Details of Award
NERC Reference : NE/C510583/1
Unravelling the Ca isotope curve: shoring up global budgets and identifying responses to long- and short-term climatic perturbations.
Grant Award
- Principal Investigator:
- Professor MJ Bickle, University of Cambridge, Earth Sciences
- Co-Investigator:
- Professor H Elderfield, University of Cambridge, Earth Sciences
- Co-Investigator:
- Dr A Tripati, University of California Los Angeles, UNLISTED
- Co-Investigator:
- Dr A Galy, University of Cambridge, Earth Sciences
- Grant held at:
- University of Cambridge, Earth Sciences
- Science Area:
- Marine
- Freshwater
- Overall Classification:
- Marine
- ENRIs:
- Global Change
- Science Topics:
- Biogeochemical Cycles
- Ocean - Atmosphere Interact.
- Climate & Climate Change
- Abstract:
- The last ~55 million years have! seen a significant drop in global average temperatures by 15?C. One of the big questions that remains to be answered is to what extent this can be explained by a change in the relationship between temperature and the rates of weathering of silicate rocks. Atmospheric CO2 is consumed during weathering and it is thought that, if weathering rates are high when temperatures are warm (and if the converse), then this may have provided a negative feedback operating to limit major glaciations and stabilize climatic fluctuations. However, the uplift of large mountain belts such as the Himalayas may have resulted in elevated weathering rates that were sustained at low temperatures, and caused this long-term global cooling. Superimposed on this drop in temperatures are periods of rapid global change that lasted a few hundred thousand years , when weathering rates have changed dramatically and ocean pH has changed, such as when ice sheets on Antarctica have expanded. The magnitude of these climatic events, and the relationship between rapid climate changes, ocean chemistry, and weathering rates, are just beginning to be explained. The work we propose will study both the long-term changes and the severe, abrupt disturbances in the climate-weathering-ocean chemistry system. We will track changes in the concentration of dissolved calcium in seawater by looking at changes in the ratio of two stable isotopes of calcium (44Ca and 42Ca) in calcium carbonate deposited in seafloor sediments. Changes in the 44Ca/42Ca ratio will help us to identify times when the input to the ocean of dissolved calcium weathered from rocks is unequal to the output of dissolved calcium from the ocean in the form of carbonate sediments. Such imbalances should occur during those times when climate is changing and affecting weathering rates, and also when atmospheric CO2 changes are affecting the formation and preservation of carbonate sediments in the ocean. Supporting the work on the sediments, we will also determine the 44Ca/42Ca ratio of the major inputs and outputs of calcium to the ocean: river waters, hydrothermal fluids, arid sedimentary calcite and aragonite. This survey will allow us to greatly improve our understanding of the isotopic composition of all these materials and put limits on our expectation of the 44Ca/42Ca changes in seawater due to perturbations to the global calcium cycle We will also model these changes, using a basic model of inputs and outputs and include the climatic controls on carbonate sedimentation.
- NERC Reference:
- NE/C510583/1
- Grant Stage:
- Completed
- Scheme:
- Standard Grants Pre FEC
- Grant Status:
- Closed
- Programme:
- Standard Grant
This grant award has a total value of £150,801
FDAB - Financial Details (Award breakdown by headings)
| Total - Staff | Total - T&S | Total - Other Costs | Total - Equipment | Total - Indirect Costs |
|---|---|---|---|---|
| £73,320 | £4,293 | £17,900 | £21,562 | £33,726 |
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