Hydrous Mica Research Articles

Thermodynamics of K‐Ca exchange in soils

SUMMARYSurface soils from six ADAS long‐term experiments, including two on Andover series, were examined for K‐Ca exchange by exchange isotherm and calorimetric methods. Preference for K decreased in the order Worcester > Clwyd > Newport. The latter two acid soils showed ‘no preference’ and Ca preference respectively. Preference for K decreased with decreasing surface area and increasing surface charge density. The enthalpic factor favoured K preference in every soil, but the entropic factor favoured Ca preference in all but one soil. The magnitude of the enthalpic factor was greater than that of the entropic factor, resulting in K preference, in the Andover, Hanslope and Worcester soils, while the reverse was the case in the Newport soil. In the Clwyd soil, enthalpic and entropic forces were counterbalanced. These relative contributions were related to the interactions between clay mineralogy, pH and manurial history.Differential heat measurements, ‐d (ΔHx)/dx revealed exchange site heterogeneity in five of the soils. Five regions of constant ‐d (ΔHx)/dx were found, ranging from 6 to 12 kJ eq−1, a maximum of three occurring in any one soil. These were assigned to montmorillonite (two regions), mica, hydrous mica and vermiculitic mica surfaces. The 2: 1 phyllosilicate contents of the clay fractions of the whole soils calculated thus differed from those determined by XRD analysis of the clay fractions.Residual K decreased the cation exchange capacity of some of the soils but did not alter their surface areas. Its effect on K preference, K binding strength and the arrangement of the components of the system (the entropic factor) was complex.

Smectite synthesis in volcanic ash soils ‐ a probable cause of zinc deficiency in wetland rice

Abstract In an effort to ascertain the role of clay type in the widespread Zn deficieny on certain important wetland rice soils, 200 surface soil samples both from problem and non‐problem areas were investigated for clay mineralogy and available Zn content and correlated, as information on this aspect is scanty. Results showed prevalence of Zn deficiency on soils having x‐ray amorphous and smectitic clays of volcanic ash origin. Smectite synthesis from the x‐ray amorphous constituents particularly appeared responsible for the disorder presumably either through Zn incorporation in the crystal structure to form ‘sauconite’ or through its preferential sorption on the synthesized crystallites. Other mineral species ‐ chlorite, vermiculite, kaolinite, halloy‐site and hydrous mica ‐ did not appear to be related to Zn deficiency on these soils.

Loess in the Cypress Hills, Alberta, Canada

Loess deposits in the Cypress Hills were derived from a single, local source located adjacent to the southwestern margin of the plateau. The distributions of sand, clay, and heavy minerals, the changes in thickness of the deposits, and the orientation of the clasts all indicate that the direction of transport was from southwest to northeast. The changes in the textural composition of the loess are reflected in variations in the sorting, with the best sorted material being located in intermediate positions. The loess is depleted in feldspar relative to the source sediments. This depletion is due to the combined effects of weathering of the feldspar to hydrous mica clays and aeolian sorting. The platy clay mineral grains would be less likely to be incorporated into the aeolian load than the spherical and bladed angular quartz grains, and the partially weathered feldspar grains would be similarly preferentially winnowed. The variations noted indicate that loess deposits formed from a single local source will not have uniform textural characteristics, but will vary in texture, sorting, and mineralogy. Similar variations would be expected in continent-wide loess sheets, although the effects of each local source would be masked by the long-distance transport component of the sediment.

Critical potassium potentials for crops. I. The effect of soil type on the growth of ryegrass and creeping red fescue

