The Pleistocene Olorgesailie Formation in the southern Kenya Rift has yielded a remarkable assemblage of Acheulean artifacts and vertebrate fossils, including hominin specimen KNM-OG 45500. Members 1 and 7 both contain clay-rich deposits that have been pedogenically modified into paleosols (UM1p and UM7p, respectively). This study provides the first detailed mineralogical and geochemical analyses of the clays of this important Pleistocene basin. The smectitic clays, which show abundant evidence for pedogenesis, were apparently originally deposited under lacustrine conditions. They have an average structural formula of (Ca0.01Na0.32K0.26)(Si3.76Al0.24)(Al0.86Ti0.04Fe0.68Mg0.42)O10(OH)2. The high layer charge clays indicate diagenetic alteration of detrital clay derived from the volcanic drainage basin, probably involving alkaline waters of variable salinity. Despite overall lower salinity compared to other Plio–Pleistocene basins of the region (e.g. Olduvai Gorge), the basin still shows evidence for authigenic clay mineral precipitation. Clay chemistry and bulk geochemical indicators of pedogenesis imply that UM1p clays more closely reflect depositional paleo-waters, whereas UM7p clays have been more pedogenically altered due to subaerial exposure. UM1p smectites show some Mg enrichment near the western Lava Hump locality, consistent with discharge of Mg-bearing paleo-waters from a volcanic aquifer into a siliceous and alkaline (though not highly saline) paleo-lake. UM7p smectites were deposited in a more saline paleo-lake, but have lost substantial amounts of Mg due to post-depositional weathering. Locally abundant artifacts and vertebrate fossils found in these deposits accumulated at times following deposition of the lacustrine clay, probably concurrent with pedogenesis. The limnological conditions associated with initial clay deposition, therefore, preceded hominin occupation of the exposed surfaces.

This article critiques the decision of the Court of Appeal in Re SA (Declaration of Non-Recognition of Marriage) [2023] EWCA Civ 1003. In Re SA the Court of Appeal held that: (1) by operation of section 16 of the Matrimonial Causes Act 1973, a voidable marriage is not void at its inception and is therefore not caught by section 58(5)(a) of the Family Law Act 1986, and (2) the effect of section 16 of the 1973 Act is that a voidable marriage starts off fully valid but only on making a decree absolute of nullity becomes invalid. This article contends that the approach adopted by the Court of Appeal in SA is conceptually challenging, based on a misreading of the statutory language, and is directly contrary to long-established and powerful authorities.

Natural soils change by long-term pedogenetic mechanisms, but tillage effects can also strongly affect the evolution of soils, mainly their physicochemical properties. The present paper describes the impact of fertilizers and amendments on soil mineralogy in experimental plots, without plant interaction.

The soils of the 42 plots experiment at the INRA experimental station in Versailles (France) have been managed with fertilizers without plant growth since 1929. Strong changes in pH were observed and cation exchange capacities doubled between low and high pH (from 3.6 to 8.2). Strong acidification caused more evolution in the clay particle distribution without selective action on the clay composition.

While the clay content varied only slightly, the organic matter content changed considerably, decreasing with non-organic treatment and increasing in the plot with manure treatment. The major clay minerals in the experimental plots are two disordered illite-smectite mixed-layer minerals, with minor amounts of illite/mica and kaolinite. Most treatments effected only minor changes in clay mineralogy. However the illite (non-expandable mineral) content increased in plots with K addition either as KCl treatment or in manure amendments by increasing the illite content and the illite (non-expandable layer) content of the I-S minerals. Manure changed the I-S mineral to a greater extent.

In the search for rare earth and other critical elements in coal measures, the coals are emphasized with lesser consideration for the accompanying rocks. In this investigation, the focus is on a lanthanide-rich, 315–317 Ma (after Machlus et al., Chemical Geology, 539, art. no. 119485, 2020) volcanic ash-fall trachyandesite to trachyte tonstein which occurs in association with the Middle Pennsylvanian Duckmantian-age Fire Clay coal in eastern Kentucky. The tonstein was deposited largely during peat accumulation, although it is known to occur at the base of the coal or within the underclay. The mineralogy is dominated by kaolinite with illite and quartz as minor to major minerals. A number of accessory minerals, as detected by X-ray diffraction + Siroquant XRD software and scanning and transmission electron microscopy (S/TEM), include REE-bearing phosphates (apatite, crandallite, florencite, monazite), and Y-bearing zircon. The highest rare earth element + Y concentrations occur in the weathered tonsteins, probably due to the concentration of these minerals after weathering of kaolinite from the rock.

