Inclusions silicate

Fluid inclusions from Kuroko deposits were studied first by Tokunaga and Honma (1974) who showed that Kuroko deposits formed in a range of 200-260°C for the siliceous... 

Marutani and Takenouchi (1978) clarified the variations in homogenization temperature and salinity of inclusion fluids in quartz from stockwork siliceous orebodies at the Kosaka mine (Fig. 1.35 Urabe, 1978). They showed that the temperature decreases stratigraphically upwards from stockwork ore zone (280-320°C) to bedded ore zone (260-310°C). Pisutha-Arnond and Ohmoto (1983) carried out fluid inclusion studies of the stockwork siliceous ores from five Kuroko deposits (Kosaka, Fukazawa, Furutobe, Shakanai, and Matsumine) and revealed that black ore minerals (sphalerite, galena, barite) and yellow ore minerals (chalcopyrite, quartz) formed at 200-330°C and 330 50°C, respectively, and salinities of the ore fluids remained fairly constant at about 3.5-6 equivalent wt% NaCl. They analyzed fluids extracted from sulfides and quartz Na = 0.60 0.16 (mol/kg H2O), K = 0.08 0.05, Ca = 0.06 0.05, Mg = 0.013 0.008, Cl = 0.82 0.32, C (as CO2) = 0.20 0.15 and less than 6 ppm each for Cu, Pb, Zn and Fe. 

These predictions are generally in agreement with the observations homogenization temperatures of fluid inclusions in quartz from siliceous ore zone and in barite from black ore zone in the Kuroko deposits is relatively high, ranging from 350 to 250°C, and low, ranging from 250 to 150°C, respectively. 

Marutani, M. and Takenouchi, S. (1978) Fluid inclusion study of stockwork siliceous ore bodies of Kuroko deposits at the Kosaka mine, Akita, Japan. Mining Geology, 28, 349-360. 

Michael PJ (1988) Partition coefficients for rare earth elements in mafic minerals of high silica rhyohtes the importance of accessory mineral inclusions. Geochim Cosmochim Acta 52 275-282 Mysen BO (1979) Nickel partitioning between olivine and silicate melt Henry s Law revisited. Am Mineral 64 1107-1114... 

Nucleic acids, DNA and RNA, are attractive biopolymers that can be used for biomedical applications [175,176], nanostructure fabrication [177,178], computing [179,180], and materials for electron-conduction [181,182]. Immobilization of DNA and RNA in well-defined nanostructures would be one of the most unique subjects in current nanotechnology. Unfortunately, a silica surface cannot usually adsorb duplex DNA in aqueous solution due to the electrostatic repulsion between the silica surface and polyanionic DNA. However, Fujiwara et al. recently found that duplex DNA in protonated phosphoric acid form can adsorb on mesoporous silicates, even in low-salt aqueous solution [183]. The DNA adsorption behavior depended much on the pore size of the mesoporous silica. Plausible models of DNA accommodation in mesopore silica channels are depicted in Figure 4.20. Inclusion of duplex DNA in mesoporous silicates with larger pores, around 3.8 nm diameter, would be accompanied by the formation of four water monolayers on the silica surface of the mesoporous inner channel (Figure 4.20A), where sufficient quantities of Si—OH groups remained after solvent extraction of the template (not by calcination). 

Salt glands of plants from Atriplex genus contain inclusions in the form of crystals of siliceous or sulphate salts of calcium and magnesium (Fahn, 1979). Usually the crystal particles also include phenols (see Chapter 7). The crystals are seen as dark dense spots within the structures on OCM images of the optical slices from the gland (Fig. 4). Profiles of signal intensity along... 

The mixed willemite-smithsonite ore has the simplest mineral composition of the three basic ore types. The silicate, goethite and barite are the principal gangue minerals. Will-emite is a major zinc oxide mineral present as free crystals ranging from 50 to 500 pm in size. Smithsonite is usually stained with Fe-hydroxides and sometimes is associated with silicate as inclusion and/or attachments. The barite content of the ore may vary from several percent up to 12%. A few deposits of this ore type are found in Mexico and South America. 

Roedder E. and Wieblen P W. (1971). Lunar petrology of silicate melt inclusions, Apollo 11 rocks. Proc. Apollo 11 Lunar Scl Conf, 1 801-837. 

We have included here, for comparison, the results of a study of zirconolite-rich Synroc nominally composed of 80 wt% Ce- or Pu-doped zirconolite plus 10 wt% hollandite and 10 wt% rutile (Hart et al. 1998). Inclusion of this study in this section is significant because the two additional phases are both highly durable in their own right and the experiments were conducted at two different temperatures (90 and 200 °C) and in three different aqueous solutions (pure water, silicate, and brine). The authors found no major differences in the release rates of Ca, Ce, Hf, Ti, Zr, Pu, and Gd apart from those for Ce and Ti, which appeared to be somewhat higher in the brine. On average, for all elements, the increase in temperature caused the release rates to increase by a factor of approximately seven. Release rates were generally below 10 2 g/m2/d for Ca, 10 3 g/m2/d for Ce and Gd, and 10 4 g/m2/d for Ti, Zr, Hf, and Pu (except for the brine at 200 °C, which gave a Ti release rate of 2 x 10 3g/m2/d). Hart et al. (2000) also determined the release rate of Pu in an LLNL-type zirconolite ceramic. After nearly one year in pure water at 90 °C the release rate of Pu decreased from 2 x 10-3 g/m2/d to less than 10-5 g/m2/d (Fig. 7). 

The secondary phase that contained the leach-able REE was identified in alteration rims around small salt inclusions in the peripheral parts of the dyke where numerous phosphate grains with high REE concentrations occur in association with secondary sheet silicates (Fig. 5). This secondary phosphate could be... 

Fig. 5. SEM photograph showing a secondary apatite crystal within a rim of altered basalt around a salt inclusion. The other minerals contained in the rim are sheet silicates and hematite.

Calcium—Silicon. Calcium—silicon and calcium—barium—silicon are made in the submerged-arc electric furnace by carbon reduction of lime, silica rock, and barites. Commercial calcium—silicon contains 28—32% calcium, 60—65% silicon, and 3% iron (max). Barium-bearing alloys contains 16—20% calcium, 9—12% barium, and 53—59% silicon. Calcium can also be added as an alloy containing 10—13% calcium, 14—18% barium, 19—21% aluminum, and 38—40% silicon These alloys are used to deoxidize and degasify steel. They produce complex calcium silicate inclusions that are minimally harmfiil to physical properties and prevent the formation of alumina-type inclusions, a principal source of fatigue failure in highly stressed alloy steels. As a sulfide former, they promote random distribution of sulfides, thereby minimizing chain-type inclusions. In cast iron, they are used as an inoculant. 

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