Chemical weathering rates of a soil chronosequence on granitic alluvium: III. Hydrochemical evolution and contemporary solute fluxes and rates

White, Art F.; Schulz, Marjorie S.; Vivit, Davison V.; Blum, Alex E.; Stonestrom, David A.; Harden, Jennifer W.

doi:10.1016/j.gca.2004.10.003

Cited by 90 publications

(116 citation statements)

References 64 publications

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“…However, factors such as soil age, lithology, runoff and land cover may have a more pronounced effect on weathering rates at the regional to continental scale White et al, 2005). Tropical river basins play a major role in chemical weathering and transfer of dissolved Si and alkalinity to rivers and oceans due to their geological and climatic settings (Jennerjahn et al, 2006).…”

Section: Weatheringmentioning

confidence: 99%

Nutrient dynamics, transfer and retention along the aquatic continuum from land to ocean: towards integration of ecological and biogeochemical models

et al. 2013

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Abstract. In river basins, soils, groundwater, riparian zones and floodplains, streams, rivers, lakes and reservoirs act as successive filters in which the hydrology, ecology and biogeochemical processing are strongly coupled and together act to retain a significant fraction of the nutrients transported. This paper compares existing river ecology concepts with current approaches to describe river biogeochemistry, and assesses the value of these concepts and approaches for understanding the impacts of interacting global change disturbances on river biogeochemistry. Through merging perspectives, concepts, and modeling techniques, we propose integrated model approaches that encompass both aquatic and terrestrial components in heterogeneous landscapes. In this model framework, existing ecological and biogeochemical concepts are extended with a balanced approach for assessing nutrient and sediment delivery, on the one hand, and nutrient in-stream retention on the other hand.

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Section: Weatheringmentioning

confidence: 99%

Nutrient dynamics, transfer and retention along the aquatic continuum from land to ocean: towards integration of ecological and biogeochemical models

et al. 2013

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“…Measurements of precipitation at each terrace suggest that sea spray is an important source of solutes in precipitation. Soil gas samples for CO 2 and O 2 were collected from stainless steel gas samplers following the procedure of White et al (2005b). Because the pore water samples degas during collection, the measured CO 2 and alkalinity values were used to calculate the field pH.…”

Section: 4mentioning

confidence: 99%

The role of reaction affinity and secondary minerals in regulating chemical weathering rates at the Santa Cruz Soil Chronosequence, California

Maher

Steefel

White

et al. 2009

Geochimica et Cosmochimica Acta

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281

269

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ABSTRACT:In order to explore the reasons for the apparent discrepancy between laboratory and field weathering rates and to determine the extent to which weathering rates are controlled by the approach to thermodynamic equilibrium, secondary mineral precipitation and flow rates, a multicomponent reactive transport model (CrunchFlow) was used to interpret soil profile development and mineral precipitation and dissolution rates at the 226 ka marine terrace chronosequence near Santa Cruz, CA. Aqueous compositions, fluid chemistry, transport, and mineral abundances are well characterized (White et al., 2008, GCA) and were used to constrain the reaction rates for the weathering and precipitating minerals in the reactive transport modeling. When primary mineral weathering rates are calculated with either of two experimentally determined rate constants, the nonlinear, parallel rate law formulation of Hellmann and Tisserand [2006] or the aluminum inhibition model proposed by Oelkers et al. [1994], modeling results are consistent with fieldscale observations when independently constrained clay precipitation rates are accounted for. Experimental and field rates, therefore, can be reconciled at the Santa Cruz site.Observed maximum clay abundances in the argillic horizons occur at the depth and time where the reaction fronts of the primary minerals overlap. The modeling indicates that the argillic horizon at Santa Cruz can be explained almost entirely by weathering of primary minerals and in situ clay precipitation accompanied by undersaturation of kaolinite at the top of the profile. The rate constant for kaolinite precipitation was also determined based on model simulations of mineral abundances and dissolved Al, SiO 2 (aq) and pH in pore waters. Changes in the rate of kaolinite precipitation or the flow rate do not affect the gradient of the primary mineral weathering profiles, but instead control the rate of propagation of the primary mineral weathering fronts and thus total mass removed from the weathering profile. Our analysis suggests that secondary clay precipitation is as important as aqueous transport in governing the amount of dissolution that occurs within a profile because clay minerals exert a strong control over the reaction affinity of the dissolving primary minerals. The modeling also indicates that the weathering advance rate and the total mass of mineral dissolved is controlled by the thermodynamic saturation of the primary dissolving phases plagioclase and K-feldspar, as is evident from the difference in propagation rates of the reaction fronts for the two minerals despite their very similar kinetic rate laws.

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“…Chemical weathering can transform surface deposits and bedrock (possibly including preexisting overlying non-carbonate rock, eolian dust, or even preexisting terra rossa) into aqueous solutes (Birkeland, 1974;Moresi and Mongelli, 1988;Patino et al, 2003;White et al, 2005;Merino and Banerjee, 2008). Preexisting overlying deposits and/or bedrock could then be partly or entirely eroded away.…”

Section: Origin Of Clay Mineralsmentioning

confidence: 99%

Origin of terra rossa over dolomite on the Yunnan-Guizhou Plateau, China

2009

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The origin of terra rossa and its relationship with its underlying carbonate rocks pose long-standing and controversial questions. This study focuses on one 5.4 m thick terra rossa profile on dolomite. The authors examined the quartz content, size distribution of quartz grains, mineral composition, surface micro-texture and crystal morphology of quartz, oxygen isotope ratios of quartz, and other tracers in the terra rossa and underlying dolomite to determine the derivation of terra rossa. The results indicate that terra rossa in the Dashandong profile on the Yunnan-Guizhou Plateau, China, is an in situ weathering solum. The terra rossa originates mostly from insoluble residues of the parent dolomite. The debris minerals (quartz and feldspar) derive completely from the parent dolomite. The clay minerals, and Al, Fe and Mn oxides and hydroxides likely have three origins. One portion derives from insoluble residues of the parent dolomite. A second portion converts from primary minerals in the parent dolomite. The last contribution comes from authigenic minerals from aqueous solutes transported by the water cycle. Authigenic minerals constitute the main components of the terra rossa. During weathering processes, the dolomite weathering functions as a "trap" against the escape of in situ insoluble residues and external aqueous solutes by means of poly-genetic chemical and physical barriers.

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Chemical weathering rates of a soil chronosequence on granitic alluvium: III. Hydrochemical evolution and contemporary solute fluxes and rates

Cited by 90 publications

References 64 publications

Nutrient dynamics, transfer and retention along the aquatic continuum from land to ocean: towards integration of ecological and biogeochemical models

Nutrient dynamics, transfer and retention along the aquatic continuum from land to ocean: towards integration of ecological and biogeochemical models

The role of reaction affinity and secondary minerals in regulating chemical weathering rates at the Santa Cruz Soil Chronosequence, California

Origin of terra rossa over dolomite on the Yunnan-Guizhou Plateau, China

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