Various physicochemical characteristics of a sepiolite sample from the Eskişehir area, Turkey, were investigated to help in making predictions about possible uses of the material. The sample was examined by chemical analysis (CA), thermal analysis (DTA/TGA), X-ray diffraction (XRD) analysis, particle-size analysis (PSA), linear dilatometry (LD), scanning electron microscopy (SEM), mercury porosimetry (Hg-Por.), and low-temperature nitrogen adsorption/desorption (N2-AD) techniques. The CA and XRD data indicated that the sepiolite contains only 6% dolomite by mass. The XRD patterns showed that sepiolite anhydride, enstatite, diopside, and opal-CT form upon heating the sepiolite above 600, 800, 900, and 1200°C, respectively. The maximum rate of endothermic changes in the DTA and TGA curves were observed at 82, 287, and 491°C, corresponding to the loss of external, zeolitic, and bound water from the sepiolite, respectively. Dehydroxylation and recrystallization of the sepiolite were fastest at 845°C and 862°C, respectively. The LD curve indicated that the shrinkage began at 800°C and reached 4.0% at 1000°C. The proportion of particles with diameters of <2 µm, and the external surface area of the long-term (24 h) water-treated sepiolite were determined by PSA as 79% by volume, and 8 m2g−1, respectively. The SEM view revealed discrete bundles of sepiolite fibers of various lengths. The specific surface area found from adsorption data was 316 m2g−1. The specific micro-, meso-, macro-, and total-pore volumes obtained from the combination of Hg-Por. and N2-AD results were 0.16, 0.21, 0.45, and 0.82 cm3g−1, respectively. The average macropore and micro-mesopore radii in the sepiolite were estimated (using the Hg-Por. and N2-AD data) tobe 35 and 2.4 nm, respectively.

The characterization of freshly cleaved mica surfaces for surface structure and chemical composition was briefly reviewed and focused on surface crystal chemistry using X-ray photoelectron spectroscopy (XPS) and other surface-sensitive techniques. This paper considers micas, which are useful as a first approximation for the behavior of many clay surfaces. Emphasis was given to phyllosilicate XPS binding energies (“chemical shift”), which were described and used to obtain oxidation state, layer charge, and chemical bonding information from the chemical shifts of different peaks. The chemical shift of the Si2p binding-energy to lower values can result from a negative charge increase because of Si4+ replacement by Al3+ and/or Fe3+. The apparent interlayer coordination number reduction from twelve to eight at muscovite and tetraferri-phlogopite (001) surfaces was indicated by the XPS measured K2p binding-energy and is consistent with bond relaxation. Although chemical shifts are valuable to distinguish chemical bonding and oxidation state, chemical shifts usually cannot distinguish between different Al coordination environments where Al is in both tetrahedral and octahedral sites.

The objective of this study was to design new, functional, nanostructured materials from the abundant clay mineral kaolinite, in spite of development problems with the interlayer chemistry of kaolinite because of its non-swelling properties. A particular goal of this work was to graft, in a controlled way, alkylammonium groups onto the aluminol interlayer surfaces of kaolinite. This was successfully achieved by soft-chemical approaches, more specifically by the melting intercalation process of alkylammonium ionic liquids which were synthesized for this purpose. The resulting nanohybrid materials were characterized chemically and structurally by X-ray diffraction analysis, thermal analysis (TG/DTA), 13C cross polarization magic angle spinning nuclear magnetic resonance spectroscopy, and Fourier-transform infrared spectroscopy. The amount of grafted organic material was quantified from TGA results. Alkylammonium salts with a short alkyl chain were grafted directly using a melting reaction at 180°C under N2 involving the in situ displacement of dimethylsulfoxide (DMSO) from a DMSO-kaolinite pre-intercalate; for longer alkyl chains, the grafting was done in two steps. In the first step, the corresponding amino-alcohol was grafted into the kaolinite by displacement of DMSO from the interlayer space. The second step consisted of quaternarization of the grafted material by reaction with iodomethane or iodoethane.

