abyssal [s'bissl] , ; bypabbsal [,hips'bis(3)l] a
adjacent [s'dseissnt] ,
ash [aefl n
belt [belt] ; ;
body ['bodi] , ; solid (liquid, gaseous) bodies (, ) ; ; ; ;
common ['komsn] ; ; syn general; ant uncommon
cool [ku:l] v (); ; ; ant heat -()
dimension [di'men/(s)n] ; pi ; ; syn measurement, size
dust [dASt]
dyke [daik]
extrusion [iks'tru:3(9)n] ; ; ant intrusion ; . ( )
fine [fain] , ; ; -
; ; , ( ); ; fine-graded (fine-grained) , ; fines pi ;
flow [] v ; ; ; ; flow of lava
fragmentary [ 'fnegnuntan] ,
glass [gla:s] ; glassy ['glorsi] , ;
gold [gould]
inclined [m'klaind]
mica ['maika]
permit [pa'mit] v , ; syn allow, let; make possible
probably ['probsbli] adv ; syn perhaps, maybe
shallow ['Jaelouj ; ; ant deep
sill [sil] ,
stock [stok] ,
vein [vein] , ,
3. ) -Iff.
intrusive, extrusive, creative, descriptive
) , :
1. Igneous rocks are those which have crystallized from magma. Magma may rise through fissures to the surface of the Earth as lava.
Unit 5_____________________________________________ 115
In geology this process is called extrusion. Thus,... rocks are formed either as lavas or as fragmentary rocks.
2. Igneous rocks on the other hand may be cooled among the
other rocks of the crust. The process is known as intrusion and such
rocks are called....
3. In his Reminiscences of a Mining Engineer Academician Ter-
pigorev gave ^description of the training of specialists at the Mining
Institute in St.Petersburg before the Revolution. Students' specia
lization was based on... courses and elementary practical training.
4. :
fragmentary rocks slowly-cooled rocks
intrusive igneous rocks at shallow depths
exposed igneous rocks adjacent rocks
coarse-grained minerals deep-seated rocks
of great scientific value enormous lateral pressure
of unequal hardness at a slow rate
different mineral particles rock fissures
bedded veins clay veins
flat veins numerous veins
steep veins smaller dimensions
coal fines glassy surface
inclined coal seams mode of occurrence
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different sources of fuel volcanic ashes and dust
5.
:
intrusive and extrusive rocks; intrusive magma; large crystals; volcanic rocks; mountain zones; zones of major deformation; mineral grains; granites and diorites; the group of intrusive or plutonic rocks; straight parallel walls; gigantic crystals; several tons; slowly-cooled batholiths; thick laccoliths; other plutonites; coarse-grained pegmatites; lava flow
6. .
:
Igneous Rocks
Igneous rocks have crystallized from solidified magma..
Igneous rocks can be classified in a number of ways and one of them is based on mode of occurrence. They occur either as intrusive (below the surface) bodies or as extrusive masses solidified at the
116________________________ ____________________ Unit 5
.'" V >.
Earth's surface. The terms "intrusive" and "extrusive" refer to the
place where rocks solidified,
The grain size of igneous rocks depends on their occurrence. The intrusive rocks generally cool more slowly than the extrusive rocks and crystallize to a larger grain size. The coarser-grained intrusive rocks with grain size of more than O.5 mm called plutonic or abyssal are referred ito as intrusive igneous rocks because they are intruded into older pre-existing rocks. Extrusive or volcanic rocks have even fitier grains, less than 0.05 nun and are glassy.
Exposed igneous rocks are most numerous in mountain zones
for two reasons. First, the mountain belts have been zones of major
deformation. Second, uplifts in mountain belts have permitted
plutonic masses to be formed.
The largest bodies of igneous rocks are called batholiths (Fig. 2).
Batholiths cooled very slowly. This slow cooling permitted large min
eral grains to form. It is not surprising that batholiths are composed
mainly of granitic rocks with large crystals called plutons. As is
known, granites and diorites belong,to the group of intrusive or
plutonic rocks formed by solidification of igneous mass under the
Earth's crust. Granites sometimes form smaller masses called stocks,
when the occurrence has an irregular ihipe;but smaller dimensions
than the batholiths.
