作者：托福听力 严若涵 周菲菲
1. Volcano 火山
Volcanoes are formed when magma from within the Earth's upper mantle works its way to the surface. There are three main types of volcano - composite or strato, shield and dome.
Most of the world's volcanoes occur at the boundaries of the tectonic plates such as the so-called "Ring of Fire" in the Pacific Ocean. However, some occur not at the edges, but in the middle of a continental or oceanic plate like Hawaii islands.
2. Glacier 冰川
A glacier is a huge mass of ice that moves slowly over land. It is formed from compacted layers of snow. Basically, glaciers fall into two groups: alpine glaciers and ice sheets.
It’s really no secret that glaciers flow because of gravity. Basically, it happens in two ways, basal slip and deformation.
3. Basin 盆地
A basin is a depression, or dip, in the Earth’s surface. Basins are shaped like bowls, with sides higher than the bottom. They can be oval or circular in shape, similar to a sink or tub you might have in your own bathroom. Some are filled with water. Others are empty.
The formation of basin: Basins are formed by forces above the ground (like erosion) or below the ground (like earthquakes). They can be created over thousands of years or almost overnight.
4. Plain 平原
A Plain is an area of lowland, either level or undulating. It seldom rises more than a few hundred feet above the sea level.
Plains are usually categorized into three types -- structural plain, depositional plain and erosional plain -- based on their mechanism of formation.
5. Waterfall 瀑布
A waterfall is an area where water flows over a vertical drop or a series of steep drops in the course of a stream or river.
6. Valley 山谷
A valley is a low area between hills or mountains typically with a river running through it. There are three main types of valleys, the V-shaped valley, the flat floored valley and the U-shaped valley.
Valleys generally contain fertile land that are suitable for farming and thus ideal places for ancient civilization to flourish. Also, the mining resources are abundant in some valleys.
7. Oasis 绿洲
An oasis refers to an area that is fertile and has water within an area that is arid. Life is harsh in the desert, but the presence of an oasis makes it bearable.
The formation of oasis: 1)It is formed when faulting and climatic conditions create a depression in an arid region. When the depression deepens enough to reach the water table, the underground water comes into the surface to form an oasis. 2) Surface rivers, rainstorms, and other natural factors also lead to the formation of oases.
8. Butte /bjuːt/ 小丘
An isolated hill or mountain with steep sides and a flat top rising abruptly above the surrounding land.
The formation process of butte:Buttes are created as streams slowly cut through a mesa or plateau.The hard top layers of buttes, called caprock, resist weathering and erosion. As a result, the formations stay about the same height as the original plateau or mesa. Weathering and erosion slowly erode the softer rock surrounding the caprock. Caprock protects the more vulnerable rock beneath it. Buttes slowly become slender spires.
9. Dune 沙丘
Dunes are large masses of wind-blown sand, and are most common in deserted environments and also near beaches. There are five basic types of dunes: crescentic, linear, star, dome, and parabolic.
Since sand dunes contain other types of particles such as clay and silt, a layer that water couldn’t penetrate forms whenever it is raining. Once this pan formed, further run-off collected, and lakes can be formed int he desert.
10. Plateau 高原
Extensive area of flat upland usually bounded by an escarpment (i.e., steep slope) on all sides but sometimes enclosed by mountains.
The formation of plateau: A plateau is formed by a process of geological uplift, either due to the collision of continental plates, pressure from magma below or the burial of land by volcanic lava and ash flows, resulting in a high, flat surface.
11. Canyon 峡谷
A canyon is a deep, narrow valley with steep sides and often with a stream flowing through it. “Canyon” comes from the Spanish word cañon, which means “tube” or “pipe.” The term “gorge” is often used to mean “canyon,” but a gorge is almost always steeper and narrower than a canyon.
The formation of canyon: The movement of rivers, the processes of weathering and erosion, and tectonic activity create canyons.
12. Strait 海峡
A strait is a naturally formed, narrow, typically navigable waterway that connects two larger bodies of water. Most commonly it is a channel of water that lies between two land masses. Some straits are not navigable, for example because they are too shallow, or because of an unnavigable reef or archipelago.
The formation of strait:It may be formed by a fracture in an isthmus(地峡), a narrow body of land that connects two bodies of water or tectonic shifts. A strait can also be formed by a body of water overflowing land that has subsided or has been eroded.
13. Tributary 支流
A tributary is a freshwater stream that feeds into a larger stream or river. Tributaries do not flow directly into the ocean. It takes many tributary streams to form a river.
Tributaries are an integral component of river networks, serving as valuable links in the landscape for enhancing biodiversity. But projects like hydro-power dams may fragment river ecosystems by changing peak flow magnitude and rates.
14. Bay 海湾
A bay is a body of water partially surrounded by land. It is usually smaller and less enclosed than a gulf.
Common pollutants in bay areas are nitrogen, phosphorous and sediment. To protect such areas, both efforts to reduce scattered source pollution and increase buffer zones of trees are required.
15. Gulf 海湾
A gulf is a portion of the ocean that penetrates land, an arm of an ocean, one may say. 海湾（gulf）是深入陆地的一部分海洋，也有人说它像海洋的一个手臂。
The Gulf of Mexico is the largest gulf in the world. It was formed approximately 300 million years ago when a seafloor sank. It is located on the coast of Mexico and The United States of America.
16. Peninsula 半岛
A peninsula is a piece of land that is almost entirely surrounded by water but is connected to the mainland on one side.
Europe could be seen as a peninsula from Eurasia. Within Europe, there are tons of peninsulas as well: Scandinavian, Jutland, Italian, Balkan and Iberian.
17. Archipelago 群岛
An archipelago is a group of islands closely scattered in a body of water. Usually, this body of water is the ocean, but it can also be a lake or river.
The formation of archipelago: Archipelagos generally originate from volcanic activities associated with large magma eruptions. They can also be the result of erosion or soil deposition processes.
18. Atoll/lagoon 珊瑚环礁
An atoll , sometimes called a coral atoll, is a ring-shaped coral reef including a coral rim that encircles a lagoon partially or completely.
The formation of atoll/lagoon:
19. Delta 三角洲
Deltas are wetlands that form as rivers empty their water and sediment into another body of water, such as an ocean, lake, or another river. Although very uncommon, deltas can also empty into land.
Delta formation process: 1)River have sufficient load; 2)velocity of river water is low; 3)subsidence in area of deposition.
20. Fjord /fjɔrd/ 峡湾
Geologically, a fjord or fiord is a long, narrow inlet with steep sides or cliffs, created by a glacier.
The formation process of fjord: A fjord is formed by the movement of a glacier that cuts rock formations, forming steep ridges or cliffs on each side of a valley. The valley fills with water from a nearby ocean or sea, leaving steep rock formations above water on either side.