A soil formed on a preexisting landscape under a previous pedogenetic regime, and not subsequently buried by geologically younger materials.
See also paleosol.
A soil formed on a preexisting landscape under a previous pedogenetic regime, and not subsequently buried by geologically younger materials.
See also paleosol.
“Remolded quick clay” refers to the material after the flocculated microstructure of the quick clay has been destroyed. By definition, remolded quick clay behaves as a liquid. The flow properties of remolded quick clay are required for analysis of the flow behavior of landslide debris as it leaves the landslide scar and flows. Most remolded quick clays behave in the ‘modern viscometric’ thixotropic manner of shear resistance increasing and decreasing, respectively, as the shear rate increases and decreases. The change is never more than a trivial portion of the quick clay strength prior to collapse. Remolded silt-rich, quick clay may exhibit extreme dilatancy at high shear rates, leading to shear blockage.
Cf., quick clay, quick clay landslide, dilatancy
An obsolete, local term for talc pseudomorphic after pyroxene from northern New York state and Canada.
Soil formed in place by in-situ weathering of parent rock material.
Cf., sedimentary clay.
The residual strength is the shear resistance or the capacity of a clay, soil, or rock to withstand significant pressure that develops after strain-softening at large strains. Residual strength is controlled by the characteristics of the internal failure surface where either significant particle movements have occurred (as in soils) or the fracture interface is the peak failure surface (as in rocks). The residual strength is typically smaller than the peak failure strength of a clay, soil, or rock.
A texture visible at hand-specimen or thin-section scale in which one generation of secondary minerals or soil plasma is arranged in a net or network geometry.
See soil plasma
An obsolete term for a resinous, massive, yellow to green serpentine.
A discredited name of a material that is primarily pimelite.
See reyerite group.
Reyerite is comprised of a sheet of edge-sharing Ca octahedra with adjacent tetrahedral sheets of Si8O20 and a double tetrahedral sheet of Si14Al2O38, and an overall chemical composition of (Na,K)2Ca14Si22Al2O58(OH)8 . 6H2O (Merlino, 1988a). The tetrahedral sheets are formed from 6-fold rings of tetrahedra with some tetrahedra pointing up and some down. Na, K, and H2O occupy partially filled sites within the double tetrahedral sheet network. Truscottite, Ca14(Si24O58)(OH)8 . 2H2O, is similar to reyerite, but with alkali and aluminum generally absent, although a limited amount of K and Al can be present and the composition can approach reyerite. Gyrolite, Ca16Si24O60(OH)8 . (14+x)H2O, has a Ca octahedral sheet bounded by Si8O20 tetrahedral sheets as a unit (layer charge may vary from -4 to -5 depending on Al content) separated from other similar units by an interlayer of 2Ca + Na octahedra (Merlino, 1988b). Fedorite, K2(Ca5Na2)Si16O38(OH,F)2 . H2O, has a sheet of edge-sharing Ca octahedra with double tetrahedral sheets, Si16O38, on adjacent sides. Minehillite, (K,Na)2Ca28Zn5Al4Si40O112(OH)16, has a central edge sharing Ca octahedral sheet with a single tetrahedral sheet on one side (similar to reyerite), but a complex slab that differs from reyerite on the other. The structure of cairncrossite, Sr2Ca7-xNa2x(Si4O10)4(OH)2(H2O)15-x, where x is between 0 and 1, forms a unit consisting of edge-sharing Ca octahedral sheets with adjacent Si tetrahedral sheets. These units are cross linked by SrO8 polyhedra. The structure of orlymanite (chemical composition approximately Ca4Mn3Si8O20(OH)6 . 2H2O), which has not been determined, is believed related to reyerite. Synthetic (“K-phase”, “Z-phase”) phases with structural similarities to reyerite are known. Reyerite group minerals are potentially important in cements used to case geothermal wells where phases form at elevated temperatures and pressures in a steam-rich environment.