Classification, strength and water retention characteristics of lateritic regolith

Kew, Geoffrey; Gilkes, Robert

doi:10.1016/j.geoderma.2006.03.025

Cited by 14 publications

(21 citation statements)

References 12 publications

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“…To do so, we used independent, field-based measurements to quantify the strength of the parent material underlying the mobile soil layer. Jones and Graham, 1993;Johnson-Maynard et al, 1994;Schoeneberger et al, 1995;Jiao et al, 2005;Kew and Gilkes, 2006). Quantifying strength can be done in a number of ways.…”

Section: Methodsmentioning

confidence: 99%

Strength matters: Resisting erosion across upland landscapes

Heimsath

Whipple

2019

Earth Surf Processes Landf

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Soil‐covered upland landscapes comprise a critical part of the habitable world and our understanding of their evolution as a function of different climatic, tectonic, and geologic regimes is important across a wide range of disciplines. Soil production and transport play essential roles in controlling the spatial variation of soil depth and therefore hillslope hydrological processes, distribution of vegetation, and soil biological activity. Field‐based confirmation of the hypothesized relationship between soil thickness and soil production is relatively recent, however, and here we quantify a direct, material strength‐based influence on variable soil production across landscapes. We report clear empirical linkages between the shear strength of the parent material (its erodibility) and the overlying soil thickness. Specifically, we use a cone penetrometer and a shear vane to determine saprolite resistance to shear. We find that saprolite shear strength increases systematically with overlying soil thickness across three very different field sites where we previously quantified soil production rates. At these sites, soil production rates, determined from in situ produced beryllium‐10 (10Be) and aluminum‐26 (26Al), decrease with overlying soil thickness and we therefore infer that the efficiency of soil production must decrease with increasing parent material shear strength. We use our field‐based data to help explain the linkages between biogenic processes, chemical weathering, hillslope hydrology, and the evolution of the Earth's surface. © 2019 John Wiley & Sons, Ltd.

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Section: Methodsmentioning

confidence: 99%

Strength matters: Resisting erosion across upland landscapes

Heimsath

Whipple

2019

Earth Surf Processes Landf

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“…The recognition of regolith materials left after bauxite mining in the Darling Range of Western Australia is possible using a field key developed by Kew and Gilkes (2006). Distinct zones of morphological properties (texture, pedality, colour, coarse fragment content) can be described using the key.…”

Section: Discussionmentioning

confidence: 99%

“…A field key to the regolith materials left after bauxite mining in the Darling Range of south Western Australia was developed by Kew and Gilkes (2006). The key uses field morphological properties (texture, pedality, colour, coarse fragment content) to map the spatially diverse materials that strongly affect plant growth and the success of mine pit rehabilitation (Tables 1 and 2).…”

Section: Bauxite Mine Floor Regolithmentioning

confidence: 99%

“…These materials vary greatly in composition and structure; sometimes providing a physically hostile medium for the growth of plant roots, so hindering rehabilitation. Kew and Gilkes (2006) established a field morphological key for these materials that is related to the regolith nomenclature of Anand and Paine (2002) and is a more comprehensive extension of the initial scheme published by Mengler et al (2006). The key identifies bauxite mine floor materials that require intensive rehabilitation treatments, including ripping to generate a medium that can be exploited by plant roots.…”

Section: Introductionmentioning

confidence: 99%

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Properties of regolith beneath lateritic bauxite in the Darling Range of south Western Australia

Kew

Gilkes

2007

Soil Res.

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A morphological key has been developed for regolith that is exposed during mining of lateritic bauxite in the Darling Range of south Western Australia. The key distinguishes materials with different mineralogical and chemical properties. Iron oxide cemented (Zh) regolith has a gibbsitic matrix, quartz-rich (Zm) regolith has a gibbsite and kaolin matrix, and clay-rich (Zp) regolith has a kaolin matrix. An Si affinity element map (Si, Hf, Th) and a K affinity element group (K, Ba, Rb) are associated with granitic quartz-rich regolith and an Al/Fe element affinity group (Al, Fe, Ti, P, Ni, Co, Cu, Mn, Zn, Ga, Cr, V) is associated with clay and iron rich regolith. Doleritic regolith is generally associated with the Al/Fe affinity group. Although granite and granitic regolith exhibit similar element affinity groups, the abundance of elements within each is highly variable, which reflects the diversity in composition of granite within the region. The degree of euhedral character of clay-size platy crystals (kaolinite/gibbsite) does not differ for materials distinguished by the key, as both quartz-rich (Zm) and clay-rich (Zp) regolith and both granitic and doleritic saprolite contain subhedral kaolin crystals. The crystal size of platy kaolin (approximately 0.5 µm) is similar for different mine pits and for different regolith materials (Zm and Zp) within mine pits. There is a difference in halloysite tube length (0.52-1.18 µm) between mine pits, which may be related to the presence of weathered mica or to the alteration of halloysite in gibbsite-rich regolith. The internal and external diameters of halloysite tubes (about 0.11 and 0.24 µm) are similar for different mine pits and different regolith types within mine pits. The resin used during thin section preparation contains chlorine, so that determination of chlorine by EMPA provides a measure of the porosity of regolith material. A systematic negative relationship exists between chlorine concentration and total oxide weight % of porous regolith matrix determined by EMPA; both measurements provide an indication of the porosity of the clay matrix in regolith.

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“…The second subclass number indicates increasing coarse fragment content from 0 to 50% (1), 50 to 80% (2), and greater than 80% (3). Some class and subclass categories dominate and several may be present at any given location (adapted from Kew and Gilkes 2006).…”

Section: Methodsmentioning

confidence: 99%

Regolith Strength, Water Retention, and Implications for Ripping and Plant Root Growth in Bauxite Mine Restoration

Kew

Mengler

Gilkes

2007

Restoration Ecology

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The lateritic bauxite in the Darling Range of Western Australia is approximately 4-6 m deep and is composed of caprock (duricrust) and underlying friable bauxite developed from highly weathered granite and dolerite. This paper investigates the impact of mine floor ripping operations on materials exposed after mining in relation to strength, water retention, and plant root growth. Deep ripping has been shown to create a structured rootzone and increase both recharge and plant available water. Material classified as quartz rich (Zm) lacks structural features for plant root growth, yet the material requires the least force to rip. These materials require deep preripping followed by contour or multi-tine ripping for successful restoration. Materials that contain 50% or more coarse fragments (gravels, cobbles, and stones) increase the force required for pre-ripping operations but only require contour or multi-tine ripping; doleritic clay with a high coarse fragment content may be readily colonized by roots without pre-ripping. Localized compression (smearing) of materials may occur during ripping due to the pre-ripping tine working deeper than its critical depth of 1.0-1.5 m and/or ripping of materials at high moisture content. A relationship exists between the ratio of reactive silica to total silica and the clay content of regolith, both properties being determined from pre-mining borehole samples. This ratio can be used to identify future mine floor materials from borehole data prior to mining and to target ripping operations to appropriate regolith types to enable the most effective and economical restoration practice.

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Classification, strength and water retention characteristics of lateritic regolith

Cited by 14 publications

References 12 publications

Strength matters: Resisting erosion across upland landscapes

Strength matters: Resisting erosion across upland landscapes

Properties of regolith beneath lateritic bauxite in the Darling Range of south Western Australia

Regolith Strength, Water Retention, and Implications for Ripping and Plant Root Growth in Bauxite Mine Restoration

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