• Economic and Environmental Geology
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• v.17 no.2
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• pp.115-139
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• 1984

The Cu-Pb-Zn-Ag hydrothermal vein-type deposits which comprise the Sambong mine occur within calc-alkaline volcanics of the Cretaceous Gyeongsang Basin. The ore mineralization took place through three distinct stages of quartz (I and II stages) and calcite veins (III stage) which fill the pre-existing fault breccia zones. These stages were separated in time by tectonic fracturing and brecciation events. The reflection variations of one mineral depending on mineralization sequence are considered to be resulted from variation in its chemical composition due to different physico-chemical conditions in the hydrothermal system. The reflection power of sphalerite increases with the content of Fe substituted for Zn. Reflectances of the sphalerite grain are lower on (111) than on (100) surface. The spectral profiles depend on the internal reflection color. Sphalerite, showing green, yellow and reddish brown internal reflection, have the highest reflection power at $544m{\mu}$ (green), $593m{\mu}$ (yellow) and $615m{\mu}$ (red) wavelength, respectively. Chalcopyrite is recognized as biaxial negative from the reflectivity data of randomly oriented grains measured at the most sensitivity at $544m{\mu}$. The microindentation hardness against the Fe content (wt. %) for the sphalerite increases to 8.05% Fe and then decreases toward 9.5% Fe content. Vickers hardness of the sphalerite is considerably higher on surface of (100) than on (111). The relationship between Vickers hardness and crystal orientation of the galena was determined to be $VHN_{(111)}$ > $VHN_{(210)}$ > $VHN_{(100)}$. The softer sulfides have the wider variation of the diagonal length in the indentation. Diagonal length in the indentation is pyrite

• The Journal of Engineering Geology
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• v.15 no.2 s.42
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• pp.169-184
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• 2005

Unagsan and Sogrisan granites are widely distributed in the northern Gyeonggi massif and middle Ogcheon belt, respectively, and they show different petrologic characteristics as follows. The former has compact textures and light grey colors, and the latter has spotted miarolitic textures and pink colors. Most of the samples selected for tests are fresh and coarse-grained. And bored core samples were prepared so that they are vertical to the rift plane. The results of modal analysis show that Unagsan granite has significantly higher quartz and plagioclase contents (Qz+Pl) than Sogrisan granite. In contrast, alkali feldspar content (Af) of Sogrisan granite is much higher than that of Unagsan granite. Therefore, it is believed that the light grey colors of Unagsan granite are due to relatively high Qz+Pl, and the pink colors of Sogrisan granite are caused by higher Af. Fractures in Sogrisan granite have strongly perpendicular strike patterns and more dip values close to vertical compared with the fractures in Unagsan granite. Results of the fracture pattern analysis suggest that the Sogrisan granite has better potential to produce dimension stones than the Unagsan granite. However, miarolitic textures often found in the Sogrisan granite may be one of the factors reducing the granite quality. The Unagsan and Sogrisan granites have similar specific gravity values of 2.60 and 2.57, respectively. Absorption ratios and porosity values of Sogrisan granite are higher than those of Unagsan granite, and they shows linearly positive correlations. Compressive and tensile strengths of the Unagsan granite are generally higher than those of Sogrisan granite. These differences and variation trends found in physical properties of Unagsan and Sogrisan granite can be explained by the differences in the textures of Unagsan and Sogrisan granites, namely compact and miarolitic textures respectively. For Unagsan granite, compressive and tensile strengths are negatively correlated with porosity but for Sogrisan granite no specific correlations are found. This is probably due to the irregular dispersion patterns of miarolitic textures formed during the later stages of magmatic processes. Contrary to the trends found in absorption ratios, both granites have similar values of abrasive hardness, which can be explained by higher Qz+Af of the Sogrisan granite than those of the Unagsan granite and that quartz and alkali feldspar have relatively larger hardness values. For Sogrisan granite, compressive strength shows slightly positive correlations with Qz+Af+Pl and negative correlations with biotite and accessory mineral contents (Bt+Ac).

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.4
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• pp.37-55
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• 2000

Two-dimensional numerical experiments and field surveys have been conducted to clarify some environmental variations in the flow and sedimentation in the adjacent seas after the construction of a tidal embankment. Velocities of flow and water levels in the bay decreased after the construction of the barrage. When the freshwater was instantly released into the bay, the conditions of flow were unaltered, with the exception of a minor variation in velocities and tidal levels around the sluices at the ebb flow. The computational results showed that freshwater released at the low water reached the outside of the bay and then returned to the inside with the tidal currents at the high water. The front sea regions of the embankment had a variety of sedimentary phases such as a clayish silt, a silty clay and a sandy clayish silt. However, a clayish silt was prevalent in the middle of the bay. On the other hand, the skewness, which reflects the behaviour of sediments, was $\{pm}0.1$ at the front regions of the embankment while it was more than ±0.3 in the middle of the bay. Analytical results of drilling samples acquired from the front of the sluice gates showed that the lower part of the sediments consists of very fine silty or clayish grains. The upper surface layer consisted of shellfish, such as oyster or barnacle with a thickness of 40～50 cm. Therefore, it seemed that the lower part of the sediments would have been one of intertidal zones prior to the embankment construction while the upper shellfish layer would have been debris of shellfish farms formed in the adjacent seas after the construction of the embankment. This shows the difference of sedimentary phases reflected the influence of a tidal embankment construction.

