|Late Visean-Serpukhovian foraminiferans and calcareous algae from the Adarouch region (central Morocco), North Africa|Cozar, P.; Vachard, D.; Somerville, I.D.; Berkhli, M.; Medina-Varea, P.; Rodriguez, S.; Said, I. (2008). Late Visean-Serpukhovian foraminiferans and calcareous algae from the Adarouch region (central Morocco), North Africa. Geol. J. 43(4): 463-485. dx.doi.org/10.1002/gj.1119
In: Geological Journal. Liverpool Geological Society/Manchester Geological Association: Liverpool. ISSN 0072-1050, more
foraminiferans; calcareous algae; biostratigraphy; Mississippian;Visean; Serpukhovian; Adarouch; Morocco; North Africa
|Authors|| || Top |
- Cozar, P.
- Vachard, D.
- Somerville, I.D.
- Berkhli, M.
- Medina-Varea, P.
- Rodriguez, S.
- Said, I.
Three Upper Viséan to Serpukhovian limestone formations from the Adarouch region (central Morocco), North Africa, have been dated precisely using foraminiferans and calcareous algae. The lower and middle part of the oldest formation, the Tizra Formation (Fm), is assigned to the latest Asbian (upper Cf6? Subzone), and its upper part to the Early Brigantian (lower Cf6d Subzone). The topmost beds of this formation are assigned to the Late Brigantian (upper Cf6d Subzone). The lower part of the succeeding Mouarhaz Fm is also assigned to the Late Brigantian (upper Cf6d Subzone). The Akerchi Fm is younger than the other formations within the region, ranging from the latest Brigantian (uppermost Cf6d Subzone) up to the Serpukhovian (E1–E2). The base of the Serpukhovian (Pendleian Substage, E1) is repositioned, to coincide with the appearance of a suite of foraminiferans including Archaediscus at tenuis stage, Endothyranopsis plana, Eostaffella pseudostruvei, Loeblichia ukrainica, Loeblichia aff. minima and Biseriella? sp. 1. The upper Serpukhovian (Arnsbergian Substage, E2) is marked by the first appearance of Eostaffellina ex. gr. paraprotvae and Globoomphalotis aff. pseudosamarica. The biostratigraphical scheme used for the reassessment of the foraminiferal zones and subzones in the Adarouch area closely compares with that for the British succession in northern England (Pennine Region), where the stratotypes of the Upper Viséan (Asbian and Brigantian) and Early Serpukhovian (Pendleian) substages are located. Thus, a succession equivalent to an interval from the Melmerby Scar Limestone to the Great (or Little) Limestone is recognized. These assemblages are also compared to other foraminiferal zones proposed in other regions of Morocco. Several foraminiferans have been identified that are proposed as potential Serpukhovian markers for other basins in Western Europe, and compared to sequences in Russia and the Donets Basin, Ukraine.