Distribution of copper and zinc in volcanic ashes

The distribution of copper and zinc in volcanic ashes was investigated. It was found that the total copper of volcanic ashes decreased with the increase of their total silica, showing a close relationship between the total copper and the rock types of volcanic ashes. On the other hand, the total zinc showed no such correlation with the rock types.

The contents of copper and zinc in the constituent minerals Indicated that zinc was more concentrated in the heavy minerals and was closely related to the iron contents of the constituent minerals. According to the concentrations of copper and zinc in the constituent minerals and the total contents of the minerals in the andesitic ash samples, the distribution of these elements was determined to be the following order.

Cu: volcanic glass>plagioclase>pyroxenes> titanomagnetite

Zn; pyroxenes > volcanic glass> titanomagnetite>plagioclase

Since volcanic ashes belonging to rhyolite and basalt were overwhelmingly composed of volcanic glass, it was obvious that the distribution of copper and zinc was much greater in the volcanic glass of these ashes.     

Chemical and mineralogical studies on the citrus soils in Wakayama Prefecture,Japan

Wakayama Prefecture is one of the important districts of citrus production in Japan. The citrus groves are located in the northern districts of the prefecture along the watershed of the Kii, and Arita rivers. Geologically, the rocks in these districts are classified into crystalline schist, Palaeozoic Upper Chichibu and Mesozoic Cretaceous systems. The associated soils are chiefly members of the Red Yellow Podzolic and Lithosol group.⁷⁾     

Biological and mineralogical features of Andisols in the Mexican volcanic higlands

In the montane grasslands of Mexico, perennial grass and black Andisols are linked in a complex mechanism of soil formation in which both biogenic and mineral products interact. In this ecosystem, typical of the volcanic highlands, a sequence of profiles has been studied by macro- and micro-morphology, scanning and transmission electron microscopy (TEM), infra-red spectroscopy of soil samples and humic acid (HA) extracts, radiocarbon dating and pollen record, soil moisture and available water determinations and soil water analyses. The grass Muhlennberrgia macroura is important in the soil-forming process as it is the host of micro- and meso-fauna which produce abundant organic micro-aggregates. Soil formation began 7550 years ago and continued through several climatic and vegetation changes. The soil thickens as its age increases. Mineral neoformation is oriented towards allophane and halloysite, rather than Al-rich minerals such as imogolite and gibbsite, and high Si contents are observed in the soil water. The black Andisols have high water and carbon storage capacities and play a prominent role in regulating drainage. Presentday destruction of the grassland for potato cultivation will decrease the waterer reserve of these volcanic highlands.     

Soil formation on acid and basic volcanic ashes of different ages in Kamchatka

The use of tephrochronological data on the ages of volcanic eruptions and the corresponding ash layers buried in the profiles of forest soils in Kamchatka makes it possible to distinguish between two groups of volcanic soils related to different stages of the volcanic activity. In the Holocene, the southern group of volcanoes was characterized by the ejection of acid pyroclasts typical of the mature stage of volcanism (the stage of caldera formation). The northern group of volcanoes ejected basic pyroclasts typical of the early (basaltic) stage of volcanism. Thus, the effect of the full cycle of volcanism on the soil formation can be traced in the soil profiles. It is shown that soil formation in volcanic areas depends on the frequency and intensity of ash falls and on the composition of the pyroclastic material.     

Crystalline clay minerals of the soils derived from recent volcanic ashes in Hokkaido,Japan

For the past ten years much work has been carried out on clay minerals of volcanic ash soils. Most investigators have reported that allophane is dominant among clay minerals of volcanic ash soils and crystallizes to halloysite or meta-halloysite with the advance of weathering (1–8). On the other hand, UCHIYAMA, MASUI and ONIKURA (1960) found that montmorillonite predominates in the clay fraction of volcanic ash soil in Kawatabi (9). Furthermore, MASUI, SHOJI and UCHIYAMA (1966) showed that the major crystalline clay minerals of volcanic ash soils in the Tohoku district are montmorillonite, vermiculite, intergradient montmorillonite-vermiculite and chlorite (10). They also showed that these minerals increase with the advance of weathering and that kaolin minerals are minor constituents.     