Laccoliths and sills, which are very similar, are intruded be-
tween sedimentary rocks. Sills are thin and they may be horizontal,
inclined or vertical. Laccoliths are thicker bodies and in some cases
they form mountains.
Dykes are also intrusive bodies. They ranges in JhicJmeSs from a few inches to several thousand feet. Dykes, are gerjraify much longer than they are wide. Most dykes occupy cracks and have strai&nt parallel walls. These bodies cool much more rapidly and are commonly fine-grained. For example, granite may occur 4n dykes that cut older rocks.
Pegmatites (quartz, orthoclase and mica) also belong to the
group of plutonic or intrusive rocks. They occur in numerous veins
which usually cut through other plutonites, most often granite, or
adjacent rocks.
Extrusive,igneous rocks have been formed from lava flows which come from fissures to the surface and form fields of volcanic rocks such as rhyolite, andesite, basalt, as well as volcanic ashes and dust, tuff, etc. As a rule, these rocks of volcanic on|in cool rapidly and are fine-grained. It is interesting to note that basalt is the most
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Unit 5
| Satellite Cone |
| Laccolith \ |
Volcano
Fig. 2. Igneous rocks
abundant of all lavatypes.lt is the principal rock type of the ocean
Igneous rocks are rich in minerals that are important economically or have great scientific value. Igneous rocks and their veins are rich in iron, gold, zinc, nickel and other ferrous metals.
7. , . .
1. Igneous rocks have been formed by sedimentation.
2. Intrusive rocks have been formed by the cooling of rocks of
the Earth's crust.
3. Extrusive rocks have been formed the same way.
4. The grain size of igneous rocks depends on mode of occur
rence.
5. Exposed igneous rocks are numerous in mountain zones.
6. Granites and diorites belong to the group of extrusive rocks.
7. As a rule, granite may occur in dykes.
8. Pegmatites do not belong to the group of plutonic or intrusive
rocks.
8. :
1. Have igneous rocks crystallized from magma or have they been formed by sedimentation?
118______________________________________________ Unit 5
2. Which types of igneous rocks do you know?
3. What does the grain size of igneous rocks depend on?
4. Can you give an example of intrusive or plutonic rocks?
5. Are diorites intrusive or extrusive formations?
6. What do you know about batholiths?
7. Do pegmatites belong to the group of plutonic or volcanic rocks?
8. How do pegmatites occur?
9. What minerals are igneous rocks rich in?
9. )
:
1. adjacent layers )
2. abyssal rocks )
3. dimensions of crystals )
4. valuable minerals ) ()
5. shape and size of grains ) ()
6. mode of occurrence e)
7. coarse-grained )
8. uplifts )
9. zones of major deformation )
) :
1. a) irregular shape
2. ) at a certain depth
3. ) economically important
4. ) solidified masses
5. ) scientific value
6. e) to cool slowly
7. ) existing types of rocks
8. ) fine-grained
9. ) fragmentary rocks
10. ) numerous cracks or fissures
10. ,
:
accelerated process weathered fragments of rocks
crystallized magma generally applied method
successfully improved design unconsolidated and consolidated rocks \
weakly deformed minerals unfrozen ground
rapidly cooled rocks detailed studies of the Earth's crust
utilized equipment dissolved minerals
minerals dissolved by the consolidated rocks
action of water rocks consolidated by some substances
rocks formed by solidification stratified sediments
rocks exposed on the Earth's exposed rocks
surface transformations caused by new
conditions...
Unit 5_____________________________________________ 119
11. ,
. . :
1. Igneous rocks form a large group of minerals which are eco
nomically important.
2. The igneous rocks formed by cooling occur either as intrusive
or extrusive rocks.
3. Orthoclase is particularly used in great quantities as raw mate
rial in the production of porcelain ().
4. The clayey mass obtained by the decomposition of orthoclase is usually
white and is called kaolin. The product obtained is used in industry.
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5. Quartz occurs in the form of small grains. Quartz crystals found in
the cracks and fractures of rocks are very hard and beautiful.
