• Journal of the Mineralogical Society of Korea
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• v.30 no.4
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• pp.179-186
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• 2017

This study investigated the mineralogical characteristics of lime mortars used in pointing of Namhansanseon Yeojang from Joseon dynasty. Polarization microscopy revealed quartz, feldspar, mica, pyroxene and opaque minerals in the lime mortars. XRD analysis also confirmed clay minerals chlorite and kaolin. As a result of particle size analysis of lime mortars, the particle size distribution was wide and size was not uniform. 60% of samples were corresponded to the sand area. The chemical components detected from XRF analysis, 8.71-11.18 % of Ca as the main component of lime and $SiO_2$, $Al_2O_3$, and $Fe_2O_3$ in soil minerals were main components. The lime mortars showed an endothermic peak due to decarbonization reaction of $CaCO_3$ at $750^{\circ}C$ and weight reduction rate of 10%. The microstructures were agglomerated amorphous and observed rhombohedral calcite crystals by scanning electron microscope. It is considered that the pointing of Yeojang is a mortar mixed with lime and soil. In addition the Hanbongseong Yeojang was constructed using the same materials and construction technique because the minerals composition is not different according to the Yeojang location and use.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.3
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• pp.110-116
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• 1981

Soil surface charge which manipulates some important soil physico-chemical properties such as nutrient and water holding abilities, colloidal stability and soil erosion was investigated in wide range of soil pH, using soils developed originally from same volcanic ash deposit but under different rainfall condition in Hawaii. The results can be summarized as follows : 1. Ustollic Camorthid (Kawaihae soil) which was developed under the lowest rainfall (less than 500 mm/yr) revealed low Z.P.C. (4.5-5.0) and less dependence of net charge on concentration of indifferent electrolytes. 2. Typic Hydrandepts (Akaka and Hilo soils) which were developed under the high rainfall (3050-7600 mm/yr) showed the Z.P.C. in between 5.5-7.0 and high dependence of net charge on concentration of indifferent electroytes. 3. It was found by X-ray diffraction together with total chemical analysis that amorphous materials were dominant (above 6.0%) in Typic Hydrandepts while dehydrated halloy-site (1 : 1 clay minerals) was dominant (45-50%) in Ustollic Camorthid. 4. In spite of little difference in particle size distribution of the soils, the difference of specific surface area was remarkable showing the order of Akaka (289) > Hilo (268) > Kawaihae (93). 5. It was evident, taking account of apparent field pH values, 5.2 of Akaka, 5.5 of Hilo and 7.0 of Kawaihae soil, respectively, that Akaka, and Hilo soils would show either positive or near zero (+ or 0) of ${\Delta}pH$ while Kawaihae soil would exhibit negative (-) of ${\Delta}pH$ at natural field condition.

• Journal of the Mineralogical Society of Korea
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• v.25 no.2
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• pp.63-76
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• 2012

Tachylite, black basaltic glass formed by the rapid cooling of molten basalt, locally occurs at the Basaltic Agglomerate Formation (BAF), the lowest formation of Ulleung Island. The purposes of this study are to characterize the occurrence and mineralogy of tachylite and to elucidate its formation condition, with emphasis on its fracture pattern, which can serve as implications for the early volcanic activity of Ulleung Island. To this end, we investigated the occurrence pattern of tachylite in the field and carried out mineralogical analyses using optical microscope, XRD, EPMA, and SEM. Tachylite occurs at the chilled margin of basic dikes which are distributed in Naesujeon, Dodong and Jeodong seasides, Turtle Rock, and Yaerimwon, whose widths vary from several cm to 10 cm. It is evident that the outer surface of tachylite is dense and smooth, whereas the inner surface, if fractured, is characterized by conchoidal fracture. The matrix of tachylite consists of amorphous, glass and some fine-grained phenocrysts present in tachylite include biotite, anorthoclase, sanidine, plagioclase, hornblende, and Fe-Ti oxides. The fracture patterns characteristic of tachylite are subrounded, oval, or less commonly polygonal, bounded by joints to form globule or lump. Taking into account texture and mineralogy, tachylite is interpreted to have undergone little subsequent alteration at low temperature via hydration or hydrolysis that could form clay minerals after it was formed. Because tachylite with peculiar fractures occurs as dikes in a close association with BAF, its presence is considered as reliable evidence that when tachylite formed, the most part of BAF was still under subaqueous conditions, or at least saturated with seawater.

• Economic and Environmental Geology
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• v.35 no.6
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• pp.491-508
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• 2002

While about 80% of Jeju soils are classified as Andisols, the soils derived from volcanic ash in Dangsanbong are not Andisols. There is a significant difference of precipitation in localities of Jeju island. The study area is characterized by the lowest amount of annual rainfall in Jeju Island, and by the layered silicates as dominant solid phase in clay fraction. The purpose of this study was to characterize the mineralogy of the non-Andie soils in detail, especially hydroxy-interlayered silicates. Two major soil horizons are recognized in the soil profile developed in the Dangsanbong area, which can be designated as A and C. The soil pH($H_{2}0$), ranges from 6.6 to 7.3 increasing with depth, is higher than that of typical Andisols(pH<6.0). While the pH(NaF), ranges from 9.49 to 9.81, indicates that significant amount of amorphous phases might be present as exchanging complexes. It is estimated to about 1.542.88 wt% by using chemical selective dissolution. The organic content of surface horizon is about 2 wt%. This soil are composed of quartz, feldspar and olivine as major constituents with minor of silicate clays. Quartz is frequently observed in A and distinctly decreases in its amount with depth, while olivine is dominant phase in C and rarely observed in A. In the <0.2$\mu\textrm{m}$ size fraction, smectite and kaolinite/smectite interstratification are dominant with minor of illite. The amounts of smectite decrease with depth, while the amounts of kaolinite/smecite interstratification increase with depth, which indicates the trend of mineral transformation with increasing the degree of weathering. The proportion of kaolinite in kaolinite/smectite interstratification is about 85%, and is not changed significantly through the profile. In the 2-0.2$\mu\textrm{m}$size fraction, vermiculite, smectite, illite and kaolinite are major components with minor of chlorite. Most of chlorite are interstratified with smectite. Chlorite which is not interstratified with smectite occurs only in surface horizon. The proportion of the chlorite in the chlorite/smectite interstratification is 59-70(%) and increases with depth. Hydroxy-interlayered vermiculite(HIV) with hydroxy-Fe/AI in their interlayers occurs in both A and C horizon. The amounts of hydroxy-Fe/AI decrease with depth. Hydroxy-interlayered smectite(HIS) of which interlayers might be composed of hydroxy-Mg/Al occurs only in C horizon. As the results of mineralogical investigation for the soil profile in the study area, clay minerals might be changed and evolved through the following weathering sequences: 1) Smectite Kaolinite, HIS, Vermiculite, 2) Vermiculite HIV Chlorite.