• Title/Summary/Keyword: Be age-dating

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U-Pb(SHRIMP) and K-Ar Age Dating of Intrusive Rocks and Skarn Minerals at the W-Skarn in Weondong Deposit (원동 중석 스카른대에서의 관입암류와 스카른광물에 대한 U-Pb(SHRIMP) 및 K-Ar 연대)

  • Park, Changyun;Song, Yungoo;Chi, Se Jung;Kang, Il-Mo;Yi, Keewook;Chung, Donghoon
    • Journal of the Mineralogical Society of Korea
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    • v.26 no.3
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    • pp.161-174
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    • 2013
  • The geology of the weondong deposit area consists mainly of Cambro-Ordovician and Carboniferous-Triassic formations, and intruded quartz porphyry and dyke. The skarn mineralized zone in the weondong deposit is the most prospective region for the useful W-mineral deposits. To determine the skarn-mineralization age, U-Pb SHRIMP and K-Ar age dating methods were employed. The U-Pb zircon ages of quartz porphyry intrusion (WD-A) and feldspar porphyry dyke (WD-B) are 79.37 Ma and 50.64 Ma. The K-Ar ages of coarse-grained crystalline phlogopite (WD-1), massive phlogopite (WDR-1), phlogopite coexisted with skarn minerals (WD-M), and vein type illite (WD-2) were determined as $49.1{\pm}1.1$ Ma, $49.2{\pm}1.2$ Ma, $49.9{\pm}3.6$ Ma, and $48.3{\pm}1.1$ Ma, respectively. And the ages of the high uranium zircon of hydrothermally altered quartz porphyry (WD-C) range from 59.7 to 38.7 Ma, which dependson zircon's textures affected by hydrothermal fluids. It is regarded as the effect of some hydrothermal events, which may precipitate and overgrow the high-U zircons, and happen the zircon's metamictization and dissolution-reprecipitation reactions. Based on the K-Ar age datings for the skarn minerals and field evidences, we suggest that the timing of W-skarn mineralization in weondong deposit may be about 50 Ma. However, for the accurate timing of skarn mineralization in this area, the additional researches about the sequence of superposition at the skarn minerals and geological relationship between skarn deposits and dyke should be needed in the future.

The Elevation of Paleo-shoreline and Formation Age of the 1st Marine Terrace in Dadaepo, Busan, South Korea (부산 다대포 지역 해안 단구 제1면의 구정선 고도와 형성 시기)

  • Shin, Jae-Ryul;Hong, Yeong-Min;Hong, Seong-Chan
    • Journal of The Geomorphological Association of Korea
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    • v.26 no.4
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    • pp.67-79
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    • 2019
  • This study documents the level of paleo-shoreline and the timing of formation of the lowest marine terrace (1st terrace) distributed in Dadaepo, Busan, South Korea. In the study area, the elevation of paleo-shoreline of the 1st terrace is clearly identified as 5 meters above mean high tide based on the elevation of wave-cut platforms and the elevation of boundary between marine and terrestial sediments. This is well consistent with the fact that are found along the Southern coast of the Korean Peninsula including Daepo-dong, Sacheon-si. The timing of formation of the 1st terrace in Dadaepo is confirmed to have been deposited around 70,000~80,000 years BP (MIS 5a) according to OSL and IRSL dating ages. However, because the formation age of the 1st terrace in Sacheon-si Daepo-dong (Southerm coast) and Pohang-si Umok-ri (Eastern coast) previously identified as about 90,000~100,000 years BP (MIS 5c), further discussion of what is needed. Possibly, it can be interpreted that the sub-interglacial (MIS 5a and 5c) sea-level records during the last interglacial period are likely to be selective on land depending on regions.

