plinthite


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plinthite

[′plin‚thīt]
(geology)
In a soil, a material consisting of a mixture of clay and quartz with other diluents, that is rich in sesquioxides, poor in humus, and highly weathered.
References in periodicals archive ?
Plinthite occurs in the deeper part of Ultisols profiles (Kc, Tim2, Pga, Pk, Cp).
A second field experiment was set up during the second week of October 1999 at Ukulinga Farm, near Pietermaritzburg in KwaZulu-Natal on a shallow, poorly drained soil underlain by soft plinthite (Table 1), classified as Westleigh form, Helena family (Soil Classification Working Group 1991), Typic Plinthaquept (Soil Survey Staff 1998), and Hydrosol (Isbell 1996).
The soils were mostly from the Bassendean Association and all consisted of litter on an organic sandy topsoil overlying either deep grey or yellow sands, or in two cases a grey clay loam E horizon (duplex soils) over plinthite (McArthur 1991) with an Australian Soil Classification (Isbell 1996) of Podosols.
Either above this or directly on top of the pallid zone, there is a mottled plinthite zone with strongly platey structure.
The transformation sequence of the mottles in the plinthite, as soil formation progresses downward in the profile, appears to be red (2.
The strong brown mottles that form from the red mottles of the plinthite are well developed in the brown yellow B-horizon on the crest and on the upper part of the B-horizon on the shoulder (G-0 to G-2, `plinthic on crest').
When using Isbell, salinisation (marked presence of sodium), the presence of plinthite (indicating a potential perched water table), and the marked presence of ironstone gravel are reflected in the soil names.
Some have plinthite at depth, causing water to perch at depth (i.
At Gatum these include, for instance, sharp increases in clay content with depth, and horizons with periodic saturation, high salt contents, or plinthite.