• Title/Summary/Keyword: 한국 동남부

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한반도 동남부 연안해역의 저서성유공충 분포특성

  • 정규귀;김귀영;강소라
    • Proceedings of the Korean Society of Fisheries Technology Conference
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    • 2000.05a
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    • pp.211-212
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    • 2000

  • 유공충은 껍질(test)을 가지는 원생동물로 기수역(brackish) 내지는 해양에 널게 분포하고 있다. 대부분 석회질 혹은 사질(arenaceous)의 껍질로 구성되어 있으며, 해양퇴적물의 중요한 생물원 요소가 되고 있다(Matoba, 1975). 유공충은 서식환경에 따라 종조성을 달리하거나 종내변이(variety 혹은 ecophenotype)를 보이며 환경의 변화에 민감하게 반응한다. 본 연구에서는 한반도 동남부 연안해역의 내 대륙붕 니질대(nearshore mud belt) 및 영일만에 분포하는 저서성유공충의 분포특성을 파악하고 저질환경인자에 대한 반응 종을 탐색함으로써 연안환경에 서식하는 유공충의 환경지시자를 밝히고자 한다. (중략)

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Characteristics of the Cenozoic crustal deformation in SE Korea and their tectonic implications (한반도 동남부 신생대 지각변형의 주요 특징과 지구조적 의의)

  • Son, Moon;Kim, Jong-Sun;Chong, Hye-Yoon;Lee, Yung-Hee;Kim, In-Soo
    • The Korean Journal of Petroleum Geology
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    • v.13 no.1
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    • pp.1-16
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    • 2007

  • The southeastern Korean Peninsula has experienced crustal multi-deformations according to changes of global tectonic setting during the Cenozoic. Characteristic features of the crustal deformations in relation to major Cenozoic tectonic events are summarized as follows. (1) Collision of Indian and Eurasian continents and abrupt change of movement direction of the Pacific plate (50${\sim}$43 Ma): The collision of Indian and Eurasian continents caused the eastward extrusion of East Asia block as a trench-rollback, and then the movement direction of the Pacific plate was abruptly changed from NNW to WNW. As a result, the strong suction-force along the plate boundary produced a tensional stress field trending EW or WNW-ESE in southeastern Korea, which resultantly induced the passive intrusion of NS or NNE trending mafic dike swarm. (2) Opening of the East Sea (25${\sim}$16 Ma): The NS or NNW-SSE trending opening of the East Sea generated a dextral shear stress regime trending NNW-SSE along the eastern coast line of the Korean Peninsula. As a result, pull-apart basins were developed in right bending and overstepping parts along major dextral strike slip faults trending NNW-SSE in southeastern Korea. The basins can be divided into two types on the basis of geometry and kinematics: Parallelogram-shaped basin (rhombochasm) and wedged-shaped basin (sphenochasm), respectively. In those times, the basins and adjacent basement blocks experienced clockwise rotation and northwestward tilting contemporaneously, and the basins often experienced a kind of propagating rifting from NE toward SE. At about 17Ma, the Yonil Tectonic Line, which is the westernmost border fault of the Miocene crustal deformation in southeastern Korea, began to move as a major dextral strike slip fault. (3) Clockwise rotation of southeastern Japan Island (about 15 Ma): The collision of the Izu-Bonin Arc and southeastern Japan Island, as a result of northward movement of the Philippine sea-plate, induced the clockwise rotation of southeastern Japan Island. The event caused the NW-SE compression in the Korea Strait as a tectonic inversion, which resultantly tenninated the basin extension and caused local counterclockwise rotation of blocks in southeastern Korea. (4) E-W compression in the East Asia (after about 5 Ma): Decreasing subduction angle of the Pacific plate and eastward movement of the Amurian plate have constructed the-top-to-west thrusts and become a major cause for earthquakes in southeastern Korea until the present time.

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