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Research Paper |
1 Department of Geology, Colgate University, Hamilton, New York 13346, and 2 Department of Civil and Environmental Engineering, Syracuse University, Syracuse, New York 13244, USA
* E-mail: rapril{at}mail.colgate.edu
(Received 30 July 2003; revised 7 November 2003)
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ABSTRACT |
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 TOP ABSTRACT MATERIALS AND METHODSRESULTSDISCUSSIONACKNOWLEDGMENTSREFERENCES |
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KEYWORDS: Adirondacks, Podzols, smectite, soils, Spodosols, vermiculite, weathering
Smectite is common in soils that are poorly drained, influenced by or formed from volcanics, and in which the mineral is inherited directly from the parent material (Borchardt, 1989). Also now widely recognized is the occurrence of smectite as a weathering product in well drained soils, in particular, Spodosols (Podzolic soils), which formed under temperate climates from parent material of granitic composition (Brown & Jackson, 1958; Gjems, 1960, 1962; Franzmeier & Whiteside, 1963; Ross & Mortland, 1966; Kodama & Brydon, 1968; Melkerud, 1983, 1985; Hluchy, 1984; Keller, 1988; Allen & Hajek, 1989; Feldman et al., 1991; Carnicelli et al., 1997; Righi et al., 1999; Gillot et al., 2000). Most often the smectite is restricted to the albic (E) horizon and appears to form from the progressive weathering of phyllosilicates, primarily muscovite, biotite and chlorite, present in the underlying parent material. Ross (1980), in reviewing the mineralogy of Spodosols, suggested that the dominance of smectite or vermiculite, or both, in the E horizon is characteristic of the clay mineralogy of this soil type.
Previous studies of the mineralogy of soil and glacial deposits from forested sites across the Adirondack Mountains of New York State reported on the up-profile mineral weathering sequence of mica 
mixed-layered mica-vermiculite vermiculite low-charge vermiculite (April & Newton, 1983; April et al., 1986). Although this weathering sequence in soils is well documented, it can vary according to the specific mica mineral involved and the prevailing climatic, biotic and soil conditions (e.g. Jackson, 1963; Lagaly, 1982; Borchardt, 1989; Douglas, 1989; Fanning et al., 1989; Feldman et al., 1991; Wilson, 1999). Intermediate products in this weathering sequence, such as mixed-layered and hydroxy-interlayered clays, as well as other end products such as kaolinite have been noted (e.g. Sawhney & Voigt, 1969; Gilkes & Suddhiprakarn, 1979; Banfield & Eggleton, 1988). However, in any given solum all intermediate and final products may not be present (see, e.g. Ahn & Peacor, 1987). In the Adirondack Mountains, Johnson & McBride (1989) identified a hydroxy-interlayered smectite and found that the mineral was concentrated in E horizons.
In the present paper we report on clay minerals identified in the upper horizons of Adirondack soil profiles, including the Bhs, the albic E and the organic-rich A and O horizons. We show that the previously described up-profile mineral weathering sequence of mica mixed-layered mica-vermiculite vermiculite low-charge vermiculite progresses further to smectite, and that smectite is a common clay mineral in the uppermost soil horizons.
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MATERIALS AND METHODS |
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TOPABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONACKNOWLEDGMENTSREFERENCES |
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The mineralogy of surficial sediments at any given locality is strongly influenced by and closely reflects the mineralogy of the regional bedrock. Till and outwash sands typically contain abundant feldspar (both K-feldspar and plagioclase) and quartz, and minor amounts of hornblende, ilmenite, magnetite and garnet (April & Newton, 1983). Phyllosilicates, including muscovite, biotite and chlorite, may be present or absent depending on location. The last remnants of glacial ice disappeared from the region 12,000 to 14,000 years ago and soils, which today are dominated by acidic Spodosols, developed on the glacial sediments.
Sampling and analytical techniques
For this investigation we focused our soil sampling in Huntington Forest, a 6000 ha preserve near the geographic centre of the Adirondack Park, located in the Town of Newcomb, western Essex County and in the Town of Long Lake, eastern Hamilton County, New York (latitude 44°00' N; longitude 74°13' W). Additional samples were collected from the Big Moose Lake area in the west-central portion of the Adirondacks (latitude 43°50' N; longitude 74°51' W); and from the Whiteface Mountain area of the high peaks region (latitude 44°22' N; longitude 73°54' W) (Fig. 1
). The Spodosols sampled comprise well to moderately drained Typic Haplorthods and Fragiorthods (Becket-Mundell series sandy loams – coarse-loamy, mixed, frigid typic Haplorthods) developed on till. Profile depths generally average ~75 cm or less and may terminate on bedrock or grade into the underlying parent material. Soil samples were collected using trowels and straight edged tools from horizons exposed on the sides of excavated pits ~1 m square. In all, 20 composite Oa and A horizon samples (referred to hereafter as ‘O+A composites’), some individual Oa and A horizons, and 30 E, B and C horizon samples were analysed for bulk mineralogy and clay mineralogy.
