• Journal of the Mineralogical Society of Korea
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• v.21 no.1
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• pp.37-44
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• 2008

This study was performed to synthesize Na-A type zeolite with melting slag from the Mapo incineration site and recycle the zeolite as an environmental remediation agent. The melting slag used had a favorable composition containing 26.6% $SiO_2$, 10.9% $Al_2O_3$ and 2.7% $Na_2O$ for zeolite synthesis although there were high contents of iron oxides, including 19.6% $Fe_2O_3$ and 18.9% FeO, which had been used as a flux for the melting. It was confirmed that the Na-A type zeolite could be successfully synthesized at $80^{\circ}C$ and $SiO_2/Al_2O_3\;=\;0.80{\sim}1.96$. The cation exchange capacities (CEC) of the zeolites was determined to be about 220 cmol/kg leveled off at the synthetic time more than 10hrs. The adsorption capacities of zeolite to heavy metals (Cd, Cu, Mn and Pb) were high except for As arid Cr. It was also confirmed through the Eh and pH analysis that As and Cr existed in the forms of $HAsO_4^{2-}$ and $CrO_4^{2-}$. The low absorption rates of zeolite for As and Cr are attributed to the fact that the pore size ($4\;{\AA}$) of Na-A type is smaller than those of $HAsO_4^{2-}$ and $CrO_4^{2-}$ ions ($4\;{\AA}$ ionic radii and $8\;{\AA}$ diameter).

• 한국해양학회지
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• v.24 no.3
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• pp.132-147
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• 1989

A total of 83 surface sediments and 55 sea water samples, collected from the southwestern sea of Cheju Island, were analyzed in order to understand their textural characteristics, geochemical composition and the clay mineralogical features. The sediments were subdivided into ten textural classes, namely clayey sand, slightly gravelly muddy sand, sandy clay, clay and mud. The coarse and fine-grained mixed sediments are distributed in the northern part and around the Island, whereas the fine-grained deposits are mainly distributed in the central and southern parts of the study area; small scale mud patches are distributed in the southwestern and northern parts of Cheju Island. The high concentration of total suspended matter in study area gradually increase toward the southwestern and northwestern offshore area. The concentration of geochemical elements is as follow: the content of Mn, Al, Zn, Cr, Cu and Sn increase toward the southern part which is covered mainly with fine-grained deoposits, whereas the content of Ca, Mg and Ag is higher in the northern area; the elements such as Ni, Na, Fe and Pb are more concentrated relatively in muddy deposits rather than in sandy sediments. The light minerals such as Na-Ca feldspars show a high content around the Socotra Rock, toward the Soheugsan and Cheju Islands, but the K-feldspars are relatively high around the Cheju Island. It was noticed that the provenance of these sediments is partly influenced by the geological characteristics near the island. X-ray diffractogram for clay minerals from the southeastern mud patch and around the Soheugsan Island shows the diagnostic calcite peak indicating that the greater part of these clay fraction may have been derived from present and ancient Hwangho River. The high concentration of smectite in the northern part near the Cheju and around the Soheugsan Islands, eastern side of Socotra Rock probably result from supplies smectite altered from volcanic materials distributed in the Cheju Island and Socotra Rock, whereas the samples near the Chuja and northern parts of the Cheju Island contain weak calcite peak and high concentration of kaolinite and chlorite which is closely related to the geolgical characteristics on the adjacenting land area.

• The Journal of the Petrological Society of Korea
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• v.6 no.1
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• pp.19-33
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• 1997

This study reports the results about the petrography and geochemical characteristics of 10 representative volacanic rocks. The Cretaceous volcanic rocks distributed in the vicinity of the Kageo island composed of andesitic rocks, dacitic welded tuff, and rhyolitic rocks in ascending order. Sedimentary rock is the basement in the study area covered with volcanic rocks. Andesitic rocks composed of pyroclastic volcanic breccia, lithic lapilli tuff and cryptocrystallin lava-flow. Most dacitic rocks are lapilli ash-flow welded tuff. Rhyolitic rocks consists of rhyolite tuff and rhyolite lava flow. Rhyolite tuff are lithic crystal ash-flow tuff and crystal vitric ash-flow tuff with somewhat accidental fragments of andesitic rocks, but dacitic rocks. The variation of major and trace element of the volcanic rocks show that contents of $Al_2O_3$, FeO, CaO, MgO, $TiO_2$ decrease with increasing of $SiO_2$. On the basis of Variation diagrams such as $Al_2O_3$ vs. CaO, Th/Yb vs. Ta/Yb, and $Ce_N/YB_N$ vs. $Ce_N$, these rocks represent mainly differentiation trend of calc-alkaline rock series. On the discriminant diagrams such as Ba/La and La/Th ratio, Rb vs. Y + Nb, the volcanic rocks in study area belongs to high-K Orogenic suites, with abundances of trace element and ternary diagram of K, Na, Ca. According to the tectonic discriminant diagram by Wood, these rocks falls into the diestructructive continental margin. K-Ar ages of whole rocks are from andesite to rhyolite $97.0{\pm}6.8~94.5{\pm}6.6,\68.9{\pm}4.8,\61.5{\pm}4.9~60.7{\pm}4.2$ Ma, repectively. Volcanic rocks in study area show well correlation to the Yucheon Group in terms of rock age dating and geochemcial data, and derived from andesitic calc-alkaline magma that undergone low pressure fractional crystallization dominated plagioclase at <30km.

• Korean Journal of Heritage: History & Science
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• v.43 no.3
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• pp.122-143
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• 2010

The Shilla Stone Monument in Jungseongri was found during the road-construction in Pohang. It has approximately two hundreds of letters inscribed on the surface of one side, and it is estimated to be older than Shilla Stone Monument in Naengsuri which had been known for the oldest stele in Shilla Period. This monument is made of fine to medium-grained biotite granite, while the Shilla Stone Monument in Naengsuri is made of fine-grained granodioritic porphyry bearing feldspar and amphibole phenocrysts. Both rock types of the monuments are interpreted to be cognate with biotite granite in Shinkwangmyeon, and with granodioritic porphyry in Gigyemyeon. They are characterized by xenolith and miarolitic cavity. Damage aspects in both monuments are discoloring, cracking and breaking. These damages do not cause structural instability of the monuments, but attenuate aesthetic value. Black and brown discoloring contaminants on the surface of the Jungseongri Monument contain a high amount of manganese and iron. As a result of ultrasonic test, both monuments were evaluated to be medium-weathered (MW), although the velocity of the Shilla Monument in Jungseongri was slightly lower than the Shilla Monument in Naengsuri. This is because the Monument in Juengseongri had been exposed to outdoor environment for long time until the discovery. It is necessary for Shilla Monuments to be protected by appropriately environmental control and management.