SummaryThe quantity: potential relationships for Ca→K exchange in six soils were evaluated, where potential is defined by ΔGK,Ca+Mg. Using the percentage K saturation of the CEC as the index of quantity, the Worcester Series soil, rich in hydrous micas, was shown to have the highest concentration of K selective sites, and Newport Series soil, with mainly kaolinitic clay, the lowest. The other soils, containing mainly smectites, had intermediate K selectivities.An algebraic transformation of this relationship to separate the effects of exchangeable K and CEC showed that 0.01 m CaCl2 released more K than m ammonium acetate. From the exchangeable K : ΔG relationship, two regions of K buffering were observed for all but the Newport soil, the transition occurring at a mean ΔGK,Ca+Mg value of −20.7 kJ mol−1, signifying the K concentration below which K from ‘perlpheral’ regions of micaceous minerals is released. This may explain why the percentage K saturation of the CEC of a soil cropped exhaustively (without K manuring) in the field does not drop below a minimum value.Based on pot experiments, exhaustion and optimum K potentials (ΔGexh and ΔGopt) were derived from second‐degree polynomials fitted to the response curves of plant dry matter yield against ΔGK,Ca+Mg for five soils, the Worcester soil showing little response. ΔGexh was inversely related to the 2 : 1 layer silicate content of the soil (r2=0.98 and 0.94 for ryegrass and fescue respectively), and similarly, ΔGopt, to their CEC values (r2=0.74 and 0.77). Potassium uptake was more closely correlated with exchangeable K than with ΔGopt.

Soil Clay Mineralogies in Relation to Fertility Management: Effect of Clay Mineral Types on Ammonium Fixation under Conditions of Wetland Rice Culture1

AbstractTo assess the influence of soil clay mineralogy on the efficiency of normally used nitrogeneous fertilizers on soils under wetland rice (Oryza sativa L.) culture, ammonium fixation studies were carried out under hydromorphic conditions on 14 soil clays with a range of mineralogical compositions. Beidellitic and vermiculitic clays fixed more than 90% of the applied ammonium, while montmorillonitic clay fixed about 50%. Clays of all other mineralogical compositions, containing chlorite, hydrous mica, halloysite, kaolinite, and amorphous material did not fix significant amounts of ammonium. There is a need to develop management practices for soils of beidellitic and vermiculitic clay mineralogies to increase efficiency of ammonium (or ammonium‐forming) fertilizers on them through minimizing fixation.

Clay mineralogical and ammonium fixation characteristics of some tropical upland rice soils

Abstract In view of the agronomic and economic significance of NH4 fixation in soils, an attempt has been made to relate this to the most reactive mineral constituents of soils ‐ the clay minerals, under the temperature‐moisture regimes normal to tropical upland rice soils. Laboratory fixation study was done with NH4, concentrations similar to those common in soils upon N fertilization, and under alternate wetting and drying at ambient temperatures rather than at 100°C as in many published studies. Results of the investigation show that soil clays with dominant vermiculite and montmorillonite fix the greatest proportion of applied NH4 (94 and 91%), followed by beidellite (72%) and x‐ray amorphous (45–64%) clays. Fixation is negligible (10%) in the clay with mineral suite consisting of hydrous mica, halloysite, and chlorite. Crystallinity of minerals seems to influence NH4 fixation appreciably.

Soil clay mineralogy in relation to fertility management: Effect of soil clay mineral composition on potassium fixation under conditions of upland rice soils

Since K fixation in soils is largely a function of clay mineralogy, an effort was made to elucidate the influence of mineralogical variations in soil clays on K fixation, under the moisture-temperature regimes usually prevalent in tropical upland rice soils. Beidellitic clay turned out to be the most severe fixer of addedK (80%), followed by vermiculitic (69%) clays. Fixation is not appreciable (< 15%) in clays consisting of montmorillonite, x-ray amorphous material, chlorite, hydrous mica, kaolinite and halloysite. Fixation by beidellite and vermiculite clays is reduced by the simultaneous occurrence of other mineral species.

Clay minerals formed from micas and chlorites in some New Zealand soils

AbstractClay mineralogical differences between eight soils in South Island, New Zealand, are related to differences in climate, vegetation, and formation time. Alteration of chlorite follows the sequence chlorite→interlayered hydrousmica→chlorite-swelling chlorite→chlorite-vermiculite, with increased weathering leading to the destruction of the chloritic layers. Mica (muscovite) follows two alteration sequences depending on the overlying vegetation. Under tussock grassland the sequence is mica→mica-vermiculite→mica-beidellite→beidellite. This sequence is also followed under beech forest, together with the sequence of mica→vermiculite→beidellite, with pedogenic chlorite forming when the pH is &gt; 4·5. All but one of the interstratified products (the interlayered hydrous mica) appear to be based on a 1:1 regular interlayering of the two components.

