Details of Award
NERC Reference : NE/D000521/1
Neogene Climatic Change and the Emergence of the Grassland Biome
Grant Award
- Principal Investigator:
- Dr ND Sheldon, Royal Holloway, Univ of London, Earth Sciences
- Grant held at:
- Royal Holloway, Univ of London, Earth Sciences
- Science Area:
- Terrestrial
- Earth
- Atmospheric
- Overall Classification:
- Terrestrial
- ENRIs:
- Global Change
- Science Topics:
- Land - Atmosphere Interactions
- Palaeoenvironments
- Soil science
- Abstract:
- Increasingly, scientists believe that the Earth is warming due to greenhouse gas emissions from the burning of fossil fuels. One of the primary challenges facing this and future generations is to understand how these changes will affect the biosphere (plants and animals), and by extension, our quality of life. In order to model best how the biosphere will react to a warming Earth, it is necessary first to understand how it has responded to global climatic change in the recent past and to past times of high atmospheric levels of greenhouse gases such as carbon dioxide (CO2). Grassland ecosystems, which now cover 25% of the Earth's surface, evolved during the Neogene (the time from 23.7 to 1.6 million years ago) and marked the transition to a 'modern' assemblage of plants and the animals that grazed upon them such as horses. By examining how and when this modern grassland biosphere evolved (e.g., was it warmer than it is now?), it will be possible to understand how it will change in the future in response to warmer conditions and higher levels of CO2. They way that I propose to do this is by studying a continuous Neogene record of the fossil soils, called palaeosols, that were on the landscape when the grasslands and their co-existing grazers evolved. Soils form at the Earth's surface, in direct contact with its atmosphere and with the climate that shapes its surface. By looking at the losses of certain elements (Ca, Na, Mg, K) during weathering relative to the original chemical composition of the rocks that were weathered to form the soils, it is possible to reconstruct the amount of precipitation falling on the landscape. Other elements, such as carbon and oxygen, occur naturally in more than one form, called isotopes, with extra neutrons that make them heavier. Many processes in nature such as photosynthesis discriminate against the heavier isotopes, so by looking at the ratio between the heavier and lighter isotopes, it is possible to determine which type of process was involved in the deposition of those isotopes. Because the plants living in the soils at a given time use the carbon dioxide in the atmosphere for photosynthesis, carbon and oxygen left behind in the soils and fossilized as small nodules of calcrete (a rock like limestone) preserve information about the composition of the atmosphere and about the kind of plants that were growing in the soil. By studying a nearly continuous set of palaeosols preserved in Neogene sediments, I hope to do the following: 1. To use the chemistry of the palaeosols' to make a record of palaeoprecipitation and palaeotemperature conditions and to examine if the climate was warmer or wetter in the past, and when those changes took place in this record relative to other palaeoclimatic records. 2. To use carbon isotopes from palaeosol calcretes to examine the balance between grasses and non-grasses in order to find out if the spread of grasslands was driven by increasingly arid conditions. 3. To use carbon isotopes from palaeosol calcretes to examine the atmospheric levels of the greenhouse gas carbon dioxide during the middle Miocene climatic optimum, a time when many other palaeontological and isotopic records indicate very warm and wet palaeoclimatic conditions. 4. To compare the newly generated records with other terrestrial and marine records of palaeoclimatic and biotic change in order to determine if the record represents localized changes or fits with the pattern of global changes, and to see if the timing of the spread of grasslands was different in Montana than it was in other parts of North America and Asia. These newly compiled records of long- and short-term palaeoclimatic and palaeoenvironmental changes will increase our understanding of past climatic change, and, because much of the record will track the 'modern' biosphere represented by grasslands and grazers, increase our understanding of how the biosphere will respond to future climatic change.
- NERC Reference:
- NE/D000521/1
- Grant Stage:
- Completed
- Scheme:
- New Investigators Pre FEC
- Grant Status:
- Closed
- Programme:
- New Investigators
This grant award has a total value of £48,547
FDAB - Financial Details (Award breakdown by headings)
| Total - Staff | Total - T&S | Total - Other Costs | Total - Equipment | Total - Indirect Costs |
|---|---|---|---|---|
| £13,609 | £6,020 | £18,366 | £4,292 | £6,260 |
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