Mid- to Late Holocene progradational pattern of Shinduri Dunefield : implications for sea level and climatic changes in the western coast of Korea

Seongchan Hong,Jeong-Heon Choi,Jong-Wook Kim 대한지질학회 2009 대한지질학회 학술대회 Vol.2009 No.

한반도 해안단구 퇴적물에 대한 OSL 연대 측정 결과 고찰

홍성찬 ( Seongchan Hong ) 한국지리학회 2018 한국지리학회지 Vol.7 No.2

한반도에 위치하는 해안단구의 형성 시기에 대해 오랫동안 다양한 연구가 진행되었지만 아직 논란이 지속되고 있다. 본 연구에서는 해안단구의 형성 시기를 보다 전체적이고 객관적으로 파악하기 위해 지금까지 연구, 발표된 광여기 루미네선스(OSL: Optically Stimulated Luminescence, 이하 OSL) 연대 측정 결과를 종합, 검토하였다. 기존 발표된 OSL 연대 측정 결과 중 일부는 시료 채취 퇴적층의 특성, OSL 연대 측정의 종류, 해안단구 퇴적층과 관련 없는 대상 시료 선정 등의 문제로 실제 연대와 차이를 보이는 경우가 발생하였다. 보다 정확한 해안단구 형성 연대를 밝히기 위해서 대상 퇴적층의 특성과 적용하는 OSL 연대 측정법의 특성을 고려하여 실제 연대와 관계가 먼 특이값을 제외하는 방안이 강구될 필요가 있다. 그리고 보다 정확한 OSL 연대 측정을 위해 연대 측정 과정뿐만 아니라 현장에서의 퇴적층에 대한 연구자의 지형학적, 퇴적학적 해석이 우선적으로 요구된다. Many studies have been carried for a long time about formation timing of the marine terrace in Korea. However, there has been much debate on the age and characteristics of the deposit. In this study, we summarized and analyzed published OSL (Optically Stimulated Luminescence) ages to understand the age of the marine terrace in Korea. Previously published OSL ages differed from real timing of marine terrace formation due to problems such as characteristic of sediment for OSL sampling, type of applied OSL technique, selection of sample not related to marine terrace deposit. It is necessary to exclude abnormal ages considering characteristic of sediment and applied OSL technique to define accurate and precise the age of the marine terrace. Furthermore, researcher’s geomorphological and sedimentological interpretation at the field is important to obtain reliable age result.

