characterized by profiles ranging from undercoal solution horizons to palaeokarsts. Incised fluvial channels are reported at two stratigraphic levels to the west of the study area. The deepest incisions developed from the Kholm Disconformity (top of the Mikhailov Formation). This disconformity also exhibits the deepest palaeokarst profile and represents the major hiatus in the Oka–Zaborie succession. The new sea‐level curve presented herein shows two major cycles separated by the Kholm Unconformity at the Mikhailov/Venev boundary. The Lower Serpukhovian transgression moved the base‐level away from falling below the seafloor so that the section becomes conformable above the Forino Disconformity (lower Tarusa). The maximum deepening is interpreted to occur in the lower dark‐shale part of the Gurovo Formation. The base of the Serpukhovian Stage is defined by FADs of the conodont Lochriea ziegleri and the foraminifer Janischewskina delicata in the middle of the sequence VN2. The Aleksinian–Mikhailovian interval is provisionally correlated with the Asbian (Lower–Middle Warnantian) in Western Europe. Based on FODs of Janischewskina typica and first representatives of Climacammina, the Venevian is correlated with the Brigantian in Western Europe. The Tarusian–Protvian interval contains diverse fusulinid and conodont assemblages, but few forms suitable for international correlation. FADs of the zonal conodont species Adetognathus unicornis and Gnathodus bollandensis at several metres above the Protvian base suggest correlation of the entire Zaborie Group and may be the basal Protvian to the Pendleian. Copyright © 2014 John Wiley & Sons, Ltd.

Mississippian lithofacies and foraminiferal biozonation of the Alborz Mountains, Iran: Implications for regional geology

“…We have used our data from five studied sections (Dozdehban and Naserabad in north‐central Alborz, Jaban in east‐central Alborz, and Peyghambaran and Kalariz in eastern Alborz) and those previously studied by several workers across the entire Alborz from south‐east to north‐west (Figure ; Bozorgnia, ; Brenckle et al, ; Falahatgar et al, ; Lys et al, ; Najafi, ; Payami‐e Rad, ; Saeidi et al, ; Vachard, ; Zandkarimi, ; Zandkarimi et al, ; Zandkarimi, Vachard, Cózar, et al, ; Zandkarimi, Vachard, Najafian, et al, ). Foraminiferal data collected from the Alborz have been compared with those of the stratotypic area in Belgium (Conil & Lys, ; Conil, Groessens, Laloux, Poty, & Tourneur, ; Devuyst & Hance in Poty, Devuyst, & Hance, ; Mamet, ), the former USSR (Gibshman, , ; Kabanov et al, ; Kulagina, Gibshman, & Pazukhin, ; Nikolaeva et al, ; Kulagina, ; Vdovenko, ), England and Scotland (Conil, Longerstaey, & Ramsbottom, ; Cózar et al, , ; Cózar & Somerville, , , ; Fewtrell, Ramsbottom, & Strank, ; Somerville & Cózar, ; Strank, ), and in Morocco (Cózar et al, ; Cózar et al, ; Cózar et al, ; Vachard & Berkhli, ; Vachard & Tahiri, ). We have identified Early Tournaisian to Late Serpukhovian biozones in the Alborz as follows:…”

“…For a synthesis of the Mississippian foraminiferal zonation and Late Palaeozoic stratigraphy of Alborz, we have followed the works of Assereto (), Bozorgnia (), Stöcklin and Setudehnia (), Vachard (), Brenckle, Gaetani, Angiolini, and Bahrammanesh (), Falahatgar et al (), Zandkarimi et al (), Zandkarimi et al (), Zandkarimi, Vachard, Cózar, et al () and Zandkarimi, Vachard, Najafian, et al (), and several unpublished MSc and PhD theses (Bastami, ; Mosaddegh, ; Najafi, ; Payami‐e Rad, ; Zandkarimi, ) carried out on the Late Palaeozoic of Alborz, and for foraminiferal classification and correlation of zonation with well‐known Mississippian references, we have followed the works of Pirlet and Conil (), Vachard and Tahiri (), Vachard and Berkhli (), Hance, Hou, and Vachard (), Gibshman (, ), Gibshman, Kabanov, Alekseev, Goreva, and Moshkina (), Nikolaeva, Kulagina, Pazukhin, Kochetova, and Konvalova (2009), Kabanov, Alekseev, Gibshman, Gabdullin, and Bershov (), Vachard (), and various papers of Cózar and Somerville (, , , , ), Somerville (), Cózar, Somerville, and Burgess (, ), Cózar, Somerville, Aretz, and Herbig (); Cózar et al (), Cózar et al (), Cózar, Sanz‐López, and Blanco‐Ferrera (), and Cózar et al (). The microfacies and depositional interpretation follow the works of Dunham (), Read (), Burchette and Wright (), Mosaddegh (), and Flügel ().…”

Environmental controls on the development of Mississippian microbial carbonate mounds and platform limestones in southern Montagne Noire (France)

“…This is true for all of the substages, except for the Aleksian, where the change in the trend of the curve appears to occur just at the boundary between the Aleksian and Mikhailovian, and the Venevian in shallower environments. The comparison with the sequences in the South Russian platform (Kabanov et al ., ), where the control is eustatic, shows that there are 11 sequences in that platform, from the Venevian up to the Protvian (probably high frequency and fourth order sequences), and some sequences coinciding with the substage boundaries (Fig. ).…”

“…Sequence in the Russian Platform (first column left) based on Kabanov et al . (). CB, Coteau de Bergue; CsN, Castelsec North; Ma, Malac mound railway; PaN, Les Pascales North; PaS, Les Pascales South; RM, Roc de Murviel; ROQ, Roquemallière; RR, Roque Redonde; Se, La Serre; Sp, Serre de Péret.…”

Serpukhovian (Mississippian) foraminiferal zones from the Fenghuangshan section, Anhui Province, South China: implications for biostratigraphic correlations

“…rugosa has been reported from the Protvian in the type Serpukhovian region (e.g. Gibshman, ; Kabanov et al ., ) and Donets Basin (Aizenverg et al ., ) and possibly from beds in northern Britain equivalent to the Steshevian Substage (Cózar and Somerville, ). Nevertheless, because the type Chesterian region does not have Monotaxinoides transitorius and B .…”