• Korean Journal of Heritage: History & Science
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• v.42 no.1
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• pp.40-61
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• 2009

The Cretaceous Gyeongsang Supergroup, composed of clastic sediments mostly deposited in the lacustrine and fluvial environment, is widely distributed in the southern part of the Korean Peninsula. Diverse fossils of plants, molluscs, insects, footprints of dinosaurs, pterosaurs and birds, and eggs, bones, and teeth of dinosaurs have been found from the Gyeongsang Supergroup. New types of dinosaur, pterosaur, and bird tracks recently discovered from the Gyeongsang Supergroup attract great attention from the world. Several tracksites of dinosaurs and birds were designated as Natural Monument and nationally conserved, and many efforts have given to them for nomination of UNESCO World Heritage. Bird tracks from the Gyeonsang Supergroup are Koreanaornis hamanensis, Jindongornipes kimi, Goseongornipes markjonesi, Ignotornis yangi, Uhangrichnus chuni, and Hwangsanipes choughi, which correspond approximately one third of Mesozoic bird tracks recorded from the world. The Gyeongsang Basin of the Korean Peninsula yields world most diverse bird tracks which may be called a paradise of Mesozoic birds and they are important natural heritage providing significant information about evolution and paleogeographic distribution of birds.

• The Journal of Engineering Geology
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• v.26 no.3
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• pp.315-324
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• 2016

Because of a fissility characteristics of shale in the Gyoungsang super-group, it breaks down to debris when daylighted by construction work and causes a slope unstability. To assess the durability property of shale, a series of slake durability tests was conducted by controlling test conditions such as shape of specimen, number of specimen, revolution speed, revolution number, drying temperature and pH of submerging liquid. For the specimen shape, cube one showed relatively lower durability index than cuboid and/or fan shape one. The test with the more number of specimens showed the less durability index because of a higher friction among specimens in the drum. The durability index is linearly decreased by increasing the total number of revolution, while the revolution velocity could not affect the index. And the durability index is also decreased by increasing the drying temperature of specimen and by decreasing the pH of submerging liquid. Because the durability index of shale is almost similar to that of crystalline rocks, the disintegration characteristics of shale could not be assessed by the slake durability test recommended by ISRM, and thus a new test method by changing the total revolution number may be required for the shale having fissility characteristics.

• The Journal of Engineering Geology
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• v.13 no.2
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• pp.207-225
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• 2003

According to the data analysis of the regional fracture systems in southern Korea, the fracture orientations show three dominant sets : NNE, NW and WNW. A NNE set is the most abundant and includes most of the largest fractures. The highest fracture density is shown in the Taebaegsan mineralized area corresponding to Ogchon nonmetamorphic belt and the lowest one in the southwestern area of southern Korea. In addition, the density is higher in nonmetamorphic sedimentary rocks such as Choseon Supergroup. Pyeongan Supergroup, Daedong Supergroup and Kyeongsang Supergroup than in Precambrian basements and Jurassic granites. The regional fractures in southern Korea can be classified into four orders designated $F_1,{\;}F_2,{\;}F_3{\;}and{\;}F_4${\;}and{\;}F_4$ on the basis of their trace length. It is quite significant that fractures of each order are self-similar with respect to orientation and the combined fracture length distribution indicates a power-law distribution with an exponent of -2.04. As fractures were analyzed based on the tectonic provinces, Gyeonggj Massif and Kyeongsang Basin have all orders of fractures from $F_1$ to $F_4$. Most of the large scale faults may be ascribed to the products of slip accumulation through multiple deformation. Others besides $F_1$ fractures are thought to be evenly distributed through the whole area of southern Korea.

• The Korean Journal of Petroleum Geology
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• v.2 no.2 s.3
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• pp.83-90
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• 1994

