• 한국지형학회지
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• 제28권1호
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• pp.1-12
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• 2021

This study tried to reveal relative surface denudation resistance and ranking by geologic types in the Southern Korean Peninsula using an 1:250,000 digital geologic map and ASTER GDEM. Among rock types such as igneous, sedimentary and metamorphic rocks, metamorphic rock showed the greatest resistance to surface denudation. The most resistant rock to surface denudation by geologic periods (e.g., the Precambrian, Paleozoic, Mesozoic and Cenozoic) was found from the Precambrian. Among the major tectonic settings in the Southern Korean Peninsula such as the Gyeonggi massif, Okcheon belt, Yeongnam massif, Gyeongsang basin and Pohang basin, the Okcheon belt indicated the greatest resistance. The most and least resistant rocks from the representative nine rocks in the Southern Korean Peninsula were Paleozoic limestone, and Cretaceous sedimentary rock and Cenozoic sedimentary rock, respectively. This study suggests that Paleozoic limestone, Cretaceous volcanic rock, Paleozoic sedimentary rock and Precambrian gneiss can be regarded as hard rocks with high elevation, steep slope and complicated relief, while soft rocks with low elevation, gentle slope and simple relief are Jurassic granite, Cretaceous sedimentary rock and Cenozoic sedimentary rock.

• 암석학회지
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• 제12권2호
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• pp.70-78
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• 2003

전라남도 여수시 화정면에 속하는 사도, 추도, 목도, 낭도, 적금도 등 도서지역에는 다양한 종류의 화산암과 화산쇄설성 퇴적암 및 공룡화석이 산출되는 퇴적층 등이 산출된다. 이 연구는 이러한 화산암 및 퇴적암들의 생성 및 퇴적시기를 규명하기 위하여 수행되었다. K-Ar 연대측정을 통해 알아낸 이 지역의 화성활동은 주로 91.8$\pm$3.5(l$\sigma$) Ma에서 65.5$\pm$1.3(l$\sigma$) Ma의 시기에 걸쳐 일어났음이 밝혀졌다. 조사지역 퇴적암의 퇴적연대는 야외에서 관찰된 퇴적암과 화산암과의 관계와 화산암의 연대로부터 추정하였다 이 지역에서 가장 오래된 퇴적암은 적금도의 화산력을 갖는 역암으로써 최고 생성연대는 약 8천 1백만년이다. 층서적으로 더 상위에 놓이며 많은 공룡 발자국 화석을 포함하는 추도의 셰일층은 최소 7천 7백만년, 목도의 역암은 약 7천 2백만년 내지 7천만년, 사도의 공룡화석층은 최소 6천 5백만년전에 퇴적되었던 것으로 판단된다. 즉, 여수시 도서지역에서 조사된 화산암과 퇴적암들은 모두 백악기 최후기에 분출 및 퇴적된 것이며, 이 지역에서는 공룡들이 백악기 최후기까지 활동하였던 것으로 생각된다.

• 한국지구과학회지
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• 제38권2호
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• pp.141-149
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• 2017

전남 사옥도 지역의 지질은 쥐라기 화강암, 백악기 퇴적암, 산성응회암, 산성맥암으로 구분된다. 최근 공룡 발자국, 새 발자국 및 절지동물의 보행열이 발견된 사옥도지역의 백악기층은 하부로부터 담회색 사암, 셰일, 이암 등이 교호한다. 화석을 포함하는 퇴적암은 산성응회암에 의해 덮이며, 산성암맥이 퇴적암과 응회암을 관입한다. 사옥도 지역 백악기 퇴적암의 퇴적시기를 밝히기 위해 응회질 사암과 상부의 산성 응회암에 대해 저어콘의 SHRIMP U-Pb법 절대연대를 측정하였다. 사암과 응회암의 U-Pb 연대는 각각 $83.58{\pm}0.86$와 $79.80{\pm}0.75Ma$이며 이는 백악기 후기의 캄파니안에 해당된다. 산성응회암의 연대는 응회암의 분출시기와 화석을 포함하는 퇴적암의 최소 연대를 지시한다. 따라서 공룡과 물갈퀴 새발자국의 형성연대는 83.6와 79.8 Ma 사이로 추정된다.

