Original Article

Econ. Environ. Geol. 2017; 50(2): 97-104

Published online April 30, 2017

https://doi.org/10.9719/EEG.2017.50.2.97

© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY

Reactivated Timings of Yangsan Fault in the Northern Pohang Area, Korea

Ho Sim1, Yungoo Song1*, Moon Son2, Changyun Park1, Woohyun Choi1 and Chuluunbaatar Khulganakhuu1

1Department of Earth System Sciences, Yonsei University, Seoul 120-749, Korea
2Department of Geological Sciences, Pusan National University, Pusan 609-735, Korea

Correspondence to : yungoo@yonsei.ac.kr

Received: April 17, 2017; Accepted: April 27, 2017

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License
(http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction
in any medium, provided original work is properly cited.

Abstract

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 μm, 0.1–0.4 μm, and 0.4–1.0 μm) of 4 fault clay samples. Two chronological records of brittle fault-activation events were recognized at 19.6±1.86 Ma and 26.1±2.55–27.9±3.46 Ma. 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.

Keywords Yangsan fault, fault reactivation age, illite-age-analysis(IAA), K-Ar age-dating, fault clay

포항 북부지역 양산단층의 재활동 연대

심호1 ·송윤구1* ·손문2 ·박창윤1 ·최우현1 · Chuluunbaatar Khulganakhuu1

1연세대학교 지구시스템과학과, 2부산대학교 지질환경과학과

요 약

Article

Original Article

Econ. Environ. Geol. 2017; 50(2): 97-104

Published online April 30, 2017 https://doi.org/10.9719/EEG.2017.50.2.97

Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.

Reactivated Timings of Yangsan Fault in the Northern Pohang Area, Korea

Ho Sim1, Yungoo Song1*, Moon Son2, Changyun Park1, Woohyun Choi1 and Chuluunbaatar Khulganakhuu1

1Department of Earth System Sciences, Yonsei University, Seoul 120-749, Korea
2Department of Geological Sciences, Pusan National University, Pusan 609-735, Korea

Correspondence to:yungoo@yonsei.ac.kr

Received: April 17, 2017; Accepted: April 27, 2017

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License
(http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction
in any medium, provided original work is properly cited.

Abstract

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 μm, 0.1–0.4 μm, and 0.4–1.0 μm) of 4 fault clay samples. Two chronological records of brittle fault-activation events were recognized at 19.6±1.86 Ma and 26.1±2.55–27.9±3.46 Ma. 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.

Keywords Yangsan fault, fault reactivation age, illite-age-analysis(IAA), K-Ar age-dating, fault clay

포항 북부지역 양산단층의 재활동 연대

심호1 ·송윤구1* ·손문2 ·박창윤1 ·최우현1 · Chuluunbaatar Khulganakhuu1

1연세대학교 지구시스템과학과, 2부산대학교 지질환경과학과

Received: April 17, 2017; Accepted: April 27, 2017

요 약

    KSEEG
    Apr 30, 2024 Vol.57 No.2, pp. 107~280

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