• Korean Journal of Mineralogy and Petrology
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• v.35 no.1
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• pp.13-24
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• 2022

The Arctic Ocean is very sensitive to global warming and Arctic Ocean sediments provide a records of terrestrial climate change, analyzing their composition helps clarify global warming. The gravity core sediment ARA07C-St02B was collected at the East Siberian margin during an Arctic expedition in 2016 on the Korean ice-breaking vessel ARAON, and its provenance was estimated through sedimentological, mineralogical and geochemical analysis. The core sediment was divided into four units based on sediment color, sand content and ice-rafted debris content. Units 1 and 3 had higher sand and ice-rafted debris contents than units 2 and 4, and contained a brown layer, whereas units 2 and 4 were mainly composed of a gray layer. Correlation analysis using the adjacent core sediment ARA03B-27 suggested that the sediment units were deposited during marine isotope stage 1 to 4. The bulk mineral, clay mineral, and geochemical compositions of units including a brown layer differed from units including a gray layer. Bulk and clay mineral compositions indicated that coarse and fine sediments had a different origin. Coarse sediments might have been deposited mostly by the East Siberian Coastal Current from the Laptev Sea and the East Siberian Sea or by the Beaufort Gyre from the Chukchi Sea, whereas fine sediments might have been transpoted mostly by currents from the East Siberian Sea, the Chukchi Sea and the Beaufort Sea. Some of the coarse sediments in unit 1 and fine sediments in unit 3 might have been deposited by iceberg ice, sea ice or current from the Beaufort Sea and the Canada Archipelago. Investigating the geochemical composition of the potential origins will elucidate the origin and transportation of the study area's core sediments.

• Journal of the Mineralogical Society of Korea
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• v.32 no.4
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• pp.235-247
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• 2019

The Central South Sea Mud (CSSM), developed in the Seomjin River estuary, is known to be supplied with sediments from Heuksan Mud Belt (HMB) and Seomjin River. However, in order to form a mud belt, more sediments must be supplied than supplied in the above areas. Therefore, research on additional sources should be conducted. In this study, clay minerals, major elements analyzes were performed on cores 16PCT-GC01 and 16PCT-GC03 in order to investigate the transition in the provenance and transport pathway of sediments in CSSM. The Huanghe sediments are characterized by higher smectite and the Changjiang sediments are characterized by higher illite. Korean river sediments contain more kaolinite and chlorite than those of chinese rivers. Korean river sediments have higher Al, Fe, K concentraion than Chinese river sediments and Chinese rivers have higher Ca, Mg, Na than those of Korean rivers. Therefore, clay minerals and major elements can be a useful indicator for provenance. Based on our results, CSSM can be divided into three sediment units. Unit 3, which corresponds to the lowstand stage, is interpreted that sediments from Huanghe were supplied to the study area by coastal or tidal currents. Unit 2, which corresponds to the transgressive stage, is interpreted to have a weaker Huanghe effect and a stronger Changjiang and Korean rivers effect. Unit 1, which corresponds to the highstand stage when the sea level is the same as present and current circulation system is formed, is interpreted that sediments from Changjiang and Korean rivers are supplied to the research area through the current.

• Journal of the Korean earth science society
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• v.28 no.3
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• pp.311-323
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• 2007

The Yellow and East China seas received a vast amount of sediment $(>10^9ton/yr)$, which comes mainly from the Changjiang and Huanghe rivers of China and the Korean rivers. However, there are still no direct sedimentological-geochemical indicators, which can distinguish these two end-members (Korean and Chinese river sources) in these seas. The purpose of this study is to provide the potential geochemical-tracers enabling these river materials to be identified within the sediment load of the Yellow and East China seas. The compositions of major elements (Al, Fe, Mg, K, Ca, Na, and Ti) of Chinese and Korean river sediments were analyzed. To minimize the grain-size effect, furthermore, bulk sediments were separated into two groups, silt $(60-20{\mu}m)$ and clay $(<20{\mu}m)$ fractions, and samples of each fraction were analyzed for major and strontium isotope $(^{87}Sr/^{86}Sr)$ compositions. In this study, Fe/Al and Mg/Al ratios in bulk sediment samples, using a new Al-normalization procedure, are suggested as an excellent tool for distinguishing the source of sediments in the Yellow and East China seas. This result is clearly supported by the concentrations of these elements in silt and clay fraction samples. In silt fraction samples, Korean river sediments have much higher $^{87}Sr/^{86}Sr$ ratio $(0.7229{\sim}0.7253)$ than Chinese river sediments $(0.7169{\sim}0.7189)$, which suggests the distribution pattern of $^{87}Sr/^{86}Sr$ ratios as a new tracer to discriminate the provenance of shelf sediments in the Yellow and East China seas. On the basis of these geochemical tracers, clay fractions of southeastern Yellow Sea mud (SEYSM) patch may be a mixture of two sediments originated from Korea and China. In contrast, the geochemical compositions of silt fractions are very close to that of Korea river sediments, which indicates that the silty sediments of SEYSM are mainly originated from Korean rivers.

