• 한국석유지질학회:학술대회논문집
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• spring
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• pp.29-37
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• 1998

The sedimentary succession on the northern coast of Jindo and the adjacent area comprises the thinly bedded, fine-grained deposits of an epiclastic sandstone, siltstone, black shale/mudstone, and cherty mudstone (ca. 200m in vertical thickness), which are interpreted as the finely stratified turbidites mainly by density underflow-induced currents. Most deposits can be divided into eight facies: thin-bedded, ash-rich massive sandstone layer (mS), graded and laminated mudstone layer (glM), graded mudstone layer with ripple lamination (rM), laminated and graded siltstone layer (lgZ), finely laminated black shale layer (IBS), structureless mudstone layer (mM), thin-bedded cherty mudstone layer (lCM), and contorted and laminated mudstone layer (dlM), The thin-bedded, ash-rich sandstone facies is interpreted to be deposited from high-density turbid underflows during a relatively large flooding. Most thinly bedded mudstone facies would be deposited from low-density turbid underflows (turbidity currents) with some different hydrodynamic condition and sediment concentration during the high discharge of river water. Whereas the structureless mudstone facies may result from raining down of suspended sediment intermittently supplied by overflows and interflows. From the entire succession, graded and laminated mudstone layers interbedded with thin-bedded, ash-rich massive sandstone are dominant in the lower part of the succession, and graded mudstone layers with ripple lamination ripple lamination occur mainly in the middle part of it. On the other hand, iaminated/raded siltstone and contorted/laminated mudstone layers prevail in the upper part. The transition of facies association is suggestive of the continuous change of main depositional setting from basin plain to lower slope, which could be due to the movement of depocenter by the increase of sediment supply (volcanic activity).

• Journal of the Korean earth science society
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• v.39 no.6
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• pp.545-554
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• 2018

The Cretaceous Eumsung (Eumseong) Basin is a pull-apart basin, formed along a series of the Gongju strike-slip faults trending NE-SW. The Nongdari-Meer forest of the Gugokri area in the southwestern part of the basin is comprised of thick purple mudstone, intercalating conglomerate, pebbly sandstone, and green mudstone beds. The succession mainly consists of seven sedimentary facies: stratified conglomerate (C2), conglomerate encased in siltstone (CE), stratified pebbly sandstone encased in siltstone (PSE2), purple sandy siltstone (Zp), green sandy siltstone (Zg), purple mudstone (Mp), and green mudstone (Mg). Sedimentary environment is mainly indicative of alluvial-plain setting in an alluvial-to-lacustrine sedimentary system, developed in the southwestern part of the basin. Geological survey was fulfilled in succession of the Gugokri sedimentary system using 1:5000 topographic map, which resulted in a geological route map. This study newly suggested that there be fluvial systems showing ENE and NNE trends in the study area, based on data of palaeocurrent direction and sedimentary characteristics in new outcrops of the forest. The study also revised the precedent sedimentation model of the Gugokri system.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.11b
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• pp.31-50
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• 2002

The sedimentary rocks deposited in Taegu and Kyongbuk region consist of various rocks such as the shale, mudstone, siltstone and sandstone. The characteristics of the sedimentary rocks are distinguished from those of igneous rocks and metamorphy rocks for the stratum caused by deposit environment. This study investigated engineering characteristics of the anisotropy, weathering rock and filled rock joints in the notable features of sedimentary rocks.

• Economic and Environmental Geology
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• v.54 no.3
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• pp.311-330
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• 2021

The Sinseongri site contains at least eleven theropod trackways, three sauropod trackways, and one or more ornithopod walkways of dinosaur footprints. The host rock at the site is primarily siltstone and mudstone, but thermal alterations have metamorphosed it into hornfels. Except for micro cracks and exfoliations, joint systems in various directions appeared on the surface of the fossils site and showed a low share of all damage factors. The host rocks in the fossils site demonstrated relatively high physical properties as a result of ultrasonic velocity and were classified as stable. More than half of the fossils required reinforcement to control the progression of cracks if the type of conservation treatment was subdivided according to the damage type of dinosaur footprint fossils. The white paint used to visualize the footprints seems to deteriorate, allowing rock debris to spill out and causing damage to the fossil site, and alternative visualization schemes should be considered.