한반도 해안-하안단구 퇴적층에 대한 K 장석 pIR-IRSL연대측정법 적용가능성 고찰

홍성찬(Seongchan Hong),최정헌(Jeong-Heon Choi) 한국암석학회 2016 암석학회지 Vol.25 No.3

이 논문에서는 K-장석 pIR-IRSL<SUB>290</SUB> 연대측정법의 한반도 해안-하안단구 퇴적층의 연대측정 적용가능성을 알아보기 위하여, 다양한 환경(해성, 하성, 풍성)에서 형성된 한반도 해안-하안단구 시료들의 K-장석 pIRIRSL<SUB>290</SUB>, IRSL<SUB>50</SUB>, 석영 OSL 신호특성을 살펴보고, 경북 울진군 노음리 하안단구 퇴적층과 구산단층 퇴적물에 대한 연대측정을 실시하였다. 연구에 사용된 27개의 시료들에 대한 K-장석 pIR-IRSL290 신호의 2D<SUB>0 </SUB>값은 평균적으로 약 700 Gy로, IRSL<SUB>50 </SUB>신호의 2D<SUB>0 </SUB>값과 유사하였으며, 석영 OSL 신호의 2D<SUB>0</SUB> 값(약 250 Gy) 보다는 3배 정도 높았다. 일부 시료에 대한 K-장석 pIR-IRSL<SUB>290</SUB>, IRSL<SUB>50</SUB>, 석영 OSL 연대측정 결과, K-장석 pIRIRSL<SUB>290</SUB> 연대는, IRSL<SUB>50 </SUB>및 석영 OSL 연대보다 상당히 높았다. 이는 퇴적과정동안 장시간 햇빛에 노출되어도 제거되지 않는(unbleachable) pIR-IRSL<SUB>290</SUB> 신호에서 기인했을 가능성이 있다. 경북 울진군 노음리의 하안단구 퇴적층과 구산단층 퇴적층에서 분리한 K-장석 pIR-IRSL<SUB>290</SUB> 신호와 석영 OSL 신호도 모두 방사선포화상태에 있어, 정확한 퇴적연대를 측정하는데 한계가 있었다. 하지만, 각 신호의 성장곡선으로부터 얻은 2D<SUB>0 </SUB>값은 노음리 하안단구 퇴적층은 109-140 ka 이전, 구산단층에 의해 절단된 퇴적층은 적어도 100-105 ka 이전에 형성되었을 가능성을 강력히 시사한다. 이 결과는, 기존 ~40-50 ka의 석영 OSL 신호를 기반으로 한 구산단층 퇴적층의 연대가 방사선포화현상에 의해 과소평가된 연대임을 의미한다. In this paper, in order to test the possibility of applying K feldspar pIR-IRSL<SUB>290</SUB> signal(read out at 290℃) to date old terrace sediments(up to ~ 200 ka, MIS 7) in Korea, we investigated luminescence properties of pIR-IRSL<SUB>290</SUB> signals in K feldspar extracts from 27 marine and fluvial terrace sediment samples, and these were compared with those of quartz OSL and conventional K feldspar IRSL<SUB>50</SUB> (readout at 50℃) signals. The averaged 2D<SUB>0</SUB> value of K feldspar pIR-IRSL<SUB>290</SUB> growth curves was ~ 700 Gy, which is consistent with that of IRSL<SUB>50 </SUB>signal, and this is 3 times higher than that for quartz OSL (~ 250 Gy) on average. Where possible, K feldspar pIR-IRSL<SUB>290</SUB> ages were compared with quartz OSL and conventional IRSL<SUB>50</SUB> ages. Our preliminary K feldspar pIR-IRSL<SUB>290</SUB> ages were older than quartz OSL ages by about 200%, while fading rate-corrected conventional IRSL<SUB>50</SUB> ages are in good agreement with those based on quartz OSL. This seems to indicate the possibility of K-feldspar pIR-IRSL<SUB>290</SUB> age overestimation due to the presence of unbleachable pIR-IRSL<SUB>290</SUB> signals, even with a prolonged exposure to sunlight. Both quartz OSL and K-feldspar pIR-IRSL<SUB>290</SUB> signals for the samples from Noeum fluvial terrace and Gusan fault site were all in dose saturation level, thus unable to estimate the formation ages of the sediments. However, 2D<SUB>0</SUB> values derived from the dose response growth curves strongly indicate that the Noeum fluvial terrace sediments have formed before 109-140 ka, while the fluvial sediments from Gusan fault were desposited before 100-105 ka. Further, this seems to suggest that the previous quartz OSL ages of ~40-50 ka for Gusan fault sediments should be the underestimated ones due to dose saturation problem.

K-장석 IRSL 연대측정을 이용한 정동진 해안단구의 융기율 변화연구

홍성찬(Seongchan Hong),최정헌(Jeong-Heon Choi),김종욱(Jong-Wook Kim) 대한지질학회 2014 대한지질학회 학술대회 Vol.2014 No.10

퇴적 환경에 따른 루미네선스 신호의 특성

홍성찬 ( Hong Seongchan ),최광희 ( Choi Kwang Hee ) 한국지형학회 2021 한국지형학회지 Vol.28 No.2

This study aims to determine the sunlight exposure according to depositional environment to improve the accuracy of optically simulated luminescence (OSL) dating. Sufficient sunlight exposure during transportation of sediment is a basic assumption of the OSL dating, and if the process does not occur enough, the results may be overestimated compared to the actual depositional age. Therefore, the main purpose of this study is to establish a correction method by determining residual or unbleachable dose after sunlight exposure in the actual deposition process, not in the laboratory measurement. Four samples from two sites were collected according to the depositional environment from rivers and coasts, and various OSL signals, including the size of residual dose, degree of dispersion between grains, and OSL signal sensitivity, were measured. As a result, it was confirmed that sediments formed under temporarily high energy environments, such as floods and surges, had relatively high residual dose or large dispersion of residual dose between particles. In further studies, the OSL signal characteristics of river sediments by flow velocity will be identified and the relationship between energy and OSL signal characteristics will be identified in more detail. Moreover, a method of reconstructing the paleo-environment at the time of deposition for existing sediments will be devised. It is expected to provide important information for the frequency of disaster recurrence and prediction of future climate change.