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radiation, a 1° beam slit, medium resolution soller slit and a 0.1° receiving slit. X-ray fluorescence (XRF) analyses of the bulk soil and selected clay fractions, fused into glass discs with lithium tetraborate, were made using a Diano XRF-8560 vacuum-path X-ray spectrometer equipped with a dual target Cr/W tube. Calibration curves for major elements were prepared by multiple linear regression and matrix correction techniques using 40 rock, mineral and synthetic glass standards. In addition, the <1 µm clay fractions of selected samples were mounted on carbon stubs and analysed chemically with a Tracor Northern energy dispersive X-ray analysis system (EDS), mounted to a Cambridge Stereoscan 200 SEM, using a 200 s count time, 15 kV acceleration potential, and a 50 µm spot diameter. Grain size was determined on 10–15 g aliquots of soil by wet sieving following the procedures of Jackson (1974). Samples were rinsed with dilute ammonium hydroxide through standard sieves and separated into sand and silt + clay. The sand fractions were oven dried and weighed. The silt + clay mixtures were poured into 1000 ml settling tubes for grain-size analysis using the pipette method (Jackson, 1974).
Mineral abundances in the fine-sand fraction of both light (sp.gr. <2.95) and heavy (sp.gr. >2.95) mineral separates were determined by point counts of ~300 grains per slide using a petrographic microscope (Galehouse, 1969, 1971). Grain mounts were also inspected in the scanning electron microscope (SEM) and the identity of grains was checked using the semi-quantitative elemental spectrum obtained by the EDS system. Chemical analyses of biotite grains were acquired using both the EDS system and a JEOL 8900M Superprobe electron microprobe (Binghamton University).
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RESULTS |
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TOPABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONACKNOWLEDGMENTSREFERENCES |
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). Heavy minerals are most abundant in the lower horizons (the C, B/C and lower B), constituting almost 20% of mineral grains, and comprise hornblende, opaques (ilmenite and magnetite), pyroxene, garnet and apatite. Minor amounts of sphene, rutile and kyanite are also present (Table 2a).
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and 2b (cf. Newton et al., 1987). As in Huntington Forest, the light minerals are composed primarily of quartz and feldspar and the distribution of heavy minerals in the soils exhibits a marked depletion of the more weatherable minerals toward the top of the profile. Grain-size analysis of soils from both the Huntington Forest and Big Moose Lake area shows that the relative proportions of sand, silt, and clay varies markedly in the different soil horizons, but what seems clear from the data, and what seems typical of Adirondack soils, is that the clay fraction is quite low, at ~2.5%, or less.
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Clay mineralogy
Results from the XRD analysis of the <2 µm clay fractions showed that smectite is a common constituent in the upper soil horizons of Spodosols collected at all sites included in this study. In general, the presence of smectite in the clay fraction was indicated by a 14 Å reflection in the air-dried, Mg-saturated state that shifts to an 18 Å reflection following glycerol solvation. (There is some disagreement in the literature as to how to distinguish smectite from high- and low-charge vermiculite in XRD patterns [Moore & Reynolds, 1997; Douglas, 1989, pp. 652–657]. We use the conventional operational definition here for distinguishing between vermiculite and smectite, as discussed in Moore & Reynolds, 1997, p. 160.) Using peak height as a rough indicator of relative abundance, smectite ranged from being the dominant mineral in the clay fraction of several O+A horizons collected from the Big Moose area to being a minor constituent (Fig. 2). Variable amounts of vermiculite and small to trace amounts of kaolinite and a 10 Å mica were also present in some samples.
