A Review of the Mineralogy of Scottish Soil Clays

Mitchell, W. A.

doi:10.1111/j.1365-2389.1955.tb00833.x

Cited by 25 publications

(8 citation statements)

References 2 publications

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“…It is postulated that these illite minima and montmorillonite maxima on or just behind the terminal moraines are due to weathering of the subsoil clay under conditions o0A of poor drainage. Thus one might speculate that the melt water impounded by the terminal moraines contributed to excess moisture and consequent poor drainage in the immediate vicinity of the terminal moraine with the resultant weathering of the illite to montmorillonite (Mitchell, 1955). As previously mentioned, there was good agreement between percent illite in the coarse clay and total K20 in the coarse clay, the correlation coefficients for the 0-6 in.…”

Section: Mineralogical Composition Of the Clay Fractionsupporting

confidence: 58%

Time Factor and the Genesis of Soils on Early Wisconsin Till

Hensel

1958

Clays clay miner. (Natl. Conf. Clays Clay Miner.)

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Radiocarbon dates indicate that the maximum time of weathering for soils of the Tazewell substage may be about 6400 years longer than that available for weathering of soils of the Cary substage.Detailed mineralogical and chemical studies were made of the 2-0.2/~ fractions of 0-6 in. and 30-36 in. samples from 24 sites along a traverse extending from the Cary substage across the Tazewell substage in east-central Indiana. The major clay mineral constituents of the 0-6 in. samples were illite and 14~. material ; illite and montmorillonite were the main components in the 30-36 in. samples. The correlation coefficients between illite content and percentage K20 for the 0-6 in. and 30-36 in. samples were 0.85 and 0.92, respectively.The end and terminal moraines of the Tazewel[ substage were found to have a higher itlite content than the ground moraines. This was attributed te suporglacial movement and enrichment of foreign materials, i.e. mica schists from the Canadian shield, on end and terminal moraines.The results of saturation of the clay fraction with potassium and magnesium on the proportion of 10/~, 12.7/~ and 14/~ spacings indicated that weathering had lowered the surface charge density of the micaceous minerals in the 0-6 in. samples to a greater extent than in the 30-36 in. samples. This effect, in addition to other weathering reactions, resulted in partially expanded micaceous minerals in the 0-6 in. samples which were much more resistant to collapse than were the minerals in the 30-36 in. samples.The rate of weathering of K20 from the 2-0.2/~ fraction of the 0-6 in.

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Section: Mineralogical Composition Of the Clay Fractionsupporting

confidence: 58%

Time Factor and the Genesis of Soils on Early Wisconsin Till

Hensel

1958

Clays clay miner. (Natl. Conf. Clays Clay Miner.)

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“…Under conditions of impeded drainage the factors responsible for the weathering of rock-forming minerals and the formation of cla minerals Mitchell (1955) has pointed out that in Scottish soils derived from rocks . .…”

Section: ( C ) Eflect Of Drainage Status On Trace-element Mobilizationmentioning

confidence: 99%

Trace‐element Distribution in Soil Profiles

Swaine¹,

Mitchell²

1960

Journal of Soil Science

131

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Summary The contents of total and extractable trace elements present in Scottish soil profiles are primarily related to the geological parent material from which the soils are derived. Little or no effect within the profile attributable to pedological factors has been observed in the total contents. The most marked effect on the contents of extractable trace elements, notably Co, Ni, Cu, Mn, Mo, Zn, and Pb, is their increased mobilization in conditions of restricted drainage. Very high extractable contents occur in gleyed horizons of very poorly drained soils. No marked accumulation of trace elements has been observed in the iron pan or illuvial horizons of podzolized profiles. Higher contents of acetic‐acid‐extractable Al occur in soils with unrestricted drainage, the amounts present being of the same order as the exchangeable‐Ca contents.

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“…Information on the stability and weathering of chlorite in British 145 soils is very confusing. Mitchell (1955), on the basis of decrease in amount of chlorite with depth and an even distribution throughout the particle-size range of the clay fraction, has considered chlorite to be highly stable in many Scottish soils, and Ball (1966) could find no clear pedogenic trend and no indication of new mineral phases being formed from chlorite in highly chloritic brown earths and rankers of Snowdonia. On the other hand, Perrin (1971) reported that chlorite derived from Lower Palaeozoic shales is destroyed fairly rapidly in the soil, and others have reported that the mineral readily weathers to oxides of iron and aluminium (MacEwan, 1948), saponite or vermicu lite (Smith, 1962), kaolinite (Stevens and Wilson, 1970) and vermiculite or amorphous silica (Adams et al ,197 1 ).…”

Section: Introductionmentioning

confidence: 99%

The Weathering of Chloritic Minerals in Some Scottish Soils

Bain¹

1977

Journal of Soil Science

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The mineralogy of 14 chloritic soils of various drainage classes developed on different parent materials from the Loch Awe area of Argyllshire, Caithness, and the Southern Uplands reveals only minor variations'in clay mineralogy with profile depth, the frequent presence of primary minerals indicating that all the soils are immature, and that weathering is at an early stage. Iron-rich chlorite generally persists throughout the profiles, varying little in amount or chemical composition between horizons; where identifiable, the polytype is 11 b. Oxidation of iron modifies the thermal characteristics of the chlorite in all the freelydrained soils but usually only in the surface horizons of gleys. Irrespective of soil type or drainage class, in most profiles chlorite weathers only slightly, probably by vermiculitization around the edges of flakes.

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A Review of the Mineralogy of Scottish Soil Clays

Cited by 25 publications

References 2 publications

Time Factor and the Genesis of Soils on Early Wisconsin Till

Time Factor and the Genesis of Soils on Early Wisconsin Till

Trace‐element Distribution in Soil Profiles

The Weathering of Chloritic Minerals in Some Scottish Soils

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