• Journal of the Mineralogical Society of Korea
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• v.26 no.3
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• pp.189-196
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• 2013

In this study, we tried to define the origin of fine-grained sediments in Southwestern Cheju Island Mud (SWCIM) using principal component analysis. We used relative clay mineral compositions using 138 marine surface sediments, 4 Huanghe sediments and 3 Changjiang river sediments by the semi-quantitative X-ray diffraction analysis. We made bioplot diagram using R program with principal component 1 and component 2 because they might contain more than 90% of all data. Although the distribution pattern of each clay minerals in SWCIM is so intricate, smectite and kaolinite contents are high in the west region, but illite and chlorite contents are rich in the east region. In the biplot, the east region of SWCIM distribute around Changjiang river, whereas west region of SWCIM disperse around Huanghe. Our results might reveal that west region of SWCIM is mainly originated by Huanghe, but east region of SWCIM by Changjiang River.

• 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.24 no.4
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• pp.337-345
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• 2003

Surficial sediments from the northern coastal area of Jeju Island, southeastern Yellow Sea (South Sea of Korea) were analyzed for grain-size texture, some geochemical characteristics and clay mineralogy in order to assess their provenance. Rare-earth element compositions and some geochemical discrimination diagrams, especially of Ti/Al, Nb/Al and Rb/Al ratios, were revealed to be useful indices for identifying the origin of sediments. These indices, together with clay mineral compositions, suggest that the coarse-grained sediments originate from the volcanic rocks of Jeju Island, whereas the fine-grained sediments are derived from Chinese rivers, especially the Changjiang River. The oceanic circulation pattern and the physical-chemical properties of seawater in the Yellow and East China seal support the possibility that the fine-pained Changjiang (Yangtze River) sediments can reach the coastal area of Jeju Island (southeastern Yellow Sea).

• Journal of the Korean Geographical Society
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• v.42 no.6
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• pp.898-913
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• 2007

We examined soil properties and provenance of loess-paleosol sequences at the Daebo Granite area of Buan, Jeonbuk Province, South Korea. The section consists of the surface layer, Layer 1(paleosol), Layer 2(loess), Layer 3(paleosol), Layer 4(loess), and Layer 5(paleosol), from top to bottom and thickness of the exposed section is approximately 280cm. The magnetic susceptibility values show the distinct variations between the loess- and the paleosol layer. Even though pH, ORP, water content, and soil hardness do not display the obvious differences in the section, the organic content indicates the variation similar to those of the magnetic susceptibility. In the respect of the soil colors measured under 3 conditions, although the variations of the wet soil color exceedingly reflect the difference of the layers, these variations are obscure in some points in the section due to the characteristics of the Munsell color system. Based on the geomorphological properties, sedimentary structure, the difference of the major element composition and the condrite-normalized rare earth element(REE) patterns showing the clear difference from the adjacent bedrocks and stream sediments and the similarity to those of the Chinese Loess Plateau, it is suggested that the section was formed by the material originated from the Chinese Loess Plateau and peripheral areas. However, because the material experienced the alteration after sedimentation under the environment of the sediment area, it has the properties different from the material in the provenance areas. This phenomenon may result in the climatic condition of Korea, especially in precipitation.

