Computer simulation of calcic soil development for paleoclimatic reconstructions using an iterative forward method structured on the compartment model
Key factors that influence the development of calcic soils include climate, vegetation, water-holding capacity of soil horizons and carbonate influx rates. Each factor may change over time. The authors model generates synthetic distributions showing the mass of calcium carbonate as a function of soil depth and time. Monthly mean values for precipitation and temperature are used to account for the amount of water that enters the soil and the amount lost be evapotranspiration. They are thus able to simulate various climatic scenarios, including high variance stationary climates and nonstationary climates. Nonstationary climatic series can be either trend/drift or threshold types which simulate gradual climatic changes or abrupt climatic changes, respectively. Soil PC02 and variable transpiration factors accounts for vegetation and soil biological variation. Calcic-dust flux and soil texture changes can be introduced after each computer run. Physical and chemical characteristics of the soils, such as texture, water content, temperature, and PC02 are monitored for each soil horizon during every computer iteration. As a point of departure, they authors have assumed rapid rates of carbonate dissolution and that the soil is initially nonreactive except for calcite disseminated in the parent material. Comparison of the synthetic carbonate distributions with those measured by laboratory analysis of desert soils allows them to test paleoclimatic reconstructions using dated soils and helps us explain many features of calcic soils such as polymodal carbonate distributions and depth to carbonate.
- Research Organization:
- Geological Survey, Menlo Park, CA (USA)
- OSTI ID:
- 6456871
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
CLIMATES
CLIMATE MODELS
COMPUTERIZED SIMULATION
SOILS
CHEMICAL COMPOSITION
CARBON DIOXIDE
CARBONATES
GEOLOGIC HISTORY
GEOLOGIC MODELS
GROUND COVER
PALEOCLIMATOLOGY
PARTIAL PRESSURE
SOIL CHEMISTRY
USES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMISTRY
MATHEMATICAL MODELS
OXIDES
OXYGEN COMPOUNDS
PALEONTOLOGY
SIMULATION
580100* - Geology & Hydrology- (-1989)
510200 - Environment
Terrestrial- Chemicals Monitoring & Transport- (-1989)