DOI: 10.1016/j.quascirev.2016.03.026
Scopus记录号: 2-s2.0-84962030657
论文题名: The timing of Mediterranean sapropel deposition relative to insolation, sea-level and African monsoon changes
作者: Grant K.M. ; Grimm R. ; Mikolajewicz U. ; Marino G. ; Ziegler M. ; Rohling E.J.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2016
卷: 140 起始页码: 125
结束页码: 141
语种: 英语
英文关键词: African monsoon
; Eastern Mediterranean
; Ice sheets
; Insolation
; Meltwater pulses
; Precession
; Sapropels
; Sea level
Scopus关键词: Atmospheric thermodynamics
; Deposition
; Glacial geology
; Incident solar radiation
; Isotopes
; Solar radiation
; Surface waters
; African monsoons
; Eastern Mediterranean
; Ice sheet
; Meltwater pulse
; Precession
; Sapropels
; Sea level
; biochronology
; deposition
; geochemistry
; Holocene
; ice sheet
; Last Glacial
; marine isotope stage
; meltwater
; monsoon
; planktonic foraminifera
; sapropel
; sea level change
; seasonal variation
; stable isotope
; Aegean Sea
; Atlantic Ocean
; Atlantic Ocean (North)
; Indian Ocean
; Mediterranean Sea
; Mediterranean Sea (East)
; Red Sea [Indian Ocean]
英文摘要: The Mediterranean basin is sensitive to global sea-level changes and African monsoon variability on orbital timescales. Both of these processes are thought to be important to the deposition of organic-rich sediment layers or 'sapropels' throughout the eastern Mediterranean, yet their relative influences remain ambiguous. A related issue is that an assumed 3-kyr lag between boreal insolation maxima and sapropel mid-points remains to be tested. Here we present new geochemical and ice-volume-corrected planktonic foraminiferal stable isotope records for sapropels S1 (Holocene), S3, S4, and S5 (Marine Isotope Stage 5) in core LC21 from the southern Aegean Sea. The records have a radiometrically constrained chronology that has already been synchronised with the Red Sea relative sea-level record, and this allows detailed examination of the timing of sapropel deposition relative to insolation, sea-level, and African monsoon changes. We find that sapropel onset was near-synchronous with monsoon run-off into the eastern Mediterranean, but that insolation-sapropel/monsoon phasings were not systematic through the last glacial cycle. These latter phasings instead appear to relate to sea-level changes. We propose that persistent meltwater discharges into the North Atlantic (e.g., at glacial terminations) modified the timing of sapropel deposition by delaying the timing of peak African monsoon run-off. These observations may reconcile apparent model-data offsets with respect to the orbital pacing of the African monsoon. Our observations also imply that the previous assumption of a systematic 3-kyr lag between insolation maxima and sapropel midpoints may lead to overestimated insolation-sapropel phasings. Finally, we surmise that both sea-level rise and monsoon run-off contributed to surface-water buoyancy changes at times of sapropel deposition, and their relative influences differed per sapropel case, depending on their magnitudes. Sea-level rise was clearly important for sapropel S1, whereas monsoon forcing was more important for sapropels S3, S4, and S5. © 2016 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59611
Appears in Collections: 过去全球变化的重建
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作者单位: Research School of Earth Sciences, The Australian National University, Canberra, ACT, Australia; Max-Planck-Institute for Meteorology, Bundesstrasse 53, Hamburg, Germany; Department of Earth Sciences, University of Utrecht, Budapestlaan 455, Utrecht, Netherlands; Ocean and Earth Science, University of Southampton, National Oceanography Centre, European Way, Southampton, United Kingdom
Recommended Citation:
Grant K.M.,Grimm R.,Mikolajewicz U.,et al. The timing of Mediterranean sapropel deposition relative to insolation, sea-level and African monsoon changes[J]. Quaternary Science Reviews,2016-01-01,140