期刊
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
卷 36, 期 2, 页码 -出版社
AMER GEOPHYSICAL UNION
DOI: 10.1029/2020PA004061
关键词
benthic foraminifera; Heinrich Stadials; Mg; Ca; northern Nordic Seas; stable isotopes
资金
- CAGE (Centre for Arctic Gas Hydrate, Environment and Climate) - Research Council of Norway through its Centers of Excellence funding scheme [223259]
- Cushman Foundation for Foraminiferal Research
- Research Council of Norway
- Co-funding of Regional, National, and International Programmes (COFUND)-Marie Skodowska-Curie Actions under the EU [274429]
The study found significant changes in bottom water temperature and oxygen isotopes in the Nordic Seas during glacial Greenland Interstadial and Greenland Stadial events, revealing different environmental conditions. The results suggest that during some Stadials and Heinrich Stadials, deep water generation was reduced, allowing the spreading of Atlantic subsurface water to the Nordic Seas.
The Svalbard margin, in the eastern Fram Strait with its high sediment accumulation, form a key area for the reconstruction of water mass and heat exchange between the North Atlantic and Arctic Ocean in relation to abrupt climate changes as seen in glacial Greenland Interstadial and Greenland Stadial (GI-GS) events. Here, we present a bottom water temperature (BWT) record from the northern Nordic Seas (79 degrees N) at 1,273 m water depth based on benthic foraminiferal Mg/Ca. The BWT reconstructions, combined with benthic foraminiferal stable isotopes, benthic foraminiferal fauna compositions and ice-rafted debris (IRD), reveal at least two distinctive scenarios for the GI-GS events during the last glacial period (13-63 ka). During GIs, conditions were similar to modern with high productivity, low BWT and deep convection. During GS6, GS8, and GS15 and during Heinrich Stadials (HSs), BWT increased up to 5 degrees C +/- 1 degrees C generally concomitant with low planktic and benthic delta O-18. Our results suggest, that during some GSs and HSs, deep water generation was reduced, allowing the subsurface Atlantic water (AW) to thicken and deepen down to at least the core site depth. A strong halocline during HSs and GSs prevented heat release from the subsurface AW, which we can now trace from 45 degrees N in the North Atlantic to the Arctic Ocean >79 degrees N. Surfacing of the salty Atlantic subsurface water preconditioned the Nordic seas for convection. Release of the subsurface heat from this vast reservoir must have contributed to the large and abrupt atmospheric warmings at the start of GIs.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据