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, 4 and 5 exemplify the suite of clay minerals observed for the Huntington Forest soil profiles inspected in this study. The expanding properties and basal spacings of the clays extracted from the O+A composite and from the E and Bhs horizons (Figs 3 and 4) suggest the presence of smectite, vermiculite, and a transitional clay of intermediate layer charge (henceforth referred to as low-charge vermiculite). In the E horizon, and in the O+A composite horizon, the clay that expanded to ~16.5–17 Å after ethylene-glycol solvation and to ~18 Å after Mg-saturation + glycerol solvation is smectite. The 18 Å peak is symmetrical in the XRD pattern for the O+A composite horizon (Fig. 3) indicating the presence of only smectite. However, as inferred from the asymmetry of the 18 Å peak towards lower d values in the XRD pattern for the E horizon sample (Fig. 3), both smectite and low-charge vermiculite appear to be present. The low-charge vermiculite shows up particularly well in the XRD pattern for the Bhs horizon in Fig. 4. This mineral produced a 16.5 Å peak after ethylene-glycol solvation, but showed little or no expansion following Mg-saturation and glycerol solvation (see Fig. 3). The second mineral in the Bhs horizon, which in XRD patterns gave a 14 Å reflection after both ethylene-glycol solvation and Mg-saturation + glycerol solvation, is vermiculite. The fact that the 14 Å mineral in the C and B horizons did not expand after Mg-saturation and glycerol solvation, nor after solvation with ethylene glycol (Fig. 4), and collapsed towards 10 Å only after saturation with K and heat treatments to 530°C (Fig. 5), suggests that it is an hydroxy-interlayered vermiculite (HIV) of the type most commonly found in Adirondack soils (April et al., 1986).
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) show that both the vermiculite and the smectite are Al-rich, base-cation poor and, most likely, dioctahedral. The latter assignment is supported by corroborating evidence from XRD analyses of randomly oriented powder mounts of these same samples which showed diffuse but recognizable d060 reflections near 1.50 Å, and by simulation of the diffraction curves using the computer program NEWMOD (Moore & Reynolds, 1997).
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DISCUSSION |
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TOPABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONACKNOWLEDGMENTSREFERENCES |
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and 4, can be explained by a sequence of pedogenically induced mineralogical transformations. Typical of Spodosols is a marked pH gradient with depth; the O, A and E horizons in the Adirondacks are often ultra (pH <3.5) to extremely (pH 3.6–4.5) acid compared with B and C horizons that usually range from very strongly to medium acid (pH values of 4.5 to >5.5) (Cronan, 1985). The presence of both organic acids produced by plant and microbial activity and litter decay, and strong inorganic acids (sulphuric and nitric) derived from atmospheric deposition in the Adirondack Mountains (Gherini et al., 1985; Driscoll et al., 1991), creates an intense weathering environment in the upper part of the soil profile, which decreases in strength downwards. Clay mineral stabilities in the soil profile are reflected by the depth-dependent conversions of hydroxy-interlayered vermiculite to vermiculite to low-charge vermiculite to smectite, up profile. Humic, fulvic and other organic acids have been shown to be aggressive weathering agents in soils, especially with respect to the dissolution of clay minerals (Huang & Keller, 1971; Antweiler & Drever, 1983; Sposito, 1989; Ugolini et al., 1991). Chemical conditions, therefore, are most extreme in the O and A horizons where, as observed for the sites sampled in this study, only low-charge aluminous vermiculite and aluminous smectite (e.g. beidellite – however, the Greene-Kelly test gave us variable and inconclusive results; Lim & Jackson, 1986) co-exist as the end-products of weathering. Kaolinite is also present in these horizons, but its origin has yet to be determined.
An intermediate product in the conversion vermiculite to smectite is the low layer charge variety of vermiculite, which could form chelation in the upper soil horizons progressively removes Al from the interlayer and structural sites of vermiculite. The latter process would result in gradual decrease of net layer charge on the clay (as Si substitutes for Al in tetrahedral sites) towards the top of the soil profile and the eventual formation smectite. The chemistry of soil solutions collected from lysimeters installed in Huntington Forest and Big Moose Lake area soils is consistent with these mineralogical transformations (Fig. 6). In all soil solutions studied, concentrations of organic complexes of Al (and Si) were significant in Oa horizon leachates, suggestive of Al cheluviation (see Cronan & Schofield, 1990; Walker et al. 1990). The data suggest that the Al released by the weathering of phyllosilicates and other aluminosi licates is transported downwards in the soil profile, largely as organically complexed Al, to the spodic (B) horizon where it eventually precipitates as amorphous to poorly crystalline hydroxide and oxyhydroxide grain coatings or cement, is (re-?)incorporated into the interlayer sites of vermiculite to produce Al hydroxy-interlayered vermiculite, or forms para- or non-crystalline aluminosilicates (Johnson & McBride, 1989). As stated, although kaolinite was found (by XRD analysis) to be present in most samples, we have no evidence to indicate whether the mineral formed from the continued alteration of smectite, or whether it was simply inherited from previously weathered material (e.g. Stevens et al., 1987).