Thermal maturation and diagenesis of the Gyeongsang Supergroup in the Euiseong area are studied by means of organic geochemical techniques and illite crystallinity. Black mudrocks of the Singdong Group contain organic matter of $0.5{\~}2{\%}$ derived from higher plants, being compared to type Ⅲ. Thermal maturity of organic matter reached dry gas generation phase. Tmax by Rock Eval pyrolysis varies between $578^{\circ}C$ and $593^{\circ}C$ regardless of stratigraphic position and localities, and vitrinite reflectance is about 2.9 and $3{\~}4{\%}Ro$ in the Jinju and the Nagdong Formations, respectively. Vitrinite reflectance measurements indicate that the maturation is mainly due to burial and partly to be affected by post-depositional intrusions. Illite crystallinity values from the Nagdong, Hasandong, Jiniu Formations and part of the Iljig Formation are plotted around the boundary between diagenesis and anchizone, indicating dry gas generation stage. However, the values are not dependent on stratigraphic position. The values from the Iljig, Hupyeongdong, Geomgog, and Sagog Formations fall into the range of anchizone, probably resulted from the post-depositional intrusions which occur locally. Both organic geochemical and illite crystallinity data indicate thermal maturation stage of dry gas generation. Diagenesis of the Gyeongsang strata is mostly controlled by burial, and partly affected by post-depositional intrusions. Paleotemperature of the Sindong Group is estimated at around $200^{\circ}C$ on the basis of illite crystallinity.

• Proceedings of the KGS Conference
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• 2002.11a
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• pp.97-100
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• 2002

지표의 기복은 암석의 차별적 풍화와 침식을 반영하므로, 기복의 형성에서 암석이 차지하는 몫을 이해하는 것은 중요하며 이 문제는 근대지형학의 발달 초기부터 중요하게 다루어져 왔다(권혁재, 2002).(Picture Omitted) 대구분지 북쪽 분수계를 이루고 있는 팔공산의 기반암은 중생대 백악기 말부터 제 3기초기에 걸쳐 백악기 퇴적암인 경상누층군을 관입하여 형성된 불국사화강암이다.(중략)

• The Journal of the Petrological Society of Korea
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• v.14 no.1
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• pp.38-44
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• 2005

Hornblende $^{40}Ar/^{39}Ar$ age of $113.4{\pm}2.4(2{\sigma})$ Ma was determined from the volcanic pebble of the Silla Conglomerate which belongs to the Hayang Group of the Cretaceous Gyeongsang Supergroup. This age corresponds to the top of Aptian. Based on the reported age information, onset and duration of deposition of the constituting formations of the Hayang Group are constrained as follows; deposition of the Jindong Formation started from ca. 96~97 Ma and lasted for about 15 Ma. Therefore, Jindong Formation was deposited since Cenomanian to Santonian and it is likely to be extended to the early Campanian. We propose 81~80 Ma, which is in early Campanian, as the boundary between Hayang and Yucheon Groups. We suggest that the Silla Conglomerate was deposited during the early Albian and the Haman Formation was deposited during the rest of the Albian and also during the Cenomanian. The Chilgok Formation seems to be deposited during the late Aptian.

• Journal of the Korean earth science society
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• v.44 no.2
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• pp.161-168
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• 2023

While numerous previous studies investigated the provenance and tectonic history of the Gyeongsang Supergroup, less are known about other Cretaceous strata in South Korea. This study presents preliminary results from petrographic analysis of the Cretaceous Icheonri Formation distributed in Gijang-gun, Busan. Based on the immature texture and composition of the Icheonri sediments, we interpret that they were derived from weakly denudated Cretaceous arc volcanoes developed along the eastern margin of the Asian continent, with limited weathering and transport. Additionally, the presence of chrome spinel grains in the sediments suggests the existence of ultramafic bodies exposed in their provenance. Further studies will advance our understanding of the tectonic developments in the southeastern Gyeongsang Basin, and facilitate a comprehensive correlation between the Icheonri Formation and the Gyeongsang Supergroup.

• Journal of the Korean earth science society
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• v.21 no.4
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• pp.423-436
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• 2000