Soil clay mineralogies in relation to fertility management: Effect of soil clay mineral compositions on potassium fixation under conditions of wetland rice culture

Abstract To evaluate the impact of soil clay mineralogy on the utilization efficiency of potassium fertilizers by rice, potassium fixation studies were made on fourteen soil clays having a range of mineralogical compositions. Soil clay with monomineralic beidellite fixed the highest proportion (76%) of the added potash, followed by clays containing either dominant or major vermiculite (51–66%). Fixation was significantly less severe (<35%) in vermiculitic clays containing hydrous mica. All the clays with mineralogical suites without beidellite or vermiculite, but consisting of montmorillonite, chlorite, hydrous mica, halloysite, kaolinite, and x‐ray amorphous material did not fix appreciable amounts (<18%) of the applied potassium.

Structure And Properties of Oil Sands Clay Tailings

Abstract Oil sands clay tailings settle to a gel-like sludge or slime which is still relatively low in solids content, and the tailings show extremely slow dewatering beyond this point. These characteristics imply a significant degree of structure in the slime. Based on a comparison of some of the rheological and stability characteristics of the material and those of a bentonite gel over a range of pH, a structure is proposed which depends for its stability on the presence of residual bitumen as well as a clay-bound organic component. Introduction The clay slimes associated with the hot water extraction of Athabasca oil sands result from the settling of the clay fraction of the process tailings. They are of gel-like consistency, still containing up to 80% water. Further dewatering beyond this point is extremely slow, and the slimes have already accumulated to a massive degree as a result of the Great Canadian Oil Sands Ltd. (GCOS) operation. The accumulation is described in detail by Camp(1). The oil sands clay slimes have been likened to similar slimes produced by other extractive industries, including phosphate, diamond, china clay and bauxite refining(2). Although impoundment and disposal techniques for these wastes are in general similar throughout the industries, the compositions of the various slime types are sufficiently different to warrant individual and detailed examination if attempts are to be made to dewater them further or to reduce the volume produced. Dewatering is desirable in that it would release large quantities of water locked up in existing slime ponds. Volume reduction would also reduce the need for the very large and environmentally worrisome impoundment areas now used. Some of the slimes are readily identifiable as having their properties controlled by the presence of swelling clays. Phosphate slimes owe their characteristics to the presence of attapulgite and montmorillonite(3), both important as swelling clays, and used accordingly in drilling muds as rheology control agents. Saponite, another well-characterized three-layer swelling clay of the smectite group, has been identified as the structure-forming agent in diamond mine slimes(4). On the other hand china-clay slimes owe their properties mainly to the presence of micas and kaolinite(5); -bauxite (red mud) slimes consist predominantly of hematite, complex aluminum silicates, silicate hydroxides and compound carbonates, with some evidence for the presence of kaolinite, chlorite and hydrous micas(6). In the case of oil-sands slimes, montmorillonite has been implicated as a factor in the poor dewaterability of these materials(l). Its role has remained unclear, however and close inspection of available data would seem to indicate that stable oil-sands slimes may be formed in the absence of any well defined swelling clay. There is evidence that sediment volumes, Technology, January-March, 1979, Montreal and consequently water retention, are related to structure formation (7). The structure in non-Newtonian liquid systems is also reflected in their flow properties. This study therefore compared certain rheological and stability characteristics of oil-sands slime, which contained no detectable swelling clay content, with a relatively pure montmorillonite gel.

