• The Korean Journal of Quaternary Research
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• v.17 no.1
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• pp.7-16
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• 2003

A 31m-long sediment core (SSDP-102) was taken from the inner shelf (about 40m water-depth) off the northwestern coast of the Korea Strait. Detailed lithofacies and organic-geochemical analyses were performed to establish a high-resolution stratigraphy in the Korea Strait shelf and to reconstruct the paleoenvironmental changes associated with the Holocene marine transgression. The stratigraphic framework of the core was primarily established using 6 AMS $^{14}C$ ages. The sedimentary record of the core SSDP-102 allows for the reconstruction of the paleoenvironmental changes during the last 12.1 ka BP. According to the high-resolution seismic reflection profiles, lithofacies and organic-geochemical data, the core SSDP-102 can be divided into three units (III to I in ascending order) above the acoustic basement. The three units reflect distinct changes of depositional environments resulted from the post-glacial marine transgression. Therefore, it is suggested that three phases of sea-level change have occurred within the inner shelf of the Korea Strait following the Holocene marine transgression. (1) estuarine environments from ca. 12.1 to 6.2 ka BP; (2) near-shore environments with a period of decreased rising of sea level between 6.2 and 5.1 ka BP; (3) near-shore to modem marine environments after 5.1 ka BP. In particular, the present marine conditions influenced by the warm Tsushima Current have been gradually established after ca. 5.1 ka BP.

• Economic and Environmental Geology
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• v.57 no.4
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• pp.431-447
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• 2024

This study aims to analyze the supply and demand trends and regional distribution characteristics of the stone industry through transaction records of the domestic natural stone market. The demand for natural stone is increasing globally, but domestic stone producers are facing financial difficulties due to the influx of low-cost stone, and the government is implementing various support policies, such as mandating the use of domestic stone. However, the influx of low-cost stones has led to management deterioration for domestic stone producers, prompting the government to implement various support policies such as mandating the use of domestic stones. An analysis of the natural stone transaction records from the Public Procurement Service revealed that granite was the main type of rock. The main trading items were natural stone curbs and natural stone slabs, with an average annual transaction amount of approximately 312.8 billion KRW from 2017 to 2021. A comparison of the stone distribution status between the metropolitan area and non-metropolitan areas showed that the metropolitan area had high demand, while non-metropolitan areas served as major supply sources. Cities such as Pocheon in Gyeonggi-do, Iksan in Jeollabuk-do, and Geochang in Gyeongsangnam-do play important roles as major stone suppliers. Based on these results, this study proposes fostering the stone industry tailored to regional characteristics, diversifying distribution channels, and establishing a sustainable supply chain for the sustainable development of the stone industry. Additionally, it emphasizes the need for close cooperation and support among the government, industry, and research institutions.

• Economic and Environmental Geology
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• v.55 no.2
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• pp.137-148
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• 2022

In this study, ship movement simulation was performed based on a marine physics model for the ancient port presumed under the past environmental conditions in the coastal area of Hwaseong, which played an important role as a center of trade in the Three Kingdoms and Unified Silla periods. The paleo topographical surface was reconstructed through the analysis of borehole sediments, and the paleo coastline was extracted through the geomorphological maps published during before independence. Based on the established paleo environmental conditions of the Hwaseong coast, the marine physics model (FVCOM) was used to simulate the flow of surface currents and the route of floating materials assumed to be ancient ships. As a result, the processes of moving ships from the port to the open sea in the Eunsupo area, which is estimated location of the ancient port related to Dangseong, was well simulated, and thus the reliability of the location of the ancient port estimated by the scientific method was secured. This study is significant as a result of convergence research that encompasses archeology, history, geomorpology, geology, and oceanography.

• The Korean Journal of Quaternary Research
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• v.14 no.1
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• pp.33-48
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• 2000

Vegetation disturbance history of the Korean Peninsula from the Palaeolithic Age to the Koryo Dynasty (1392) has reconstructed by the use of various data sources. Active vegetation disturbance, which has begun during the Neolithic Age, seems to be more widespread on lowland and coastal areas in the early stages, but later expanded into inland areas. The ploughing of a field and the selective cutting of certain trees, such as oak trees, nettle trees and pine trees are noticeable, and eventually caused deforestation during the Bronze Age. The use of iron tools of the Iron Age has enabled the forest clearing to develope the dry fields. During the Three Kingdoms period (BC 57∼AD 918) extensive deforestation has maintained for the development of cultivated fields, as well as other activities, such as timber, lumbering, production of iron farm implement, ploughing by cattle. The encouragement of disafforestation on mountain slope and creation of terraced field during the Koryo Dynasty (918∼1392) has caused the deforestation over the country, along with the consumption of large amount of wood and timber for fire-wood, ship-building, mining, xylography and so on.

