| Kietzmann | Дата: Saturday, 03.09.2022, 01:54 | Сообщение # 1 |
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| Kietzmann D.A., Iglesia Llanos M.P, González Tomassini F., Lanusse Noguera I., Vallejo D. & Reijenstein H. (2021) Upper JurassiceLower Cretaceous calpionellid zones in the Neuquén Basin (Southern Andes, Argentina): Correlation with ammonite zones and biostratigraphic synthesis // Cret. Res. Vol. 127, 104950.
This work presents the first regional biostratigraphic study on the calpionellid zones and assemblages of the Tithonian - lower Valanginian interval in the Neuquén Basin, Southern Andes, Western Argentina. The lower Tithonianelower Valanginian in the Neuquén Basin is mainly represented by the Vaca Muerta Formation, which is a thick sucession (100e1250 m thick) of rhythmic marlstone and limestone alternations corresponding to the distal hemipelagic facies of a carbonate ramp. This formation is one of the most important unconventional hydrocarbon reservoirs in the world and has become a relevant target in Argentina during the last decade. The Vaca Muerta Formation is characterized by an abundant fossil content and a remarkable stratigraphic continuity along several hundred meters, encompassing the Jurassic/Cretaceous boundary. The detailed study of seven outcrop and well sections (three of them studied for the first time herein), allowed the elaboration of a reliable stratigraphic scheme based on the correlation of ammonites, microfossils, magnetostratigraphy and cyclostratigraphy. The Vaca Muerta Formation contains moderate to poorly preserved calpionellids. Despite that, twenty-six calpionellid species and five calpionellid biozones known in the Tethyan regions have been identified: Chitinoidella, Crassicollaria, Calpionella, Calpionellopsis and Calpionellites. Additionally, nine subzones were recognized: Slovenica, Boneti, Remanei, Massutiniana, Alpina, Elliptica, Simplex, Oblonga, and Darderi. These results allow chronostratigraphic correlations between the Tethys and the Southeastern Pacific domains.
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