 |
| Titel |
Laminated sediments in the Bering Sea reveal atmospheric teleconnections to Greenland climate on millennial to decadal timescales during the last deglaciation |
| VerfasserIn |
H. Kuehn, L. Lembke-Jene, R. Gersonde, O. Esper, F. Lamy, H. Arz, G. Kühn, R. Tiedemann |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1814-9324
|
| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 10, no. 6 ; Nr. 10, no. 6 (2014-12-16), S.2215-2236 |
| Datensatznummer |
250117087
|
| Publikation (Nr.) |
 copernicus.org/cp-10-2215-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| During the last glacial termination, the upper North Pacific Ocean underwent
dramatic and rapid changes in oxygenation that lead to the transient
intensification of oxygen minimum zones (OMZs), recorded by the widespread
occurrence of laminated sediments on circum-Pacific continental margins. We
present a new laminated sediment record from the mid-depth (1100 m) northern
Bering Sea margin that provides insight into these deglacial OMZ maxima with
exceptional, decadal-scale detail. Combined ultrahigh-resolution micro-X-ray-fluorescence
(micro-XRF) data and sediment facies analysis of laminae reveal an alternation between
predominantly terrigenous and diatom-dominated opal sedimentation. The
diatomaceous laminae are interpreted to represent spring/summer productivity
events related to the retreating sea ice margin. We identified five laminated
sections in the deglacial part of our site. Lamina counts were carried out on
these sections and correlated with the Bølling–Allerød and Preboreal
phases in the North Greenland Ice Core (NGRIP) oxygen isotope record, indicating
an annual deposition of individual lamina couplets (varves). The observed
rapid decadal intensifications of anoxia, in particular within the
Bølling–Allerød, are tightly coupled to short-term warm events through
increases in regional export production. This dependence of laminae formation
on warmer temperatures is underlined by a correlation with published Bering Sea
sea surface temperature records and δ18O data of planktic
foraminifera from the Gulf of Alaska. The rapidity of the observed changes
strongly implies a close atmospheric teleconnection between North Pacific and
North Atlantic regions. We suggest that concomitant increases in export
production and subsequent remineralization of organic matter in the Bering
Sea, in combination with oxygen-poor waters entering the Being Sea, drove
down oxygen concentrations to values below 0.1 mL L−1 and caused
laminae preservation. Calculated benthic–planktic ventilation ages show no
significant variations throughout the last deglaciation, indicating that
changes in formation rates or differing sources of North Pacific mid-depth
waters are not prime candidates for strengthening the OMZ at our site. The
age models established by our correlation procedure allow for the
determination of calendar age control points for the Bølling–Allerød and the Preboreal
that are independent of the initial radiocarbon-based chronology. Resulting
surface reservoir ages range within 730–990 yr during the
Bølling–Allerød, 800–1100 yr in the Younger Dryas, and 765–775 yr
for the Preboreal. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|