忠州層群과 瑞山層群의 比較硏究

• 영문명: Comparative studies between Chungju and Seosan groups
• 발행기관: 대한자원환경지질학회
• 저자명: Ki Chang Na(羅基昌) Hyung Shik Kim(金亨植) Dong Jin Lee(李東鎭) Sang Hun Lee(李尙憲)
• 간행물 정보: 『자원환경지질』15권 4호, 177~188쪽, 전체 12쪽
• 주제분류: 자연과학 > 지질학
• 파일형태: PDF
• 발행일자: 1982.12.30

영문 초록

The Chungju and Seosan Groups have been known usually as Precambrian formations in Korea. But their relative and absolute ages have been controvericial problem in relation with other geologic system such as so-called Ogcheon and Yeoncheon Systems in Korea. This study has mainly focused on the corelation of the Chungju Group with the Seosan Group in their stratigraphy, structure, metamorphism, and iron ore deposits. In the process of study, the auther surveyed and reclassified the Chungju and Seosan Groups and corelated with Gyeonggi and Ogch cheon metamorphic belts and got some new data. The Chungju iron-bearing formations showing transtitional relation with the Gyeonggi Gneiss Complex and the Jangamri Formation consisting mainly of pebble bearing calcarious phyllite, should be seperated from the Gyemyeongsan formation which is mainly composed of metavolcanic rocks. The Jangamri Formation and the coaly phyllite, which can be corelated respectively with the Hwaggangri Formation and Changri Formation in Ogcheon Group, are repeated in the Gyemyeonsan and Munjuri Formations with the overturned anticlinal folding(F1). So the Chungju Group which was defined as an indipendant geologic unit from the Ogcheon Group should be limited only on the Chungju iron Formation. The Seosan Group can be classified stratigraphically such as Seosan Formation consisting of iron-bearing quartzite and mica schist, Daesan Formation overlying unconformably on the Seosan Formation and Gyeonggi Gneiss Complex. Taean Formation overlying unconformably on the Daesan Formation should be seperated from Seosan Group. There are many similarity in the stratigrphy, structure, and metamorphic facies between Chungju and Seosan Groups exept the metavolcanic rocks in the Gyemyeongsan and Munjuri Formations and the pebble bearing calcareous phyllite in the Jangamri Formation. The two Groups were deformed with two kinds of differant stages, the first shows N30°-40°E trend of fold axis, the second N70°-80°W respectively. The Seosan Formation, which is the lowest formation in Seosan Group and bearing the iron formation, was metamorphosed at 2500m.y. before. These age is similar with the metamorphic age of Gyeonggi metamorphic belt and with the age of Algoman and Kenoran Orogenies which devide the Precambrian into Archean and Proterozoic Era. So the Seosan Formation, which is included in some migmatitic rocks of Gyeonggi Gneiss Complex, is the oldest formation in Korea and can be corelated with the Anshan Group which bears the oldest iron formation in China. The metamorphic facies of the Precambrian metamorphism in Seosan area is simillar with that of Chungju area, showing high temperature-low pressure amphibolite facies which is corelated with the Gyeonggi metamorphic belt, the oldest metamorphic belt in Korea(650°-680℃, 3.2-4.4 Kb). The high temperature intermediate pressure amphibolite facies in Seosan area with the low temperature-intermediate presure greenschist facies of Taean formation is corelated with that of Ogcheon Group (590°-640℃, 5.2-6.3 Kb). The Chungju and Seosan iron formations were deposited in Archean, showing geochemical composition of Precambrian iron formations. The Chungju iron formation was mainly formed by the chemical precipitation, on the other hand, the Seosan iron formation was formed by alternated action of chemical and detrital depositions.

목차

Abstract

I. 序論

II. 忠州層群과 瑞山層群의 層序 및 地質構造 比較

III. 變成作用과 變成作用 時期

IV. 鐵鑛床 對比

V. 忠州層群과 瑞山層群의 變成相 및 鐵鑛床의 相互比較

VI. 結論

參考文獻