DOI: 10.5194/cp-11-687-2015
Scopus记录号: 2-s2.0-84928387361
论文题名: Subsurface North Atlantic warming as a trigger of rapid cooling events: Evidence from the early Pleistocene (MIS 31-19)
作者: Hernández-Almeida I. ; Sierro F.-J. ; Cacho I. ; Flores J.-A.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2015
卷: 11, 期: 4 起始页码: 687
结束页码: 696
语种: 英语
Scopus关键词: benthic foraminifera
; carbon isotope
; climate modeling
; cooling
; ice-rafted debris
; iceberg
; marine isotope stage
; meridional circulation
; paleoceanography
; paleoclimate
; planktonic foraminifera
; Pleistocene
; proxy climate record
; reconstruction
; sediment core
; warming
; Atlantic Ocean
; Atlantic Ocean (North)
; Gardar Drift
; Foraminifera
; Neogloboquadrina pachyderma
英文摘要: Subsurface water column dynamics in the subpolar North Atlantic were reconstructed in order to improve the understanding of the cause of abrupt ice-rafted detritus (IRD) events during cold periods of the early Pleistocene. We used paired Mg / Ca and δ18O measurements of Neogloboquadrina pachyderma (sinistral - sin.), deep-dwelling planktonic foraminifera, to estimate the subsurface temperatures and seawater δ18O from a sediment core from Gardar Drift, in the subpolar North Atlantic. Carbon isotopes of benthic and planktonic foraminifera from the same site provide information about the ventilation and water column nutrient gradient. Mg / Ca-based temperatures and seawater δ18O suggest increased subsurface temperatures and salinities during ice-rafting, likely due to northward subsurface transport of subtropical waters during periods of weaker Atlantic Meridional Overturning Circulation (AMOC). Planktonic carbon isotopes support this suggestion, showing coincident increased subsurface ventilation during deposition of IRD. Subsurface accumulation of warm waters would have resulted in basal warming and break-up of ice-shelves, leading to massive iceberg discharges in the North Atlantic. The release of heat stored at the subsurface to the atmosphere would have helped to restart the AMOC. This mechanism is in agreement with modelling and proxy studies that observe a subsurface warming in the North Atlantic in response to AMOC slowdown during Marine Isotope Stage (MIS) 3. © Author(s) 2015. CC Attribution 3.0 License. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49147
Appears in Collections: 气候变化与战略
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Recommended Citation:
Hernández-Almeida I.,Sierro F.-J.,Cacho I.,et al. Subsurface North Atlantic warming as a trigger of rapid cooling events: Evidence from the early Pleistocene (MIS 31-19)[J]. Climate of the Past,2015-01-01,11(4)