On the nature of fresh volcanic ashes as parent material ejected from the Sakurajima and Aso volcanoes

There are few pedological studies in Japan of fresh volcanic ash. Fundamental information of the material from which Japanese volcanic-ash soils have developed, is of importance to obtain a better understanding of pedogenesis of such soils. The present paper deals with the mechanical. mmeralogical, and chemical characteristics of fresh ash ejected from the Sakurajima and Aso volcanoes which are among the most active in Japan.     

Chemical and mineralogical changes in a polygenetic soil of Galicia,NW Spain

The soils of Galicia, NW Spain, developed on gabbro often include one or more buried profiles. In the modern overlying soil, gibbsite is common and the Fe oxyhydroxides include maghemite. In the buried soil interstratified kaolinite–smectite is abundant, gibbsite is present in traces and the Fe oxyhydroxides are mostly formed by goethite. Chemical and mineralogical data show that the modern soil has developed under strongly leaching conditions that contrast with those in which the buried soil formed. We suggest that the interstratified kaolinite–smectite is a relict mineral that helps reconstruction of the pedogenetic history of these soils.     

Surface charge characteristics of volcanic‐ash‐soils from Spain. Effect of organic matter and mineralogical composition

Abstract

Surface charge characteristics of several Spanish Andosols were investigated. The relationship between these characteristics and the mineralogical composition and organic matter content of the soils were also taken into account.

The electro‐chemical behaviour of the soils was similar to that of many metallic oxides, in which the surface charge is determined exclusively by the activity of potential determining H and OH^‐ ions in the bulk solution.

The ZPC of the soils varies between 3.7 and 5.1 and always remains below the zero point of titration (between 0.6 and 10 meq/100g). These low ZPC values seem to be related to the high content of organic matter in the soils, but no clear correlation between both values has been found.

The mineralogical composition and the percentage of amorphous oxides in the soils, on the other hand, had an effect on the charge characteristics’. A correlation coefficient (r=0.801) was found between the Al₂O₃% and ZPC value of the soils.     

Analytical and thermodynamic approaches to the mineralogical and compositional studies on anoxic sediments

Background, Aim and Scope  The identification of certain minerals directly in the raw sediment has proved to be difficult, if not impossible, because of their instability and/or low contents. This explains why the characterization/composition/crystalline nature of multiple (co)precipitates and solid solutions often necessitate the combined use of density separation methods and macro and microanalytical techniques, and in some cases the possible existence of certain mineral solids is only sustained from thermodynamic considerations. In this context, the comparison of porewater concentration profiles with thermodynamic calculations recently proved to be a convenient way of obtaining clues relative to the potential occurrence of natural minerals. Methods  Porewaters and sedimentary-solid phases were extracted from sliced sediment samples collected in the Seine estuary (northern France), and studied as a function of sediment depth. Porewater concentration profiles were determined for Ca, Fe, Mg, Mn, Na, P and Sr using inductively coupled plasma atomic emission spectroscopy, and for dissolved sulfur using square wave, cathodic stripping voltammetry. To obtain information about sediment mineralogy, sedimentary solid phases were analysed directly and after density separation with a heavy liquid (CHBr₃) by means of several techniques: X-ray diffraction; electron spin resonance and micro-Raman spectroscopies. Furthermore, using sequential extraction procedures, the chemical speciation versus depth of several elements (Al, Ca, Fe, Mg, Mn, P, Pb, Sr, Ti, and Zn) and particularly sulfur [i.e. acid volatile sulfides (AVS) and chromium reducible sulfurs (CRS)] were undertaken. Results and Discussion.  From these analytical data, some thermodynamic calculations [using ion activity products (LAP)] were attempted for the anoxic porewaters where most of the ionic complexing species were measured to support the involvement of relevant geochemical equilibria between these ions and some metals and the existence of any discrete solid phases (calcite, dolomite, greigite and probably vivianite, apatite and siderite), as well as coprecipitates and solid solutions in calcium carbonate. Conclusions  Thermodynamic equilibria in sedimentary media are rarely achieved because many chemical processes in these systems are established in long periods. Nevertheless, these calculations remain useful to increase our insight into the considered system. They help to support our view about the possible existence of certain minerals (iron sulfides, calcite, dolomite...). They also help account for the real power of ESR for indicating the presence of hypothesised solid solutions, Mn_xCa_1-xC0₃. The critical investigations of the authors, however, reveal some weaknesses of XRD and Raman microscopy for identifying minor minerals/precipitates, which result from combinations between the inorganic anions P0₄ ^3-, C0₃ ^2- and S^2- and the metallic cations Fe²⁺, Mn²⁺, Mg²⁺, and Sr²⁺.     

