The effect of land plants on weathering rates of silicate minerals

Drever, James I.

doi:10.1016/0016-7037(94)90013-2

Cited by 494 publications

(267 citation statements)

References 41 publications

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“…The value of η is similar to what we determined previously for LD6-5412 glass [8]. In addition, the value of η for LAWABP1 glass is consistent with values reported for silicate minerals [14]. Because η is not dependent upon temperature, we can set η = 0.35 at the anticipated repository temperature of 15ºC with confidence.…”

Section: Effect Of Q/s Variationssupporting

confidence: 89%

Waste Form Release Data Package for the 2001 Immobilized Low-Activity Waste Performance Assessment

McGrail¹,

Icenhower²,

Martin³

et al. 2001

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SUMMARYThis data package documents the experimentally derived input data on the representative waste glasses LAWABP1 and HLP-31 that will be used for simulations of the immobilized lowactivity waste disposal system with the Subsurface Transport Over R eactive Multiphases (STORM) code. The STORM code will be used to provide the near-field radionuclide release source term for a performance assessment to be issued in March of 2001. Documented in this data package are data related to 1) kinetic rate law parameters for glass dissolution, 2) alkali-H ion exchange rate, 3) chemical reaction network of secondary phases that form in accelerated weathering tests, and 4) thermodynamic equilibrium constants assigned to these secondary phases. The kinetic rate law and Na + -H + ion exchange rate were determined from single-pass flow-through experiments. Pressurized unsaturated flow and vapor hydration experiments were used for accelerated weathering or aging of the glasses. The majority of the thermodynamic data were extracted from the thermodynamic database package shipped with the geochemical code EQ3/6. However, several secondary reaction products identified from laboratory tests with prototypical LAW glasses were not included in this database, nor are the thermo dynamic data available in the open literature. One of these phases, herschelite, was determined to have a potentially significant impact on the release calculations and so a solubility product was estimated using a polymer structure model developed for zeolites.Although this data package is relatively complete, final selection of ILAW glass compositions has not been done by the waste treatment plant contractor. Consequently, revisions to this data package to address new ILAW glass formulations are to be regularly expected.v CONTENTS

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Section: Effect Of Q/s Variationssupporting

confidence: 89%

Waste Form Release Data Package for the 2001 Immobilized Low-Activity Waste Performance Assessment

McGrail¹,

Icenhower²,

Martin³

et al. 2001

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“…Future studies could also examine the geomorphic features, soil or regolith depth, presence of organic matter, or perennial/ephemeral status of the catchments, which may control weathering rates or fluxes in some catchments (e.g. Drever, 1994;Oliva et al, 1999;Johnson et al, 2001). These characteristics have not been considered in this study.…”

Section: Permeability-porosity-aperture Modelmentioning

confidence: 99%

Concentration–discharge relationships reflect chemostatic characteristics of US catchments

Godsey

Kirchner

Clow

2009

Hydrological Processes

691

942

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Abstract:Concentration-discharge relationships have been widely used as clues to the hydrochemical processes that control runoff chemistry. Here we examine concentration-discharge relationships for solutes produced primarily by mineral weathering in 59 geochemically diverse US catchments. We show that these catchments exhibit nearly chemostatic behaviour; their stream concentrations of weathering products such as Ca, Mg, Na, and Si typically vary by factors of only 3 to 20 while discharge varies by several orders of magnitude. Similar patterns are observed at the inter-annual time scale. This behaviour implies that solute concentrations in stream water are not determined by simple dilution of a fixed solute flux by a variable flux of water, and that rates of solute production and/or mobilization must be nearly proportional to water fluxes, both on storm and inter-annual timescales. We compared these catchments' concentration-discharge relationships to the predictions of several simple hydrological and geochemical models. Most of these models can be forced to approximately fit the observed concentration-discharge relationships, but often only by assuming unrealistic or internally inconsistent parameter values. We propose a new model that also fits the data and may be more robust. We suggest possible tests of the new model for future studies. The relative stability of concentration under widely varying discharge may help make aquatic environments habitable. It also implies that fluxes of weathering solutes in streams, and thus fluxes of alkalinity to the oceans, are determined primarily by water fluxes. Thus, hydrology may be a major driver of the ocean-alkalinity feedback regulating climate change.

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“…For example, increases in forest cover might cause systematic variations in soil retention (45) and bedrock weathering (2) due to differences in rooting and organic ligand release (1). This should lead to differences in soil production and erosion by chemical, physical, and biological processes (46).…”

Section: Implications For Landscape Evolutionmentioning

confidence: 99%

“…Vegetation also plays an important although still incompletely understood role in the breakdown and erosion of rock (1)(2)(3) and thus the evolution of Earth's topography (4). Understanding the factors that determine where vegetation thrives-and where it does not-is therefore fundamental to many disciplines, including ecology, geomorphology, geochemistry, and pedology.…”

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confidence: 99%

Bedrock composition regulates mountain ecosystems and landscape evolution

Hahm

Riebe

Lukens

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

213

205

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Earth's land surface teems with life. Although the distribution of ecosystems is largely explained by temperature and precipitation, vegetation can vary markedly with little variation in climate. Here we explore the role of bedrock in governing the distribution of forest cover across the Sierra Nevada Batholith, California. Our sites span a narrow range of elevations and thus a narrow range in climate. However, land cover varies from Giant Sequoia (Sequoiadendron giganteum), the largest trees on Earth, to vegetation-free swaths that are visible from space. Meanwhile, underlying bedrock spans nearly the entire compositional range of granitic bedrock in the western North American cordillera. We explored connections between lithology and vegetation using measurements of bedrock geochemistry and forest productivity. Tree-canopy cover, a proxy for forest productivity, varies by more than an order of magnitude across our sites, changing abruptly at mapped contacts between plutons and correlating with bedrock concentrations of major and minor elements, including the plant-essential nutrient phosphorus. Nutrient-poor areas that lack vegetation and soil are eroding more than two times slower on average than surrounding, more nutrientrich, soil-mantled bedrock. This suggests that bedrock geochemistry can influence landscape evolution through an intrinsic limitation on primary productivity. Our results are consistent with widespread bottom-up lithologic control on the distribution and diversity of vegetation in mountainous terrain.erosion rates | bedrock weathering | critical zone | forest distribution V egetation captures solar energy and sends it cascading through ecosystems, creating habitats for other organisms and fixing nutrients and carbon from the atmosphere. Vegetation also plays an important although still incompletely understood role in the breakdown and erosion of rock (1-3) and thus the evolution of Earth's topography (4). Understanding the factors that determine where vegetation thrives-and where it does not-is therefore fundamental to many disciplines, including ecology, geomorphology, geochemistry, and pedology. As a substrate for life, lithology can influence overlying vegetation, spurring endemism due to the presence of toxins (5, 6) and limiting productivity where rock-derived nutrients are scarce (7-9). However, lithologic effects on vegetation are generally considered secondary to climatic factors such as the length of the growing season and the amount of moisture available for plant growth (10). Here we show that bedrock composition can drive differences in vegetation on par with the systematic altitudinal differences found in mountains between their hot, dry foothills and cold, wet alpine summits.

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The effect of land plants on weathering rates of silicate minerals

Cited by 494 publications

References 41 publications

Waste Form Release Data Package for the 2001 Immobilized Low-Activity Waste Performance Assessment

Waste Form Release Data Package for the 2001 Immobilized Low-Activity Waste Performance Assessment

Concentration–discharge relationships reflect chemostatic characteristics of US catchments

Bedrock composition regulates mountain ecosystems and landscape evolution

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