Incision Rate Distribution of Streams on the Northern Part of the Sobaek Mountain Range (소백산맥 북부 지역 하천의 하각률 분포)

  • Lee, Gwang-Ryul;Park, Chung-Sun
    • Journal of The Geomorphological Association of Korea
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    • v.27 no.3
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    • pp.41-51
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    • 2020
  • This study tried to reveal incision rate distribution of streams on the northern part of the Sobaek Mountain Range with OSL age dating and geomorphic analysis, and factors influencing on the distribution were also discussed. With results from the previous studies, a total of 10 sites from 7 streams in the study area showed the rates ranging from 0.220 m/ka to 0.297 m/ka. Namhan-gang and Geum-cheon indicated the highest and lowest rates, respectively. Both sides in the northern section in the study area showed similar rates, while the western side in the middle section and the eastern side in the southern section showed higher rates than the other sides. Higher rates were also found from the eastern and northern sides where the Range runs N-S and E-W directions, respectively. Certain relationships with altitude and distance from the divide can be recognized from the rates and may be attributed to active incision with altitude and location of the uplift axis near the present divide. The rates on granite and sedimentary rock were higher than those on metamorphic rock, indicating that bedrock type is one of the important factors influencing on stream incision. Tectonic movement seemed to play some roles in the rates, because areas with lineaments showed lower rates. This study suggests that incision rate distribution of streams on the northern part of the Sobaek Mountain Range reflects various local geomorphic and geologic conditions.

K-Ar Age-dating Results of Some Major Faults in the Gyeongsang Basin: Spatio-temporal Variability of Fault Activations during the Cenozoic Era (경상분지 내 주요단층의 K-Ar 연대: 신생대 단층활동의 시·공간적 특성)

  • Song, Yungoo;Sim, Ho;Hong, Seongsik;Son, Moon
    • Economic and Environmental Geology
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    • v.52 no.5
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    • pp.449-457
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    • 2019
  • We present the K-Ar age-dating results of the bulk and the less than $0.1{\mu}m$ fraction of the fault gouges collected from some major faults in the Gyeongsang basin. We try to determine the timings of fault activation based on the mineralogical characteristics, and to interpret the spatio-temporal variability of the major fault events during the Cenozoic Era by considering together with the previous results. We propose at least the 3-times of major fault events at about 50 Ma, and just after 30 Ma and 20 Ma in the Gyeongsang basin, which were inferred from the combined approach of the K-Ar ages and the clay mineralogy of the bulk fault gouges and the <$0.1{\mu}m$ fractions. The fault activation timings of the Yangsan fault tend to be younger in the northern part than in the southern part. In particular, the inferred fault events just after 30 Ma and 20 Ma are mainly detected in the Ocheon fault and the related faults, and the fault in the Gyeongju area. The fault activation timings of the major faults can be revised accurately by using illite-age-analysis(IAA) method. These geochronological determinations of the multiple events of the major faults in the Gyeongsang basin are crucial to establish the tectonic evolution in the southeastern part of the Korean Peninsula during the Cenozoic Era.

Perception of Sex Life and Sexual Desire Coping Behavior according to General Characteristics among the Spouseless Aged (무배우자 노인의 일반적 특성에 따른 성생활 인식과 성 욕구 대처행동)

  • Choi, Eun Young;Ha, Ju Young
    • Korean Journal of Adult Nursing
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    • v.26 no.1
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    • pp.58-66
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    • 2014
  • Purpose: The aim of this study was to identify factors affecting the perception of sex life and sexual desire coping behavior among the spouseless elderly. Methods: The participants were 149 elders who resided in six administrative regions of B city. Data were collected from December 1, 2012 to March 3, 2013 using a questionnaire. Data were analyzed using descriptive statistics, t-test, ANOVA, Scheff$\acute{e}$ test, Pearson's correlation coefficient, and Stepwise multiple regression in a PASW 18.0 program. Results: Stepwise multiple regression analysis of data indicated that the most likely predictor is gender. Gender, sexual relation, subjective health status and parent-child relationship explained 34% of the variance of perception of sex life. Gender, dating status and age explained 44% of the variance of sexual desire coping behavior. Conclusion: Based on the study findings, gender and current dating status should be considered to conduct comprehensive sex health care education for healthy sex life of the elderly with no spouse.

