Chapter 15. Ocean Basins : For Discussion

소개

Thompson Turk Earth Science and the Environment 정리 및 챕터 별 문제 풀이 (솔루션은 아니고 직접 푼 거)

목차

1, The east coast of South America has a wide continental shelf, whereas the west coast has a very narrow shelf. Discuss and explain this contrast.

2. Seismic data indicate that continental crust thins where it joins oceanic crust at a passive continental margin, such as on the east coast of North America. Other than that, we know relatively little about the nature of the junction between the two types of crust. Speculate on the nature of that junction. Consider rock types, geologic structures, ages of rocks, and other features of the junction.

3. Discuss the topography of Earth in an imaginary scenario in which all conditions are identical to present ones except that there is no water. In contrast, what would be the effect if there were enough water to cover all of Earth`s surface?

4. If you look at the maps of Earth, you will see that most of the world`s largest rivers drain toward passive continental margins. Confirm this for yourself and explain this observation.

본문내용

1, The east coast of South America has a wide continental shelf, whereas the west coast has a very narrow shelf. Discuss and explain this contrast.
-> Continental margin이란 continental crust가 oceanic crust를 만나는 곳이다. 여기에는 Passive continental margin과 active continental margin이 있다. Passive continental margin이란 oceanic crust와 continental crust가 하나로 연결된 것으로서 plate boundary가 아니기 때문에 tectonic activity가 비교적 적다. 하지만 active continental margin이란 convergent plate boundary로서, oceanic lithosphere가 subduction zone에서 가라앉으면서 형성된다.
남아메리카의 동부해안은 passive continental margin이고 서부해안은 active continental margin이다.

중략..

4. If you look at the maps of Earth, you will see that most of the world`s largest rivers drain toward passive continental margins. Confirm this for yourself and explain this observation.
-> 이러한 강들의 에에는 아마존, 미시시피, 콩고, 그리고 니제르 강이 있다. 보통 active continental margin에서는 subduction zone이 있고 이에 따라서 대륙에 산맥이 형성되기 때문에, 대륙에서 바다 쪽으로 흐르는 강이 짧고 경사도 급하다. 하지만 passive continental margin에서는 이러한 산맥이 없고 육지의 경사가 완만하기 때문에 강이 훨씬 더 길고, 따라서 더 커질 수 있는 것이다.

참고자료

· Thompson Turk Earth Science and the Environment