• Economic and Environmental Geology
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• v.7 no.3
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• pp.123-152
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• 1974

The study focused to the so called "Yangpyeong Igneous Complex" which intruded into the Gyeong Gi gneiss complex of Pre-cambrian basement of Yangpyeong area. The geologic sequence of the mapped area was shown in table 1. In laboratory work, 31 modal analyses and 7 chemical analyses on the rock samples taken from the igneous complex have been made to discuss the nomenclature of the rocks and the petrological relationship between rock types. The petrographical and petrochemical features based on the analyses are as follow; 1) The classification of this rocks based on the systematics of igneous rocks of IUGS showed that Yangpyeong Igneous complex consist of hornblende gabbro, diorite and porphyritic monzonite. The major rock forming minerals in hornblende gabbro are hornblende and plagiodase ($An_{46{\sim}55}$), in diorite, hornblende, biotite and plagioclase ($An_{23{\sim}33}$) and in porphyritic monzonite, K-feldspar, plagioclase ($An_{21{\sim}35}$), hornblende and biotite. Hornblende gabbro and diorite show coarse to medium grained hypidiomorphic granular texture and porphyritic monzonite was named by the characteristically porphyritic texture of K-feldspar phenocrysts. 2) Silica-oxides variation diagram (Fig.4) illustrate that the igneous complex is similar ttl that of Daly's average basalt-andesite-dacite-rhyolite and equivalent to the calc-alkalic rock series of Peacock's rock series. In AMF diagram (Fig. 5), the trend of the igneous complex is nearly pararell to that of the Skaergaard intrusion which shows the trend of the fractional crystalization of magma. 3) In normative Or-Ab-An diagram (Fig. 6) the general trend of the data points from gabbro to porphyritic monzonite of the igneous complex directs to a point of Or/Ab=1:1 on the side of Or-Ab. The field and laboratory evidences suggested that the Yangpyeong igneous complex was thought to be a series of comagmatic differential products.

• Economic and Environmental Geology
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• v.7 no.3
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• pp.101-122
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• 1974

The study area is located in between Susanri and Hwanggangri where the formations of Okcheon group and Chosun group supposedly come in contact so that the area is structurally very import. Present study reveals that the meta-volcanic rocks distribute from south to north along contact zone of Okcheon and Chosun groups in the center of the area. Meta-volcanic rocks seem to be originated from the andesite or andesitic basalt rocks which was known to be Surchangri formation consist of phyllite and black slate by previous workers. The meta-volcanic rocks intruded along the fault zone one existed between Okcheon and Chosun groups but obliterated at present by the intrusion of volcanic rocks. The fault seems to be overthrust, and one of the positive evidences of thrust fault is the Yamisan nappe structure in Yamisan near Susanri. This interpretation coincides with O.J. Kim's work which states that the Precambrian Okcheon group is largely overturned and thrusted over the Chosun group. The relation between the Surchangri and the Majeonri formation marks facies change. This fact together with northpluging anticlinal structure made it possible that both formation came into contact along direction without fault. Yongam formation is not overlain unconformably used to be believed by previous workers, but interbed in the Great Limestone series of Chosun goup. It is also clarified that the rock formerly designated as limesilicate rock was meta-liparite. The origin of amphibole pebbles in the Kunjasan formation is of primary and secondary ones; the secondary pebbles were formed by metamorphism of the fragments of limestone or dolomite.

• Economic and Environmental Geology
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• v.29 no.3
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• pp.381-393
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• 1996

Cretaceous volcanics and volcaniclastic sediments are abundantly distributed in the Haenam area located at the tip of the southwestern part of the Yongdong-Kwangju depression zone. The Cretaceous strata correlated with the Yuchon Group of the Kyongsang Supergroup are divided into three formations: Hwawon Formation, Uhangri Formation and Haenam Formation in ascending order. The stratovolcanic Hwawon Formation is mainly composed of andesite and andesitic pyroclastics. The Uhangri Formation is the lacustrine sedimentary deposit. The Haenam Formation is composed of Hwangsan tuff, Haenam tuff, Yongdang tuff, Seoho tuff, and also Acidic lava, both being formed by a cogenetic acidic volcanism. The topographic circular structure of the Cretaceous strata was controlled by the doming of Jurassic Sani granite. Cretaceous volcanism in the study area is characterized by the two stages of intermediate volcanic activity in Cenomanian to Albian, and acidic volcanic activity in Campanian to Coniacian.