This study offers a fresh explanation for the characterisation of the women in Luke 23.27 as mourning. It argues that the uniquely Lukan material of women mourning on the walk to Calvary subtly fashions that walk into a funeral procession. The phrase μὴ κλαίɛτɛ in the following verse, Luke 23.28, recalls accounts of Jesus bringing the dead to life earlier in the Gospel, thereby evoking the concept of resurrection. Luke 23.27-8 works in conjunction with material later in Chapter 23 about the ritual preparation of Jesus’ body, to portray funerary ritual for Jesus conducted in reverse (the funeral procession precedes rather than follows the preparation of the body). This inverted order of funeral allusions adds extra resonance to the endpoint of the Gospel, casting it as the logical culmination of a reverse funeral—the resurrection of Jesus from death to life. The interpretation in this paper highlights one way that lived ritual experiences among the Gospel's readers, in this case, the paradigm of funeral ritual, informed the narrative technique in the Gospel of Luke, complementing other well-recognised uses of Greco-Roman rhetorical devices and literary themes.

Clay minerals from soils of a red-black soil complex developed from basaltic parent material in Sardinia are formed along a short toposequence (200 m). At the foot of the sequence, a clay-rich, black Vertisol forms, whereas at the summit, the soil is a dark reddish-brown Inceptisol. X-ray diffraction, infrared spectroscopy (FTIR), cation exchange capacity (CEC) and permanent and variable charges analyses were used, and the data show that clay minerals varied according to soil horizon and topographic position of the soil. Clay minerals in the Inceptisol are dominated by kaolinite and mixed-layer kaolinitesmectite (K-S, K:S >0.5), whereas the Vertisol contains smectites and K-S with K:S proportions <0.5. In the Vertisol, the proportion of kaolinitic layers in the K-S increases from the C horizon (K:S ∼0.35–0.40) to the Ap horizon (K:S ∼0.40–0.45). This soil clay-mineral distribution, in relation to topography, is similar to that reported for other (kaolinitic) red-black (smectitic) soil associations in subtropical and tropical areas. The sequence forms by downward drainage on summits and slopes, and buildup of ions in ‘lows’ produces smectites. Fourier transform infrared spectra indicate that two types of smectite are formed in the C horizon of the Vertisol; one is more ferric (Fe-beidellite, nontronite), the other more aluminous. Mineralogical evolution in the soil profile (from C to Ap horizon) shows a decreasing proportion of ferric smectite layers (compared to the more aluminous smectite layers). This would indicate that ferric smectite layers are preferentially transformed (or dissolved) to give kaolinite layers, with Fe precipitating as oxides and/or oxy-hydroxides or retained partly in kaolinite layers. Because the surface properties of clay minerals are related to mineralogy, the CEC (33–41 cmol kg−1) in the brown Inceptisol is ∼50% pH-dependent charge while in the Vertisol up to ∼75% of the CEC (48–61 cmol kg−1) comes from accessible permanent charges.

Tropical soils range from nutrient-depleted lateritic soils rich in halloysite or kaolinite to Inceptisols rich in interstratified kaolinite-smectite (K-S), smectite, or related 2:1 clays. Given the strong influence of clay minerals on tropical soil quality, better understanding of factors influencing their occurrence is important for modeling and managing tropical environments. This study examines the alteration of smectite to kaolinite by way of intermediate K-S and halloysite in a 120 ka moist tropical chronosequence. Iron-rich smectite (11.6 ± 2.2% Fe2O3) is the dominant mineral in Holocene soils (1–8 ka) originating from sediments rich in plagioclase and clinopyroxene. The cation exchange capacity (CEC) of smectite is 54–84 cmolc/kg and pH is 6.1 to 7.4. Within 50 ka, smectite fixes Al-hydroxy complexes into interlayers, K+ is retained preferentially over Ca2+, and 2:1 layers are stripped of tetrahedral sheets; the resulting K-S inherits flaky smectite crystal habit and the 2:1 layers — which only expand partially — include Al-hydroxy smectite and some illite-like layers. After 50 ka, the dominant mineral is K-S, the CEC is 18–28 cmolc/kg, and the pH is 5.3. Flaky Fe-kaolinite with ~10% residual smectite layers and halloysite (7.4% Fe2O3) also occur in 50 ka soil. The 120 ka soils are dominated by flaky Fe-kaolinite (<10% residual smectite layers) and halloysite (4.9% Fe2O3), and Fe-poor hexagonal kaolinite also occurs (5–10% of soil). The CEC is 11–16 cmolc/kg and the pH is 4.7–5.3.

