Details of Award
NERC Reference : NE/S008853/1
Hikurangi Trough late Pleistocene palaeoceanography, biostratigraphy and Cretaceous Ocean Anoxia Events (OAEs)
Grant Award
- Principal Investigator:
- Dr TL Aze, University of Leeds, School of Earth and Environment
- Grant held at:
- University of Leeds, School of Earth and Environment
- Science Area:
- Atmospheric
- Earth
- Freshwater
- Marine
- Terrestrial
- Overall Classification:
- Unknown
- ENRIs:
- Biodiversity
- Environmental Risks and Hazards
- Global Change
- Natural Resource Management
- Pollution and Waste
- Science Topics:
- Ocean atmosphere interaction
- Ocean drilling
- Ocean modelling
- Ozone
- Palaeoclimate observation
- Regional climate
- Sea level rise
- Sea surface temperature
- Sea-ice processes
- Surface ocean circulation
- Trace gases
- Climate & Climate Change
- Atmospheric carbon cycle
- Atmospheric carbon dioxide
- Carbon capture and storage
- Climate modelling
- Climate variability
- Deep ocean circulation
- Dissolved organic matter
- Ecosystem impacts
- Fossil fuels
- Greenhouse gases
- Isotopic record
- Ocean acidification
- Palaeoenvironments
- Anoxic events
- Cenozoic climate change
- Climate change
- Dating - isotopic
- Deep water circulation
- Evolutionary history
- Fossil record
- Ice ages
- Ice sheets
- Large igneous provinces
- Marine carbonates
- Marine sediments
- Mass extinctions
- Mesozoic climate change
- Ocean acidification
- Ocean drilling
- Palaeo proxies
- Palaeoclimatology
- Palaeoecology
- Palaeogeology
- Quaternary climate change
- Sea level history
- Surface water circulation
- Anoxic events
- Biodiversity
- Carbon cycling
- Isotopic analysis
- Marine sediments
- Ocean acidification
- Primary production
- Biogeochemical Cycles
- Ocean modelling
- Particulate organics
- Phytoplankton
- Sea ice
- Sea surface temperature
- Ocean - Atmosphere Interact.
- Sea level
- Ocean circulation
- Atmospheric circulation
- Atmospheric composition
- Carbon cycle
- Dissolved organics
- Greenhouse gases
- Heat transport
- Meridional circulation
- Benthic foraminifera
- Carbon cycle
- Climate transitions
- Deep convection
- Deep ocean circulation
- Ecosystem modelling
- Heat transport
- Ice shelves
- Marine biogeochemistry
- Marine carbonates
- Meridional overturning circ
- Ocean drilling
- Ocean modelling
- Organic matter
- Palaeo-ocean circulation
- Phytoplankton transport
- Sea ice
- Sea level
- Sedimentary record
- Shelf ocean dynamics
- Thermohaline circulation
- Water mass analysis
- Ocean Circulation
- Abstract:
- Part I: The regions of the world's oceans, which border Antarctica, are critical for controlling the Earth's climate. Firstly, the largely unhindered transit of ocean currents (the Antarctic circumpolar current, ACC) that circle and Antarctic continent enables the continued maintenance of its huge continental ice sheets. Secondly, a permanent thermal boundary between water masses extends to the ocean surface within the Subtropical Convergence (STC) in this region. Consequently, this is a region of high biological productivity due to the mixing of micronutrient-rich subtropical waters (STW) with macronutrient-rich subantarctic waters (SAW). As such the STC is a highly important sink for atmospheric CO2 due to high levels of primary productivity. This region is also influenced by the presence and extent of the Western Antarctic Ice Sheet (WAIS). The extent of this ice sheet has been shown to alter the latitudinal positioning of the Southern Hemisphere STC by up to 7 degrees from stadial-interstadial cycles of the Late Pleistocene epoch (last 800 ka), and may subsequently partially decouple global climate from atmospheric partial pressure of carbon dioxide. Previous studies highlighting the Late Pleistocene evolution of sea surface and intermediate waters within the southwest Pacific have indicated complex behaviour of the subtropical front (STF) throughout this interval. Utilizing samples from site U1520D from within the Hikurangi Trough (Expedition 375), we propose a high resolution (<1 kyr) study of late Pleistocene foraminifera to better constrain the regional paleoceanography over the last 130 ka, and how this relates to climate forcing. We aim to better understand the STC through paired measurements of oxygen isotopes and Mg/Ca trace element ratios of both planktonic (Globigerina bulloides) and benthic foraminifera (Uvigerina peregrina). G. bulloides is a symbiont-barren, opportunistic species which often dominates the foraminifer fauna, and sediment assemblage of the ocean floor, and is therefore an important source of geochemical information for palaeoceanographic studies. U. peregrina is an infaunal benthic species, which has also been used extensively to calculate intermediate water properties throughout the Pliocene-Pleistocene. These stable isotope and trace metal records are required to assess the scale and timing of surface and intermediate water temperature, and salinity across the STC. This data will subsequently contribute to our knowledge of the extent and influence of the WAIS and meridional gradient variability response to orbital forcing during a critical period of cryosphere development. Part II: The Cenomanian-Turonian boundary (CTB) can be correlated globally in pelagic carbonate facies by a major turnover in fossil groups, and by a positive carbon isotope excursion, typically associated with dark marls or shales enriched in organic carbon. The dramatic changes within lithology are attributed to increased rates of oceanic-turnover and upwelling of nutrient-rich deep water masses, and high surface-water productivity. Oxygen depletion and eutrophication of the Earth's oceans has been associated with warming in the geological past, and current observations show expansion of modern oxygen minimum zones. Clarifying the nature and mechanism of these oceanic anoxia events (OAEs), and there effect upon life is imperative to our understanding the possible implications that anthropogenic climate forcing may have upon the biodiversity of the modern ocean. We plan to utilize samples sourced from IODP Expedition 375 Hole 1520C, within the Hikurangi Trough, where an expanded section is been identified detailing the Cenomanian-Turonian boundary. Through foraminiferal faunal analysis and paired measurements of oxygen and carbon isotopes we aim to elucidate the nature of the CTB within the Hikurangi Trough, which represents a rare, well-preserved high-latitude example of a Cretaceous OAEs.
- NERC Reference:
- NE/S008853/1
- Grant Stage:
- Completed
- Scheme:
- Directed (RP) - NR1
- Grant Status:
- Closed
- Programme:
- UK IODP Phase2
This grant award has a total value of £23,898
FDAB - Financial Details (Award breakdown by headings)
| DI - Other Costs | Indirect - Indirect Costs | DA - Investigators | DI - Staff | DA - Estate Costs | DA - Other Directly Allocated |
|---|---|---|---|---|---|
| £6,618 | £1,197 | £1,274 | £14,555 | £219 | £34 |
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