• Korean Journal of Heritage: History & Science
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• v.46 no.1
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• pp.268-289
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• 2013

The Dinosaur tracksite at Jeori, Geumseongmyeon, Euiseonggun, Gyeongsangbukdo, Korea (National Monument No. 373) has been studied in the aspects of location, stratigraphy, sedimentology, fossil occurrence, unique geological records, literature, significance in natural history, preservation, and management. On the basis of these features, the Jeori tracksite has been assessed semiquantitavely. The Jeori tracksite occurs in the Sagok Formation (Albian) of the Euiseong sub-basin, and over 300 footprints forming 12 sauropod trackways, 10 ornithopod trackways, and 1 theropod trackways are preserved in this tracksite. The track-bearing deposits consist of tabular-bedded medium- to fine-grained arkose with mudstone drape, interlaminated fine-grained sandstone to siltstone and mudstone, and shaly mudstone. The dinosaur tracks are preserved in the interlaminated fine-grained sandstone to siltstone and mudstone, and most of them are observed as underprints. The track-bearing deposits are interpreted as sheetflood deposits on the floodplain under a seasonal paleoclimatic condition with alternating of wetting and drying periods. Multiple tension fractures with NE strike were formed in the track-bearing bed, which resulted in that tracks seem to occur in several horizons. The significance in natural history of the tracksite can be summarized as follows: 1) the historical implication of the Jeori tracksite as the firstly designated National Monument of dinosaur fossil sites, 2) the high density of the occurrence of diverse footprints (over 300) within small area (about $1,600m^2$), and 3) the significance of the tension fractures associated with the track-bearing bed as geoeducational records for the understanding the development of fault. In order to share the value of the Jeori tracksite in the aspect of natural history with the community and public, the interpretive panel should be modified to include figures explaining paleoenvironment and tension fault development. In addition it is recommended that a brochure be published briefly explaining the tracksite and to educate the residents about the natural and social significance of the tracksite. For the safety of visitors it would be desirable for the road in front of the tracksite to be moved at least 10 m southward, which could mitigate the shaking of the track bed caused by traffic.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.5-17
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• 2000

The physical and mechanical properties of the sedimentary rocks deposited in Taegu and Kyongbuk region have been measured in the laboratory and at the field. Four kinds of rocks such as the shale, the mudstone, the siltstone and the sandstone were the object of this study. In sedimentary rock joint, bedding made it impossible to extract cores for uniaxial compressive test. Some correlations between the uniaxial compressive strength and the other characteristic values such as Point load index, Schmidt hammer rebound, Brazilian strength, P-wave velocity and Absorption ratio are made. The chemical and mineral compositions are also investigated by the XRF and XRD analysis. In addition, the weathering grade of rocks are classified by the quantitative indices of Point load index, Schmidt hammer rebound and Absorption ratio.

• Journal of the Korea Concrete Institute
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• v.23 no.1
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• pp.49-55
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• 2011

The distresses of alkali-silica reaction (ASR) was recently reported at highway cement concrete pavement in Korea, which showed typical cracking and spalling patterns of ARS. Korea is was no longer safe zone against ASR, needding to find a control methodology against ASR. The purpose of this research was to provide a control methodology against ASR using mineral admixtures through a series of laboratory test program. Laboratory works included the accelerated mortar bar test (AMBT) by ASTM C 1260 regulation with five types of aggregate and three types of mineral admixtures (fly ash, ground granulated blast-furnace slag and silica fume). The result of ASTM C 1260 test for five types of aggregates without mineral admixtures showed that Siltstone and Mudstone were found to be "reactive." Tuff and Andesite-1 were found to be "possiblely reactive." In case of concrete mixed with 10, 20, and 30% fly ash, all specimens except Mudstone mixed with 10% FA were found to be "non-reactive". In cases of concrete mixed with 30, 40, and 50% ground granulated blast-furnace slag and 5, 7.5, and 10% silica fume, all specimens were found to be "non-reactive." These results could be selectively applied in constructions in Korea.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2773-2784
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• 2023

