• Journal of The Geomorphological Association of Korea
• /
• v.26 no.4
• /
• pp.67-79
• /
• 2019

This study documents the level of paleo-shoreline and the timing of formation of the lowest marine terrace (1st terrace) distributed in Dadaepo, Busan, South Korea. In the study area, the elevation of paleo-shoreline of the 1st terrace is clearly identified as 5 meters above mean high tide based on the elevation of wave-cut platforms and the elevation of boundary between marine and terrestial sediments. This is well consistent with the fact that are found along the Southern coast of the Korean Peninsula including Daepo-dong, Sacheon-si. The timing of formation of the 1st terrace in Dadaepo is confirmed to have been deposited around 70,000~80,000 years BP (MIS 5a) according to OSL and IRSL dating ages. However, because the formation age of the 1st terrace in Sacheon-si Daepo-dong (Southerm coast) and Pohang-si Umok-ri (Eastern coast) previously identified as about 90,000~100,000 years BP (MIS 5c), further discussion of what is needed. Possibly, it can be interpreted that the sub-interglacial (MIS 5a and 5c) sea-level records during the last interglacial period are likely to be selective on land depending on regions.

• Economic and Environmental Geology
• /
• v.30 no.3
• /
• pp.263-275
• /
• 1997

Compound calcrete deposits are recognized from the Dadaepo Formation in Dusong peninsula, Pusan, and their textures, structures, morphology, and stratigraphic distribution are examined. The Dadaepo Formation in study area consists of fluvial plain deposits including floodplain-lake deposits, and the compound calcrete deposits occur above floodplain deposits and below lacustrine deposits. The compound calcrete deposits are composed of nodular to massive (micritic), laminar, nodular, nodular to massive (marly), and marly calcrete deposits. In these calcretes, circumgranular and curved cracks, alveolar structures, fitted peloids, tubular fenestrae with laminar micrite wall (rootlet casts), microstalactic calcite, and tepee structures are observed, which indicates that they are calcic paleosols. Considering their stratigraphic occurrences and pedogenic origin, compound calcrete deposits are interpreted to have formed on distal fluvial plain to palustrine environment by the repetetion of deposition and subsequent calcification due to alternation of lake expansion and contraction. The repetetion of calcrete formation suggests that arid climatic condition was alternated with humid condition in short-term period. Such alternated paleoclimatic condition is similar to those of the Sindong and Hayang groups, and indicates that short-term fluctuations from arid to humid climate were prevailing in overall Gyeongsang Basin. In stratigraphic sense, the compound calcrete deposits can be used as a marker deposit for the correlation of the Dadaepo Formation.

• The Journal of the Petrological Society of Korea
• /
• v.23 no.2
• /
• pp.153-162
• /
• 2014

The social demands to conserve the geological outcrops with important scientific values are increasing. Accordingly public programs such as national geopark are recently established. In this study, outcrops with geological values in the Dusong Peninsula geosite of the Busan National Geopark are investigated in details with a discussion in the aspects of geoheritage values. The Dusong Peninsula is located in the late Cretaceous Dadaepo Basin interpreted as an intra-arc pull-apart basin extended in the Cretaceous Yucheon Subbasin. In this area, a number of noticeable geological records, such as andesitic sills, lower Dadaepo Formation, paleo-seismites, clastic dikes, compound calcrete deposits, syn-depositional normal faults, and unconformity between basin-fill and basements, are observed. Considering their unique geological significance, the strategic plans for their conservation and management should be urgently provided.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.44 no.3
• /
• pp.207-215
• /
• 2011

An endosulfan degrading bacterial strain, K-1321, was isolated by endosulfan-enrichment culture from a seaside sediment collected at Dadaepo Beach, Busan, Korea. The strain was identified as a Serratia sp. based on the results of morphological, biochemical and 16S rDNA homology analyses. Serratia sp. K-1321 was able to completely degrade 50 ppm endosulfan in culture media and soil within 6 weeks at $25^{\circ}C$. GC/MS analysis revealed that endosulfan diol was an intermediate of the bacterial endosulfan degradation. Considering the above results, we concluded that Serratia sp. K-1321 utilized endosulfan as a carbon source and metabolized endosulfan via a less toxic pathway, such as the formation of endosulfan diol as an intermediate.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.19 no.6
• /
• pp.563-574
• /
• 1986

The structure of gonads, gametogenesis and reproductive cycle of the jackknife clams, Solen strictus and Solen gordonis were investigated mainly by histological observation. The first species used were monthly sampled at the coastal area of Dadaepo, Pusan, Korea and Naechodo, Kunsan, Korea for one year from February 1982 to January 1983. The second species were monthly sampled at the sand beach of Dadaepo, Pusan, Korea, from February 1982 to January 1983. Sexualities of Solen strictus and Solen gordonis are dioecious, and these species are oviparous. The gonads are irregularly arranged from the subregion of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary was composed of a number of small ovarian sacs and the testis was composed of several testicular lobuli which from the tubular structure. Early multiplicating oogonium was about $10{\mu}m$ in diamater. Nucleus and nucleolus, at that time, were distinct in appearance. Each of the early growing oocytes made an egg-stalk, connected to the germinal epithelium of the ovarian sac. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed in the ovarian sacs in the early development stages. With the further development of gonad, these tissue and cells gradually disappeared. Then the undifferentiated mesenchymal tissue and eosinophilic granular cells function as nutritive cells in the formation and development of the early stage germ cells. Mature oocytes were free in the lumen of ovarian sacs and gradually become round or oval. Ripe oocyte was about 80 to $90{\mu}m$ in diameter. With the further development of testis, each of the testicular lobuli formed stratified layers composed of spermatogonia, spermatocytes, spermatids and spermatozoa in groups on the germinal epithelium. After spawning, the gonad gradually degenerated, and disorganized completely. Then new differentiated tissues were rearranged next year. The annual reproductive cycle of those species could be classified into five stages; multiplicative, growing, mature, spent, degenerative and resting stage. It seems that the spawning season is closely related to the water temperature, and the spawning of Solen strictus occurs from June to July at above $20^{\circ}C$ in water temperature. The peak spawning season appeared in June at Dadaepo and in July at Kunsan, The spawning of Solen gordonis occurs from May to June with the peak spawning season in June. Percentages of the first maturity in female of Solen strictus ranging from 5.1-6.0 cm and 7.1-8.0 cm in shell length were $50\%$ and $100\%$, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.11 no.2
• /
• pp.115-121
• /
• 1978

Early developmental stages of Mactra chinensis were bioassayied to determin the water quality of the costal waters of Busan. The water samples were obtained at 12 stations from July 12 to July 17, 1977. Water quality evaluation was made in terms of the rates of normal development to abnormal development in three indicatory states, i. e. fertilization membrane formation, morula and trochophore larvae. The pollution degree of the waters brought from five swimming beaches was found to be highest at Haewundae followed by Songdo, Kwang-anri, Songjeong and Dadaepo with decreasing order. The highest value of the water at Haewundae was mainly due to the accidental oil spill from an oil tanker which happened on July 7, 1977. At Dongsamdong the rate of total abnormal development was $47.17\%$. This result is apparently attributable to fish byproducts discarded from a number of restaurants. At Chungmudong where a large fish-market is located, the rate of total abnormal development was $61.14\%$. At Suyeng Bay and Yongho Bay the rates of total abnormal development were $73.82\%$ and $72.90\%$ respectively. At these bays the drainage presumably contains a large amount of chemical pollutants from the industrial areas. This result shows that no organisms can normally breed in these regions.