Water mass exchange between the Nordic seas and the Arctic Ocean on millennial timescale during MIS 4–MIS 2

Abstract

[1] The climate of the last glaciation circa 65,000-25,000 years ago was interrupted by about 15 abrupt temperature fluctuations, the so-called Dansgaard-Oeschger events consisting of warm interstadials and cold stadials recorded in Greenland ice cores. The largest fluctuations occur in the North Atlantic region, but they have been registered over the most of the world. The events are linked to changes in deep water formation in the Nordic seas and North Atlantic, disrupting the thermohaline circulation. Yet, Dansgaard-Oeschger events have so far not been recorded north of the convection areas in the central Nordic seas, and it is not known if they affected the water exchange between the Nordic seas and the Arctic Ocean. In this study, we analyze core JM05-31GC from the northern Fram Strait at the very entrance to the Arctic Ocean. The core contains sediments from marine isotope stages (MISs) 4-2. The results show millennial timescale shifts in all the investigated proxies including the distribution of planktonic and benthic foraminifera, planktonic and benthic oxygen and carbon isotopes, and several sedimentological parameters. In JM05-31GC, the interstadials are characterized by relatively high surface and low bottom water temperatures, low content of ice-rafted debris, and well-ventilated bottom water. Stadials are characterized by the presence of icebergs and decreasing surface water and increasing bottom water temperatures due to increased inflow of Atlantic subsurface water. Ventilation decreased during Heinrich events and most stadials. The results show that the DansgaardOeschger events strongly affected the water exchange between the Nordic seas and the Arctic Ocean.

Diagenetic disturbances of marine sedimentary records from methane‐influenced environments in the Fram Strait as indications of variation in seep intensity during the last 35 000 years

“…6). This assemblage has been shown to be characteristic for the H1 event as well as older Heinrich events Rasmussen et al 2014). 6).…”

Ice‐rafting patterns on the western Svalbard slope 74–0 ka: interplay between ice‐sheet activity, climate and ocean circulation

“…), (B) JM 04‐025 PC (Jessen & Rasmussen ) and (C) JM 03‐374 PC (Jessen & Rasmussen ) correlated with JM 05‐031 GC from Rasmussen et al . () (D, E). Records (A, B) and (E) are measured on planktic foraminiferal species Neogloboquadrina pachyderma s ( NPS ), while (C) and (D) are measured on benthic foraminiferal species.…”

“…Location of investigated cores (black circles) and core JM 05‐031 GC used for correlation and age models (blue circle) (Rasmussen et al . ). Northward flow path of Atlantic Water is indicated (red arrow).…”

Atlantic Water advection vs. glacier dynamics in northern Spitsbergen since early deglaciation

“…therefore be linked to the intrusion of AW into bottom waters. The advection of AW as a subsurface or even bottom water mass during Heinrich Stadial 1 as well as during earlier Heinrich stadials has already been proposed for the Svalbard area by Rasmussen et al (2007) and T. L. Rasmussen (2014b). Today, basal melting of tidewater glaciers in Spitsbergen from high advection rates of the relatively warm AW is evident (Luckman et al, 2015).…”