韓國南部 의 白堊紀末 以後의 火成活動과 鑛化作用에 對한 板構造論의 適用性 硏究(Ⅰ)

• 영문명: Applicability of plate tectonics to the post-late Cretaceous igneous activities and mineralization in the southern part of South Korea(Ⅰ)
• 발행기관: 대한자원환경지질학회
• 저자명: Kyung Duck Min(閔庚德) Ok Joon Kim(金玉準) Suckew Yun(尹碩奎) Dai Sung Lee(李大聲) Sung Whan Joo(朱承煥)
• 간행물 정보: 『자원환경지질』15권 3호, 123~155쪽, 전체 33쪽
• 주제분류: 자연과학 > 지질학
• 파일형태: PDF
• 발행일자: 1982.09.30

영문 초록

Petrochemical, K-Ar dating, S and Rb/Sr isotopes, metallogenic zoning, paleomagnetic and geotectonic studies of the Gyongsang basin were carried out to examine applicability of plate tectonics to the post-late Cretaceous igneous activity and metallogeny in the southeastern part of Korean Peninsula. The results obtained are as follows: 1. Bulgugsa granitic rocks range from granite to adamellite, whose Q-Ab-Or triangular diagram indicates that the depth and pressure at which the magma consolidated increase from coast to inland varying from 6km, 0.5-3.3kb in the coastal area to 17km, 0.5-10kb in the inland area. 2. The volcanic rocks in Gyongsang basin range from andesitic to basaltic rocks, and the basaltic rocks are generally tholeiitic in the coastal area and alkali basalt in the inland area. 3. The volcanic rocks of the area have the initial ratio of Sr87/Sr86 varying from 0.706 to 0.707 which suggests a continental origin; the ratio of Rb/Sr changing from 0.079-0.157 in the coastal area to 0.021-0.034 in the inland area suggests that the volcanism is getting younger toward coastal side, which may indicate a retreat in stage of differentiation if they were derived from a same magma. The K₂O/SiO₂(60%) increases from about 1.0 in the coastal area to about 3.0 in the inland area, which may suggest an increase indepth of the Benioff zone, if existed, toward inland side. 4. The K-Ar ages of volcanic rocks were measured to be 79.4m.y. near Daegu, and 61.7m.y. near Busan indicating a southeastward decrease in age. The ages of plutonic rocks also decrease toward the same direction with 73m.y. near Daegu, and 58m.y. near Busan, so that the volcanism predated the plutonism by 6m.y. in the continental interior and 4m.y. along the coast. Such igneous activities provide a positive evidence for an applicability of plate tectonics to this area. 5. Sulfur isotope analyses of sulfide minerals from 8 mines revealed that these deposits were genetically connected with the spacially associated ingeous rocks showing relatively narrow range of δ³⁴S values(-0.9‰ to +7.5‰ except for +13.3 from Mulgum Mine). A sequence of metallogenic zones from the coast to the inland is delineated to be in the order of Fe-Cu zone, Cu-Pb-Zn zone, and W-Mo zone. A few porphyry type copper deposits are found in the Fe-Cu zone. These two facts enable the sequence to be comparable with that of Andean type in South America. 6. The VGP’s of Cretaceous and post Cretaceous rocks from Korea are located near the ones(71°N, 180°E and 90°N, 110°E) obtained from continents of northern hemisphere. This suggests that the Korean peninsula has been stable tectonically since Cretaceous, belonging to the Eurasian continent. 7. Different polar wandering path between Korean peninsula and Japanese islands delineates that there has been some relative movement between them. 8. The variational feature of declination of NRM toward northwestern inland side from southeastern extremity of Korean peninsula suggests that the age of rocks becomes older toward inland side. 9. The geological structure(mainly faults) and trends of lineaments interpreted from the Landsat imagery reveal that NNE-, NWW- and NEE-trends are predominant in the decreasing order of intensity. 10. The NNE-trending structures were originated by tensional and/or compressional forces, the directions of which were parallel and perpendicular respectively to the subduction boundary of the Kula plate during about 90m.y. B.P. The NWW-trending structures were originated as shear fractures by the same compressional forces. The NEE-trending structures are considered to be originated as tension fractures parallel to the subduction boundary of the Kula plate during about 70m.y. B.P. when Japanese islands had drifted toward southeast leaving the Sea of Japan behind. It was clearly demonstrated by many authors that the drifting of Japanese islands was accompanied with a rotational movement of a clock-wise dir

목차

Abstract

1. 序論

2. 慶尙盆地內의 火成岩類

3. 火成岩類의 岩石化學的 特徵

4. 火成岩類의 年代

5. 板構造運動과 鑛化作用

6. 殘留磁氣 測定과 古地磁氣 硏究

7. 火成活動과 地殼運動의 板構造論的 解析

8. 結論

참고문헌