It is essential to evaluate the blasting-enhanced permeability (BEP) feasibility of a low-permeability sandstone-type uranium deposit. In this work, the mineral composition, reservoir physical properties and rock mechanical properties of samples from sandstone-type uranium deposits were first measured. Then, the reformability evaluation method was established by the analytic hierarchy process-entropy weight method (AHP-EWM) and the fuzzy mathematics method. Finally, evaluation results were verified by the split Hopkinson Pressure Bar (SHPB) experiment and permeability test. Results show that medium sandstone, argillaceous sandstone and siltstone exhibit excellent reformability, followed by coarse sandstone and fine sandstone, while the reformability of sandy mudstone is poor and is not able to accept BEP reservoir stimulation. The permeability improvement and the distribution of damage fractures before and after the SHPB experiment confirm the correctness of evaluation results. This research provides a reformability evaluation method for the BEP of the low-permeability sandstone-type uranium deposit, which contributes to the selection of the appropriate regional and stratigraphic horizon of the BEP and the enhanced ISL of the low-permeability sandstone-type uranium deposit.

• Economic and Environmental Geology
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• v.53 no.1
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• pp.87-98
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• 2020

The bird track fossil site in Haman Formation is divided into seven sedimental layers by the sedimentary structures, lithofacies and sequences. The bird tracks top on the highest layer, which includes ripple marks and suncracks. The layer has lithofacies with reddish grey siltstone and dark grey mudstone, alternately. As an analysis for the same rocks of the fossil site, physical properties show on mean values for 0.62% of absorption rate, 1.64% of porosity and 2.63 of specific gravity. Rock-forming minerals composed mainly of plagioclase, quartz, calcite, chlorite and mica. Meanwhile, we executed an experiments based on the petrography and weatherings to find a proper consolidants. In the experiments, the OH 100 reagent proved stable aspect and the lowest transition rate in terms of weight and chromaticity. Also, it showed the highest increase in ultrasonic velocity, improving the physical properties of the rocks. In the case of applying the OH 100 with antihygro, an swelling inhibitors on the sedimentary rocks, the chromaticity indicated an stable transition aspect. When it comes to the physical properties, the antihygro also decreases the porosity effectively. Thus, the most proper method for the fossil site of Haman Formation is to apply antihygro and OH 100 reagents since the rocks includes clay minerals that show swelling characteristics. However, this result is deduced from an indoor application experiments, leaving the necessity of verification how these reagents would affect the bird tracks site under the field condition.

• Korean Journal of Heritage: History & Science
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• v.47 no.2
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• pp.46-67
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• 2014

The Dinosaur track-bearing deposits recently found at Bangudae Petroglyph site in Ulju (National Treasure No. 285) have been studied in the aspects of sedimentology, paleoenvironments, and significance in natural history. The dinosaur tracks occur in the Daegu Formation (late Early Cretaceous), and over 80 footprints including 43 ornithopod footprints, 36 sauropod footprints, and 2 theropod footprints are preserved in this tracksite. The track-bearing deposits consist of irregularly interlaminated siltstone and mudstone, calcareous sandy to silty mudstone, thin-bedded tuffaceous sandstone, planar- to cross-laminated sandstone, and thin- to medium-bedded graded sandstone, and they are interpreted to be sheetflood deposits on an alluvial plain. Diverse types of ripples and mudcracks, rainprints, and invertebrate trace fossils are observed in these deposits, and the crest-lines of wave ripples do not show preferred orientation. Dinosaur footprints occur as true prints, underprints, overtracks, and casts on the bedding surfaces, and the orientation of trackways are scattered. It is interpreted that paleoclimatic condition of the track-bearing deposits were semiarid with alternation of wetting and drying periods, and that dinosaurs frequented small and shallow ponds during wetting periods and recorded their tracks on an alluvial plain. The frequent occurrence of dinosaur tracks in study area indicates that the Cretaceous deposits around Daegokcheon Stream are very useful sedimentological and paleontological records to understand the paleoecology and paleoenvironments during the dinosaur age in Korean Peninsula. Consequently the dinosaur track-bearing deposits around Daegokcheon Stream should be further studied in sedimentary geology and paleontology in order to enhance cultural heritage value of the Petroglyphs of Bangudae Terrace as the World Heritage.