• Title/Summary/Keyword: igneous rock

Search Result 68, Processing Time 0.106 seconds

Analysis of and Ideas for Improving Descriptions of Igneous Rock Textures in High School Earth Science II Textbooks (고등학교 지구과학 II 교과서에서 화성암의 조직에 대한 용어 분석)

  • Koh, Jeong-Seon;Yun, Sung-Hyo;Han, Jong-Soo
    • Journal of the Korean earth science society
    • /
    • v.29 no.3
    • /
    • pp.305-314
    • /
    • 2008
  • The purpose of this study is to analyze the concept of igneous rock textures and to uncover incorrect descriptions regarding the concept found within high school Earth Science II course seventh curriculum textbooks. Based upon this analysis suggestions will be made so as to improve descriptions regarding the concept of igneous rock texture. At least some incorrect descriptions regarding igneous rock texture were found in all the textbooks examined. Textures of volcanic rocks are described as being either fine-grained and glassy or porphyritic, while those of plutonic rocks are described as hollocrystalline, granular, coarse-grained or equigranular. These descriptions may contribute to forming and/or reinforcing misconceptions about both the classification criteria for, as well as the general concept of igneous rock textures. Therefore, some improvement schemes for the classification of igneous rock textures have been suggested. These schemes suggest that volcanic rocks be classified as either aphanitic or porphyritic, while plutonic rocks be classified as phaneritic, hollocrystalline or equigranular according to granularity, crystallinity, and both the absolute and relative sizes of the crystals within the rock.

A study on the characteristics of landslide in heavy rainfall (a study by rock types) (폭우시 산사태 특성에 관한 연구 (암종에 따른 특성 연구))

  • 이수곤;박지호;선건규
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • /
    • pp.131-136
    • /
    • 2003
  • Landslide is a natural disaster frequently noticed In korea during monsoon season in flicting nationwise damages on human lives, properties, transportation networks, construction sites, etc. This study is about landslide characteristic in rainfall. This study selects seven sites that occured in 2001 and 2002. So elect areas divide and studied special quality by carcinoma by igneous rock, metamorphic rock, sedimentary rock. According to study finding, because igneous rock area is very thin into 1m interior and exterior soil layer, failures happened much rock and soil interface. There was place that depth of soil layer becomes about 2∼3m being area that receive serious weathering case of metamorphic rock. Therefore, at collapse much debriflow occurrence expect. Case that sedimentary rock area is broken through stratification looked. When see such results, it may become many helps to study characteristics of landslide occurrence area grasping collapse special quality by rock type.

  • PDF

Igneous Activity in Ogcheon Geosynclinal Zone, Korea -with Special Reference to the Igneous Activity in its Northeastern Part- (옥천대(沃川帶)에서의 화성활동(火成活動) -특(特)히 옥천대동북부(沃川帶東北部)에서의 화성활동(火成活動)-)

  • Lee, Dai Sung;Kim, Yong Jun
    • Economic and Environmental Geology
    • /
    • v.18 no.1
    • /
    • pp.23-39
    • /
    • 1985
  • The northeastern part of Ogcheon zone which consisted mainly of Cambro-Ordovician arenaceous, argillaceous and calcareous formations and Carboni-Triassic arenaceous and argillaceous formations is delineated as the eastern mass of a thrust fault along Choongju-Moongyong-Cheongsan in the middle of the zone. The present study proposes a geotectonic line, Imgye-Samchog fault(see, figure 1) which divides the northeastern part into two blocks, Hambacksan block in the west and East coast block in the east. The igneous rocks in the Hambacksan block ranging from granite to gabbro are distributed in a symmetrical zones parallel to general direction of Ogcheon zone as follows (Fig. 2 and Table 2). Southeast igneous rock zone: it aligns Jurassic granites in its south and Precambrian leucocratic granites in its north. Central igneous rock zone: it aligns Cretaceous granites in its south and Jurassic granites, and some of diorite and gabbro in its north. Northwest igneous rock zone: aligns Jurassic granites in its south and huge batholithic granodiorite in its north. The distribution of the igneous rocks in the East coast block shows an entirely different features from those of Hanbacksan block. In the southern part of the block they assemble in a narrow area ranging in age from Early Proterozoic, through Middle to Late Proterozoic, Devonian, Jurassic, Cretaceous to Tertiary, whereas, the igneous rocks in the northern part of the block gathered to a restricted area, in ages of Middle Proterozoic and Cretaceous. The assemblage of the igneous rocks in the studied area shows a compositionally restricted, mixed S-type and I-type granites, $^{87}Sr/^{86}Sr$ > 0.706, rare volcanics and shortening with upright folding. These lithologic and structural features suggest that the igneous activity in this part related intimately to Hercynotype Orogeny of Pitcher(1979). Chronological episodes of igneous activity from Early Proterozoic to Early Tertiary in the northeastern part are figured.

