VIII. Read the text.

If you drill a hole into the ground in most places, its bottom fills with water after a few days. The water appears even if no rain falls and no streams flow nearby. The water that seeps into the hole is part of the vast reservoirs of subterranean ground water that saturates the Earth’s crust in a zone between a few meters and a few kilometers below the surface.

Ground water is exploited by digging wells and pumping the water to the surface. It provides drinking water for more than half of the populations of North America and is a major source of water for irrigation and industry.

However, deep wells and high-speed pumps now extract ground water more rapidly than natural processes replace it in many parts of the central and western United States. In addition, industrial, agricultural, and domestic contaminants seep into ground eater in many parts of the world. Such pollution is often difficult to detect and expensive to clean up.

Are the following statements true or false?

1. Ground water saturates the Earth’s crust at depth of ten kilometers.

2. Ground water is a source of drinking water for the whole population of North America.

3. Water pollution by industrial, agricultural, and domestic contaminants is difficult to detect and expensive to clean up.

IX. Translate from Russian into English.

1. Грунтовая вода течет из зон с высоким уровнем водного зеркала в сторону областей с низким уровнем.

2. В некоторых регионах подземная вода течет из влажной среды в засушливую, и поэтому она является очень ценным источником.

3. Существует много источников загрязнения грунтовой воды.

Test IX unit IX ocean basins

I. Give Russian equivalents.

Submarine currents; continent and ocean crust; sea-floor rocks; mid-oceanic ridges; subduction zones; the heat exchange; rift valley; terrigenous sediment; pelagic sediment; abyssal plains; a continental margin; a convergent plate boundary; a continental slope; submarine canyons; an abyssal fan.

II. Give English equivalents.

Химическая реакция с морской водой; океанический бассейн; центр спрединга; плавучесть; осадок; рифтовая долина; крупнозернистый эквивалент базальта; континентальный шельф; океаническая литосфера; мутные течения; континентальная кора; геологическое время; карбонатные платформы; накапливание морской воды в мировых океанических бассейнах.

III. Match the words from “a” and “b” to make word combinations.

1. ocean; the northern; profoundly; seismic; pillow; plate; sediment; an abyssal; gradual; a continental;

2. affect; basalt; extension; profiling; boundary; basins; slope; fan; transition; accumulation.

IV. Complete the sentences.

1. . . . . sediment is sand, silt, and clay eroded from the continents and carried to the deep sea floor by submarine currents.

2. . . . . is a place where continental crust meets oceanic crust.

3. In contrast, . . . . occurs at a convergent plate boundary.

4. The sediment forms a shallow, gently sloping submarine surface called . . . . on the edge of the continent.

5. In many places, sea-floor maps show deep valleys called . . . . eroded into continental shelf and slope.

6. Geologists subsequently discovered that submarine canyons are cut by . . . .

7. This region, called . . . . , consists of an apron of terrigenous sediment that was transported across the continental shelf.

(a continental margin; a continental shelf; turbidity currents; an active continental margin; the continental rise; terrigenous; submarine canyons)