釜山地域의 佛國寺酸性火成岩類의 岩石學的 硏究

• 영문명: Petrological study on the Bulgugsa acidic igneous rocks in Busan area
• 발행기관: 대한자원환경지질학회
• 저자명: Moon Sung Cha(車文星)
• 간행물 정보: 『자원환경지질』9권 2호, 85~112쪽, 전체 27쪽
• 주제분류: 자연과학 > 지질학
• 파일형태: PDF
• 발행일자: 1976.06.30

영문 초록

The Bulgugsa acidic igneous rocks of the late Cretaceous age are largely distributed in Busan area, which is located in the southeastern corner of the Korean Peninsula. These igneous rocks comprise in ascending order, felsite, dacitic-rhyolitic welded tuffs, granite porphyry and granitic rocks. The former three members represent the early phase of volcanic activities, so that they are named as Jangsan volcanic rocks. The granitic rocks consist of granodiorite, hornblende biotite granite, Kumjongsan granite, fine grained granite, and Daebyen granite, represent the late phase of igneous activities. The Kumjongsan grainte, the largest pluton of the granitic mass, emplaced between two great vertical faults trending NNE. New chemical analyses of 33 rock samples of these acidic rocks are given. Their chemical compositions are generally similar to those of the late Mesozoic acidic igneous rocks of the northern Ashio mountains, and C-Zone granite group of the Ogcheon geosyncline, with their characteristic variation trends of several oxides. Their chemical compositions also show that Al₂O₃ is high value, and differentiation index is high, too. Systematically developing joints in Kumjungsan granite are divisible into two types at least. One is the NS-N 20˚E trending, 85˚~90˚ dipping type of joint system which coincides with the trends of distribution of the granite mass and the dikes intruding this granite. Joints of this type may be cooling joints generated as tension cracks. The other is the N60˚~70˚W or N40˚~60˚E trending type of joint systems. It is considered that joints belonging to this type may be shear joint occurring under the state of south-north tectonic couple acting at the east and west side of the granite mass. Igneous activities of the the Bulgugsa acidic igneous rocks in Busan area was taken place as follows, formation of the magma reservoir, eruption and intrusion of felsite, consolidation of vents and increasing vapor pressure in magma reservoir, eruption of pyroclastic flows, caldera collapse, intrusion of granite porphyry, and intrusion of granitic rocks at the latest stage.

목차

Abstract

I. 序論

II. 地形

III. 地質槪要

IV. 佛國寺酸性火成岩類의 産出狀態와 岩石記載

V. 佛國寺酸性火成岩類의 化學組成

VI. 金井山花崗岩體의 貫入機構

VII. 佛國寺酸性火成岩類의 成因的考察

VIII. 結論

參考文獻