Publication details
Refinement of the lower Tournaisian (Mississippian) conodont, foraminiferal and carbon isotope stratigraphy of the Moravosilesian Basin (Czech Republic) and implications for global correlation
| Authors | |
|---|---|
| Year of publication | 2025 |
| Type | Article in Periodical |
| Magazine / Source | Newsletters on Stratigraphy |
| MU Faculty or unit | |
| Citation | |
| web | https://doi.org/10.1127/nos/2024/0830 |
| Doi | https://doi.org/10.1127/nos/2024/0830 |
| Keywords | Carboniferous; Palaeotethys Realm; Rhenohercynian Zone; biostratigraphy; chemostratigraphy |
| Description | An extensive conodont, foraminiferal, and carbonate carbon isotopic (?13C) integrated stratigraphic study of lower Tournaisian (Mississippian) carbonate slope deposits was conducted in eleven sections of the Moravian Karst Unit, Moravosilesian Basin, Czech Republic. Some biostratigraphic challenges were encountered and solutions were proposed: 1) identification of the global Siphonodella sandbergi conodont Zone is complicated in the Moravosilesian Basin due to the scarcity of index conodont species (a common feature of European regions) and Pseudopolygnathus triangulus triangulus was used as an auxiliary index; 2) the issue with the determination of the base of the Siphonodella quadruplicata conodont Zone is related to the morphological plexus of early ontogenetic stages of Si. quadruplicata and its ancestor Si. wilberti, therefore only adult specimens have to be considered to avoid misinterpretation. The radiation in the Siphonodella wilberti (~Upper duplicata Zone) and Siphonodella sandbergi conodont zones is documented by first occurrences of new conodont species of the genera Siphonodella, Polygnathus, and Pseudopolygnathus, described herein in the open nomenclature. Siphonodella sp. A is discussed as a possible link to the evolutionary lineage between Siphondella bella and Siphonodella carinata of the East European siphonodellid group. The base of the Tournaisian foraminifer zone MF2 is correlated with the base of the Siphonodella wilberti conodont Zone. Several ?13Ccarb positive excursions are documented in the Moravian lower Tournaisian. Three small-scaled lower Tournaisian Carbon Isotopic excursions (LTICE) occur above the prominent Hangenberg carbon isotopic excursion: LTICE1 around the Si. bransoni/Si. duplicata Zone boundary, LTICE2 in the Si. wilberti Zone, and LTICE3 at the Si. sandbergi/quadruplicata Zone boundary. These excursions are correlated between two facies successions of the Moravian Karst Unit (the calciturbiditic Horákov and hemipelagic Hostěnice facies) and further correlated with those known from several basins in the Palaeotethys Realm (shelves of SE and NE Laurussia and the South China Continent), as well as (tentatively) with the Panthalassa Realm (W Laurussian shelf). Our findings support global correlative potential for the lower Tournaisian ?13Ccarb positive excursions (LTICE 1–3) providing better global stratigraphic resolution for the interval. Positive excursions were documented in Horákov Facies from regressive deposits, supporting the interpretation of their origin being in enhanced organic carbon burial during early Tournaisan glacioeustatic falls, as similarly interpreted for the large-scale Tournaisian isotope excursions. Therefore, at least three small-scale glaciation events are tentatively proposed during the early Tournaisian, between the extensive Hangenberg and mid-Tournaisian glaciation events. |
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