Changes in crystal chemistry of the soil clays (decreasing Fe, Mg, Ca, and K; increasing Al) over time reflects two reaction mechanisms: (1) cell-preserved transformation of smectite layers to kaolinite layers that accompanies conversion of smectite to K-S and eventually kaolinite; this results in the formation of flaky Fe-rich kaolinites after 50 ka; and (2) dissolution of K-S followed by crystallization of halloysite. Neoformation of hexagonal kaolinite and/or halloysite with low Fe (<3% Fe2O3) follows dissolution of Fe-kaolinite or halloysite after 100 ka. This sequence is probably common in moist tropical soils and these findings may inform modeling of soil composition in tropical landscapes where tectonic, volcanic, or geomorphic activity periodically exposes unweathered parent material, producing a range of soil ages.

The presence of nitrate and other redox-active anionic contaminants in terrestrial ecosystems poses a significant risk to humans and other forms of life on Earth. The purpose of the present study was to test a potential in situ system, using poly-(D) glucosamine (chitosan) adsorbed to mineral surfaces under redox-active conditions in order to degrade nitrate to lower oxidation states. Chitosan is a linear polysaccharide derived from the chitin found in the shells of shrimp and other shellfish. Five different loadings of chitosan (0, 0.075, 0.25, 0.50, and 1.0 g/L; labeled C0, C1, C2, C3, and C4, respectively) were adsorbed to ferruginous smectite (SWa-1) to form chitosan-SWa-1 composites (CSC) in the pH range 5.8–4. The CSC was then reduced by Na2S2O4 in a citrate-bicarbonate buffered dispersion and washed free of excess salts under inert-atmosphere conditions. Upon addition of the nitrate, the solution pH remained slightly acidic, ranging from 5.5 to 4.7. Samples were analyzed for Fe(II) content, reacted with a NaNO3 solution, and then re-analyzed for structural Fe(II) content. Supernatant solutions were analyzed for nitrate, nitrite, and ammonium. In samples C1 to C4, extensive concentrations of nitrite were observed in the supernatants with a corresponding increase in the reoxidation of structural Fe(II), proving that a coupled redox reaction had occurred between the nitrate and the structural Fe in the clay mineral. The most efficient loading, defined as the largest percentage of adsorbed nitrate reduced to nitrite, occurred in sample C1. The total amount of nitrate reduced and Fe(II) reoxidized followed the trend 0 = C0 < C2 < C3 < C4 ≈ C1. Chitosan showed the potential to reverse the surface charge of constituent clay minerals, thereby enabling the CSC to remove nitrate anions from aqueous mineral systems via redox reactions with structural Fe(II) in clay minerals.

Material Order is an academic consortium of material sample collections for art, architecture, and design disciplines. Founded by the Graduate School of Design at Harvard University and Fleet Library at Rhode Island School of Design and since comprising several more institutions in the US, it provides a community-based approach to management and open access utilizing and developing standards and best practices. Now in its twelfth year and reaching a level of maturation, Material Order offers research and pedagogical value to current and potential members and the larger design communities.

Todorokite is a common manganese oxide mineral, with a tunnel structure, found in Earth surface environments, and is easily synthesized from layered birnessite. The aim of the current study was to prepare birnessites with different average manganese oxidation states (AOS) by controlling the ${\text{MnO}}_4^{-}{\text{/Mn}}^{2+}$\$\end{document} ratio in concentrated NaOH or KOH. A series of (Na,K)-birnessites, Na-birnessites, and K-birnessites with different AOS was synthesized successfully in strongly alkaline media. The (Na,K)-birnessites and Na-birnessites prepared in NaOH clearly contained both large (500–1000 nm) and small (40–400 nm), plate-shaped crystallites. The K-birnessites prepared in KOH media consisted mostly of irregular (100–200 nm), plate-shaped crystallites. The degree of transformation of birnessite to todorokite at atmospheric pressure decreased as the AOS values of (Na,K)-birnessites and Na-birnessites increased from 3.51 to 3.80. No todorokite was present when a Na-birnessite with an AOS value of 3.87 was used as the precursor. Pyrophosphate, which is known to form strong complexes with Mn3+ at a pH range of 1–8, was added to a suspension of (Na,K)-birnessites in order to sequester the available Mn3+ in (Na,K)-birnessites. Removal of Mn3+ from birnessite MnO6 layers by pyrophosphate restricted transformation to todorokite — no (Na,K)-birnessite transformed to todorokite after pyrophosphate treatment. The interlayer K+ initially within (Na,K)-birnessites could not be completely ion-exchanged with Mg2+ to form todorokite at atmospheric pressure. No todorokite was forthcoming from K-birnessites even from those with small AOS values (3.50).