Chemical and mineralogical weathering rates and processes in an upland granitic till catchment in Scotland

Weathering in an upland granitic till catchment receiving an intermediate level of acidic deposition has been studied by chemical and mineralogical analyses of soil profiles and chemical analysis of precipitation and streamwater. Long-term weathering rates for base cations calculated from analyses of soil profile horizons using Zr as an internal, immobile, index element are similar for alpine podzols and peaty podzols and are 2–3 meq.m^–2.a^–1 for Ca and Mg, and 10–11 meq.m^–2.a^–1 for K and Na. The high loss of Na is associated with the weathering of oligoclase, particularly in the coarse sand fraction. Loss of K is related to weathering of K-feldspar and micas. Current weathering rates for base cations calculated from input-output budgets are higher than long-term rates by factors of 12, 8 and 3 for Ca, Mg and Na, but lower by a factor of 7 for K probably due to biomass uptake. The higher current overall loss of base cations may be due to increased rates of weathering in recent times but this is not conclusive as there are large uncertainties inherent in both methods of estimation.     

Organic matter in volcanic soils in Chile: Chemical and biochemical characterization

Abstract

Determinations were made of total soil organic matter (SOM), stable and labile organic fractions, biomass carbon (C), and chemical composition of several humus‐soil‐fractions in Chilean volcanic soils, Andosols and Ultisols. Their physico‐chemical properties and humification degree at different stages in edaphic evolution were also assessed. In addition, organic matter models were obtained by chemical and biological syntheses and the structures and properties of natural and synthetic humic materials were compared with SOM. Results indicate that Andosols have higher SOM levels than Ultisols, but the fraction distribution in the latter suggests a shift of the more stable fractions to the more labile ones. Moreover, contents of humines, and humic and fulvic acids suggest that Chilean volcanic soil SOM is highly humified. On the other hand, among the SOM labile fractions, carbohydrate and biomass are about 15% of the SOM which are one of the most important fractions in soil fertility.     

Chemical and mineralogical characterization of soils derived from ophites in mediterranean climate (North of Spain)

Abstract

We have studied the chemical and mineralogical characteristics of ophites located in a diapiric formation in Burgos (North of Spain), and the soils derived from them. The ophites studied show mineralogical uniformity. Their main components are clinopyroxenes, plagioclases, biotite, and olivine. Generally, they show deuteric alteration mainly affecting the olivine. The presence of talc is attributed to an outpouring of basic magma (ophite) in an evapotiric environment of Keuper facies. Chemically, they are basic rocks, of basaltic nature, poor in silicon dioxide (SiO₂) and rich in magnesium oxide (MgO) and ferric oxides (Fe₂O₃). The weathering of the ophites results in clay consisting of chlorite, vermiculite, and interlayer chlorite‐vermiculite‐smectite inherited from original material. Small amount of extractable silica (Si), aluminum (Al), and iron (Fe) show the scarcity of amorphous material attributed to the high content in organic carbon (C) which prevents formation of allophane, and to the xeric moisture regime of soils in this location.     

