Mineral dissolution rates in plot-scale field and laboratory experiments
In recent years, much research has been focused on the mechanisms by which acid deposition from the atmosphere is neutralized as it passes through soil. Although there are several short-term mechanisms of acid buffering, the dominant long-term mechanism is mineral weathering. Understanding the rates at which minerals weather in the soil is thus essential for predicting the long-term effects of acid deposition on surface-water chemistry. Mineral dissolution rates were measured on identical mineral material in field and laboratory experiments. Field dissolution rates were measured in 6 small (2 sq m) plots on a spodosol in eastern Maine, USA. The plots were irrigated with HCl at pH's 2, 2.5 and 3; soil solutions were collected by tension lysimeters at 25-cm depth. The composition of the soil solutions, together with the grain-size distribution and mineralogy of the soil, were used to calculate mineral dissolution rates. Laboratory dissolution experiments were performed on the 75-150 micrometer size fraction of soil from the site in flow-through reactors at pH-values corresponding to the pH of the bulk soil solution. The use of small plots and 'untreated' minerals from the same plots eliminates many of the uncertainties encountered in previous field-laboratory comparisons.
- Research Organization:
- Wyoming Univ., Laramie, WY (United States). Dept. of Geology and Geophysics
- OSTI ID:
- 5509019
- Report Number(s):
- PB-94-112976/XAB
- Resource Relation:
- Other Information: Pub. in Chemical Geology, Vol. 105, 51-69(1993)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACIDIFICATION
WEATHERING
MINERALS
DISSOLUTION
ACID NEUTRALIZING CAPACITY
ACID RAIN
AIR POLLUTION
CALCULATION METHODS
DEPOSITION
FIELD TESTS
GEOCHEMISTRY
GRAIN SIZE
KINETICS
LYSIMETERS
MAINE
MINERALOGY
PH VALUE
PROBABILISTIC ESTIMATION
SOILS
SURFACE WATERS
WATER CHEMISTRY
WATER POLLUTION
WATERSHEDS
ATMOSPHERIC PRECIPITATIONS
CHEMISTRY
DEVELOPED COUNTRIES
MEASURING INSTRUMENTS
MICROSTRUCTURE
NORTH AMERICA
POLLUTION
RAIN
SIZE
TESTING
USA
540220* - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)