Vibrational spectra of two kaolinite-dimethylsulfoxide intercalates, obtained using inelastic neutron scattering (INS), were analyzed with a view to understanding the dynamics of the hydrogen atoms in the structure. The main focus was on the spectral region 0–1700 cm−1, which is difficult to analyze using optical spectroscopy. The experimental vibrational spectra of kaolinite:dimethylsulfoxide and kaolinite:d6-dimethylsulfoxide collected using two different spectrometers were interpreted by means of the solid-state DFT calculations. Calculated spectra were obtained by both normal-mode analysis and molecular dynamics going beyond the harmonic approximation. The Al-O-H bending modes were found to be spread over the large interval 100−1200 cm−1, with the dominant contributions located between 800 and 1200 cm−1. The shape of the individual hydrogen spectrum depends on whether or not the respective hydrogen atom is involved in an O-H⋯O hydrogen bond and on its strength. The modes corresponding to the in-plane movements of the inner-surface hydrogen atoms are well defined and always appear at the top of the intervals of energy transfer. In contrast, the modes generated by the out-of-plane movements of the hydrogen atoms are spread over large energy intervals extending down to the region of external (lattice) modes. The C-H modes are concentrated mainly in the three regions 1200–1450 cm−1, 800–1100 cm−1, and 0–400 cm−1. While the first two regions are typical of the various deformational modes of methyl groups, the low-energy region is populated by the modes corresponding to the movements of the whole dimethylsulfoxide molecule.

Chlorites formed as a replacement of phenocrysts in metabasites from the pumpellyite-actinolite to lower-greenschist facies Mikabu and North Chichibu belts in southwest Japan were studied by X-ray powder diffraction, electron microprobe analysis (EMPA) and high-resolution transmission electron microscopy (HRTEM). The metabasites contain a small quantity of fine-grained smectite and corrensite in the <1 μm size fraction. The chlorite also contains trace amounts of Ca, Na and K, which generally appear to be associated with smectite stacked in chlorite packets. The smectite layers comprise up to 13% of the chlorite domains. Theoretical estimates of the smectite ratio by the Wise method using EMPA data coincide well with the ratio determined based on HRTEM observations in most chlorites. However, in some chlorites with high proportions of Ca, Na and K, the cations cannot be reasonably attributed to smectite alone. Based on the present analyses, Ca, Na and K cations are also hosted in discrete interstitial phases of fine-grained smectite and corrensite as possible retrograde metamorphic products. These findings suggest that care should be taken in application of the Wise method to estimate the smectite ratio, and that the whole-rock chlorite composition may not be suitable as a geothermometer.

Drinking-water supply remains a significant challenge in tropical areas; to help meet this challenge, the purpose of the present study was to manufacture low-thermal conductivity ceramic membranes suitable for the retention/removal of particles found in non-potable water. These membranes with significant chemical and mechanical resistances were developed from Cameroonian clays, cassava starch, and bovine bone ash. Up to 30% of Cassava starch and bovine bone ash were added to the membrane as porogens (materials used to make pores in membranes). Membranes were manufactured by uniaxial pressing, drying at 105°C, and sintering at 1150°C for 2 h. The effects of various types of porogen on the thermal behavior, microstructure, flexural strength, porosity, and permeability of ceramic membranes were investigated to determine possible applications of those membranes for water filtration in the tropics. The thermal conductivity of membranes produced without a pore-forming agent (SM0) was greater (0.54 Wm–1K–1) than those produced with starch (SM1 and SM3) (0.45–0.40 Wm–1K–1) or bovine bone ash (SM2) (0.49 Wm–1K–1). The total porosity of SM0s (30.72%) was less than those of starch and bovine bone membranes (37.87–45.99%). The average pore size (0.04 μm) of SM2 membranes was the smallest: SM0 (0.09 μm), SM1 (0.10 μm), and SM3 (0.07 μm). The maximum pore size was 0.37 μm, indicating that membranes contain mesopores and macropores. The flexural strengths of SM1 and SM3 membranes (8.85 and 6.97 MPa, respectively) were less than those of SM2 (10.53 MPa) and SM0 (10.28 MPa), and water permeability from 108 L/h·m2 bar to 2198 L/h·m2 bar. Filtered water properties showed that pH values were upgraded from 5.9 to 7, the turbidity reduction rates and levels were >94% and <0.65 NTU. Particle-size distributions moved from 1150–39,000 nm in polluted water to <2 nm in filtered water. Judging by the sizes of particles present in filtered waters, these membranes may be suitable for elimination of viruses, pigments, proteins, colloids, and bacteria.