DOI: 10.1016/j.palaeo.2016.07.016
论文题名: Response of calcareous nannoplankton to the Late Cretaceous Oceanic Anoxic Event 2 at Oued Bahloul (central Tunisia)
作者: Aguado R. ; Reolid M. ; Molina E.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2016
卷: 459 起始页码: 289
结束页码: 305
语种: 英语
英文关键词: Biostratigraphy
; Cenomanian–Turonian
; Chemostratigraphy
; Micropalaeontology
; Palaeoceanography
英文摘要: Oued Bahloul is a reference section for the Cenomanian–Turonian that was located on the North African palaeomargin, where Oceanic Anoxic Event 2 (OAE2) is represented by black limestones and grey marls. Biostratigraphic study allowed the identification of calcareous nannofossil UC3 to UC6 zones. Quantitative analyses of calcareous nannofossil assemblages indicate that high-fertility surface-water conditions predominated throughout most of the OAE2 interval. The most eutrophic conditions probably developed during deposition of the lowermost part of the Whiteinella archaeocretacea Zone (UC3 to UC4 zones), where nannofossil-derived fertility indices reach high values and the small Zeugrhabdotus gr. predominates over Biscutum spp. The temperature index based on calcareous nannofossil assemblages indicates a warming at the beginning of the OAE2, followed by progressive cooling (the same trend indicated by δ18Obulk values). The significant proportion of holococcoliths suggests high-stress conditions in surface waters during most of the OAE2 interval. The enrichment in redox-sensitive elements, together with the abundance of low-oxygen tolerant benthic foraminifera, indicates dysoxic conditions both in the deep-water column and sea-bottom at the beginning of the OAE2 (W. archaeocretacea Zone). Geochemical detrital proxies indicate an enhanced rate of terrigenous supply during the OAE2 interval resulting from increased riverine influx related to a more humid climate. Enhanced fluvial run-off increased nutrient input to marine surface waters contributing to eutrophication (recorded by calcareous nannoplankton and planktic foraminifera). Plankton consumption of surface water nutrients increased organic matter production, whose decay contributed to the decrease in dissolved oxygen, generating increasingly dysoxic/anoxic conditions and favoring preservation of organic matter. Although low-latitude nannofossil assemblages such as those of Oued Bahloul reflect an increase in nutrient availability during the OAE2 interval, assemblages from mid-latitude areas record a decreased nutrient content. © 2016 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/68312
Appears in Collections: 过去全球变化的重建
There are no files associated with this item.
作者单位: Departamento de Geología and CEACTierra, Universidad de Jaén, Campus Científico-Tecnológico de Linares, Jaén, Spain; Departamento de Geología and CEACTierra, Universidad de Jaén, Campus Las Lagunillas, Jaén, Spain; Departamento de Ciencias de la Tierra and IUCA, Universidad de Zaragoza, Pedro Cerbuna 12, Zaragoza, Spain
Recommended Citation:
Aguado R.,Reolid M.,Molina E.. Response of calcareous nannoplankton to the Late Cretaceous Oceanic Anoxic Event 2 at Oued Bahloul (central Tunisia)[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2016-01-01,459