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Evaluating sensitivity of silicate mineral dissolution rates to physical weathering using a soil evolution model (SoilGen2.25)

Emmanuel Opolot and Peter Finke UGent (2015) BIOGEOSCIENCES. 12(22). p.6791-6808
abstract
Silicate mineral dissolution rates depend on the interaction of a number of factors categorized either as intrinsic (e.g. mineral surface area, mineral composition) or extrinsic (e.g. climate, hydrology, biological factors, physical weathering). Estimating the integrated effect of these factors on the silicate mineral dissolution rates therefore necessitates the use of fully mechanistic soil evolution models. This study applies a mechanistic soil evolution model (SoilGen) to explore the sensitivity of silicate mineral dissolution rates to the integrated effect of other soil-forming processes and factors. The SoilGen soil evolution model is a 1-D model developed to simulate the time-depth evolution of soil properties as a function of various soil-forming processes (e.g. water, heat and solute transport, chemical and physical weathering, clay migration, nutrient cycling, and bioturbation) driven by soil-forming factors (i.e., climate, organisms, relief, parent material). Results from this study show that although soil solution chemistry (pH) plays a dominant role in determining the silicate mineral dissolution rates, all processes that directly or indirectly influence the soil solution composition play an equally important role in driving silicate mineral dissolution rates. Model results demonstrated a decrease of silicate mineral dissolution rates with time, an obvious effect of texture and an indirect but substantial effect of physical weathering on silicate mineral dissolution rates. Results further indicated that clay migration and plant nutrient recycling processes influence the pH and thus the silicate mineral dissolution rates. Our silicate mineral dissolution rates results fall between field and laboratory rates but were rather high and more close to the laboratory rates possibly due to the assumption of far from equilibrium reaction used in our dissolution rate mechanism. There is therefore a need to include secondary mineral precipitation mechanism in our formulation. In addition, there is a need for a more detailed study that is specific to field sites with detailed measurements of silicate mineral dissolution rates, climate, hydrology, and mineralogy to enable the calibration and validation of the model. Nevertheless, this study is another important step to demonstrate the critical need to couple different soil-forming processes with chemical weathering in order to explain differences observed between laboratory and field measured silicate mineral dissolution rates.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
soil, geochemistry, weathering, ALKALI FELDSPAR DISSOLUTION, PROFILE MODEL, SURFACE-AREA, FOREST SOILS, REACTION PATHS, KINETICS, FIELD, SCALE, PH, 25-DEGREES-C
journal title
BIOGEOSCIENCES
Biogeosciences
volume
12
issue
22
pages
6791 - 6808
Web of Science type
Article
Web of Science id
000365442600016
JCR category
GEOSCIENCES, MULTIDISCIPLINARY
JCR impact factor
3.7 (2015)
JCR rank
17/184 (2015)
JCR quartile
1 (2015)
ISSN
1726-4170
DOI
10.5194/bg-12-6791-2015
language
English
UGent publication?
yes
classification
A1
copyright statement
I have retained and own the full copyright for this publication
id
6994399
handle
http://hdl.handle.net/1854/LU-6994399
date created
2015-11-27 14:15:22
date last changed
2017-03-31 11:49:12
@article{6994399,
  abstract     = {Silicate mineral dissolution rates depend on the interaction of a number of factors categorized either as intrinsic (e.g. mineral surface area, mineral composition) or extrinsic (e.g. climate, hydrology, biological factors, physical weathering). Estimating the integrated effect of these factors on the silicate mineral dissolution rates therefore necessitates the use of fully mechanistic soil evolution models. This study applies a mechanistic soil evolution model (SoilGen) to explore the sensitivity of silicate mineral dissolution rates to the integrated effect of other soil-forming processes and factors. The SoilGen soil evolution model is a 1-D model developed to simulate the time-depth evolution of soil properties as a function of various soil-forming processes (e.g. water, heat and solute transport, chemical and physical weathering, clay migration, nutrient cycling, and bioturbation) driven by soil-forming factors (i.e., climate, organisms, relief, parent material). Results from this study show that although soil solution chemistry (pH) plays a dominant role in determining the silicate mineral dissolution rates, all processes that directly or indirectly influence the soil solution composition play an equally important role in driving silicate mineral dissolution rates. Model results demonstrated a decrease of silicate mineral dissolution rates with time, an obvious effect of texture and an indirect but substantial effect of physical weathering on silicate mineral dissolution rates. Results further indicated that clay migration and plant nutrient recycling processes influence the pH and thus the silicate mineral dissolution rates. Our silicate mineral dissolution rates results fall between field and laboratory rates but were rather high and more close to the laboratory rates possibly due to the assumption of far from equilibrium reaction used in our dissolution rate mechanism. There is therefore a need to include secondary mineral precipitation mechanism in our formulation. In addition, there is a need for a more detailed study that is specific to field sites with detailed measurements of silicate mineral dissolution rates, climate, hydrology, and mineralogy to enable the calibration and validation of the model. Nevertheless, this study is another important step to demonstrate the critical need to couple different soil-forming processes with chemical weathering in order to explain differences observed between laboratory and field measured silicate mineral dissolution rates.},
  author       = {Opolot, Emmanuel and Finke, Peter},
  issn         = {1726-4170},
  journal      = {BIOGEOSCIENCES},
  keyword      = {soil,geochemistry,weathering,ALKALI FELDSPAR DISSOLUTION,PROFILE MODEL,SURFACE-AREA,FOREST SOILS,REACTION PATHS,KINETICS,FIELD,SCALE,PH,25-DEGREES-C},
  language     = {eng},
  number       = {22},
  pages        = {6791--6808},
  title        = {Evaluating sensitivity of silicate mineral dissolution rates to physical weathering using a soil evolution model (SoilGen2.25)},
  url          = {http://dx.doi.org/10.5194/bg-12-6791-2015},
  volume       = {12},
  year         = {2015},
}

Chicago
Opolot, Emmanuel, and Peter Finke. 2015. “Evaluating Sensitivity of Silicate Mineral Dissolution Rates to Physical Weathering Using a Soil Evolution Model (SoilGen2.25).” Biogeosciences 12 (22): 6791–6808.
APA
Opolot, E., & Finke, P. (2015). Evaluating sensitivity of silicate mineral dissolution rates to physical weathering using a soil evolution model (SoilGen2.25). BIOGEOSCIENCES, 12(22), 6791–6808.
Vancouver
1.
Opolot E, Finke P. Evaluating sensitivity of silicate mineral dissolution rates to physical weathering using a soil evolution model (SoilGen2.25). BIOGEOSCIENCES. 2015;12(22):6791–808.
MLA
Opolot, Emmanuel, and Peter Finke. “Evaluating Sensitivity of Silicate Mineral Dissolution Rates to Physical Weathering Using a Soil Evolution Model (SoilGen2.25).” BIOGEOSCIENCES 12.22 (2015): 6791–6808. Print.