• Economic and Environmental Geology
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• v.49 no.6
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• pp.417-432
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• 2016

It was firstly revealed in this research that the marine terrace of the Ijin-ri (Bukpyung-myeon, Haenam-gun) was formed during the last interglacial (Marine Isotope Stage 5e; MIS 5e). The marine terrace totally ranging from 4.8 m (asl) to 8.8 m (asl) is subdivided into 4 units; Unit I ranges 4.8-5.3 m, unit II ranges 5.3-6.9 m, unit III ranges 6.9-8.3 m, and unit IV ranges 8.3-8.8 m. Strong evidences that units II and III were formed during MIS5e were obtained based on OSL dating, the physical characterizations such as particle size distribution, magnetic susceptibility and water content, principal element and trace element analyses, and quantitative clay mineral analysis for samples at the 30 cm intervals. The rounded gravels on the marine terrace are regarded to be originated from the clastic materials transported directly from the surrounding mountains toward the marine and abraded in the coastal area, without any fluvial processes. During the warmest period (125k, unit II), the increase in rainfall, along with the rapid rise in sea level, was likely caused the high amount of clastic materials transported to the upper part of the beach. As a result of comparing clay mineral ratios of study site with those derived from sediments of either tidal flats, or the Yellow Sea, it is interpreted that the sediments of study site were influenced from the marine. The results will be used to investigate the hydrological activity and sedimentary environment during the high sea level in the past.

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.171-181
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• 2002

Glauconization was investigated by morphological and chemical analysis of glaucony from the Pohang Tertiary marine sediments. The glaucony, which is present sparsely in turbidite sandstones, shows two distinct stages in morphology and chemistry. Crystallization of glaucony starts preferentially from the interior of pellet-like grains, then to the outer region of the grains with increasing K and Fe, and decreasing Al. Furthermore, smectite-like glaucony is evolved into illite-like glaucony through interstratified glauconite-smectite with increases in K and Al, and decrease in Fe.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.349-356
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• 2010

Analysis of high-resolution seismic profiles acquired from the southeastern continental shelf of Korea reveals that the late Quaternary transgressive deposits consist of six seismic units created in response to sea-level rise. These units with different seismic facies and geometry can be grouped into two distinct depositional wedges (paralic and marine) bounded by a ravinement surface. The paralic component underlying the ravinement surface consists of the sediment preserved from shoreface erosion and contains incised-channel fill, ancient beach-shoreface deposit and estuarine deposit. The top of paralic unit is truncated by a ravinement surface and overlain by marine component. The marine component consists of the sediment produced through shoreface erosion during landward transgression and contains mid-shelf sand sheet, mid-shelf sand ridge and inner shelf sand sheet. Such transgressive stratigraphic architecture of six sedimentary units is controlled by a function of lateral changes in the balance among rates of relative sea-level rise, sediment input and marine processes at any given time.

• Economic and Environmental Geology
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• v.42 no.2
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• pp.107-120
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• 2009

Spacial variation in organic components and temporal variation in the origin was examined through the organic geochemical (TC, TN, TS, $CaCO_3$, TOC, C/N, and $\delta^{13}C$) and pyrolysis analysis (HI, OI, and Tmax) in the core sediments which were acquired in the continental shelf of the South Sea close to Seomjin River. Levels of TC, TN, and TS show relatively low and constant in the core SJ03 located close to the Seomjin River mouth, while those are increased a little with being varied with low amplitude in the core SJ02 and SJ04 acquired at the middle of inner shelf area. They fluctuated with high amplitude in the core SJ01 and SJ05 near to the outer boundary of inner shelf. The vertical characteristics of organic components in the core SJ01 acquired at the outer boundary show that the area has undergone distinctly the environmental change at 9.0 kyr B.P. After 9.0 kyr B.P., Levels of TC, TOC, TN, $CaCO_3$, $\delta^{13}C$, HI, and Tmax are rapidly increased, while C/N and or are significantly decreased. Even though the contents of organic components are not high, such a changes reflect that the terrigenous organic matters were predominant before 9.0 kyr B.P due to the influence of Seomjin River, but after then, the marine organic matters have dominated due to the inflow of the Tshusima current.

• Geophysics and Geophysical Exploration
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• v.8 no.3
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• pp.201-206
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• 2005

Interpretation of high-resolution seismic profiles from the southeastern continental shelf of Korea reveals that the sedimentary deposits consist of seven seismic units formed during the late Quaternary. These units comprise lowstand, transgressive, and highstand systems tracts. The lowstand systems tract consists of a lowstand prograding wedge (SU1) and a mass flow deposit (SU2) including slumps and slides. The transgressive systems tract contains four seismic units: an ancient beach/shoreface deposit (SU3), a channel-fill deposit (SU4), a transgressive sand layer (SU5), and a transgressive sand ridge (SU6). The highstand systems tract consists of an inner-shelf mud deposit (SU7) derived from the Nakdong and Seomjin rivers during the last 6 ka when sea level was close to the present level.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.1
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• pp.69-81
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• 2021