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shows XRD patterns of representative E and Bhs horizon samples from soils in the Big Moose Lake region that contained a clay mineral assemblage of vermiculite + low-charge vermiculite (similar to the Huntington Forest Bhs horizon described above). In these samples, as in the Huntington Forest samples, the low-charge vermiculite gave a 16.5–17 Å peak with ethylene-glycol solvation, but remained at ~14 Å following Mg-saturation + glycerol solvation. Again, using peak-height comparisons as an approximate measure of abundance, the XRD patterns in Fig. 7 indicate that the amounts of vermiculite and low-charge vermiculite vary considerably from sample to sample. Although low-charge vermiculite is present within the top 10 cm of the Huntington Forest soil profile (see Fig. 4), its appearance in other soil profiles occurs within a depth range of 14 to 31 cm (Fig. 7).
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,b). However, several silt-sized grains were identified in grain mounts and epoxy impregnated thin sections of soil cores inspected under the SEM/EDS. Many of these grains were embedded in sand- or silt-sized rock fragments; the surrounding grains of feldspar and quartz probably slowed the process of chemical alteration. The few isolated grains identified all showed signs of weathering. Whereas the core of these grains showed minor losses of K, the rims were largely depleted in K, enriched in Mg, and displayed the characteristic splayed edges caused by hydration, oxidation, and swelling of the layer structure (Fig. 8). Little biotite remains in these soil profiles (we estimate <0.5%), and, based on our results, we suggest that whatever biotite was present in the past probably transformed to vermiculite via a mixed-layered biotite/vermiculite. The few muscovite grains identified appeared relatively fresh and showed no signs of weathering.
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show small amounts of chlorite present in the C horizon of a Huntington Forest sample, but absent in the E horizon, suggesting that the mineral weathers out towards the top of the soil profile.
Although most of the E and composite O+A horizons examined in this study contained the clay mineral assemblage described above, XRD patterns of upper horizon soil from the Whiteface Mountain site, in the High Peaks region (Fig. 1), displayed weak reflections that only hinted at the presence of low-charge vermiculite or smectite in the clay fraction of the upper soil horizons. Peak definition in these XRD patterns was generally poor, probably due to a lack of clay-sized material. One reason for the lack of clay development may be the low mica content of parent till in the High Peaks region. Anorthosite, the dominant bedrock type in the area, contains almost no micas or chlorite. In one of the few earlier studies of Adirondack Spodosols, Coen & Arnold (1972) suggested that smectite in soils of the Whiteface Mountain area may have been derived largely from aeolian inputs, or from the subsequent weathering of minerals, such as mica and chlorite, that are added to the soil as dust. Whereas our findings do not rule out the possibility that aeolian-derived material adds to the amount of smectite in Adirondack soils, especially those containing little to no pre-existing phyllosilicates, our data suggest that when phyllosilicates are present in the parent material, podzolization leads to the formation of smectite in upper soil horizons.
In summary, the results from this study lend support to the growing and convincing body of evidence that smectite forms through transformation of micas in the upper horizons of Spodosols (for a recent summary of this literature see Wilson, 1999). Futhermore, as suggested by Feldman et al. (1991), and others, as long as mica is present as a primary aluminosilicate, the weathering sequence of mica mixed-layered mica-vermiculite vermiculite smectite, and the presence of these minerals in Podzols, will be controlled more by biotic and climatic factors than by any differences in initial parent-material composition.
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ACKNOWLEDGMENTS |
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TOPABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONACKNOWLEDGMENTSREFERENCES |
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REFERENCES |
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TOPABSTRACTMATERIALS AND METHODSRESULTSDISCUSSIONACKNOWLEDGMENTSREFERENCES |
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Ahn J.H. & Peacor D.R. (1987) Kaolinitization of biotite: TEM data and implications for an alteration mechanism. American Mineralogist, 72, 353–356.[Abstract][ISI][GeoRef]
Allen B.L. & Hajek B.F. (1989) Mineral occurrences in Soil environments. Pp. 199–278 in: Minerals in Soil Environments, 2nd edition (J.B. Dixon and S.B. Weed, editors). Soil Science Society of America, Madison, Wisconsin, USA.
