Match the words in the right column with the words in the left one.
UNIT 5 IGNEOUS ROCKS
COMPREHENSION
Read the following text «Anatomy of a volcano»
Vocabulary Pronunciation
Western Mexico 1943
Paricutin 490 ft.(150 m)
Western Argentina 1500 ft.(450 m)
Aconcagua 22,834 ft.(6 960 m)
basic (volcano)- основной, balloon (outward) - подниматься базитовый | |
fissure - трещина, разрыв | relieve - понижать давление |
linear - линейный | weakness - слабое место |
emit - извергать | conduit - канал, жерло вулкана |
ash - пепел, шлак | dissolved gas(es) - растворенный газ |
shield – щит / щитовой | expanding bubbles -расширяющиеся пузыри |
cone - конус (вулкана) / конический | blast - взрыв |
mound- куполовидная постройка, холм | vent - жерло вулкана |
extinct - потухший, угасший | outlet - выходное отверстие |
tower - возвышаться | cinder - шлак, пепел |
hemisphere - полушарие | inverted (cone) - перевернутый конус |
cross section - поперечный разрез | side (vent) - боковой (кратер) |
chamber -камера, | on the flanks - на склонах |
reservoir - резервуар | subsidiary (cone) - дочерний (конус) |
pressurized - находящийся под давлением, сжатый |
ANATOMY OF A VOLCANO
Pay attention to the following terms in bold. (R.P. – 5.3)
Volcanoes take two main forms. Fissure or linear volcanoes chiefly emit basic lava from a crack in the Earth’s crust. Central volcanoes yield lava, ash and other products from a single hole. These products build a shield- or cone-shaped mound: the typical volcano shape. Central volcanoes can grow high and fast. In western Mexico in 1943 Paricutin grew 490 ft. (150 m) high in a week and reached 1500 ft. (450 m) in a year. In western Argentina extinct Aconcagua towers 22,834 ft. (6 960 m) above sea level; this is the highest mountain in the western hemisphere.
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A cross section through an active central volcano would reveal these features. Miles below the surface lays the magma chamber- a reservoir of gas-rich molten rock under pressure. This pressurized magma may “balloon outward” against the surrounding solid rock until it can relieve the pressure by escaping through a weakness in the crust above. From the chamber, magma then rises through a central conduit. As magma rises the pressure on it is reduced and its dissolved gases are freed as expanding bubbles. Finally the force of gases blasts opens a circular vent on the Earth’s surface. From this outlet ash, cinders and flows of lava build the main volcano shield or cone. Vent explosions shape its top as an inverted cone or crater. Meanwhile, side vents on the flanks of the volcano release ash or lava that may build subsidiary cones.
(David Lambert “The Field Guide to Geology” 1988, Cambridge University Press)
Fig. 25 Volcano.
Lava flow; 2 – cloud (steam, ashes, rock clasts); 3 – main crater; 4 – secondary
Crater; 5 – secondary chimney; 6 – magma chamber; 7 – laeyers (lava, ashes).
EXERCISES
2.1 Read the text (once) more carefully and choose the correct alternative
for these words:
1. round-formed opening
2. upside-down
3. to let out
4. non-active
5. reservoir
6. to be under pressure
7. to be above
8. to decrease ( to become less in volume)
9. to explode
10. the form of a hill
Use two words from the corresponding line to complete each sentence.
1. emit magma bubbles products
2. tower ash mountain lava
3. linear cone chamber inverted
4. circular active extinct crack
5. fissures balloon conduit weakness
1. The volcano _________ ____________ such as ash and cinder.
2. The ________ ____________ over the island.
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3. The top of a volcano is like a _________ ___________ .
4. Volcanoes can be ________ or __________ .
5. _________ form as a result of the Earth’s __________ .
2.3. Give the Russian equivalent the following phrases:
1. volcanoes emit basic lava
2. typical volcano shape
3. volcanoes can grow high
4. above sea level
5. a cross section through a volcano
6. miles below the surface
7. gas-rich molten rocks
8. surrounding solid rocks
9. escape through a weakness in the crust
10. force of gases blast open
11. vent explosions shape its top
12. on the flanks
Match the words in the right column with the words in the left one.
pressurized volcano
single section
shield-shaped gases
extinct vent
western bubbles
cross crater
dissolved cone
circular conduit
expanding magma
inverted hole
subsidiary mound
central hemisphere
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