• 자원환경지질
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• 제5권1호
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• pp.1-20
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• 1972

A large anorthositic mass outcropped as mushroom-like body extending up to 46km which occurs in the Hadong kaoline district of southern Korea. The anorthositic mass is in contact with the metamorphic, plutonic and sedimentary rocks. The metamorphic rocks are of granitic gneiss and banded gneiss, etc; the plutonic rocks are of gabbroic and dioritic rocks, schistose granite, syenite, diorite and granite. The sedimentary rocks include siltstone and pebbly sandstone of Lower Gyeongsang System, Cretaceous in age. The anorthositic mass shows a gradational contact with the metamorphic and sedimentary rocks, and is cut by the plutonic rocks except gabbroic and dioritic rocks. The anorthositic mass is leucocratic in the central portion of the mass, and, in turn, grades to rock phases in which ma/ic minerals are irregularly scattered, then to the well-lineated rock and finally to the banded gneiss. Lineation of the anorthositic mass is accordant with that of the surrounding banded gneiss, and the lineation continues toward the gneiss. In some places, the rock phases in which mafics are scattered is gradational with adjacent sedimentary rocks. The anorthositic mass in contact with gabbroic and dioritic rocks shows spotted features. Various replacement features seen under the microscope and paragenetic sequence of the mineral components in the anorthositic rocks cannot be considered as the origin of magmatic crystallization. From the field and microscopic observations, it is concluded that the anorthositic mass was formed from replacement of the metamorphic rocks and plutonic rocks by the anorthositic magma.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.652-661
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• 2006

The cut slopes in Jinju area constitute the Cretaceous Sedimentary rock which is one of the most poor ground conditions. The geological rocks of the cut slopes are correlated with Jinju Formation. Most of the rocks consist of Black Shale layer, but the lower parts consist of Alkorsic White Sandstone. So, It is characteristic of the differential weathering due to the difference of rock species. Moreover, vertical joints which concentrate on the released rock and weak rock fragments are accompanied with minor faults. We make out face mapping about each slopes through the detailed field-study and deduce RMR and SMR from the field data. The strength properties of rocks were obtained from references, indoor tests, and Back Analysis method. And, choosing properties were used in the stability analysis as stereographic projection and limit equilibrium analysis and we establish the countermeasures for the cut slopes.

• 자원환경지질
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• 제29권2호
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• pp.193-209
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• 1996

Paleomagnetic and rock-magnetic data have been obtained from the Cretaceous rocks (Yeongdong Group, volcanic rock, and intrusive rocks) which are exposed in the Yeongdong Basin. The characteristic remanent directions of these rocks, which are mainly carried by magnetite and hematite of single and pseudo-single domain sizes, are normally magnetized (Yeongdong Group: $D/I=29.6/59.0^{\circ}C$, k=75.7, ${\alpha}_{95}=3.3^{\circ}$, N=25 sites, paleopole at $198.0^{\circ}E$, $66.4^{\circ}N$, K=46.1, $A_{95}=4.3^{\circ}$; volcanic rock: $D/I=352.8/44.1^{\circ}$, k=44.2, ${\alpha}_{95}=18.8^{\circ}$, N=3 sites, paleopole at $340.0^{\circ}E$, $78.8^{\circ}N$, $K=49.8^{\circ}E$, $A_{95}=17.6^{\circ}$X>; intrusive rocks: $D/I=358.4/51.9^{\circ}C$, k=20.0, ${\alpha}_{95}=13.8^{\circ}$, N=7 sites, paleopole at $338.1^{\circ}E$, $86.8^{\circ}N$, K=13.5, $A_{95}=17.1^{\circ}$). The stepwise unfolding of the characteristic remanent magnetization (ChRM) of the Yeongdong Group reveals that a maximum value of k is observed at 60% of unfolding with $D/I=13.0/58.6^{\circ}$ (k=124.62, ${\alpha}_{95}2.6^{\circ}$) indicating that the ChRM was aquired during ti1ting of the strata. This remagnetized ChRM in the sedimentary strata is due to acquisition of geomagnetic field direction at the time of formation of authigenic magnetic minerals, although it is not totally ruled out that the formation of authigenic magnetic minerals was affected indirect1y by the elevated temperature originated from the volcanic and intrusive rocks which intruded between Late Cretaceous and Early Tertiary.