• Journal of the Korean Society of Earth Science Education
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• v.8 no.2
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• pp.128-138
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• 2015

The purpose of this study is to examine potential as a geological field course of Odongdo located to the east of Yeosu city, Korea. The total area and the height from the sea level of Odongdo is about 0.13km2 and 42m, respectively. Odongdo area belongs to the Hallyeohaesang National Marine Park, and is famous for rock scenery in the rocky coast and living of rare plants. For this study, diversity of geomorphology and geology was investigated at the sites called as dragon cave, windy area, seal rocks, sunrise viewing platform, second seashore rocks and first seashore rocks along the coast of Odongdo. The results of this study are as follows: A lot of geomorphological and geological resources like sea cliff, sea cave, strata, various sedimentary rocks(conglomerate, sandstone, mudstone), andesite, fault and examples of rock weathering were found in the rocky coast of the study area. These field resources are pertinent to the field work materials for the teaching and learning of geology units in elementary school science. Odongdo is to be recommended as a site of outdoor geological field course for the elementary school students inhabited in Yeosu city and neighborhood area because each site of the rocky coast in this study area has various field work materials and the wide space for observe activities, and is equipped with the facilities as a trail for rock observation.

• Economic and Environmental Geology
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• v.25 no.2
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• pp.167-177
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• 1992

The gravity measurement has been conducted at 53 and 34 stations with an interval of 1~1.5 km along the national roads of about 47 km and 34 km running from Duksungri to Yangpori and from Angangri to Byungpori, Kyungsangbookdo, respectively. The subsurface geology and geologic structure of Tertiary Pohang and Janggi basins along two survey lines are interpreted quantitatively by applying Fourier series and Talwani methods for Bouguer gravity anomaly. The depths of Conrad discontinuity vary from 11.8 to 12.5 km and 11.5 to 13.2 km along the survey lines between Duksungri and Yangpori, and Angangri and Byungpori, respectively. The depths of pre-Cambrian Gneiss complex underneath Kyungsang Supergroup vary from 3.8 to 4.2 km and 3.8 to 4.6 km along the survey lines between Duksungri and Yangpori, and Angangri and Byungpori, respectively. Massive granite bodies which are not exposed along the survey line between Duksungri and Yangpori are distributed on a large scale at the subsurface between Duksungri and Ochun, and Daegokri and Yangpori. Along the survey line between Angangri and Byungpori, it is exposed at Angangri, and extends underneath Chungrimdong, Pohang city. Andesite is distributed on a small scale underneath Pohang city and Ochun. The thicknesses of Tertiary Yonil and Janggi Groups are 0.2~0.9 km and 0.1~0.5 km, respectively. The Tuffaceous rocks which are the lowest formation of Tertiary sedimentary rocks are distributed with the thickness of 0.2 km at the surface and between Kyungsang Supergroup and Yonil or Janggi Groups. The Yonil and Janggi Groups are in fault contact by a fault running through Ochun and Chungrimdong, Pohang city. Two other faults are newly found near Heunghae-eup and Hyungsan river.

• Journal of Conservation Science
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• v.35 no.1
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• pp.41-49
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• 2019

This study analyzes the material characteristics of stone tools of the Paleolithic period excavated from the Osong site, located at the project site for the creation of the Osong 2nd Life Science Complex, and estimates the provenance of the stone materials. Because the stones had been buried for a long time, their surfaces had become heavily weathered yellow or yellowish-brown, and the magnetic susceptibility values varied from 0 to 15(${\times}10^{-3}SI$). The excavated stone tools were rocks with various magnetic susceptibility values that could not be specified. Five stone tools subjected to destructive analysis were divided into two groups, one with a value of 1-3(${\times}10^{-3}SI$) and the other with a value of 5-9(${\times}10^{-3}SI$), both based on visible characteristics. The results of the thin-section analysis showed that most of the stone tools were basaltic rocks comprising plagioclase, quartz, and pyroxene, and some had iron content as high as 20 wt.%. These findings and the present geological map suggest that the stone tools were not made from the surrounding rocks because there are no areas containing basaltic rocks surrounding Bongsan-ri in Osong-eup. Andesite and tuff are distributed along with basaltic rocks in the Doan-myeon area in Jeongpyeong-gun, Chungcheongbuk-do Province, but the distance from the excavation site is too far. To determine whether this region is actually related to the provenance of the raw rock, it is necessary to conduct additional field surveys and comprehensive and precise analyses.

• Economic and Environmental Geology
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• v.54 no.1
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• pp.137-150
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• 2021

The rock-carved standing Buddha triad in Seoak-dong is a large stone Buddha statue of the Unified Silla era (AD 676 to 935) in ancient Korea, built near the top of the southeastern side of mountain Seondosan in Gyeongju, is characterized by its locational importance, the powerful Amitabha and the gentle sculptural technique of the Bodhisattva. In particular, Amitabha Buddha in andesite rock slope with biotite granite pedestal and two Bodhisattva parallel made by alkali granites seems to express the dignity through the color and texture of the stones. In the Amitabha Buddha, deterioration characteristics are accelerating due to the combination of various joint systems, instability of the slopes and relaxation by the root pressure of plants occurring at the top. In addition, physical properties have deteriorated owing to the increase of discontinuous surfaces as joints, cracks and scalings, and the coverage of algae and lichen is also high. Therefore, deterioration degree in Buddha triad is accelerated due to the physical weathering characteristics from natural rock mass and various biological invasion.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.311-316
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• 2007