Review of engineering behaviour of marine clays in Eastern Canada

Leda clay deposits are thought to belong to a single marine episode that sedimented in the Champlain Sea between 12000 and 9000 years BP. Differential uplift ended the marine episode and subsequent sediments were deposited in estuarine followed by near-freshwater to lacustrine conditions. Rock-forming minerals consisting of feldspars, quartz and amphiboles make up a large part of the clay size fraction. The dominating phyllosilicates are micas and illites, or hydrous micas. The fabric of the deposit consists of an assemblage of silt and clay size rock fragments in which clay minerals are generally randomly oriented.Major engineering problems are reviewed against the background of depositional history, nature of the soil fabric formed during sedimentation, subsequent structural alterations, mineral composition and pore water chemistry, all among the more important factors responsible for the engineering behaviour of these soils.

Replacement in the Octahedral and Interlayer Positions in Micas

IN a paper read at the eleventh National Clay Conference, Ottawa, 19621, one of us (I. Th. R.) presented results of a radioactive tracer technique and infra-red spectroscopy applied to dioctahedral and trioctahedral micas. The mineral powders had been pre-treated with deuterium oxide and tritium-bearing water. The results indicated that dioctahedral hydrous micas contained water molecules in interlayer positions substituting some of the K+ ions of the ideal end member. The necessary charge balance in the crystal model was achieved by substituting some of the apical O's by OH (or by filling in H+ in vacant positions of the octahedral layer).

Moisture‐Expansion Characteristics of a Fired Kaolinite‐Hydrous Mica‐Quartz Clay

The natural and autoclave moisture expansions of a fired clay containing kaolinite, hydrous mica, and quartz were studied. A relation was established between the two expansions, which, together with a moisture‐expansion peak at about 1000°C, is explained in terms of the poorly crystalline and noncrystalline phases developed during firing. When low‐fired specimens that were exposed to moisture were desorbed by re‐firing, the shrinkage that accompanied the loss of moisture was interrupted by an expansion at about 5OOOC. This expansion depended on the firing temperature and probably was caused by the dehydroxylation of hydrous mica regenerated from mica anhydride by moisture sorbed after firing. In the case of specimens fired above the moisture‐expansion peak, the moisture responsible for expansion must be held in much the same way in the natural and in the autoclaved specimens. A study of the kinetics of moisture expansion showed a linear relation between the magnitude of expansion and the log of time for the period during which the specimens were exposed to moisture in the air. A similar relation existed for specimens fired from 1000° to 1150°C and autoclaved from 2 to 200 hours. It is further shown that it was possible, using preexisting data, to estimate, from the magnitude of expansion after a short period, the expansion to be expected at any time within the period to which the preexisting data referred.

CLAY MINERAL STUDIES OF SOME EGYPTIAN DESERT AND NILE ALLUVIAL SOILS

SummaryEgyptian desert soils are generally of coarser texture than Nile alluvium with only slight depositional changes within the same profile. Total N is lower in desert soils than in alluvial soils under similar climatic conditions. On the basis of clay mineral analysis the soils fall into four groups, having (1) kaolinite (Ganah and Kharga), (2) montmorillonite (Beris, Boulaq, Nile alluvium), (3) hydrous mica (Kharga), (4) attapulgite (desert road), as the dominant mineral.The very slight difference in clay mineral composition between the soil and subsoil or parent material indicates that clay minerals in these soils are derived mainly from a pre‐existing sediment.The mechanical analysis and mineralogical study of the heavy mineral fraction showed that the soils of Kharga oasis are either water‐laid sediments (Boulaq and Beris) or wind‐modified (Ganah and Kharga).Whether or not the qualitative similarity of the clay minerals of the soils from mid and southern Kharga with those of the Nile alluvium indicates a genetical relationship cannot be definitely ascertained from this study.

Polymorphic phase changes during heating of dioctahedral layer silicates

Abstract It is demonstrated that dioctahedral layer silicates, upon heating, transform into trioctahedral modifications. The mechanism of the transformation must be a redistribution of the sixcoordinated trivalent ions over all the octahedral positions; every site will be occupied by two-thirds Al-atom. In this way pyrophyllite, e. g., will aquire a lalc-like structure. Besides pyrophyllite, the studied minerals are hydrous mica, montmorillonite, and paragonite.

