Details of Award
NERC Reference : NE/C517109/1
A multi-geochemical approach to determine millennial-scale surface and deep-water variability in the Eastern North Atlantic.
Grant Award
- Principal Investigator:
- Professor IN McCave, University of Cambridge, Earth Sciences
- Co-Investigator:
- Professor I Cacho, ,
- Grant held at:
- University of Cambridge, Earth Sciences
- Science Area:
- Marine
- Atmospheric
- Overall Classification:
- Marine
- ENRIs:
- Global Change
- Science Topics:
- Ocean Circulation
- Land - Ocean Interactions
- Palaeoenvironments
- Population Ecology
- Climate & Climate Change
- Abstract:
- The North Atlantic Basin is one of the most climatic sensitive regions of the Earth, where the ocean-atmosphere-cryosphere are intimately connected and have reacted to changes in insolation through jumps in its mode of operation. Millennial-scale variability seems to be present in both glacial and interglacial periods, suggesting a persistent internal mode of variability in the ocean-climate system. The potential to obtain long, detailed sedimentary sequences has increased over the last decade the effort to drill into different sectors of the sea-floor and look back in time to glacial/interglacial intervals older than the last climatic cycle. This research gave particular emphasis to the reconstruction of the sea-surface palaeonvironment from the planktonic foraminifera fauna [e.g.1, 2] and although several benthic stable isotope records [2, 3, 4] have already been created there are not many projects focussing on changes in deep-water hydrology, in particular beyond the last glacial. One of the main issues that urgently needs addressing is that these changes in deep-water may have accompanied perturbations in the thermohaline circulation system, which may have behaved in an oscillatory manner, alternating between stable modes, characterised by the dominance of either northern or southern sourced deep-water. Agreeing well with the main objectives for IODP Leg 301 [5] we propose to use both geochemical, micropalaeontological and sedimentological approaches to investigate how deep-water characteristics may have varied throughout a succession of glacial/interglacial intervals, with particular emphasis put on interglacials which bear a climate record close to the Holocene. For this purpose we propose to generate evidence of deep-water variability by paired 18O and Mg/Ca analysis of the same samples of monospecific benthic foraminifera [6]. These analyses will enable us to investigate the changes in the local isotopic composition and temperature of deep-water which would have left their imprint of the benthic 18Occ record, thus recording the millennial-scale benthic variability. The geochemical approach proposed will be complemented by the creation of a planktonic stable isotope stratigraphy and grainsize analysis [7], which will enable us to determine if even during important interglacials, changes in surface circulation may be connected to the strength variability and characteristics of the North Atlantic Deep Water. This piece of research will be novel, both by expanding the current high-resolution studies into older time intervals than those recovered so far with the current piston core techniques, and more important we hope to create one of the first deep-water temperature records for the North Atlantic, contributing to the improvement of this geochemical method. Knowledge of deepwater temperature variations is important to understand the vigour and mode of ocean circulation, as well as the nature of climatic interactions between the ocean and the atmosphere. This information will be fundamental in clarifying the mechanisms behind the millennial-scale variability and distinguish the combined influence of factors such as temperature, salinity and 18O of sea-water, that may have generated a climate record in some aspects close to the Holocene, even at periods when global ice-volume may have been lower than in present days [8].
- NERC Reference:
- NE/C517109/1
- Grant Stage:
- Completed
- Scheme:
- Directed Pre FEC
- Grant Status:
- Closed
- Programme:
- IODP
This grant award has a total value of £8,528
FDAB - Financial Details (Award breakdown by headings)
| Total - Staff | Total - Other Costs | Total - Indirect Costs |
|---|---|---|
| £2,289 | £5,186 | £1,053 |
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