영덕 남부 내연산응회암의 화산학적 연구 = volcanology of Naeyeonsan Tuff in the southern Yeongdeok, Kyiongsangbuk-do

다국어 초록 (Multilingual Abstract)

The Naeyeonsan Tuff is situated in the middle western part of Cheongha geological map(1:50,000) and is one of stratigraphic units of Cretaceous volcanic rocks which is included into the Yucheon Group of the Kyeongsang Supergroup in the northeastern Kyeongsang basin.
The unit is tinged with dark-blue to dark grey color in the field and is composed of plagioclase, quartz, hornblende and biotite phenocrysts and opaque mineral. Also pumices in the tuffs include the same minerals. The unit belongs to a tuff according to the granulometric classification and to vitric tuff according to the constituent classification. The crystal content is more or less rich in the matrix than pumices in the tuffs. This may mean that the tuffs have suffered crystal fractionation during volcanic processes. The Naeyeonsan Tuff is subdivided into two welding zones, partial welding zone which appears in the bottom and top of the unit, and densely welding zone which is located in the middle thick part of the unit and show an eutaxitic texture.
The elongated pumices and lithic fragments are aligned in the welding foliation. The lineations for their alignments are roled on an excellent indicator of flow direction for pyroclastic flow that have deposited in the Naeyeonsan Tuff. The flow direction approximately shows SE-NW trend and broadly makes a fan shape away from the southeastern part. Isopleth map which is plotted with average largest lithic fragments in the geological map increases from northwestern part to southeastern one. So, the central area of the fan shape is corresponded to largest central part of the isopleth map. They support that the source area of the Naeyeonsan Tuff is located in southeastern part of the study area.

목차 (Table of Contents)

• 목차 = ⅰ
• 제1장. 서언 = 1
• 제1절. 연구배경 = 1
• 제2절. 연구목적 = 1
• 제3절. 연구동향 = 2
• 제2장. 연구방법 = 5
• 제1절. 지질도 작성 = 5
• 제2절. 유향도 작성 = 5
• 제3절. 입경변화도 작성 = 6
• 제4절. 박편관찰 = 6
• 제3장. 지질개요 = 7
• 제4장. 내연산응회암 = 13
• 제1절. 야외관계 = 13
• 제2절. 응회암의 분류 = 13
• 제3절. 암질기재 = 21
• 제4절. 용결상 = 28
• 제5절. 흐름의 지시자 = 31
• 제6절. 입경의 점이현상 = 40
• 1. 횡적인 점이현상 = 40
• 2. 수직적인 점이현상 = 43
• 제5장. 토의 = 46
• 제6장. 결론 = 50
• 참고문헌 = 51
• Abstract = 56