• Economic and Environmental Geology
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• v.29 no.2
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• pp.171-182
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• 1996

Quaternary Jungok basalts are distributed along the old Hantan river in Mid-Korean Peninsula. They were flowed out from Mt. Ori and Upland (680 m), and they formed narrow and long basalt plateau showing the layers of 10 to 20 meters in thickness and about 95 km in length. Fifty seven samples were collected from the study area, and sixteen rock samples were selected and analysed for major and trace elements. The analyzed samples have alkalic composition and show a relatively restricted variation in major element chemistry (except MgO), as comparing to the that of trace element. Based on major element chemistry, a quantitative modelling of fractional crystallization by multiple linear regression method suggests that the chemical evolution of the evolved rocks can be generated by fractionation of olivine, plagioc1ase, clinopyroxene, and magnetite in proportion of 56 : 25 : 17 : 2, respectively. The calculated trace element abundances by mineral proportions estimated from major element modelling, however, underestimate the incompatible element concentrations in the evolved rocks. According to the incompatible element abundances, simple fractional crystallization process has difficulty to explain the chemical variation of the evolved rocks. It seems that the other processes, which enrichment of incompatible elements can occure without concomitant changes in major element compositions, are needed in order to explain the chemical variation of the Jungok basalts. Thus, the major elements and compatible trace elements variations of the Jungok basalts are due to fractional crystallization, but the incompatible elements variation is due to fractional crystallization superimposed on already varying concentrations caused by slightly different degrees of melting of the same source, and/or due to periodic replenishment, tapping and fractionation(RTF) processes.

• The Korean Journal of Quaternary Research
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• v.14 no.2
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• pp.117-123
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• 2000

This study examined the spatial distribution of precipitation in Sokcho area. The hourly, daily and monthly precipitation on the 2 stations, 5 AWS in Sokcho area were analyzed by daily, monthly, altitudinal distribution and synoptic environment. The results of the Study are as follows. The amount of Yearly precipitation, 1970~1999 in Sokcho area is gradually increasing. The amount of monthly precipitation 1970~1999 at Sorak weather observation station (altitude 148m), Compared with that in 7 Stations is greatest in spring, Summer and autumn. Because the valleys near Ssangcheon river are funnels for sea wind into Sorak weather observation station. The amount of Summerly precipitation at Mishiryong(1993~1999), the highest altitude in 7 weather observations stations is more 95.2mm than that of Sokcho airport, the lowest altitude, but the amount of winterly precipitation at Sokcho airport is more 89.6mm than that of Mishiryong. When the heavy rainfall and the heavy Snowfall occured in Sokcho area, wind systems were mainly a sea wind (north-north-eastly wind, north-westly wind) and daily mean wind speed was respectively 4.4㎧, 3.6㎧. The amount of the heavy rainfall and heavy snow fall in Sokcho area is closely associated with the north-eastly stream at the lower and the upper level toward the coast of East sea(Sokcho area).

• Korean Journal of Microbiology
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• v.53 no.3
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• pp.200-207
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• 2017

A new approach to the solubilization of waste activated sludge (WAS) using alginate-quaternary ammonium complex beads was investigated under controlled mild alkaline conditions. The complex beads were prepared by the reaction of sodium alginate (SA) with 3-(trimethoxysilyl)propyl-octadecyldimethylammonium chloride (TSA) in acid solution, followed by crosslinking with $CaCl_2$. Treatment of WAS with SA-TSA complex beads was effective for enhancing the efficacy of WAS solubilization. The highest value of soluble chemical oxygen demand (SCOD) concentration (3,900 mg/L) was achieved after 10 days of treatment with 30% (v/v) SA-TSA complex beads. The WAS solubilization efficacy of the complex beads was also evaluated by estimating the concentrations of volatile fatty acids (VFAs). The maximum value of VFAs was 2,961 mg/L, and the overall proportions of VFAs were more than 75% of SCOD. The main components of VFAs were acetic, propionic, iso-butyric, and butyric acids. These results suggest that SA-TSA complex beads might be useful for enhancing the solubilization of WAS. The potential use of VFAs as the external carbon substrate for the production of polyhydroxyalkanoate (PHA) by a mixed microbial culture (MMC) was also examined. The enrichment of PHA-accumulating MMC could be achieved by periodic feeding of VFAs generated from WAS in a sequencing batch reactor. The composition of PHA synthesized from VFAs mainly consisted of 3-hydroxybutyrate. The maximum PHA content accounted for 25.9% of dry cell weight. PHA production by this process is considered to be promising since it has a doubly beneficial effect on the environment by reducing the amount of WAS and concomitantly producing an eco-friendly biopolymer.