• Journal of the Korean earth science society
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• v.41 no.6
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• pp.588-598
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• 2020

The seafloor geology of Ieodo, a submerged volcanic island, has been poorly understood, although this place has gained considerable attention for ocean and climate studies. The main purpose of the study is to understand and elucidate types, distribution patterns and provenance of the surficial sediments in and around the Ieodo area. For this purpose, 25 seafloor sediments were collected using a box-corer, these having been analyzed for grain sizes. XRD (X-ray Diffraction) analysis of fine-grained sediments was conducted for characterizing clay minerals. The peak of Ieodo exists in the northern region, while in the southern area, shore platforms occur. The extensive platform in the south results from severe erosion by strong waves. However, the northern peak still survived from differential weathering. Grain size analyses indicated that gravels and gravelly sands with skeletons and shells were distributed predominantly on the volcanic apron and shore platform. Muddy sediments were found along the Ieodo and the adjacent deeper seafloor. Based on the analysis of clay mineral composition, illites were the most abundant in fine muds, followed by chlorites and kaolinites. The ratio plots of clay minerals for the provenance discrimination suggested that the Ieodo muds were likely to be derived from the Yangtze River (Changjiang River). As a consequence, gravels and gravelly sands with bioclastics may be supplied from the Ieodo volcanic apron by erosion processes. Wave activities might play a major role in transportation and sedimentation. In contrast, fine muds were assumed to be derived from the inflow of the Yangtze River, particularly in summer. Deposition in the Ieodo area is, therefore, probably controlled by the inflow from the Changjiang Dilute Water and summer typhoons from the south.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.1
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• pp.15-29
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• 2021

In the Arctic Ocean, the distribution of sea ice and ice sheets changes as climate changes. Because the distribution of ice cover influences the mineral composition of marine sediments, studying marine sediments transported by sea ice or iceberg is very important to understand the global climate change. This study analyzes marine sediment samples collected from the Arctic Ocean and infers the provenance of the sediments to reconstruct the paleoenvironment changes of the western Arctic. The analyzed samples include four gravity cores collected from the Araon mound in the Chukchi Plateau and one gravity core collected from the slope between the Araon mounds. The core sediments were brown, gray, and greenish gray, each of which corresponds to the characteristic color of sediments deposited during the interglacial/glacial cycle in the western Arctic Ocean. We divide the core sediments into three units based on the analysis of bulk mineral composition, clay mineral composition, and Ice Rafted Debris (IRD) as well as comparison with previous study results. Unit 3 sediments, deposited during the last glacial maximum, were transported by sea ice and currents after the sediments of the Kolyma and Indigirka Rivers were deposited on the continental shelf of the East Siberian Sea. Unit 2 sediments, deposited during the deglacial period, were from the Kolyma and Indigirka Rivers flowing into the East Siberian Sea as well as from the Mackenzie River and the Canadian Archipelago flowing into the Beaufort Sea. Unit 2 sediments also contained an extensive amount of IRD, which originated from the melted Laurentide Ice Sheet. During the interglacial stage, fine-grained sediments of Unit 1 were transported by sea ice and currents from Northern Canada and the East Siberian Sea, but coarse-grained sediments were derived by sea ice from the Canadian Archipelago.

• Journal of the Mineralogical Society of Korea
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• v.31 no.1
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• pp.1-12
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• 2018

A gravity core (RS14-C2) was collected at site RS14-C2 in the continental slope to the east of Pennell-Isellin Bank of the Ross Sea (Antarctica) during PNRA XXIX (Rosslope II Project) Expedition. In order to trace the sediment source, magnetic susceptibility (MS), sand fraction, and clay mineral compositions were analyzed, and AMS $^{14}C$ ages were dated. Core sediments consist mostly of hemipelagic sandy clay or silty clay including ice-rafted debris (IRD). AMS $^{14}C$ age of core-top indicates the modern and Holocene sediments. Based on AMS $^{14}C$ dating, sediment color, MS and sand fraction, core sediments are divided into interglacial and glacial intervals. The interglacial brown sediments are characterized by low MS and sand fraction, whereas the glacial gray sediments are characterized by high MS and sand fraction. Among clay mineral compositions of core sediments, illite is highest (61.8~76.7%), and chlorite (15.7~21.3%), kaolinite (3.6~15.4%), and smectite (0.9~5.1%) are in decreasing order, and these compositions are also divided into the interglacial and glacial/deglacial intervals. During the glacial period, the high content of illite and chlorite indicate sediment supply from the bedrocks of Transantarctic Mountains under the Ross Ice Sheet. In contrast, because of decreasing supply of illite and chlorite by the glacial retreat, smectite and kaolinite contents increased relatively during the interglacial period. During the interglacial period, smectite may be transported additionally by the northeastward flowing surface current from the coast of Victoria Land in the western Ross Sea. Kaolinite may be also supplied to the continental slope by the Antarctic Slope Current from the kaolin-rich metasedimentary rock outcropped on the Edward VII Peninsula.