• Geotechnical Engineering
• /
• v.14 no.4
• /
• pp.5-16
• /
• 1998

The ground of Taegu area consists mainly of shales with elastic sedimentary rocks. These shales have a nonhomogeneous and anisotropic characteristics. So their physical and mechanical properties are very different due to the angles($\beta$ value) of bedding planes of sedimentary rock. In this study, the physical and mechanical characteristics of shales in Taegu area are studied by performing all kinds of rock test. According to results of test, apparent specific gravity of shale decreases as the $\beta$ value increases. On the contrary, porosity and absorption increase. Elastic wave velocity shorts the highest value at the $90^{\circ}$. And Young's modulus shows the maximum value at the $30^{\circ}$. The uniaxial strength, triaxial strength, cohesion and angle of friction show the minimum value at the $60^{\circ}$respectively.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.03a
• /
• pp.103-110
• /
• 2003

This study is as for shale that attract recently geotechnical engineer more and more. like sedimentary rocks and metamorpic rocks, shales have many problem with anisotropy for stength and deformation and they have many problems with quick weathering progress and differential weathering of alternate bedding. In foreign countries, many renowned schalors, like Jaeger(1960),McLamore,Gray(1967),Donath(1972),Nova(1980),Hoek&Brown(1980),Ranamurthy(1985), have already studied for a variety of characteristic and announced high level results of their studies. In domestic also, there are many scholars who have announced high level research papers for shale. this study is a part of these stream. and this study not only analyzed strength anisotropy characteristic along with direction of testing(two-direction) by using point-load test(log-log method) but also compared uniaxial strength between the maximum saturated and dried condition. In this study, we also conducted slaking test. these results of slaking test show weathering characteristic of shales. also, we made the most of field data that obtained during slope stability project and we noticed that RQD measured in the field is much differ from drilled core RQD. In order to come close two different value or access to reality, we suggest new RQD method that artificially reduce RQD by separating core with light hand force.

• Journal of the Mineralogical Society of Korea
• /
• v.25 no.1
• /
• pp.1-8
• /
• 2012

The metamorphic environments occrrred in the Sadong and the Gobangsan formations were studied through the investigation of chloritoid and white mica in shales at Munkyung area. Two types of white mica occurs in the shale of Sadong formation; muscovite-dominant ($Mu_{76.1}Pa_{18.1}Ma_{5.8}$) and margarite-dominant ($Ma_{52.9}Mu_{31.6}Pa_{15.5}$). It is inferred that the muscovite-dominant white mica is generated by the diagenesis of Na-rich illite whereas the margarite-dominant white mica is generated by reactions between calcite and pyrophyllite separated from illite. In shales of the Gobangsan formation, chloritoids are observed with muscovite, pyrophyllite and chlorite. The chloritoids of the Gobangsan formation are considered to be originated from the reaction between pyrophyllite and chlorite. The Sadong and Gobangsan formations would have experienced the low-temperature metamorphism (anchizone) considering that white mica in general forms above the temperature of $200^{\circ}C$ and the assemblage of chloritoid-pyrophyllite-chlorite is stabilized below $280^{\circ}C$.

• Nuclear Engineering and Technology
• /
• v.12 no.2
• /
• pp.106-110
• /
• 1980

The radio-equilibrium conditions of uranium and thorium in the Okcheon black shales and monazites have been studied. As the results. a radiometric method based on the measurements of gamma ray activity has been suggested for the simple analysis of many samples in the process of the prospecting and the grading of uranium and thorium minerals.

• Journal of the Mineralogical Society of Korea
• /
• v.24 no.4
• /
• pp.313-320
• /
• 2011

Mica-type phyllosilicate particles in the shales of the Manhang formation at the Taeback area in the Kangwon Province were studied using electron probe microanalysis (EPMA) and transmission electron microscopy (TEM). The average chemical formula of the mica-type phyllosilicate mineral analysed by EPMA is $K_{1.35}(Fe_{0.18}Mg_{0.03}Al_{3.86})(Si_{6.55}Al_{1.45})O_{20}(OH)_4$. Low K contents compared to the ideal chemistry of muscovite indicate the presence of illite in the mica-type phyllosilicate particle. X-ray diffraction study showed that pyrophyllite commonly coexists with muscovite in the shales from the Manhang Formation. TEM observations showed both the interlayer and intralayer mixing of $9.3-{\AA}$ pyrophyllite and $10-{\AA}$ muscovite layers. The low K content of the mica-type phyllosilicates apparently come from the close mixing of pyrophyllite and muscovite.