• The Korean Journal of Quaternary Research
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• v.24 no.1
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• pp.11-24
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• 2010

Seongnyu Cave have developed along the NE-SW direction in carbonate rocks of the Joseon Supergroup. The cave mostly shows horizontal passages and contains three lakes. The main passage is about 330 m long with 540 m-long branches, thus the total length of the cave is about 870 m. Through cave diving, about 85 m-long new passages were discovered. Numerous speleothems such as soda straws, stalactites, stalagmites, columns, flowstones, rimstones, cave shields, cave corals, curtains (and bacon sheets), cave pearls, cave flowers, helictites and calcite rafts can be found in the cave. Especially, some speleothems which were believed to have grown in the past were discovered in the submerged passage, and a few stalactites, stalagmites, flowstones and columns were eroded (or corroded) by the cave stream that flowed on the floor. Because these speleothems only grow in subaerial environments within limestone caves, it appears that they grew when there was no lake in the cave and became submerged as the lake level rose in the cave. The presence of these speleothems in the lakes indicate that they only grew during glacial periods when sea-level was lower. Therefore, detailed investigation of these speleothems will provide invaluable information on paleoclimatic evolution around the Korean peninsula in the future.

• Economic and Environmental Geology
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• v.5 no.2
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• pp.77-86
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• 1972

The system NaAlSiO_4-KAlSiO_4-SiO_2-H_2O, Bowen's "Petrogeny's Residua System" of course is extremely important in understanding the phase relationships of igneous and metamorphic rock in the continental crust. The phase relationships in this system, however, have not been completely established in the P-T range above the Mohorovicic discontinuity. They need to be established. In this study, the most probable sequence of P-T curves around a quaternary invariant point(~5Kb/${\sim}635^{\circ}C$) in the system using Schreinemakers' rule, is deduced, essentially on the basis of Morse's(1969a and b) experimental data. Possible modifications of the sequence of the P-T curves considering likely changes of the invariant chemogram are also considered. It is concluded that the sequence of P-T curves around the invariant point (~5Kb/${\sim}635^{\circ}C$) is (L), (Anl), (Or), (V), (Ne) and (Ab) on the P-T projection, where the P-T curve (L) is extended towards lower P-T regions, and the (Anl) curve is extended towards a region of higher temperature and lower pressure from the invariant point respectively.

• 한국해양학회지
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• v.29 no.1
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• pp.17-27
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• 1994

The sediment collected from KODOS91-1 were studied using X-ray diffraction(SRD) analysis to clarify the composition and vertical distribution of clay minerals. Micropaleontological data(Radiolarians) was applied to identify the changes in post-depositional environment and chemical mechanism leading to the formation of authigenic minerals. The result show that the highest concentration of smectite is occurred in the lower part(Unit II, III) of sediment column and the lowest concentration in the upper part(Unit I) whereas terrestrial minerals, such as illite, kaolinite and quartz, indicate the opposite trends. Radiolarians in the upper part are composed entirely of Quaternary/Tertiary mixtures, whereas in lower sediment units generally revealed the middle Miocene to the Eocene. This may imply that the Quaternary and Tertiary sedimentary processes were continuously affected by reworking of older sediments and subsequent resegmentation. The changes of the sediment color, peak pattern of minerals and presence of reworked microfossils at the unit boundaries have been interpreted as evidence of authigenic formation. Mineralogical characteristics of the sediments in study area strongly indicates changes in paleoenvironments through geologic time, including changes in post-depositional conditions by physical processes and chemical mechanisms.