  • PDF

Effect of RMR and rock type on tunnel drilling speed (RMR과 암석종류가 터널 천공속도에 미치는 영향)

  • Kim, Hae-Mahn;Lee, In-Mo;Hong, Chang-Ho
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.21 no.4
    • /
    • pp.561-571
    • /
    • 2019
  • Drilling and charging of the blast holes during NATM tunneling works take more than 30% of construction time among the whole tunneling work process. Prediction of ground condition ahead of tunnel face has been studied by several researchers by correlating percussion pressure and drilling speed during tunneling work with the ground condition and/or RMR values. However, most of the previous researches were conducted in the granite rock condition which is the most representative igneous rock in the Korean peninsula. In this study, drilling speeds in igneous rocks were analyzed and compared with those in sedimentary rocks (most dominantly composed of conglomerates, sandstones, and shales) under the similar RMR ranges; it was identified that the drilling speed is pretty much affected by rock types even in a similar RMR range. Under the similar RMR values, the drilling speed was faster in sedimentary rocks compared with that in igneous rock. Moreover, while the drilling speed was not much affected by change of the RMR values in igneous rocks, it became faster in sedimentary rocks as the RMR values got lower.

A geochemical study on the metal contamination of groundwater in Taegu City (대구시 지하수의 금속 오염에 대한 지화학적 연구)

  • 이재영;김영기;이진국;서정율
    • The Journal of Engineering Geology
    • /
    • v.2 no.2
    • /
    • pp.173-200
    • /
    • 1992
  • The quality of groundwater in the central part of Taegu City is influenced by upstreams of Sin-stream and Beomeo-stream because the stream waters are main source of the groundwater, and chemical composition of the upstream waters has close relationship with andesite and monzonite in the igneous rock terrain. The pH of upstreams are weak acid ~ neutral in the igneous rock area and weak alkaline in the sedimentary rock area. Contents of $Ca^{2+}$ and $Mg^{2+}$ in the streams are apparently high, and $Na^{+}$ content is only slightly high in the sedimentary rock area. But $K^{+}$ content is lower in the Panyaweol formation area than in the monzonite area. The contents of heavy metals and $N0_3^{-}$ are also higher in the sedimentary rock area of residential sections and industrial complexes than those in the igneous rock area. The groundwater is contaminated in comparison to the upstream water of the igneous rock areas, and there are some differences in pollution level between the Panyaweol formation area of residential sections and the Haman formation area of industrial complexes. K, Na, Ca, Mg, Cl, $SO_4$ and $NO_3$ contents in the Haman formation area are relatively higher than those in the Panyaweol formation area. But pH is nearly equal in the two areas. The content of heavy metal ions is still lower than the drinking water standard of Korea and only slightly differs in the two sedimentary rock areas. But the groundwater in the Haman formation area is considerably contaminated by Kongdanstream and Dalseo-stream.

  • PDF

A Case Study on the Vibration Characteristics of Tunnel Blasting in Igneous Rock (화성암반에서 터널발파 진동측정치의 분석에 관한 사례 연구)

  • 윤성현;안명석;이광열
    • Explosives and Blasting
    • /
    • v.21 no.1
    • /
    • pp.69-76
    • /
    • 2003
  • Test blasting has been performed with V-cut to investigate the characteristics. Blasting vibrations were measured at two directions, the proceed direction and side direction. Propagation characteristics were determined by regression analysis; square root scaled distance and cube root scaled distance with maximum charge per delay of the blast. Testing result, The cross point was 62m in the allowable vibration velocity of 3mm/sec and 46m In 5mm/sec. Also, vibration level with measuring point was highest and decayed fastest, adapting to cube root scaled distance, for the proceed direction on ground.

Comparison of Sediment Disaster Risk Depending on Bedrock using LSMAP (LSMAP을 활용한 기반암별 토사재해 위험도 비교)

  • Choi, Won-il;Choi, Eun-hwa;Jeon, Seong-kon
    • Journal of the Korean Geosynthetics Society
    • /
    • v.16 no.3
    • /
    • pp.51-62
    • /
    • 2017
  • For the purpose of the study, of the 76 areas subject to preliminary concentrated management on sediment disaster in the downtown area, 9 areas were selected as research areas. They were classified into three stratified rock areas (Gyeongsan City, Goheung-gun and Daegu Metropolitan City), three igneous rock areas (Daejeon City, Sejong Special Self-Governing City and Wonju City) and three metamorphic rock areas (Namyangju City, Uiwang City and Inje District) according to the characteristics of the bedrock in the research areas. As for the 9 areas, analyses were conducted based on tests required to calculate soil characteristics, a predictive model for root adhesive power, loading of trees and on-the-spot research. As for a rainfall scenario (rainfall intensity), the probability of rainfall was applied as offered by APEC Climate Center (APCC) in Busan. As for the prediction of landslide risks in the 9 areas, TRIGRS and LSMAP were applied. As a result of TRIGRIS prediction, the risk rate was recorded 30.45% in stratified rock areas, 41.03% in igneous rock areas and 45.04% in metamorphic rock areas on average. As a result of LSMAP prediction based on root cohesion and the weight of trees according to crown density, it turned out to a 1.34% risk rate in the stratified rock areas, 2.76% in the igneous rock areas and 1.64% in the metamorphic rock areas. Analysis through LSMAP was considered to be relatively local predictive rather than analysis using TRIGRS.