• 자원환경지질
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• 제29권6호
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• pp.753-765
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• 1996

It is a well known fact that the remanent magnetization direction of the Tertiary rocks is deflected significantly clockwise (about $50^{\circ}$) in the Tertiary basins of the southeastern part of Korean peninsula. This fact has been interpreted as an evidence of north-south spreading of the East Sea (Sea of Japan) and dextral strike-slip motion of the Yangsan fault. As deflection (rotation) of remanent magnetizations is frequently reported from various regions of the world in the vicinities of strike-slip fault, such phenomena are to be expected in the Yangsan fault region also. It was the purpose of this study to clarify whether such premise is right or not. A total of 445 independently oriented core samples were collected from Cretaceous rocks of various lithology (sedimentary rocks, andesites and I-type granites) in the Yangsan fault area. In spite of through AF and thermal demagnetization experiments, no sign of remanent magnetization deflection was found. Instead, palaeomagnetic poles calculated from formation-mean ChRM directions are very similar to those of contemporary (Barremian, and late Cretaceous-Tertiary) sedimentary and plutonic rocks in the other parts of $Ky{\check{o}}ngsang$ basin as well as those of China. Therefore, possibility of tilting of granite plutons and horizontal block rotation of study area is excluded. It is also concluded that the Yangsan fault did not take any significant role in the Cenozoic tectonic evolution of southeast Korea and the East Sea region. The boundary between rotated and unrotated region of remanent magnetization is not the Yangsan fault line, but must lie further east of it.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권5호
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• pp.63-70
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• 2017

Radon concentrations were measured in 250 groundwater samples collected from the Goesan area where uraniferous black slate and granites abundantly occur in the formations. The measured radon levels ranged from 0.90 to 7,218.7 Bq/L with the median value of 54.3 Bq/L, similar to the value measured in the nationwide survey in 4,853 wells (52.1 Bq/L). The median value was highest in the Cretaceous granite area (390.0 Bq/L) while it was as low as 20.0~58.8 Bq/L in the Ogcheon meta-sedimentary rock areas. About 23.6% of the total samples exceeded the WHO guideline value of 100 Bq/L established in 2011. The exceeding rate was 69.0, 39.4, and 7.0~13.7% in the Cretaceous granite area, Jurassic granite area, and Ogcheon meta-sedimentary rock areas, respectively.

• 자원환경지질
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• 제27권4호
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• pp.411-420
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• 1994

Euiseong sub-basin, one of three sub-basins in Kyungsang basin, consists of various sedimentary and igneous rocks of Cretaceous age. Kusandong tuff and Yucheon volcanic rocks from the sub-basin were collected for the anisotropy of magnetic susceptibility (AMS) study. Maximum directions of the AMS for Kusandong tuff and Yucheon volcanic rocks are used to detect possible source areas. Although the dispersion of the maximum directions of the AMS, mainly due to low susceptibility and/or low percent anisotropy of individual specimens, is rather large, it is possible to reveal several source areas for the volcanic rocks. Areas near the Keumseongsan and Hwasan, calderas in the study area, are identified as source areas for Yucheon volcanic rocks, while the western part of Sunamsan, another collapsed caldera in Euiseong sub-basin, is inferred to be the source area for Kusandong tuff. However, it is not possible to determine detailed source areas for groups of Yucheon volcanic rocks of different lithologies, because of poor degree of convergence of the maximum directions of the AMS results from the volcanic rocks. It is also concluded that several episodic volcanic activities centered at Keumseongsan and Hwasan calderas were responsible for the formation of Yucheon volcanic rocks in Euseong area.

• 한국지반환경공학회 논문집
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• 제7권6호
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• pp.35-44
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• 2006

의성 금성산 북부지역에서 지열자원의 탐사와 화도의 자세를 파악하기 위하여 여러 종류의 지구물리학적 탐사와 지질조사를 수행하였다. 이를 위하여 자력탐사, 자연전위탐사, 방사능탐사, 비저항탐사, 지표 부근에서의 온도검층 및 지질조사 등을 수행하였으며 그 결과를 요약하면 다음과 같다. 여러 종류의 지구물리학적 이상들이 백악기의 화도와 관련되어 나타난다. 비저항 및 온도검층에서 관찰되는 이상들은 지질구조 및 지열과 관련된 것으로 판단된다. 소규모의 방사능 이상들과 자연전위 이상들은 암석의 화학적 특성과 관련된 것으로 판단된다. 연구지역의 퇴적암의 층리는 불투수층인 화산암을 향하여 급한 경사가 발달하였으며 지하수와 지열자원의 배태를 위한 이상적인 지질구조를 형성하고 있다. 또한 본 연구지역의 지질과 연구지역 주변에 분포하는 두개의 기존 온천 부근의 지질은 경상계 퇴적암류와 화산암류로 분포되어 있어 서로 유사하였다.