• Journal of Korean Society of Forest Science
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• v.79 no.2
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• pp.115-126
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• 1990

This study was performed to find differences in phototaxis response of the larva, adult emergence, sex ratio and gall formation rate of Thecodiplosis japonensis Uchida et Inouye between two areas, north and south. Larvae from these two areas, Hweng-sung in north and Moo-an in south, both considered to be the sities of severe outbreak of the insect recently, were collected from the floor and transported to the entomology larboratory, Won-Kwang University in Iri, then overwintered. These larvae were used for various experimental purposes on various dates. The following results were obtained. 1. The sizes of larvae reached 2.45 in length, 0.70 in width for north, and 2.50 in length, 0.72 in width for sourth. It seems that the differents were not significant. 2. It is known that Leaving gall of larvae to the ground for the hibernation usually occurs on rainy days. For the larvae dispersion, the phototaxis response of the larvae was hypothesized. To check this, the author manipulated some different illumination intensities adjusting the distance between the glass tube in which 100 larvae were contained and electric bulb. The glass tubes were blackened all but except a small portion. The phototaxis responses between two areas seemed to be different particularly at low light intensities, 45, 145 and 1000 lux, The larvae from north assembled to the clear portion of the glass tube were more than 30 out of 100, however less than 30 in south sample regardless of the time passage. In either cases, the saturation points came after about 8 to 10 hours. If temperature units were used, the phototaxis curve= after 1 hour illumination between two areas provided significant differences. 3. The adult emergence of south area was lagged 10 days later than that of north area. The accumulated effective day-degrees of temperature for adult emergence were $934^{\circ}C$ for north area and $1180^{\circ}C$ for south area. The emerging duration of north area appeared to be in late May through the early of July and the peak emergence occurred in middle June that was approximately 15days earlier than that of south area. The sex ratio of female to male, regardless of area, was approximately 3 : 1. 4. The rates of gall formation of the red pine(Pinus densiflora Siebold et Zuccarini), 6-year-old seedlings, were as low as 9.94% for north area and 8.87% for south area. Through the close observation, the author presumed that the population reduction was greatly affected during the prepupa stage by relative moisture content and predators, such as spiders and ants presented on the ground.

• Korean Journal of Heritage: History & Science
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• v.44 no.1
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• pp.72-105
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• 2011

This study explores the value of the Dicentra spectabilis community as a nature reserve in provincial forests at San 1-2, Daea-ri, Dongsang-myeon, Wanju-gun, Jellabuk-do, also known as Gamakgol, while defining the appropriateness of its living environment and eventually providing basic information to protect this area. For these reasons, we investigated 'morphological and biological features of Dicentra spectabilis' and the 'present situation and problems of designing a herbaceous nature reserve in Korea.' Furthermore, we researched and analyzed the solar, soil and vegetation condition here through a field study in order to comprehend its nature reserve value. The result is as follows. According to the analytic result for information on the domestic wild Dicentra spectabilis community, it is evenly spread throughout mountainous areas, and there is one particularly outstanding in size in Wanju Gamakgol. Upon the findings from literature and the field study about its dispersion, Gamakgol has been discovered as an ideal district for Dicentra spectabilis since it meets all the conditions this plant requires to grow vigorously, such as a quasi-high altitude and rich precipitation during its period of active growth duration in May. Dicentra spectabilis grows in rocky soil ranging from 300~375m above sea level, 344.5m on average, towards the north, northwest and dominantly in the northeast. The mean inclination degree is $19.5^{\circ}$. Also, upon findings from analyzing solar conditions, the average light intensity during its growth duration, from Apr. to Aug., is 30,810lux on average and it tends to increase, as it gets closer to the end. This plant requires around 14,000~18,000lux while growing, but once bloomed, fruits develop regardless of the degree of brightness. The soil pH has shown a slight difference between the topsoil, at 5.2~6.1, and subsoil, at 5.2~6.2. Its mean pH is 5.54 for topsoil and 5.58 for subsoil. These results are very typical for Dicentra spectabilis to grow in, and other comparative areas also present similar conditions. Given the facts, the character of the soil in Gamakgol has been evaluated to have high stability. Analysis of its vegetation environment shows a wide variation of taxa numbering from 13 to 52 depending on area. The total number of taxa is 126 and they are a homogenous group while showing a variety of species as well. The Dicentra spectabilis community in the Daea-ri Arboretum is an herbaceous community consisting of dominantly Dicentra spectabilis, Cardamine leucantha, Boehmeria tricuspi and Impatiens textori while having many differential species such as Impatiens textori, Pueraria thunbergiana, Rubus crataegifolius vs Staphylea bumalda, Securinega suffruticosa, and Actinidia polygama. It suggests that it is a typical subcolony divided by topographic features and soil humidity. Considering the above results on a comprehensive level, this area is an excellent habitat for wild Dicentra spectabilis providing beautiful viewing enjoyment. Additionally, it is the largest wild colony of Dicentra spectabilis in Korea whose climate, topography, soil conditions and vegetation environment can secure sustainability as a wild habitat of Dicentra spectabilis. Therefore, We have determined that the Gamakgol community should be re-examined as natural asset owing to its established habitat conditions and sustainability.