期刊名称：International Research Journal of Earth Sciences
电子版ISSN：2321-2527
出版年度：2018
卷号：6
期号：8
页码：1-10
语种：English
出版社：International Science Community Association
摘要：The late Santonian-early Paleocene sequences were investigated at the Galanderud section, to recognize the biostratigraphy scheme paleoenvironmental changes in eastern Tethys. This section mainly consists of green and gray marl, marly limestone, and limestones. A high-resolution study based upon benthic and planktic foraminiferal assemblages has been used. The planktic foraminifera were diverse and abundance, where 56 planktic species belonging to 27 genera have been recognized. In this study, first and last appearances of the planktic foraminifera have been used as major bio events to identified different biozonation. Planktic foraminiferal zonation from bottom to top of the section consists of fifteen zones include: i. Dicarinella asymetrica, ii. Globotruncanita elevata, iii. Globotruncana ventricosa, iv. Radotruncana calcarata, v. Globotruncanella havanensis, vi. Globotruncana aegyptiaca, vii. Gansserina gansseri, viii. Racemiguembelina fructicos, ix. Pseudoguembelina hariaensis, x. Pseudoguembelina palpebra, xi. Plummerita hantkeninoides, xii. Guembelitria cretacea, xiii. Parvularugoglobigerina eugubina, xiv. Parasubbotina pseudobulloides, xv. Subbotina triloclinoides. Also, three distinct zones have been defined based on benthic foraminifera morphotypes and Cibicidoides spp. First zone (Dicarinella asymetrica to Gansserina gansseri biozones) is dominated by Infauna morphotype and less abundance of Cibicidoides spp. indicating high food availability and lower oxygen condition. The second zone, with the increase of epifauna morphotype and Cibicidoides spp. show decreasing in organic matter. Finally, high abundance of epifauna species and Cibicidoides spp. indicate a collapse of food availability after the extinction of primary producers that may cause by asteroid impact after Cretaceous- Paleogene boundary mass extinction.
