Mulgeum, Yangseong, Maeri and Kimhae iron ore deposits in Gyeongnam Province are hydrothermal skarn type magnetite ore deposits in propylitized andesitic rock near the contact with Cretaceous Masanite. Symmetrical zoned skarns are commonly developed around the magnetite veins. The skarn zones away from the vein are quartz-garnet skarn, epidote skarn and epidote-orthoclase skarn. Oxygen isotope analyses of coexisting minerals from andesitic rock, Masanite and major skarn zones, and of magnetite, hematite and quartz were conducted to provide the information on the formation temperature, the origin and the evolution of the hydrothermal solution forming the iron ore deposits. Becoming more distant from the ore vein, temperatures of skarn zones represent the decreasing tendency, but most δ18O and δ18OH2O values of skarn minerals represent no variation trend, and also the values are relatively low. Judging from all the isotopic data from the ore deposits, the major source of hydrothermal solution altering the skarn zones and precipitating the ore bodies was magmatic water derived from the deep seated Masanite. This high temperature hydrothermal solution rising through the fissures of propylitized andesitic rock was mixed with some meteoric water, and occurred the extensive isotopic exchange with the propylitized andesitic rock, and formed the skarns. During these processes, the temperature and δ18OH2O value of hydrothermal solution were lowered gradually. At the main stage of iron ore precipitation, because all the alteration was already finished, the new rising hydrothermal solution formed only the magnetite ore without oxygen isotopic exchange with the wall rock.

Ministry of Environment has been operating water quality monitoring network in order to obtain the basic data for the water environment policies and comprehensively understand the water quality status of public water bodies such as rivers and lakes. The observed water quality data is very important to analyze by applying statistical methods because there are seasonal fluctuations. Typically, monthly water quality data has to analyze that the transition comprise a periodicity since the change has the periodicity according to the change of seasons. In this study, trends, SOM and RDA analysis were performed at the Mulgeum station using water quality data for temperature, BOD, COD, pH, SS, T-N, T-P, Chl-a and Colon-bacterium observed from 1989 to 2013 in the Nakdong River. As a result of trends, SOM and RDA, the Mulgeum station was found that the water quality is improved, but caution is required in order to ensure safe water supply because concentrations in water quality were higher in the early spring(1~3 month) the most.