Studies in Position and Mobility of the H Atoms in Hydrous Micas

AbstractThe hydrogen content of dioctahedral and trioctahedral micas has been investigated by means of infrared spectroscopy and radioactivo measurements. Dioctahedral and trioctahedral micas have been treated with deuterium oxide and tritium-bearing water. The introduced isotopes of hydrogen have been determined after various thermal treatments.It is concluded that dioctahedral hydrous micas may represent mixed crystals between K(Si3Al)Al2O10(OH)2 and H2O(Si3Al)Al2O9(OH)3, whereas trioctahedral micas seem to represent mixed layer minerals between phlogopite and vermiculite.

Genesis of Alluvial Soils in Arid and Semi-arid Tracts

The genesis of alluvial soils in arid, and semi-arid tracts of West Uttar Pradesh is reported in this paper. The analysis of clay fraction has given a clue that the clay fraction comprises a mixture of clay minerals like hydrous mica (Illite) and montmorillonite. The mineralogical analysis of fine sand fractions indicated that quartz, mien and feldspar wore the commonly occurring minorals in the light fractions and constituted moro than 95 por cent. Heavy minerals like magnetite, rutile, zircon, and apatito are found in traces. The minera- logical analysis of fino sand fractions thus indicated the origin of those alluvial soils from granitie and gneissie rocks and their further trans. port, by the action of water, to the plains. Depending upon the influence of local climatic factors and degree of weathering they have given rise to soils and clays with a mixture of clay minerala.

Weathering and soil formation in the arctic environment

In order to depict the nature of the weathering processes operating in the arctic regions, 4 Arctic Brown soil profiles from northern Alaska were studied. Examination of the sand and clay fractions indicates that chemical weathering is in operation; its magnitude, however, is of low order. Acid conditions in the surface facilitate the solution of carbonates, but their removal is incomplete as reprecipitation occurs within the profile. Because of increased concentration of Fe-stained opaque minerals near the surface, oxidation of Fe-bearing minerals was strongly indicated. On very sandy quartzose profiles, Fe, Al, and Mn are partially mobilized and partially translocated, suggesting a weak podzolic process. Clay-size minerals consist mainly of hydrous mica, kaolinite, chlorite, quartz, goethite, and feldspar. Hydrous mica, the most abundant clay mineral, was more hydrated at the surface, and goethite was present only in the surface horizon. Alteration of feldspar into a claylike substance was noted, but well-crystallized feldspar persisted in the clay fraction. A concentration of fines was present in the surface horizon of all Arctic Brown soil profiles. Whether this fine material forms in situ or is a result of aeolian deposition remains a moot question.

Mineralogy and origin of the yellow-brown sands and related soils

Summary Soils formed from wind-blown sand are found throughout New Zealand. In order to study their genesis the mineralogy of a large number of these soils from the Manawatu, Waverley, Dargaville, Ruakaka, Ahipara and the Canterbury Plains has been examined. The Manawatu and Waverley soils were similar in clay mineralogy, the clay minerals being micas, hydrous micas and vermiculite, with traces of halloysite. The pattern of clay content was consistent with the theory that most of the clay in these soils is derived from loess-like material blown in from the beaches after being eroded from older soils in the vicinity. A similar picture was found in a sequence from Dargaville, for the younger soils which were clearly wind-blown and had a clay mineral distribution very like the Manawatu soils. The older soils, however, appeared to be derived from water-deposited rather than wind-blown sand, and contained kaolin and gibbsite, but these also were derived from the sediment and not formed in situ. The Ruakaka soi...

Proposed Reference Illite from the Ouachita Mountains of Southeastern Oklahoma

AbstractAn exceptionally pure illitic clay is present in outcrops of the Blaylock Formation (Silurian) in the Ouachita Mountains of southeastern Oklahoma. Unweathered claystone samples from this unit in Beavers Bend State Park have been found to consist of a well-crystallized illite or hydrous mica. Impurities commonly found in illites such as non-clay minerals and non-micaceous clay minerals are conspicuously absent. The sample cannot be classified as a mica because it is hydrated and the particle-size distribution is in the clay size range. A detailed examination of the deposit suggests that it may have value as a reference illitic clay mineral.