[originaltext]W: Dr. Smith. I need to ask you about something in Chapter 12. We

游客2023-07-21  32

问题  
W: Dr. Smith. I need to ask you about something in Chapter 12. Well, it talks about erosion and the de posit of sediment(solid matter that settles at the bottom of a liquid)on the deep sea floor, but I’m confused. For that to happen, there would have to be some kind of force down there moving the mud or sand or whatever, right? But I thought there weren’t any waves or currents that deep in the ocean.
M: That’s not exactly correct. It’s true that deep down on the ocean floor we won’t have the same kinds of currents we find in shallower parts. But we do find what we call turbidity currents. This wasn’t in the book but the term came up in class. Do you remember what it means?
W: Umh, turbidity currents? Oh, yeah! Isn’t that when sediment like sand or mud gets stirred up and mixes with water. And then this mixture flows through the water around it, right?
M: Good !
W: Uhe, but I thought that only happened in rivers.
M: Well, yes. This does occur in rivers, but we see turbidity currents deep in the ocean as well.
W: But how do they get started there?
M: Earthquakes mostly, when an earthquake occurs under water, it throws up tremendous amounts of mud or sand that becomes suspended in a layer of water near the bottom of the ocean. This layer is so much denser and heavier than other ocean water that if flows right down the slopes of the ocean floor and gains more and more speed as it moves along. Then it’s just like the winds blowing across the desert picking up sand from one place and moving it along and finally dropping it somewhere else.

选项 A、By crushing large amounts of stone.
B、By causing mud or sand to mix with ocean water.
C、By creating large waves on the Surface of the ocean.
D、By greatly increasing the ocean’s depth in some areas.

答案 B

解析 推理题。短文在对turbidity cur rents进行解释时提到Isn’t that when sediment like sand or mud gets stirred up and mixes with water .....而教授认为,海底的沉淀物运动具有turbidity currents运动的同样原理,即由于地震带动泥和沙连同海水混合一起运动,所以B符合题意。
转载请注明原文地址:https://tihaiku.com/zcyy/2857130.html
最新回复(0)