A Study on Mate Selection and Sexual Consciousness(I) -Investigation for Unmarried Japanese Women College Students- (배우자선택과 성의식에 관한 연구(I) -일본 여자대학생을 대상으로-)

  • 김혜선;김영희
    • Journal of Families and Better Life
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    • v.1 no.2
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    • pp.107-125
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    • 1983
  • This study aimed to clarify the attitude toward marriage, mate selection and sexual consciousness of japanese unmarried women students whom are believed in drastic change in a overall social value system and norm due to the introduction of western civilization, so as to provide some information of the same subject of our young women in similar situation. Survey was carried out for 177 unmarried Japanese women students of 3 Universities located in Osaka prefecture situation. Data were collected by means of Questionnaire and analyzed by SPSS BATCH SYSTEM. Result are as follows; 1) Pattern of mate selection- An increasing tendency of love match is recognized 2) Attitude to marriage-94.0% of correspondences want to marry and proper age of marriage, they think, is between 22-25 years. 3) Love-marriage relation- most correspondences answered that love is a prior condition for marriage, however, 32.8% of correspondences think, love can be built after the marriage. 4) Dating- most correspondences want free dating, however, they fell that they are lacking for opportunity and they are not confident in the selection of proper mate. 5) Premarital sexual intercourse-most correspondences show a very generous attitude toward premarital sexual intercourse if they are in love and this attitude becomes more remarkable among love match makers. 6) Equality of sexes-most correspondences answered that as women are different in physiological function from men, distinctive social roles of both sexes and the inequality of sexes are inevitable.

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The Age of the Okcheon Metamorphic Belt-How Much Do We Know? (옥천 변성대의 시기-우리는 얼마만큼 알고 있나?)

  • Kwon, Sung-Tack
    • The Journal of the Petrological Society of Korea
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    • v.17 no.2
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    • pp.51-56
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    • 2008
  • The geologic age of the Okcheon metamorphic belt, used to be a longstanding puzzle, has been settled down to Neoproterozoic to Paleozoic with discovery of fossils and isotopic age dating of metavolcanic rocks. As isotopic ages become accumulated, there appeared a controversy over the age of peak metamorphism in the Okcheon metamorphic belt, i.e., a single late Permian-early Triassic metamorphism (CHIME allanite age and U-Pb age of metamorphic zircon), or earlier independent presence of early Permian metamorphism (U-Pb age of allanite within garnet porphyroblast). If we compare the isotopic ages that can represent metamorphism, the data for the latter have much larger error than those of the former with some overlap considering the error limits. It means that, the former, supported by two independent ages, is considered a better representation for the age of metamorphism of the Okcheon metamorphic belt. Therefore, I propose the idea of early Permian metamorphism should better be reserved until conclusive evidence appears. The late Permian-early Triassic metamorphic age suggest that the effect of continental collision influenced much of the middle part of Korean Peninsula, namely, the Imjingang belt, the Gyeonggi massif and the Okcheon belt.

Reactivated Timings of Inje Fault since the Mesozoic Era (인제단층의 중생대 이 후 재활동 연대)

  • Khulganakhuu, Chuluunbaatar;Song, Yungoo;Chung, Donghoon;Park, Changyun;Choi, Sung-Ja;Kang, Il-Mo;Yi, Keewook
    • Economic and Environmental Geology
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    • v.48 no.1
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    • pp.41-49
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    • 2015
  • Recently developed illite-age-analysis(IAA) approach was applied to determine the fault-reactivated events for the Inje fault that cut through Precambrian biotite granitic gneiss with NNE-SSW trend in the middle of Korean peninsula. Three distinct fault-reactivated events of shallow crustal regime were recognized using the combined approach of optimized illite-polytype quantification and K-Ar age-dating of clay fractions separated from 4 fault clay samples: $87.0{\pm}0.12Ma$, $65.5{\pm}0.05$ and $66.6{\pm}1.38Ma$, $45.6{\pm}0.15Ma$, respectively. As well, $2M_1$ illite ages of 193~196 Ma and $254.3{\pm}6.96Ma$ were discernible, which may be related to the fault-activated time in the relatively deep crust. The study results suggest that the Inje fault would be firstly formed at $254.3^{\circ}$ ${\ae}6.96Ma$ and sporadically reactivated in shallow regime since about 87 Ma. These reactivation events in shallow regime might be due to the Bulguksa orogeny that would be strongly influenced in Korean peninsula at that time.