The lithofacies, biofacies, and paleosol development of the Jindong Formation, the Geoncheonri Formation, and the lacustrine deposits of Mt. Hwangryeong at Pusan, which occur in the southeastern part of the Gyeongsang Basin, were analyzed in comparative sedimentology and in stratigraphy. The common features of these lacustrine deposits are: 1) clastic deposits are prevailing, 2) deltaic deposits are not associated, 3) mudflat deposits are common, and 4) stromatolites are absent. The distinct differences among these deposits are: 1) in the Jindong Formation, the mudflat deposits are predominant, pedogenic calcretes are commonly present, and dinosaur tracks frequently occur, compared with other two lacustrine deposits, and 2) in the Geoncheonri Formation, invertebrate fossils are relatively common and storm deposits are not recognized, compared with other deposits, and 3) evaporite mineral casts and tuffaceous turbidite deposits are common in the Mt. Hwangryeong lacustrine deposits. In stratigraphy, the Geoncheonri Formation is correlated with the lower part of the Jindong Formation, and the Mt. Hwangryeong lacutsrine deposits are deemed to overlie the Jindong Formation. On the basis of comparative sedimentology and stratigraphic relationship among these lacustrine deposits, general paleoenvironements of the southeastern part of the Gyeongsang Basin from the late Hayang time to the early Yucheon time are interpreted as follows. During the late Hayang time, tectonic and volcanic activities were generally inacitive in the Gyeongsang Basin, and lacustrine environments expanded since the paleoclimatic condition became less arid compared with the middle Hayang time. In general, however, paleoclimate during the late Hayang time was still arid, and wetting and drying periods were alternated. The occasional occurrences of severe droughts were also characteristic of the late Hayang time. Mudflats existed in wide area in the southeastern part of the Gyeongsang Basin during the late Hayang time, and sedimentation rate was accordingly low. The sedimentation rate became relatively high during the latest Hayang time and the early Yucheon time since tectonic and volcanic activities had been active. Generally arid climate continued for the early Yucheon time, enough for evaporite minerals to precipate occasionally.

• Journal of Soil and Groundwater Environment
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• v.14 no.3
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• pp.32-39
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• 2009

This study was conducted in order to get the scientific background for soil pollution criteria. The 92 soil samples derived from various geological units were taken and analyzed to survey natural heavy metal background levels using aqua regia digestion method and 0.1N HCl extraction method. From these results, the average natural contents of metals were 0.287 mg/kg for Cd, 15.26 mg/kg for Cu, 18.43 mg/kg for Pb, 25.36 mg/kg for Cr, 54.27 mg/kg for Zn, 17.68 mg/kg for Ni, 6.83 mg/kg for As by the aqua regia method, and 0.040 mg/kg for Cd, 0.48 mg/kg for Cu, 3.06 mg/kg for Pb, 0.09 mg/kg for Cr, 1.54 mg/kg for Zn, 0.27 mg/kg for Ni, 0.089 mg/kg for As by the 0.1N HCl extraction method. Ratios of soluble contents and total contents were Cd 0.14, Cu 0.03, Pb 0.17, Cr 0.004, Zn 0.03, Ni 0.02, As 0.013 and the correlation coefficients of soluble contents and total contents were 0.24(As), 0.88(Cd), 0.43(Cr), 0.65(Cu), 0.70(Pb), 0.61(Ni), 0.24(Zn). The correlation factor decreased in the order of Cd > Pb > Cu > Ni > Cr > Zn $\approx$ As.

• The Journal of Engineering Geology
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• v.24 no.4
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• pp.551-574
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• 2014

The occurrence, distribution, and hydrogeochemical characteristics of uranium and radon in groundwater within different lithologies in Gyeongnam and Gyeongbuk provinces were investigated. A total of 201 groundwater samples from sedimentary rocks taking a large portion of the geology and from igneous rocks taking a small portion of the geology were analyzed and examined using factor analysis. Their radionuclide levels were used to construct detailed concentration maps. The groundwater types, defined using a Piper diagram, are mainly Ca-$HCO_3$ with less Na-$HCO_3$. Among the samples, one site exceeds $30{\mu}g/L$ of uranium (i.e., the maximum contaminant level of the USEPA) and three sites exceed 4,000 pCi/L of radon (i.e., the alternative maximum contaminant level). No samples were found to exceed the 15 pCi/L level of gross alpha or the 5 pCi/L level of radium. The concentration of uranium ranges from 0.02 to $53.7{\mu}g/L$, with a mean of $1.56{\mu}g/L$, a median of $0.47{\mu}g/L$, and a standard deviation of $4.3{\mu}g/L$. The mean concentrations of uranium for the different geological units increase in the following order: Shindong Group, Granites, Hayang Group, Yucheon Group, and Tertiary sedimentary rocks. The concentration of radon ranges from 2 to 8,740 pCi/L, with an mean of 754 pCi/L, a median of 510 pCi/L, and a standard deviation of 907 pCi/L. The mean radon concentrations for the investigated geological units increase in the following order: Granites, Yucheon Group, Tertiary sedimentary rocks, Hayang Group and Shindong Group. According to the factor analysis for each geological unit, uranium and radon behave independently of each other with no specific correlation. However, radionuclides show close relationships with some components. Regional investigations of radionuclides throughout the country require an integrated approach that considers the main lithological units as well as administrative districts.