The exposed rocks in the Zacatecas state include mainly Mesozoic sedimentary and volcanic, Cenozoic volcanic and plutonic rocks. Paleozoic metamorphic rocks found in the northwestern portion of the state are considered as the most ancient rocks. These rocks correspond to the Caopas Formation which underlays the Later Paleozoic Rodeo Formation. The Mesozoic sequences are represented by a marine sedimentary sequence of the Later Triassic and the red beds of the Triassic-Jurassic Nazas Formation. The marine sediments of the Upper Jurassic overlay the Nazas Formation or metamorphic rocks from the Paleozoic. The Cretaceous sequences comprises marine sedimentary rocks in the north and northeast, and a volcanosedimentary set in the center and southeast. The Cenozoic is represented by volcanic nondifferentiated rocks, intrusive igneous rocks of acid and intermediate composition, and continental conglomerates with evaporitic sediments. The Quarternary sequences includes basalts, piedmont deposits, alluviums and occasionally, layers of evaporites and saltpeter. Furthermore, a great diversity of mineral deposits of both metallic and nonmetallic types occur in Zacatecas state. The rocks composing these deposits are extremely varied and include formations from Paleozoic to Tertiary. The mineralization age of ore deposits corresponds to the Tertiary in approximately 90%, and their genesis is mainly considered as epigenetic.

• Journal of the Mineralogical Society of Korea
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• v.22 no.3
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• pp.217-227
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• 2009

Heavy minerals in the marine sand near Haeju bay, Hwanghae-do, North Korea were separated using the gravity and the magnetic separators. And their mineralogical study was carried out. Ilmenite, magnetite, hematite, zircon and monazite were observed as the valuable minerals, and quartz, orthoclase, muscovite, hornblende and garnet existed as gangue minerals. In the result of quantitative analysis with SIROQUANT program, the contents of the valuable minerals separated with the 2nd gravity separation (the shaking table separation), the 1st magnetic separation (rare earth magnetic separation) and the 2nd magnetic separation (the Eddy current magnetic separation) were increased into 4%, 10% and 76~89% (under the condition of 7000 G and 10000 G in magnetic strength), respectively. The contents of ilmenite, monazite and zircon recalculated from the chemical composition differed from the results of the quantitative analyses by SIROQUANT program, but the entire tendency bears some analogy with it. Under the conditions of 7000 G and 10000 G in 2nd magnetic separation the contents of ilmenites were concentrated with 53% and 66%, respectively. The content of monazite was 1.2% in the magnetic fractions of the 1st magnetic separation. The content of zircon was shown 1.4% under the condition of 10000 G in the 2nd magnetic separation, and was displayed 9% in +50 mesh of non-magnetic fraction of 1st magnetic separation, especially.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.2
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• pp.81-92
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• 2001

According to analyses of high-resolution seismic profiles (air gun, sparker, and SBP) and a deep-drill core(YSDP 105) in the mid-eastern Yellow Sea, stratigraphic and geoacoustic models have been established and seismo-acoustic modeling has been fulfilled using ray tracing of finite element method. Stratigraphic model reflects seismo-, litho-, and chrono-stratigraphic sequences formed under a significant influence of Quaternary glacio-eustatic sea-level fluctuations. Each sequence consists of terrestrial to very-shallow-marine coarse-grained lowstand systems tract and tidal fine-grained transgressive to highstand systems tract. Based on mean grain-size data (121 samples) of the drill core, bulk density and P-wave velocity of depositional units have been inferred and extrapolated down to a depth of the recovery using the Hamilton's regression equations. As goo-acoustic parameters, the 121 pairs of bulk density and P-wave velocity have been averaged on each unit of the stratigraphic model. As a result of computer ray-tracing simulation of the subsurface strata, we have found that there are complex ray paths and many acoustic-shadow zones owing to the presence of irregular layer boundaries and low-velocity layers.

• Journal of Marine Bioscience and Biotechnology
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• v.4 no.1
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• pp.15-23
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• 2010

Seaweed has been consumed especially in the Asia since centuries ago as a vegetable (Matsukawa, 1997; Burtin, 2000; Raghavendran 2003). Seaweed has many valuable nutrients i.e. as a mineral resources, vitamin, and non-caloric fiber, also has potential antioxidant resources. Such of nutrition consists in the Seaweed is Chlorophyll, Carotene, Fucoxantine, Luteen and Zeaxantine, Polysaccharide and Diet Fiber, Mineral, Protein and Amino Acid, Fat and Fatty Acid, Vitamin, Polifenol, also Methanol. The benefits of some nutrition content on seaweed are as an antioxidant, slimmer agent, anti-diabetes, healthy for heart, eyes health, Iodium source, and some kind of vitamins functions. As a conclusion, developing research about seaweed we believe it would be a part of medicine material and food processing, also cosmetic industrial.

• Economic and Environmental Geology
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• v.41 no.2
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• pp.219-223
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• 2008

Many cross-over errors due to position errors, meter errors, observation errors, sea conditions and so on occur when marine geophysical data collected by own and other agencies are merged, and these errors can create artificial anomalies which cause an improper interpretation. Many methods have been introduced to reduce cross-over errors. However, most methods are designed to compare each point or segment data to find cross-over points, and require a long processing time. Therefore, FORTRAN program (FastXcorr) is presented to fast determine cross-over points using an overlap-sector, and to adjust cross-over errors using a weighted linear interpolation algorithm.