DOI: 10.1016/j.palaeo.2014.04.004
论文题名: Changes in Southern Ocean bottom water environments associated with the Middle Eocene Climatic Optimum (MECO)
作者: Moebius I. ; Friedrich O. ; Scher H.D.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2014
卷: 405 起始页码: 16
结束页码: 27
语种: 英语
英文关键词: Benthic foraminifera
; Bottom water chemistry
; Cerium anomaly
; Middle Eocene Climatic Optimum
; Paleoecology
; Southern Ocean
英文摘要: The Middle Eocene Climatic Optimum (MECO) was a ~ 650 kyr long interval of pronounced warmth superimposed on the long-term Eocene cooling trend. We investigate benthic foraminiferal assemblage and fossil fish tooth cerium anomaly variability from Ocean Drilling Program (ODP) Site 738 in the Indian sector of the Southern Ocean (Southern Kerguelen Plateau) to assess changes in bottom water chemistry and effects on benthic foraminiferal ecosystems. The studied section spans 41.9 to 38.4 Ma, encompassing the MECO as well as extensive Pre-MECO and Post-MECO intervals. We report a marked faunal turnover at 40.4 Ma, 200 kyrs after the onset of the MECO at ~ 40.6 Ma, from an assemblage dominated by epifaunal benthic foraminifera to an infaunal-dominated assemblage. The infaunal domination persisted until the termination of the MECO at 39.95 Ma. Thereafter, the Pre-MECO assemblage returned. This change is attributed to an increase in export productivity associated with the warming, possibly caused by an increase in continental runoff or the influence of a more eutrophic surface water mass. Superimposed on the change in tropic state the Ce/Ce* record shows a positive excursion during the 100. kyrs long MECO peak warming at around 40.05. Ma, indicative of a decrease in bottom-water oxygen content. Synchronously, infaunal benthic foraminifera drop briefly in abundance. Hence, we suggest that the peak warming is associated with bottom water oxygen depletion potentially caused by elevated productivity and/or a transient influence of an older, oxygen-depleted water mass. © 2014 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69324
Appears in Collections: 过去全球变化的重建
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作者单位: Institute for Geosciences, Goethe University Frankfurt, Altenhoeferallee 1, 60438 Frankfurt, Germany; Department of Earth and Ocean Sciences, EWS 617, University of South Carolina, 701 Sumter Street, Columbia, SC 29208, United States; Institute of Earth Sciences, University of Heidelberg, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
Recommended Citation:
Moebius I.,Friedrich O.,Scher H.D.. Changes in Southern Ocean bottom water environments associated with the Middle Eocene Climatic Optimum (MECO)[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2014-01-01,405