Mineral-Water Interaction During the Chemical Weathering of Silicates

Bricker, Owen P.; Godfrey, Andrew E.; Cleaves, Emery T.

doi:10.1021/ba-1968-0073.ch006

Cited by 49 publications

(22 citation statements)

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“…Weak to strong acid-weathering ratios are consistent with the relative reactivities of each of the bedrock types underlying the watersheds. The results of this study con®rm that geology is an excellent predictor of the relative buering capacity of a watershed and the relative importance of weak versus strong acid weathering (Bricker and Rice, 1988), but indicate that stream chemistry is not quantitatively derived from bedrock geology alone.…”

Section: Discussionmentioning

confidence: 68%

“…Mass balance techniques have also been used to approximate geochemical transformations from precipitation to surface water. The method has proven particularly useful for the analysis of stream¯ow and chemical data collected over a long period of time in intensively studied watersheds throughout the US (Garrels and Mackenzie, 1967;Cleaves et al, 1970;Bricker et al, 1968;Shaer and Galloway, 1982;Katz et al, 1985;Velbel, 1985;Swank and Waide, 1988;Mast et al, 1990;Bassett et al, 1992). The primary objectives of this research were to: (1) calculate annual solute mass balances for ®ve watersheds in the Appalachian Valley and Ridge and Blue Ridge physiographic provinces in the mid-Atlantic region of the US, and (2) examine the role of mineral weathering in producing observed stream water chemistry in each of the watersheds.…”

Section: Introductionmentioning

confidence: 99%

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Use of geochemical mass balance modelling to evaluate the role of weathering in determining stream chemistry in five mid-atlantic watersheds on different lithologies

et al. 1997

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The importance of mineral weathering was assessed and compared for ®ve mid-Atlantic watersheds receiving similar atmospheric inputs but underlain by diering bedrock. Annual solute mass balances and volume-weighted mean solute concentrations were calculated for each watershed for each year of record. In addition, primary and secondary mineralogy were determined for each of the watersheds through analysis of soil samples and thin sections using petrographic, scanning electron microscope, electron microprobe and X-ray diraction techniques. Mineralogical data were also compiled from the literature. These data were input to NETPATH, a geochemical program that calculates the masses of minerals that react with precipitation to produce stream water chemistry. The feasibilities of the weathering scenarios calculated by NETPATH were evaluated based on relative abundances and reactivities of minerals in the watershed. In watersheds underlain by reactive bedrocks, weathering reactions explained the stream base cation loading. In the acid-sensitive watersheds on unreactive bedrock, calculated weathering scenarios were not consistent with the abundance of reactive minerals in the underlying bedrock, and alternative sources of base cations are discussed.

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Section: Discussionmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Use of geochemical mass balance modelling to evaluate the role of weathering in determining stream chemistry in five mid-atlantic watersheds on different lithologies

et al. 1997

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“…The primary weathering reactions can be quantified by reconstituting the original silicates from a knowledge of the existing residual clay mineralogy and the average chemical composition of the river water corrected for the contribution from precipitation. Examples of this type of study include that of Bricker et al (1968) in Maryland, and that of Garrels and Mackenzie (1967) in Sierra Nevada.…”

Section: Introductionmentioning

confidence: 99%

The assessment of chemical weathering rates within an upland catchment in north‐east Scotland

Reid

MacLeod

Cresser

1981

Earth Surf Processes Landf

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A study has been made of weathering in Glendye, an upland catchement of heather moorland underlain mainly by granite with some gneiss in north-east Scotland. The concentrations of a range of elements and ions in precipitation and river water were measured over a twelvemonth period. The total input and output of each element or ion was calculated. The resulting balances show net outputs of all species except hydrogen ion. Large net outputs of silicon (38.5 kg ha-' a-') and bicarbonate (48 kg ha-' a-I) indicate considerable chemical weathering. A large net output of chloride (32 kg ha-' a-') indicates the importance of dry deposition of oceanic aerosols. When this is allowed for the rate of output of elements due to weathering is:These results were compared with the abundance of elements in bedrock and differential weathering ratios calculated. These are compared with data from the Hubbard Brook study in New Hampshire. In both cases calcium is by far the most mobile element. The relative importance of the atmosphere and of chemical weathering as sources of each element was calculated, and the results compared with those of a study at Wet Sleddale in the Lake District. Similar patterns emerge in both cases.

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“…Kaolinite is a characteristic mineral of low-to moderate-temperature, low-pH, high-Eh, low-alkali, intermediate-H4SiO4 environments, as indicated by Figures 8 and 9, the activity-activity diagrams of Bricker et al (1968) andMarshall (1977), and the common observation that kaolinite is better crystallized where the iron in the system is tied up in ferric minerals. Where log pH[K+,Na*,Mg 2+] > 3, smectite may form.…”

Section: Discussionmentioning

confidence: 95%

Dehydroxylation, Rehydroxylation, and Stability of Kaolinite

Hurst

1985

Clays and clay miner.

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Abstract-From hydrothermal experiments three pressure-temperature-time curves have been refined for the system A1EOa-SiOE-HEO and reversal temperatures established for two of the principal reactions involving kaolinite. The temperatures of three isobaric invariant points enable the Gibbs free energy of formation of diaspore and pyrophyllite to be refined and the stability field of kaolinite to be calculated. The maximal temperature of stable kaolinite decreases from 296~ at 2 kb water pressure to 2840C at water's liquid/vapor pressure, and decreases rapidly at lower pressures. On an isobaric plot of [H4SiO4] vs. ~ kaolinite has a wedge-shaped stability field which broadens toward lower temperature to include much of the [H4SiO4] range of near-surface environments. If [H4SiO4] is above kaolinite's stability field and the temperature is <100~ halloysite forms rather than pyrophyllite, an uncommon pedogenic mineral. Pyrophyllite forms readily instead of kaolinite above 1500C if[H4SiO4] is controlled by cristobalite or noncrystalline silica.Kaolinite and a common precursor, halloysite, are characteristic products of weathering and hydrothermal alteration. In sediments, relatively little halloysite has survived due to its low dehydration temperature and instability at low water pressure, but kaolinite commonly has survived since the Devonian Period. In btLried sediments, the water pressure and [H4SiO4] requisite for stable kaolinite generally are maintained. In oxidized sediments and in pyritic reduced sediments, kaolinite commonly has survived, but where alkalies, alkaline earths, or aqueous iron has concentrated in the pore fluid, kaolinite has tended to transform to illite, zeolites, berthierine, or other minerals.

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Mineral-Water Interaction During the Chemical Weathering of Silicates

Cited by 49 publications

References 0 publications

Use of geochemical mass balance modelling to evaluate the role of weathering in determining stream chemistry in five mid-atlantic watersheds on different lithologies

Use of geochemical mass balance modelling to evaluate the role of weathering in determining stream chemistry in five mid-atlantic watersheds on different lithologies

The assessment of chemical weathering rates within an upland catchment in north‐east Scotland

Dehydroxylation, Rehydroxylation, and Stability of Kaolinite

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