JOHN's BOARD
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Listening and Reading Comprehension
1. What is the discussion mainly about?
2. What is the process of orogeny?
3. Listen to part of the discussion again, and then answer the question...Why does the professor say, "Okay where was I?"
4. Why does the professor talk about the Appalachian mountains?
5. What can be inferred about old mountain ranges?
6. Why are the Himalays folded?
[Lesson Credits: Listening Building MP3 TOEFL, Track 2]
Geography
W1: Today, I’d like us to discuss the geological process responsible for the creation of the Himalayas---the world’s tallest mountains. You’ll recall that in our last class we talked about the two ways mountain ranges form: one being volcanic, the other being orogeny. The
Himalayas were formed by the latter process. Does
anyone remember what orogeny means?
W2: Yeah. Doesn’t it mean that they were the result of a
collision of two continents colliding together?
M: And that pushed the land up.
W1: Right. The Himalayas are a result of two continents---
Asia and the Indian subcontinent---colliding. That collision thrust them upward. Now, the Himalayas are one of the world’s youngest mountain ranges.
W2: Then how did they get to be the highest?
W1: Good question. Part of the answer lies in their origin. I’ll
get back to that in a second. Uh, another part of the answer lies in the fact that older mountains like the Appalachian Mountains in America were once as large as the Himalayas. Since they are older, wind and water have had more time to erode them and make them less massive.
W1: Okay, where was I?
W2: You were talking about the collision of Asia and India.
W1: Right. So, Asia and India are both what we call
continental plates, landmasses floating on the Earth’s liquid mantle. And, about 200 million years ago, they were nowhere near each other. But they were moving toward each other---um slowly, a few centimeters per year. So, around 70 million years ago, they first collided into each other. And this began the process of pushing up land, the land that became the Himalayas. They have been colliding into each other ever since.
M: So, are the mountains still forming?
W1: Yes, yes, they are. They are still rising and folding.
There are many folds in the Himalayas---the two continents are still pushing together, still pressing the mountains together. Think of a piece of paper folded dozens of times. That’s kind of like the Himalayas. And because the mountains are still forming, they are rising about 5 centimeters a year. They are not done growing.