Reactivated Timings of Yangsan Fault in the Northern Pohang Area, Korea (포항 북부지역 양산단층의 재활동 연대)

  • Sim, Ho;Song, Yungoo;Son, Moon;Park, Changyun;Choi, Woohyun;Khulganakhuu, Chuluunbaatar
    • Economic and Environmental Geology
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    • v.50 no.2
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    • pp.97-104
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    • 2017
  • Here we present the timings of reactivated events from a fault in the northern Pohang area, which should be located at the northern-end of Yangsan fault line, the major fault in the southeastern Korean Peninsula. Recently developed illite-age-analysis (IAA) approach was employed for determining the fault-activated timing, combined with illite-polytype quantification using the optimized full-pattern-fitting (FPF) method, and K-Ar age-dating for each size fraction($<0.1{\mu}m$, $0.1-0.4{\mu}m$, and $0.4-1.0{\mu}m$) of 4 fault clay samples. Two chronological records of brittle fault-activation events were recognized at $19.6{\pm}1.86Ma$ and $26.1{\pm}2.55-27.9{\pm}3.46Ma$. The ages are much younger than those of fault clays from Sangcheon-ri area (41.5~43.5 and 50.7 Ma), the southern part of Yangsan fault line, and are close to the timing of East Sea-opening event. Further chronological analysis for additional sites of the Yangsan fault should be needed to reveal the time-scheme of the tectonic events and their spatial distributions along the fault line.

The study about variables influencing emotional, normative, and functional marriage intentions of unmarried men and women (미혼남녀의 정서적·당위적·기능적 결혼의향에 영향을 미치는 변인 연구)

  • Park, Hye-Min;Jeon, Gwee-Yeon
    • Journal of Family Relations
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    • v.22 no.4
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    • pp.53-80
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    • 2018
  • Objectives: The purpose of this study was to investigate individual awareness variables influencing emotional, normative, and functional marriage intentions of unmarried men and women. Independent variables were values of offspring, perceptions to unmarried life, attitudes toward multiple role planning, perceptions and availabilities of marriage-related policies, views on the marriageable age, psychological burdens of pressure to marriage by significant people, and views on parents' support for marriage fund. Method: 553 unmarried men and women in Daegu, Korea were surveyed, and the data were analyzed using descriptive statistics, factor analysis, multivariate analysis of variance(MANOVA), multiple regression analysis, and hierarchical regression analysis with SPSS 22.0. Results: First, this study was more exploratory and in-depth approach to marriage intentions than precedent studies. The sub factors of marriage intentions were emotional, normative, and functional marriage ones. Second, emotional marriage intention showed significant differences depending on gender, dating, views on the marriageable age, and degree of acceptance of parents' support for marriage fund. Among the individual awareness variables, values of offspring, perceptions to unmarried life, attitudes toward multiple role planning, and psychological burdens of pressure to marriage personally or by friends influenced emotional marriage intention. Third, normative marriage intention showed significant differences depending on gender, religion, occupational status, employment condition, dating, views on the marriageable age, and degree of acceptance of parents' support for marriage fund. Among the individual awareness variables, values of offspring, perception to unmarried life, attitudes toward multiple role planning, view on the marriageable age, availabilities of marriage-related information offering policies, and psychological burdens of pressure to marriage by mother influenced normative marriage intention. Fourth, functional marriage intention showed significant differences depending on gender, job, parents' support for marriage fund, views on the marriageable age, and degree of acceptance of parents' support for marriage fund. Among the individual awareness variables, functional marriage intention was influenced by values of offspring, perception about unmarried life, attitudes toward multiple role planning, and degree of acceptance of parents' support for marriage fund. Finally, the hierarchical regression analysis showed that individual awareness variables influenced on marriage intentions. Especially, values of offspring, perceptions to unmarried, and attitudes toward multiple role planning influenced on emotional, normative, and functional marriage intentions in common. Conclusions: The findings from these analyses suggest that the selective process based on the individual awareness has become very significant to having marriage intentions. Therefore, this study will contribute as the basic data on national marriage-related policies. Furthermore, this study will be able to use to think about the marriage intention as a task to be preceded by the national policy in order to prepare for Korea 's low fertility and aging phenomenon.