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

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.

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

조선시대(1392-1910) 해일 발생의 시공간적 분포 특성

김다해 ( Kim¸ Da Hae ),홍성찬 ( Hong¸ Seongchan ),최광희 ( Choi¸ Kwang Hee ) 한국지형학회 2021 한국지형학회지 Vol.28 No.3

Analysis and prediction of storm surges are very important because the global warming has raised sea levels and increased the frequency of massive typhoons, accelerating damage of coastal flooding. However, the data for storm surge prediction is lacking due to the short history of observation in South Korea. The purpose of this study is to investigate the spatial and temporal characteristics of the previous surges and tsunamis based on the historical documents published during the Joseon Dynasty. In addition, we tried to evaluate the damage and spatial extent of such disasters, using the expressions about surge records including heights and number of administrative divisions. As a result, a total of 175 records of surges and tsunamis were compiled from 1392 to 1910: 145 events were extracted through the analysis of the ancient documents, and 30 events were from the previous research. Most of the strorm surges occurred along the west coast during summer season. More than half of the total surges were concentrated for 120 years from the mid 1600s to the mid 1700s, which was estimated to be highly relevant to the climate conditions in East Asia during the Little Ice Age. Hazardous areas by storm and tidal surges were also extracted, including Asan, Ganghwa, and Siheung during the Joseon Dyanisity period.

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.

완도군 청산도 일대에 분포하는 최종 간빙기 해안단구의 형성 시기 및 형성 과정

신재열(Shin, Jaeryul),홍성찬(Hong, Seongchan),홍영민(Hong, Yeongmin),류희경(Ryu, Huigyeong) 한국지역지리학회 2021 한국지역지리학회지 Vol.27 No.4

본 연구는 전라남도 완도군 청산면(청산도) 일대에 분포하는 최종 간빙기 해안단구 및 고해안 퇴적물의 형성 시기와 형성 과정을 규명하고 있다. 청산도 권덕리 일대에서 확인되는 해안단구 층서에 따르면 제1면과 제2면의 구정선 고도는 각각 고조위 기준 5m와 10m 내외로 나타난다. 제2면을 이루고 있는 원력층의 퇴적 연대(약 122 ka)는 최종 간빙기 극성기(MIS 5e)동안 형성된 단구로 확인되며, 장기미 해안의 고해안 퇴적물 기록에 따라서 제1면의 형성 시기(약 88~85 ka)는 최종 간빙기중 첫 번째 아간빙기(MIS 5a)에 대응하는 것으로 확인된다. 한반도 서・남해안 외해 도서 지역에서 확인되는 해안단구 및 고해안 퇴적물의 발달 특성은 각 지역의 개별적 해안 환경 및 퇴적장 조건에 영향을 크게 받은 결과로서 이들 지역에서의 해안 지형 발달사에 관한 이해를 위해서는 제4기 후기 지역 일대에서의 해수면 변동 및 지각 운동 특성과 함께 지역적 특수성이 면밀히 고려되어야 한다. This study investigates the formation ages and processes of the last interglacial marine terraces and paleo-coastal sediments in Cheongsan-myeon (Cheongsando Island) in Wando-gun, Jeollanam-do. According to the geochronology of marine terraces identified in Gwondeok-ri, the altitudes of paleo-shoreline on the first and second terrace are about 5m and 10m respectively, based on the regional high sea-level. The formation ages of the second and first terrace are 122 ka year and 88~85 ka year, responding to MIS 5e and MIS 5a in respective. The developmental characteristics of marine terraces and paleo-coastal sediments on western and southern coast of the Korean Peninsula are greatly influenced by individual coastal environments and sedimentation conditions in each region, therefore in relevant studies, regional specificities should be carefully considered with the sea-level fluctuations and crustal movements during the late Quaternary.

서해안 서천군 당정리 일대에 분포하는 육상 고해안 퇴적물의 형성 과정과 형성 시기(II): 추가 연대 자료 및 제4기 후기 연안 지형 발달 모델

신재열 ( Shin¸ Jae-ryul ),홍영민 ( Hong¸ Yeong-min ),류희경 ( Ryu¸ Hui-gyeong ),홍성찬 ( Hong¸ Seongchan ) 한국지형학회 2021 한국지형학회지 Vol.28 No.3

Following the previous study, we report a complementary dating data on the silty layers deposited in paleo-tidal conditions of the study area, Dangjeong-ri, Seocheon-gun and suggest coastal terrain development processes over the past 200,000 years. Based on the dating results, the silty layers distributed up to 25 m above mean sea level were deposited between 171 and 183 ka, and the gravel layer deposited in a fluvial environment of a paleo-Dangjeong stream was found to have formed between 78 and 83 ka. Considering relative altitudes of distribution, an uplift rate of the study area in the western coast is judged to be relatively 0.5~0.7 low to that of Pohang area in the eastern coast. Compared to Busan and Sacheon areas in the southern coast, it is assumed that an uplift rate of the study area shows a similar level with those during the late Quaternary.