Cryometamorphic gleyzems in the taiga of Western Siberia: Chemical and mineralogical properties,ecology, and genesis

Earlier studies showed considerable differences in the properties of automorphic loamy soils developing under middle-taiga vegetation in Western Siberia and on the Russian Plain. It was found that the soils without clear features of textural differentiation are common in Western Siberia. In particular, they are represented by cryometamorphic gleyzems. In this study, we analyze the properties of a cryometamorphic gleyzem in the Vakh area (the Khanty-Mansi Autonomous Okrug). The distribution pattern of clay minerals in the soil profile is analyzed in relation to the specific features of the soil hydrothermic regime. In the upper mineral horizons, the clay fraction is enriched in minerals of the group of soil chlorites and somewhat depleted of labile phyllosilicates. In the cryometamorphic horizon and in the underlying permafrost, the degree of crystallization of the clay minerals somewhat decreases. An even distribution pattern of aluminum oxide in the soil profile is explained by the increased content of Al in the clay fraction from the upper horizons combined with the loss of Al from the coarse fractions (as judged from data on the bulk elemental composition of clay-free samples). These features can be explained by the specificity of the hydrothermic regime of the cryometamorphic gleyzems with late thawing of the soil profile and frequent phase transitions of soil water in the upper humus and middle-profile cryometamorphic horizons.     

Chemical and mineralogical characteristics of podzolic soils of the central forest reserve in the area of karst sinkholes

A specific feature of the soil developing near the edge of a sinkhole in comparison with the soil at a distance of 10 m from the sinkhole is the presence of calcareous horizon from the depth of 116 cm. The soil near the edge of the sinkhole is also characterized by the increased contents of exchangeable calcium and oxalatesoluble iron in the litter layers and in the AE horizon. This may be explained by a more active biological uptake of these elements under conditions of a shallow occurrence of carbonates. With respect to pH values; the contents and distribution of humus and exchangeable potassium, sodium, hydrogen, and aluminum; the mineralogical composition of the clay and fine silt fractions; and the distribution of oxalatesoluble iron compounds in the soil profiles, palepodzolic soils of the Central Forest State Biospheric Nature Reserve developing in karst areas do not differ from similar soils beyond karst areas.     

Soils on hard rocks in the northwest of Russia: Chemical and mineralogical properties,genesis, and classification problems

Soil formation on hard rocks—nepheline syenite, amphibolite, metamorphized gabbro diabase, and their derivatives—was studied in the mountainous tundra and in the northern and middle taiga zones of the Kola Peninsula and Karelia (in the Kivach Reserve). It was found that the soils developing from these rocks could be classified into three groups: (1) petrozems with the O-M profile (the most common variant), (2) podzols and podzolized podburs on the substrates with an admixture of morainic derivatives of acid rocks, and (3) shallow (<5–10 cm) pebbly soils on the substrates without an admixture of allochthonous material (the rarest variant). In soils of the third group, the pedogenic alteration of the mineral matrix does not result in the appearance of phyllosilicates in the fine fractions if these phyllosilicates are initially absent in the rock. In these soils, the protion of the organic matter, and binding of iron released from the weathered silicate minerals into iron-organic complexes) are virtually undifferentiated by the separate soil horizons because of the very low thickness of the soil profiles. These soils have the Oao-BHFao-M profile; it is suggested that they can be classified as leptic podburs. An admixture of morainic material containing phyllosilicate minerals favors a more pronounced differentiation of the modern pedogenic processes by separate soil horizons even in the case of shallow soil profiles; the intense transformation of phyllosilicates takes place in the soils.     

Chemical studies on soil humic acids

The levels of alcoholic and phenolic hydroxyl, methoxyl, carboxyl, and carbonyl groups of 33 to 38 humic acids obtained from various types of soils were determined to analyze the relationships between the amounts of these functional groups and the degree of humification or the types of soils. The amounts of various oxygen-containing functional groups examined were all proven to be significantly different among the various types of humic acids by analyses of variance. During humification. generally, the carboxyl and carbonyl groups increased while alcoholic and phenolic hydroxyl and methoxyl groups decreased. Linear and logarithmic regression analyses of carboxyl group contents on RF values (optical density of the alkaline solution of humic acids at 600 nm) gave very significant positive correlations. The carboxyl group contents of Rp type humic acids and humic acids from calcareous soils were largely distributed in the upper side of the regression curve. The carbonyl group contents showed a very significant linear positive correlation with carboxyl group contents. and both of them showed high linear positive correlation with RF values. Phenolic hydroxyl group contents decreased with humification in Rp(l). B. and A type humic acids. Alcoholic hydroxyl group contents showed a significant negative linear association with _RF values. Methoxyl group contents decreased rapidly with increasing humification in low humified humic acids, and their negative correlation with _RF values were proven to be very significant by logarithmic regression analysis. The complicated relationship between oxygen content and RF value which was reported previously (7) has been accounted for by the results obtained in the experiments conducted here.     

