Block tectonics of the Taebaegsan basin and en echelon sedimentary wedges of the Yeonhwa-Ulchin district, mideastern South Korea

• 발행기관: 대한자원환경지질학회
• 저자명: Suckew Yun
• 간행물 정보: 『자원환경지질』11권 4호, 127~141쪽, 전체 15쪽
• 주제분류: 자연과학 > 지질학
• 파일형태: PDF
• 발행일자: 1978.12.30

국문 초록

本硏究는 太白山堆積盆을 特徵짓는 主要構造를 廣域的으로 解析하였고 特히 이의 東南側으로의 連續體이며 經濟的으로 重要한 鉛, 亞鉛鑛化帶인 蓮花-蔚珍地城에 重點을 두었다. 太白山堆積은 그의 西緣部에 重複된 沃川地向斜運動의 影響을 받았음은 事實이나 그 堆積盆自體의 形態, 堆積成分 및 變形과 火成活動의 特徵이 沃川地向斜帶의 그들과는 基本的으로 相違하다. 卽 準四角形인 그의 輪廓이 注目되며 東西方向인 咸白向斜와 石屛山-北坪弧가 南北方向인 沃川帶 및 五十川-蓮花帶와 커다란 첵크무늬로 交叉되어 中央에 中峰山塊를 끼고 있으며 이들 四大造構帶는 그 下部에 各基盤岩塊의 分離境界面의 存在를 反影한다. 이들 境界面上部는 構造的弱帶로서 그위에 最深의 堆積層이 쌓였고 이로부터 멀어짐에 따라 堆積層厚는 減少한다. 따라서 太白山堆積은 先캠브리아 末로부터의 基盤岩의 地塊化와 造構運動史의 産物이며 그의 堆積成分은 選別度가 높은 砂岩(壯山珪岩)을 下部로 大部分 두터운 石灰質岩(大石灰岩統)을 主로하는 點은 이 堆積盆이 比較的 安定된 마이크로 크라톤의 모자익 위에 놓여있었음을 指示하며 이는 보다크고 安定했던 北美大陸內陸의 크라톤에 比較된다. 地塊運動과 構造交叉는 蓮花-蔚珍地域에까지 미쳤으며 이는 咸白向斜의 東方으로의 連續帶가 東北 또는 西南方向의 橫斷層에 依해 切斷된 猫峰-豊村層群과 이를 接觸貫入한 白堊紀末-第三紀初의 石英몬조니斑岩-流紋石英安山岩을 胚胎한 傾動地塊가 雁行狀으로 反覆露出됨으로서 나타나고, 이들 火成活動을 國內鉛ㆍ亞鉛總生産高의 85%를 占하는 大規模의 스카론 鑛化帶를 이루었다.

영문 초록

The major structures characteristic of the Taebaegsan sedimentary basin were regionally analyzed with special reference to its southeastern extension to the Yeonhwa-Ulchin district of economic interest in zinc-lead mineralization. The basin geometry, basement setting, sedimentary components, and the characteristics of deformation and igneous activity of the Taebaegsan basin differ basically from those of the adjacent mobile belt of the Ogcheon geosyncline, although the latter affected the basin’s western side considerably. The subrectangular shape of the Taebaegsan basin reflects the checkered pattern of basement-block arrangement, and the carbonate-dominated lithologic components of the basin-fill indicate a cratonic depositional setting, which is comparable to some of the North American mid-continental craton. The Taebaegsan basin, however, has somewhat been less stable than the North American megacraton that is reflected in the former’s thicker sedimentary fill and steeper faults of later deformation, showing a tendency to increase in thickness close to the basement-block boundaries, which may indicate contacts of possibly detached cratonic blocks of Precambrian age; these weak zones of block boundaries have been the loci of repeated sedimentation, deformation and related igneous intrusions. A series of downthrown or uplifted tilted blocks, in which the Cambro-Ordovician sedimentary wedges and the late Cretaceous to early Tertiary igneous intrusives are involved, occurs intermittently across the Yeonhwa-Ulchin district in a noticeable pattern of en echelon type. These sedimentary wedges are correlated to the Cambro-Ordovician section of the Hambaeg syncline to the west in stratigraphy and lithology, and are considered to have resulted from the northeastern and/or northwestern cross-faulting of the pre-existing syncline belt of easterly trend, extended from the main portion of the Hambaeg syncline. These structural junctions (or intersections) of the earlier syncline belt and the later cross-faults have been acted as a guide to ascending igneous materials and hydrothermal ore-forming fluids to form a zone of zinc-lead skarn deposits across the Yeonhwa-Ulchin district showing a stepwise recurrence of these deposits toward the east.

목차

Abstract

1. Geologic sequence of Taebaegsan basin

2. Major structures and tectonics

3. Conclusions

요약

References