DOI: 10.1016/j.palaeo.2013.03.018
论文题名: Paleoenvironmental changes during the Middle Eocene Climatic Optimum (MECO) and its aftermath: The benthic foraminiferal record from the Alano section (NE Italy)
作者: Boscolo Galazzo F. ; Giusberti L. ; Luciani V. ; Thomas E.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 378 起始页码: 22
结束页码: 35
语种: 英语
英文关键词: Alano section
; Benthic foraminifera
; Central-western Tethys
; Italy
; Marine productivity
; Middle Eocene Climatic Optimum (MECO)
; Sea floor oxygenation
英文摘要: The Middle Eocene Climatic Optimum (MECO) was one of the most severe, short-term global climate perturbations of the Cenozoic that occurred at ca. 40 Ma and was characterized by a gradual 4-6 °C temperature increase of intermediate and deep-waters. We investigated the response to the MECO of the deep-sea ecosystem in the central-western Tethys, through a quantitative study of bathyal benthic foraminiferal assemblages in the expanded and continuous Alano section (northeastern Italy), for which data on stratigraphy, lithology, isotope and trace element geochemistry, and calcareous microplankton were available. During the gradual warming of MECO (lasting between 350 and 650 kyr) marine export productivity increased, causing a significant but transient restructuring of benthic foraminiferal faunas, which changed gradually from assemblages typical for oligo-mesotrophic sea floor conditions to assemblages indicative of more eutrophic conditions. Just after the peak MECO conditions, which lasted less than 100. kyr, a prolonged phase of environmental instability (~. 500. kyr) occurred, marked by even more highly increased export productivity leading to bottom-water oxygen depletion, as reflected in deposition of organic-rich sediments and multiple peaks of bi-triserial opportunistic benthic foraminiferal taxa, including buliminids, bolivinids and uvigerinids. The high productivity may have been caused by a strong influx of nutrient-bearing fresh water into the basin, due to the increased vigour of the hydrological cycle during the warm period, and this increased fresh-water influx might have been a factor in enhancing water column stratification, thus exacerbating the hypoxic conditions, which persisted about 400-500. kyr. After deposition of the organic-rich layers the environmental perturbation ended, and benthic foraminiferal assemblages recovered while conditions became very similar to what they were before the MECO. The environmental disturbance during and directly after the MECO thus strongly but transiently affected benthic foraminiferal assemblages in the central western Tethys. © 2013 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69741
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Geosciences, University of Padova, Via G. Gradenigo 6, Italy; Department of Physics and Earth Sciences, University of Ferrara, Via G. Saragat 1, Italy; Department of Geology and Geophysics, Yale University, New Haven, CT, United States; Department of Earth and Environmental Sciences, Wesleyan University, Middletown, CT, United States; School of Earth Sciences, University of Bristol, United Kingdom
Recommended Citation:
Boscolo Galazzo F.,Giusberti L.,Luciani V.,et al. Paleoenvironmental changes during the Middle Eocene Climatic Optimum (MECO) and its aftermath: The benthic foraminiferal record from the Alano section (NE Italy)[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,378