Foraminiferal, calcareous algal and problematica assemblages from the Mississippian Lower Limestone Formation in the Midland Valley, Scotland

Abstract

Foraminiferal, algal and problematica assemblages from the Mississippian (late Viséan and early Serpukhovian) Lower Limestone Formation have been studied in order to validate lithostratigraphical correlations of limestones within the central and western parts of the Midland Valley of Scotland. Analysis of more than 100 outcrops allows recognition of four calcareous microfossil assemblages, which span the late Brigantian and early Pendleian, and enables a detailed correlation to be made within the Central Coalfield (north Lanarkshire) and with the thinner sequences to the west (north Ayrshire), to the south (Douglas area, south Lanarkshire), and to the east (Bathgate area, West Lothian). The age of the Lower Limestone Formation is modified because the upper part of this formation is now assigned to the Pendleian (due to the first occurrences of new foraminiferans and the co-occurrence with the Namurian goniatites), and some individual limestone horizons within the formation are repositioned, or their precise correlation with other limestones is established. A refined stratigraphical framework is proposed for the above noted areas, and a correlation between them and the Pennine region in northern England is proposed, passing through the Archerbeck Borehole sequence in the Scottish Borders.

The Carboniferous Archerbeck Borehole, near Canonbie (Dumfriesshire, southern Scotland): biostratigraphic revision of the late Asbian to early Pendleian succession using foraminiferans and regional correlations

“…However, the main problem related to these two previous studies is the absence of diagnostic taxa for biostratigraphic purposes. These taxa are typical of the late Brigantian elsewhere (Có zar & Somerville 2004;Có zar et al 2008aCó zar et al , 2010. Within the taxa recorded by the present authors can be highlighted the lack of reference to, or illustration of, Archaediscus at tenuis stage (or transitional forms), Euxinita, Biseriella, Climacammina, Planospirodiscus and Tubispirodiscus.…”

“…In addition, a second problem arises with the potential synonymy of Eosigmoilina explicata described by Ganelina (1956) (subsequently split into numerous subspecies by Brazhnikova (1964)) with Trochammina robertsoni Brady, 1876. According to Brady (1876), the original material was collected from old and disused quarries that are currently filled and resampling is not possible a common problem in those small outcrops of the Midland Valley of Scotland (see also Có zar et al 2010). It is difficult to confirm or reject this synonymy, because specimens collected by Brady (1876) were extracted from shales, and he only illustrated external views.…”

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

“…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 ().…”

Foraminifers and conodonts from the late Viséan to early Bashkirian succession in the Saharan Tindouf Basin (southern Morocco): biostratigraphic refinements and implications for correlations in the western Palaeotethys

“…The occurrence of Planospirodiscus taimyricus , Tubispirodiscus simplicissimus and advanced archaediscids (e.g. Archaediscus donetzianus ) in beds I and J confirm an uppermost late Brigantian age for this part of the section (See Cózar et al ., 2008a, b, ).…”

“…A single specimen of Archaediscidae seems to show a rudimentary septation. It is similar to specimens recorded by the authors in the Midland Valley of Scotland and the Archerbeck Borehole, southern Scotland (Cózar et al ., ; Cózar and Somerville, , fig. 7.5), although the paucity in the number of specimens prevents us from formally defining it as a new genus.…”