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UNIT 14
IGNEOUS ROCKS
Part 1

Task 1. Read and memorize the following words:
cool - охолоджувати emit - випускати, випромінювати,
викидати (дим, лаву)
eject - викидати, вивергати outpourings – розлив, вилив
propel - рухати, виштовхувати melt - розплавлена речовина, розплав
ash - попіл chamber – проруб, отвір
mush - м'яке, кашоподібне; кашка volatile - летюча речовина; той, що
швидко випаровується
vent - вхідний або вихідний отвір; exert - викликати, спричиняти
вентиляційний отвір; віддушина;
повітряний клапан
confine by - обмежуватись immense - величезний, колосальний
surrounding - оточуючий to increase - збільшуватись

Task 2. Read the following text, translate it into Ukrainian.

Magma: The Parent Material of Igneous Rock
Igneous rocks (ignis=fire) are formed as molten rock cools and solidifies. Some
scientists believe that the parent material for igneous rocks, called magma, is formed by
melting that occurs at various levels within Earth’s crust. Once formed, a magma body
rises toward the surface because it is less dense than the surrounding rocks.
Occasionally molten rock reaches Earth’s surface where it is called lava.
Sometimes lava is emitted as fountains that are produced when escaping gases propel it
from a magma chamber. On other occasions, magma is explosively ejected, producing
dramatic steam and ash eruptions. However, not all eruptions are violent; many
volcanoes emit quiet outpourings of very fluid lava.

The Nature of Magma
Magma is completely or partly molten rock, which on cooling solidifies to form
an igneous rock composed of silicate minerals. Most magmas consist of three distinct
parts—a liquid component, a solid component, and a gaseous phase. The liquid portion,
called melt, is composed mainly of mobile ions of the eight most common elements
found in Earth’s crust—silicon and oxygen, along with lesser amounts of aluminum,
potassium, calcium, sodium, iron, and magnesium. The solid components (if any) in
magma are silicate minerals that have already crystallized from the melt. As a magma
body cools, the size and number of crystals increase. During the last stage of cooling, a
magma body is like a “crystalline mush” with only small amounts of melt. The gaseous
components of magma, called volatiles, are materials that will vaporize (form a gas) at
surface pressures. The most common volatiles found in magma are water vapor (H 2O),
carbon dioxide (CO 2), and sulfur dioxide (SO 2), which are confined by the immense
pressure exerted by the overlying rocks. These gases tend to separate from the melt as it
moves toward the surface. As the gases build up, they may eventually propel magma
from the vent. When deeply buried magma bodies crystallize, the remaining volatiles
collect as hot, water-rich fluids that migrate through the surrounding rocks. These hot
fluids play an important role in metamorphism.

Task 3. Answer the following questions, using the vocabulary from Task 1.
1. When are igneous rocks formed?

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