Test yourself

Task 1. Tell whether the sentences are true or false. Correct the false ones.

1. Rock-forming minerals and economic minerals are mutually exclusive groups.

2. Only eighty elements make up the vast majority of the rock-forming minerals and represent more than 98 percent (by weight) of the continental crust.

3. Silicon and oxygen are by far the most common elements in Earth’s crust.

4. Silicon and oxygen readily combine to form the silicates.

5. It is impossible to indicate the conditions under which each silicate mineral is formed.

6. The most common silicate minerals can be divided into two major groups on the basis of their chemical makeup: the light silicates and the dark ones.

7. The dark silicates contain some amounts of aluminum, potassium, calcium, and sodium rather than iron and magnesium.

8. The most common member of the pyroxenes group is augite.

9. Biotite has a shiny light appearance that helps distinguish it from the other dark ferromagnesian minerals.

10. Both olivine and garnet have a glassy luster.

11. When calcite is the dominant mineral, the rock is called limestone.

12. Gypsum is the mineral name for common table salt.

Task 2. Using the geologic definition of mineral as your guide, determine which of the items on the list are minerals and which are not. If not a mineral, explain.

a. gold nugget d. cubic zirconia	b. sea water e. obsidian	c. quartz f. ruby
g. glacial ice	h. amber

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; вентиляційний отвір; віддушина; повітряний клапан	exert - викликати, спричиняти
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.