Antweiler R.C. & Drever J.I. (1983) The weathering of a late Tertiary volcanic ash: Importance of organic solutes. Geochimica et Cosmochimica Acta, 47, 623–629.[CrossRef][ISI][GeoRef]
April R.H. & Newton R.M. (1983) Mineralogy and chemistry of some Adirondack Spodosols. Soil Science, 135, 301–307.[ISI][GeoRef]
April R.H., Hluchy M.M. & Newton R.M. (1986) The nature of vermiculite in Adirondack soils and till. Clays and Clay Minerals, 34, 549–556.[Abstract][CrossRef][ISI][GeoRef]
Banfield J.F. & Eggleton R.A. (1988) Transmission electron microscope study of biotite weathering. Clays and Clay Minerals, 36, 47–60.[Abstract][CrossRef][ISI][GeoRef]
Borchardt G.A. (1989) Smectites. Pp. 675–727 in: Minerals in Soil Environments, 2nd edition (J.B. Dixon and S.B. Weed, editors). Soil Science Society of America, Madison, Wisconsin, USA.
Brown B.E. & Jackson M.L. (1958) Clay mineral distribution in the Hiawatha sandy soils of northern Wisconsin. Clays and Clay Minerals, 5, 213–226.[CrossRef]
Carnicelli S., Mirabella A., Cecchini G. & Sanesi G. (1997) Weathering of chlorite to a low-charge expandable mineral in a Spodosol on the Apennine Mountains, Italy. Clays and Clay Minerals, 45, 28–41.[Abstract][CrossRef][ISI][GeoRef]
Coen G.M. & Arnold R.W. (1972) Clay mineral genesis of some New York Spodosols. Soil Science Society of America Proceedings, 36, 342–350.
Cronan C.S. (1985) Biogeochemical influence of vegetation and soils in the ILWAS watersheds. Water, Air and Soil Pollution, 26, 355–371.
Cronan C.S. & Schofield C.L. (1990) Relationships between aqueous aluminum and acidic deposition in forested watersheds of North America and Northern Europe. Environmental Science and Technology, 24, 100–1105.
Douglas L.A. (1989) Vermiculites. Pp. 635–674 in: Minerals in Soil Environments, 2nd edition (J.B. Dixon and S.B. Weed, editors). Soil Science Society of America, Madison, Wisconsin, USA.
Driscoll C.T., Newton R.M., Gubala C.P., Baker J.P. & Christensen S. (1991) Adirondack Mountains. Pp. 133–202 in: Acidic Deposition and Aquatic Ecosystems: Regional Case Studies (D.F. Charles, editor). Springer Verlag, New York.
Fanning D.S., Keramidas V.Z. & El-Desoky M.A. (1989) Micas. Pp. 551– 634 in: Minerals in Soil Environments, 2nd edition (J.B. Dixon and S.B. Weed, editors). Soil Science Society of America, Madison, Wisconsin, USA.
Feldman S.B., Zelazny L.W. & Baker J.C. (1991) High-elevation forest soils of the Southern Appalachians: II. Geomorphology, pedogenesis, and clay mineralogy. Soil Science Society of America Journal, 55 1782–1791.[ISI][GeoRef]
Franzmeier D.P. & Whiteside E.P. (1963) A chrono-sequence of Podzols in northern Michigan. Michigan Agricultural Experimental Quarterly Bulletin, 46, 1–57.
Galehouse J.S. (1969) Counting grain mounts: number percentage vs. number frequency. Journal of Sedimentary Petrology, 39, 812–815.
Galehouse J.S. (1971) Point Counting. Pp. 385–407 in: Procedures in Sedimentary Petrology (R.E. Carver, editor). Wiley-Interscience, New York.
Gherini S.A., Chen C.W., Mok L., Goldstein R.A., Hudson R.J.M. & Davis G.F. (1985) The ILWAS model: formulation and application. Water, Air and Soil Pollution, 26, 425–459.
Gilkes R.J. & Suddhiprakarn A. (1979) Biotite alteration in deeply weathered granite. I. Morphological, and chemical properties. Clays and Clay Minerals, 27, 349–360.[Abstract][CrossRef][ISI][GeoRef]
Gillot F., Righi D. & Elsass F. (2000) Pedogenic smectites in Podzols from Central Finland: an analytical electron microscopy study. Clays and Clay Minerals, 48, 655–664.
Gjems O. (1960) Some notes on clay minerals in Podzol profiles in Fennoscandia. Clay Minerals Bulletin, 4, 208–211.[CrossRef][GeoRef]
Gjems O. (1962) A swelling dioctahedral clay mineral of a vermiculite-smectite type in the weathering horizons of Podzols. Clay Minerals Bulletin, 5, 183–194.