Geological Distribution and Background Level of Copper and Zinc in Non-drinking Groundwater, South Korea

  • Jeon, Sang-Ho;Park, Sunhwa;Kim, Hyun-Koo;Song, Da-Hee;Kim, Hye-Jin;Kim, Moon-su;Kim, Deok-hyun;Lee, Gyeong-Mi;Kim, Tae-seung
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.49 no.2
    • /
    • pp.200-207
    • /
    • 2016
  • To add new groundwater standard, 7 candidate materials (copper, zinc, selenium, manganese, iron, chromium, aluminum) were calculated by CROWN (Chemical Ranking Of groundwater pollutaNts). Copper and zinc were selected as groundwater candidates through the process and monitored total 430 samples for 2 years with 113 groundwater sampling sites. In this study, geological distribution characteristics (igneous rock, metamorphic rock, sedimentary rock) of copper and zinc were evaluated and the geological background levels obtained by a cumulative probability distribution and pre-selection methods were compared. In the results, the highest average concentrations of the copper and zinc were observed both in the igneous rock. The detection concentration ranges of copper and zinc in 430 groundwater samples were $0.002{\sim}0.931mg\;L^{-1}$, and $0.002{\sim}32.293mg\;L^{-1}$, respectively. In addition, detection concentration ranges of copper and zinc were $0.002{\sim}0.931mg\;L^{-1}$, $0.002{\sim}32.293mg\;L^{-1}$ in the igneous rock, $0.002{\sim}0.134mg\;L^{-1}$, $0.004{\sim}7.038mg\;L^{-1}$ in the metamorphic rock and $0.002{\sim}0.008mg\;L^{-1}$, $0.003{\sim}3.948mg\;L^{-1}$ in the sedimentary rock, respectively. As a result of the background concentrations with two methods, zinc concentrations with the pre-selected method are comparatively higher than that of the others with the cumulative distribution.

The Classifying Ability of the Igneous Rocks with Naked Eyes for Preservice Science Teachers (예비과학교사들의 화성암 육안분류 능력)

  • Moon Byoung Chan;Jeong Jin-Woo;Chung Chull Hwan
    • Journal of the Korean earth science society
    • /
    • v.26 no.7
    • /
    • pp.630-639
    • /
    • 2005
  • The purpose of this study was to investigate the classifying ability of the igneous rocks with the naked eye for 36 preservice science teachers. For this, we selected six specimens of igneous rocks that consisted of rhyolite, andesite, basalt, granite, diorite, and gabbro, and performed the questionnaire with them. Preservice science teachers needed the average of 3 tools to classify the rocks. Most of the selected tools were loupe, streak plate, hammer and Mohs’ hardness scale. Many preservice science teachers selected basalt and granite samples to classify igneous rocks among 6 kinds of the rocks which were exhibited. However, the results of the identification with the naked eye showed that the right answer rate was significantly different based on what rock sample had been selected. Nobody gave the right answer among 10 students who chose the rhyolite sample, but all of 36 students who picked the basalt sample answered correctly. And $62\%$ of 8 students who chose the andesite sample, 62% of 32 student choosing granite, $7\%$ of 13 students choosing diorite and $44\%$ of 9 students choosing gabbro were correctly answered. In identifying igneous rock samples with the naked eye, most subjects relied on vesicular texture to basalt, and they used textural, color and empirical characters to granite. But, some felt more or less difficulty to distinguish between intermediate and light colors and to recognize porphyry.

Analysis of Regional Potential Mapping Factors of Metal Deposits using Machine Learning (머신러닝을 이용한 광역 금속 광상 배태 잠재성 평가 인자 분석)

  • Park, Gyesoon
    • Geophysics and Geophysical Exploration
    • /
    • v.23 no.3
    • /
    • pp.149-156
    • /
    • 2020
  • The genesis of ore bodies is a very diverse and complex process, and the target depth of mineral exploration increases. These create a need for predictive mineral exploration, which may be facilitated by the advancement of machine learning and geological database. In this study, we confirm that the faults and igneous rocks distributions and magnetic data can be used as input data for potential mapping using deep neural networks. When the input data are constructed with faults, igneous rocks, and magnetic data, we can build a potential mapping model of the metal deposit that has a predictive accuracy greater than 0.9. If detailed geological and geophysical data are obtained, this approach can be applied to the potential mapping on a mine scale. In addition, we confirm that the magnetic data, which provide the distribution of the underground igneous rock, can supplement the limited information from the surface igneous rock distribution. Therefore, rather than simply integrating various data sets, it will be more important to integrate information considering the geological correlation to genesis of minerals.