• Economic and Environmental Geology
• /
• v.12 no.4
• /
• pp.207-221
• /
• 1979

The studied area occupies the southern part of Haenam peninsula located in the southwestern corner of Korea. The stratigraphic sequences of the area are grouped into following three units in ascending order. (1) Late Cretaceous sedimentary rocks of Uhangri Formation which consist of the alternative beds of black shales and tuffaceous sediments, Hwangsan acidic fine grained tuffs and Jindo rhyolite flows. (2) Late Cretaceous biotite granite and acidic porphyries which intruded the Late Cretaceous sedimentary rocks. (3) Tertiary(?) pitchstone. The study purposes to delineate any of geochemical aspects on the deposition of the sequences, the average amounts of organic materials and the effect to the maturation of hydrocarbonization which has been occured by the intrusives. Sixty nine black shale samples were collected from Uhangri Formation in the northern and southern coasts of the peninsula. Organic carbons, total extracted organic matters and hydrocarbons were mainly determined by the Soxhlet extraction method, together with C-H-N elemental analyses. Based on the field and laboratory studies, the following interpretations have been obtained. (1) The paleohydrostatic condition of the sedimentation which took place was relatively calm and stable to delineate a lacustrine environment. (2) The amounts of organic material were more or less constant throughout the period of the deposition of the sediments. (3) The degree of hydrocarbonization of the Uhangri Formation in the northern coast was taken place higher than that in the southern coast due to the differences of thermal effect by the biotite granite which is assumed to be as a heat source in the area. Among the northern coast, some black shales in Uhangri and Mogsam areas which had been under the most moderate temperature environment snow symptomatic oily material, whereas, those in Sinseongri area do not, which were presumably to be intensive thermal alteration by the later acidic porphyries.

• Economic and Environmental Geology
• /
• v.9 no.1
• /
• pp.45-73
• /
• 1976

This study has been made for the enlargement of a previous work of 1964 which was carried out by an author of this work emphasizing the stratigraphy, micropaleontology, depositional environment, and structural tectonics of the studied area. The stratigraphic sequences of the area are groupped into four units: (1) basement of Pre-Cretaceous, (2) lower sediments of Late Cretaceous, (3) upper sediments of Late Cretaceous and (4) igneous rocks of Late Cretaceous and Tertiary (?). The oldest rocks consisting of schists and gneisses of Pre-Cambrian and schistose granite' of Jurassic age are exposed at the base of this area on which the thick Cretaceous sediments were deposited. These old rocks are unconformably overlain by the lower sedimens of Late Cretaceous composed of three members, an alternation of black shale and tuffaceous sediments, fine tuff and rhyollite flow in ascending order. The oily material was found from the black shales of the alternation m"ember as semi-solid greaselike material, oily order and microscopic granular spherical material and oily stain. The lower sediments are also overlain, in low-angleunconfromity, by the 'upper sediments having three members, an alternation of volcanic conglomerate and andesitic tuff, rhyollitic tuff and andesite flow in the same order. The igneous suit of diabase, diorites, biotite granite, porphyritic granite and porphyries of the latest Cretaceous and small exposure of pitchstone of Tertiary (?) intruded into the pre-existed rocks above mentioned. Considerable amount of ostra- coda microfossils have been chemically extracted from the black shales of the lower sediments and the identification of the fossils suggests that the depositional environment of the sediments were under fresh or brackish water condition. The distribution of the geology and its tectonic data also suggest a combination of dome and basin structures in the area of San-i peninsula and Jin-do as shown in fig. 8. Between these two units an anticlinal structure was constructed. As a result of this study, a seismic survey in a district between U-su-yong and north coast of Jin-do is recommended to determine the underground features.