Hluchy M.M. (1984) Surficial geology and clay mineralogy of four Adirondack lake-watersheds. M.S. thesis, Dartmouth College, Hanover, New Hampshire, USA, 87 pp.
Huang W.H. & Keller W.D. (1971) Dissolution of clay minerals in dilute organic acids at room temperature. American Mineralogist, 56, 1082–1095.[ISI][GeoRef]
Jackson M.L. (1963) Interlayering of expansible layer silicates in soils by chemical weathering. Clays and Clay Minerals, Proceedings, 11th National Conference, 11, 29–46.
Jackson M.L. (1974) Soil Chemistry Analysis – Advanced Course. Published by the author, Department of Soil Science, University of Wisconsin, Madison, Wisconsin, USA, 895 pp.
Johnson M.G. & McBride M.B. (1989) Mineralogical and chemical characteristics of Adirondack Spodosols: Evidence for para- and noncrystalline aluminosilicate minerals. Soil Science Society of America Journal, 53, 482–490.[ISI][GeoRef]
Keller D.M. (1988) The chemistry and mineralogy of forest and rhizosphere soils in the eastern United States. M.S. thesis, Colgate University, Hamilton, New York, 220 pp.
Kodama H. and Brydon J.E. (1968) A study of clay minerals in Podzol soils in New Brunswick, eastern Canada. Clay Minerals, 7, 295–309.[CrossRef][GeoRef]
Lagaly G. (1982) Layer charge heterogeneity in vermiculites. Clays and Clay Minerals, 30, 215–222.[Abstract][ISI][GeoRef]
Lim C.H. & Jackson M.L. (1986) Expandable phyllo-silicate reactions with lithium on heating. Clays and Clay Minerals, 34, 346–352.[Abstract][CrossRef][ISI][GeoRef]
Melkerud P.A. (1983) Quaternary deposits and bedrock outcrops in an area around Lake Ga °rdsjon, southwestern Sweden, with physical, mineralogical and geochemical investigations. Department of Forest Soils, Swedish University of Agricultural Sciences, Uppsala, 87 pp.
Melkerud P.A. (1985) Clay mineralogical comparisons of weathering profiles associated with spruce and birch stands. Geologiska Foreningens i Stockholm Forhandlingar, 107, 301–309.[GeoRef]
Moore D.M. & Reynolds R.C. (1997) X-ray Diffraction and the Identification and Analysis of Clay Minerals, 2nd edition. Oxford University Press, Oxford, UK, 378 pp.
Newton R.M., Weintraub J. & April R.H. (1987) The relationship between surface water chemistry and geology in the North Branch of the Moose River. Biogeochemistry, 3, 21–35.
Righi D., Huber K. & Keller C. (1999) Clay formation and podzol development from postglacial moraines in Switzerland. Clay Minerals, 34, 319–332.[Abstract][CrossRef][ISI][GeoRef]
Ross G.J. (1980) The mineralogy of Spodosols. Pp. 127–143 in: Soils with Variable Charge (B.K.G. Theng, editor). New Zealand Society of Soil Science, Lower Hutt, New Zealand.
Ross G.J. & Mortland M.M. (1966) A soil beidellite. Soil Science Society of America Proceedings, 30, 337–343.
Sawhney B.L. & Voight G.K. (1969) Chemical and biological weathering in vermiculite from Transvaal. Soil Science Society of America Proceedings, 33, 621–629.
Sposito G. (1989) The Chemistry of Soils. Oxford University Press, New York, 277 pp.
Stevens R.L., April R.H. & Wedel P.O. (1987) Sediment color and weathered preglacial sources of Quaternary clays in southwestern Sweden. Geologiska Foreningens i Stockholm Forhandlingar, 109, 241–253.[GeoRef]
Ugolini F.C., Dahlgren R., La Manna J., Nuhn W. & Zachara J. (1991) Mineralogy and weathering processes in recent and Holocene tephra deposits in the Pacific Northwest, USA. Geoderma, 51, 277–299.[CrossRef][ISI][GeoRef]
Walker W.J., Cronan C.S. & Bloom P.R. (1990) Aluminum solubility in organic horizons from northern and southern forested watersheds. Soil Science Society of America Journal, 54, 369–374.[ISI][GeoRef]
Wilson M.J. (1999) The origin and formation of clay minerals in soils: past, present and future perspectives. Clay Minerals, 34, 7–25.[Abstract][CrossRef][ISI][GeoRef]
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