Chemical studies on soil humic acids

Abstract

Relationships between elementary compositions and types of humic acids or the "degrees of humification were studied statistically using 39 humic acids prepared from various types of soils. Mean values of C%. H%. N%, 0%, H/C, N/C, and O/C of the different types of humic acids (A. B. Rp(l), Rp(2). and Po) were compared. The elementary compositions of various types of humic acids were proven by variance analyses to be significantly distinct. Linear regression analyses of C%, H%, N%. 0%, H/C, N/C, or O/C on RF or AlogK values were also carried out on 35 humic acids excluding the P_+~+++ type humic acids. The linear associations were found to be significant between C%-RF (5% level), H%-RF, H%-?logK, H/C-RF and HIC-?logK (0.1% level), N/C-RF(O.1% level). N%-RF(l% level), N%-?logK N/C-?logK(5% level), and ?logK (1% level), while no significant relationship was found with regard to C%;-?logK, 0%-?logK (both 5% level) and O/C-RF and O/C-?logK (l0% level). Carbon and oxygen contents of humic acids may be apt to reflect the different conditions of soils. The deeper the visible light absorption of humic acids and so the higher the degrees of humification, the lower the hydrogen contents of humic acids were. Though nitrogen content showed a trend similar to the trend of hydrogen content against RF values as a whole. the nitrogen content of less humified humic acids (Rp type) varied from very low to very high values. suggesting the enrichment of nitrogen into humic acid molecules in the early stage of humification. In the H/C versus O/C diagram, humic acids occupied an area reserved for the oxydation products of lignins. The area was fairly wide and “J”-shaped, that is, in the early to the middle stage of humification humic acids were arranged in the direction of dehydrogenation or demethanation, and in the later stage they were arranged in the direction of dehydration.     

Chemical studies on soil humic acids

Seventeen samples of soil humic acids, two fractions of soil fulvic acid sample, and several related compounds such as lignin, tannin, flavonoid and artificial humic substances were decomposed in conc. KOH solution at 180°C. Succinic acid, glutaric acid, phloroglucin, p-hydroxybenzoic acid, vanillic acid, protocatechuic acid, 3,4-dihydroxy-5-methoxybenzoic acid, and gallic acid were detected in the degradation products of humic acids. The amounts of these degradation products were discussed in relation to the degree of humification or the sources of the humic acid samples. Succinic acid also resulted from glucose, polymaleic acid, and the humic acid and humin prepared from glucose, but glutaric acid resulted only from glucose humic acid and glucose humin but not from glucose and polymaleic acid. Succinic acid and glutaric acid were supposed to result from the same structural portions in humic acids because of the very significant positive linear correlation between their amounts. p-Hydroxybenzoic, vanillic, protocatechuic, and 3,4-dihydroxy-S-methoxybenzoic acids were presumed to result mainly from lignin structure in humic acids. Soil humic acids yielded small amounts of gallic acid although the yields by hydrolysable tannins were in large amounts. The yields of above-mentioned degradation products from humic acids decreased with increasing degree of humification. Phloroglucin resulting from ftavonoids including condensed tannins were also found in the degradation products of humic substances. Its yield showed no linear correlation with RF value of humic acid, and is presumed to be rather related to the vegetation at the sites of soil sampling.     

凹凸棒石环境矿物材料的制备及应用

机械力改性、物理改性和化学改性是凹凸棒石环境矿物材料制备的3种主要改性方法.机械力改性法和物理改性法工艺简单,化学改性法效率高且在实际生产中应用较多,但仅仅依靠一种改性作用目前尚难以满足环境应用领域对凹凸棒石矿物物理性能和化学性能的要求.因此,深入系统地研究凹凸棒石环境矿物的基本性能,揭示环境矿物的净化机理,提出进一步提高环境矿物净化性能的改性工艺,将有利于进一步扩大其应用领域.