• Korean Journal of Environment and Ecology
• /
• v.12 no.1
• /
• pp.22-29
• /
• 1998

This study is investigated for the trace element concentration in the soils derived from different parent rocks, which are serpentinites, metamorphic rocks and black shales, and the absorption of the trace element by Pinus rigida in Hongseong and Keumsan, Chungnam, respectively. The concentrations of nickel, chrominium and cobalt are high in the serpentinites, whereas the concentrations of zinc, molybdenium and iron are high in the metamorphic rocks. These elements in black shale are lower than those in serpentinites and metamorphic rocks. The serpentine soils show high nickel, chrominium and cobalt content, while zinc and iron content are high in the mixed soils(serpentinites + metamorphic rocks) and black shales. Comparing with parent rocks, all of trace elements in their weathered soils are low. The pH of serpentine soil is high, 7.73~9.55 and that of black shale soil in 5.61. In serpentine area, the absorptions of chrominium by P. rigida is lower than its in the soils. The absorption of zinc by P. rigida is high relative to zinc concentration in soils. The Co/Ni and Fe/Ni quotient in P. rigida over serpentine soils are considerably lower than those growing over other soils tpes.

• The Korean Journal of Petroleum Geology
• /
• v.4 no.1_2 s.5
• /
• pp.27-39
• /
• 1996

In the Cretaceous, the Gulf Coast Basin evolved as a marginal sag basin. Thick clastic and carbonate sequences cover the disturbed and diapirically deformed salt layer. In the Cretaceous the salinities of the Gulf Coast Basin probably matched the Holocene Persian Gulf, as is evidenced by the widespread development of supratidal anhydrite. The major Lower Cretaceous reservoir formations are the Cotton Valley, Hosston, Travis Peak siliciclastics, and Sligo, Trinity (Pine Island, Pearsall, Glen Rose), Edwards, Georgetown/Buda carbonates. Source rocks are down-dip offshore marine shales and marls, and seals are either up-dip shales, dense limestones, or evaporites. During this period, the entire Gulf Basin was a shallow sea which to the end of Cretaceous had been rimmed to the southwest by shallow marine carbonates while fine-grained terrigengus clastics were deposited on the northern and western margins of the basin. The main Upper Cretaceous reservoir groups of the Gulf Coast, which were deposited in the period of a major sea level .rise with the resulting deep water conditions, are Woodbinefruscaloosa sands, Austin chalk and carbonates, Taylor and Navarro sandstones. Source rocks are down-dip offshore shales and seals are up-dip shales. Major trap types of the Lower and Upper Cretaceous include salt-related anticlines from low relief pillows to complex salt diapirs. Growth fault structures with rollover anticlines on downthrown fault blocks are significant Gulf Coast traps. Permeability barriers, up-dip pinch-out sand bodies, and unconformity truncations also play a key role in oil exploration from the Cretaceous Gulf Coast reservoirs. The sedimentary sequences of the major Cretaceous reseuoir rocks are a good match to the regressional phases on the global sea level cuwe, suggesting that the Cretaceous Gulf Coast sedimentary stratigraphy relatively well reflects a response to eustatic sea level change throughout its history. Thus, of the three main factors controlling sedimentation (tectonic subsidence, sediment input, and eustatic sea level change) in the Gulf Coast Basin, sea-level ranks first in the period.

• Journal of the Korean Geotechnical Society
• /
• v.17 no.1
• /
• pp.5-13
• /
• 2001

강도 또는 변형 이방성은 층리진 최적암, 박층모양의 변성암, 균일하게 절 리가 나있는 암석에서 흔히 볼 수 있다(Amadei, 1982, 1996). 특히, 대구지역은 퇴적암의 일종인 셰일로 구성되어 층리면의 각도에 따라 역학적인 특성이 달리 산정되어져야 한다. 이에 본 연구에서는 층리면의 각도를 달리하여 시료를 성형한 후 각종 시험을 수행하였다. 그 결과 일축 압축강도는 수평면과 층리면이 이루는 각이 0$^{\circ}$, 90$^{\circ}$에서 최고 강도를, 60$^{\circ}$에서 최저 강도를 나타내었다. 또한 간접 인장시험과 점 하중시험, 탄성파시험에서는 90$^{\circ}$에서 최고값을, 0$^{\circ}$에서 최저값을 보였다. 그리고, 층리에 따른 퇴적압의 일축 압축강도를 간접 인장강도, 점하중강도와의 상관성을 분석하여 각각의 관계를 회귀분석을 통한 상관식으로 나타내었다. 추가적으로 층리에 따른 공학적특성을 정량적으로 나타내었다.