Date

2012

Author

Özdemir, Ayşe

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Conodonts are important biostratigraphic tools for the delineation and calibration of the geochronological boundaries within the Carboniferous and used generally as stage-boundary markers for the Lower Carboniferous (Mississippian). The studied successions in the Central and Eastern Taurides were mainly deposited in a shallow marine environment during the Carboniferous time and they comprise less abundant and diversified conodont fauna. The conodont fauna represented by twenty-four species belonging to ten genera have been described from the studied sections (AS; AAO; BSE and HB) in the Taurides (Turkey). Regarding the first occurrences and last occurrences of biostratigraphically significant species within these sections, the following zones have been established across the Lower Carboniferous successions: (1) Polygnathus inornatus Zone (Hastarian-Lower Tournaisian); (2) Gnathodus cuneiformis – Polygnathus communis communis Zone (Ivorian-Upper Tournaisian); (3) Polygnathus mehli mehli Zone (Ivorian-Upper Tournaisian); (4) Gnathodus girtyi girtyi Zone (Brigantian-Upper Visean); (5) Gnathodus girtyi simplex Zone (Pendelian-Lower Serpukhovian); (6) Rhachistognathus muricatus Zone (Zapaltyubinsky-Upper Serpukhovian) and (7) Declinognathodus inaequalis - Declinognathodus noduliferus Zone (Bogdanovsky-Lower Bashkirian). Based on the recovered conodont assemblages, Visean - Serpukhovian boundary has been recognized by the first occurrence of Gnathodus girtyi simplex and the Mid-Carboniferous boundary is delineated by the first occurrence of Declinognathodus inaequalis, which is an index taxon for the basal part of the Bashkirian. Based on the microfacies studies it can be concluded that conodont elements essentially obtained from the crinoidal bioclastic packstone-grainstone, crinoidal packstone-grainstone, coated bioclastic grainstone, intraclastic grainstone and spiculite packstone facies in the studied sections. It can be concluded that that the occurrence of abundant crinoids are indicative criteria for the presence of conodonts. Additionally, geometric morphometric analyses of biostratigraphically important genus, Gnathodus, on the basis of data available in the literature emphasize the importance of numerical taxonomy and reveal that taxonomic revision of this genus is needed.

Subject Keywords

Geology, Stratigraphic., Geology, Stratigraphic, Conodonts., Taurine.

URI

http://etd.lib.metu.edu.tr/upload/12615182/index.pdf
https://hdl.handle.net/11511/22098

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Graduate School of Natural and Applied Sciences, Thesis