암석 표면 루미네선스 연대측정의 원리와 지형학적 적용

홍성찬 ( Hong Seongchan ) 한국지형학회 2016 한국지형학회지 Vol.23 No.4

Optical Stimulated Luminescence dating technique was widely applied for the purpose of confirming the age of Quaternary deposit in geomophology, archaeology, etc. Sand sized(90-250μm) or silt sized(4-11μm) sediments(quartz or K-rich feldspar) were used for conventional OSL dating procedure. However, occasionally it is impossible to collect samples from actual sediment due to the lack of that sized sediment. In this case, OSL technique from deposited cobble surface can be applied as alternative method. This paper aimed to introduce principle and procedure rock surface OSL dating technique and application. Furthermore, we investigated for limitation and improvement of rock surface OSL technique. Rock surface OSL dating technique was expected to be applied various sediment types.

Principles of K-Feldspar IRSL (InfraRed Stimulated Luminescence) Dating and Its Applications

홍성찬(Seongchan Hong),최정헌(Jeong-Heon Choi),여은영(Eun-Young Yeo),김종욱(Jong-Wook Kim) 대한지질학회 2013 지질학회지 Vol.49 No.2

DeepRain: 레이더 데이터를 이용한 강우량 예측 LSTM 네트워크

김성찬(Seongchan Kim),홍승균(Seungkyun Hong),송사광(Sa-Kwang Song) 한국정보과학회 2017 한국정보과학회 학술발표논문집 Vol.2017 No.06

퍼지 외란 관측기법을 이용한 아크로봇의 적응형 강인 스윙업 및 밸런싱제어

정성찬(Seongchan Jeong),이상협(Sanghyob Lee),홍영대(Young-Dae Hong),좌동경(Dongkyoung Chwa) 제어로봇시스템학회 2016 제어·로봇·시스템학회 논문지 Vol.22 No.5

This paper proposes an adaptive robust control method for an acrobot system in the presence of input disturbance. The acrobot system is a typical example of the underactuated system with complex nonlinearity and strong dynamic coupling. Also, disturbance can cause limit cycle phenomenon which appears in the acrobot system around the desired unstable equilibrium point. To minimize the effect of the disturbance, we apply a fuzzy disturbance estimation method for the swing-up and balancing control of the acrobot system. In this paper, both disturbance observer and controller for the acrobot system are designed and verified through mathematical proof and simulations.

남해안 사천시 대포동 일대에 분포하는 고해안 퇴적물의 형성 과정과 형성 시기: 한반도 제4기 후기 지각운동의 양식과 변형률 산출을 위한 연구(II)

신재열 ( Shin Jaeryul ),홍성찬 ( Hong Seongchan ) 한국지형학회 2018 한국지형학회지 Vol.25 No.3

This study restores onshore paleo-shoreline records and establishes the nature and strain rate of neotectonism by investigating the existence and formative age of paleo-coastal sediments emerged around Sacheon-si in the Southern part of the Korean peninsula. As a result, paleo-sand bars representing 5m of the paleo-shoreline from high tide level are formed in Sacheon-si, and the formation age of these is confirmed as MIS 5c at approximately 100,000 year BP through rock surface luminescence dating to rounded gravels in paleo-sand bars. Although it is difficult to establish the uplift rate of crust precisely due to incomplete restoration of sea level records during the last interglacial stage, the uplift rate along the Southern coast of the peninsula was assumed approximately 0.72 lower than the Eastern coast during the late Quaternary in comparison to the 1st marine terrace along the Eastern coast.