In this study, we investigated the presence of nitrogen, phosphorus, ions, heavy metals and other contaminations in the water stream and soil of the forest watershed with different geology and vegetations for one year from October 2004 to September 2005. Most of the nitrogen oxide in the soil was in the form of $NO_3^-$, and it appeared that nitrogen contents decreased as the soil depth increased. Nitrogen contents was highest in the basalt area showing 13.3 mg/g in the surface soil and 7.40 mg/g in the subsoil. Phosphorous contents showed no significant variations depending on the soil depth and was higher in the intermediate soil layer(60 cm) than in surface soil (30 cm) in granite and metamorphic rock areas. Nitrogenous compound in the soil water was 8.03 mg/L in the granite area of coniferous forest and 14.79 mg/L in the andesite area of the deciduous forest. Nitrogenous compound in the stream water was 5.53 mg/L in October and 6.99 mg/L in January in the granite area of the coniferous forest and $3.61\sim5.11$ mg/L in the andesite area of the deciduous forest. Phosphates in runoff and stream water were similar in coniferous with in deciduous forests, showing a slight increase(0.090$\sim$0.179 mg/L) in the basalt area. In the coniferous forest, pH showed a significant positive correlation with EC, $Ca^{2+}$ and $Cl^-$ at p < 0.01, and showed a negative correlation with S-Fe and S-Al. Electroconductivity showed a significant correlation of 0.601 with $Ca^{2+}$ and of -0.586 with $NO_3^-$ at p<0.01, and showed a significant correlation of 0.301 with $SO_4^{2-}$ and of -0.295 with S-Fe at p < 0.05. In the deciduous forest, pH showed a positive correlation with $Ca^{2+}$ at p < 0.05, and showed a negative correlation with $K^+$, S-Fe and S-Al at p < 0.01. Electroconductivity showed a significant positive correlation with $Ca^{2+}$ and $Cl^-$ at p < 0.05 and with $NO_3^-$ at p < 0.01.

• Journal of Korean Society of Forest Science
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• v.54 no.1
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• pp.25-35
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• 1981

Some physical and chemical properties of forest soils in Korea were analyzed for providing the reasonable management methods of forest lands, Among 375 soil series surveyed until 1979, 93 soil series of forest soils were classified and analyzed according to their characteristics. Firstly soil data were classified into 5 categories by weathered products and secondly were classified and analyzed by parent rocks. The results are as follows: 1) In forest soils characterized by weathered products volcanic ash soils were proved to be the most fertile and alluvial soils were turned out to be the most infertile soils. Residual soils on mountain and hill were mostly on the average in all kinds of soil properties analyzed except total soil depth. 2) Igneous rocks developed rather infertile soils containing large amount of organic matter and available $P_2O_5$ with relatively deep soil depth and strong acidity. On the other hand sedimentary rocks produced rather shallow soils containing small amount of organic matter and available $P_2O_5$ but they were relatively fertile with weak acidity. 3) Among igneous rocks basalt and trachyte produced very fertile soils and granite and andesite produced slightly infertile soils. 4) Among sedimentary rocks limestone soils had high fertility neutral in acidity but low amount of available $P_2O_5$ 6) Alluvial sand produced generally very infertile soils with great soil depth comparing with the arable alluvial land with high fertility.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.904-909
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• 2012

Acid sulfate soil (ASS) and potential acid sulfate soil (PASS) are distribution in worldwide and originate from sedimentary process, volcanic activity, or metamorphism and are problematic in agriculture and environmental due to their present and potential acidity developed by the oxidation. The PASS was defined as soil materials that had sulfidic layer more than 20 cm thick within 4 m of the soil profile and contained more than 0.15% of total-sulfur (T-S). A tentative interpretative soil classification system was proposed weak potential acid sulfate (T-S, 0.15-0.5%), moderate potential acid sulfate (T-S, 0.5-0.75%) and strong potential acid sulfate (T-S, more than 0.75%). PASS due to excess of pyrite over soil neutralizing capacity are formed. It provides no information on the kinetic rates of acid generation or neutralization; therefore, the test procedures used in acid base account (ABA) are referred to as static procedures. The net acid generation (NAG) test is a direct method to measure the ability of the sample to produce acid through sulfide oxidation and also provides and indication. The NAG test can evaluated easily whether the soils is PASS. The samples are mixed sandy loam and the PAS from the hydrothermal altered andesite (1:3, 1:8, 1:16, 1:20, 1:40, 1:80 and 1:200 ratios) in this study. We could find out that the NAG pH of the soil containing 0.75% of T-S was 2.5, and that of the soil has 0.15% of T-S was 3.8. NAG pH test can be proposed as soil classification criteria for the potential acid sulfate soils. The strong type has NAG pH of 2.5, the moderate one has NAG pH of 3.0, and the weak one has NAG pH of 3.5.