6. Pure quartz sands are used in the production of glass.
7. Actual observations of rocks exposed on the continent show
that shale represents 46 per cent of the total, sandstone about 32
per cent, and limestone about 22 per cent.
12.
.
: The igneous rocks which have crystallized from magma may rise through fissures to the surface of the Earth as lava. -> The igneous rocks crystallized from magma may rise to the surface of the Earth as lava.
1. The classification of igneous rocks which is given below is
based on texture and composition of minerals.
2. Igneous rocks were a hot molten mass which was known as
magma.
3. Observations have shown that the rock types which were pro
duced by molten volcanoes, include, for example, rhyolite, andes-
ite, basalt and other rocks.
4. Andesite which was first found in the Andes Mountains in
South America is the fine-grained rock, intermediate in composition
between granite and basalt.
5. Copper is second only to iron among the important metals
which are widely used in modern engineering.
13. : 1)
,
; 2) ,
; 3) ,
Perfect; 4)
, .
120______________________________________________ UnitS
14. :
1. Abyssal rocks belong to the a) that are economically important.
group of intrusive rocks
2. Uplifts in mountain belts 6) which usually cut through
have permitted erosion to plutonites.
the depths
3. Granites and dioritcs occur ) because they are intruded into
as batholiths pre-existing rocks.
4. Pegmatites (quartz, orthoclase r) at which plutonic masses are
and mica) occur in numerous formed, veins
5. Extrusive igneous rocks have ) where the changes in temperature
been formed as lavas are great.
6. Igneous rocks are rich in e) which come from fissures to
minerals the surface of the Earth's crust.
7. Physical weathering occurs ) which are large irregular masses.
in the deserts and in high mountains
15.
:
1. Batholiths are composed of....
2. Laccoliths are very similar to sills but sills....
3. Granites belong to the group of....
4. Pegmatites are also....
5. Dykes are intrusive bodies which....
6. Extrusive rocks have been formed from....
7. As for the origin of intrusive rocks, they...,
8. The grain size of igneous rocks may be different. For ex
ample....
16. . , :
It seems to be wrong; I don't agree with yon; I don't think so; on the contrary; that's not quite so; as far as I know
1. Igneous rocks have been formed by sedimentation. Nothing is
written about different types of these rocks.
2. One cannot explain the fact that exposed igneous rocks are
most numerous in mountain zones.
3. Granites and diorites belong to the group of extrusive rocks
and their mode of occurrence is unknown.
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4. Plutonic or abyssal rocks are extrusive rocks with grain size
less than 0.5 mm.
Unit 5_____________________________________________ 121
17. , .
1. The formation of igneous rocks and their types, (to be formed,
to solidify, to cool, either... or, magma, volcano, lava, fragmentary
rocks)
2. The grain size of igneous rocks and its dependence on the
mode of occurrence, (grain size, plutonic or abyssal rocks, extrusive
and volcanic rocks)
3. The causes of exposed rocks formation in mountain zones.
(various depths, zones of major deformation, uplifts, erosion)
4. Granites and diorites and their mode of occurrence, (intrusive
rock, to occur as..., irregular mass, stocks, dykes, occurrences, at a
certain depth) *
5. Pegmatites and their mode of occurrence, (plutonic rocks, to
occur, vein, to cut through, as well as adjacent rocks)
18. . (. . 2, . 118.)
:
1. What does Fig. 2 show?
2. What type of rocks are represented there?
3. What intrusive and extrusive occurrences does the figure show?
What can you say about each occurrence?
4. What minerals does each group of rocks represent?
1.
-, - -est. - more , - most , .
.
Unit 5
| long | longer | the longest |
| heavy | heavier | the heaviest |
| difficult | more difficult | the most difficult |
| late | later | latest |
| early | earlier | earliest |
| clearly | more clearly | most clearly |
| good | better | the best ; |
| well | ||
| bad \ | worse | the worst - |
| badly f | , ; | |
| little ; | less | the least |
| muchi |
| the most | ||
| . | ||
| far ; | farther , | the farthest) - |
| the furthest/ | ||
| further , | ||
much, far, still, a great deal, : , , , .
far more favourable conditions
far better results much more work
much more successfully
()
()
by far.
Unit 5______________________________________________ 123
Open-cast mining is by -
far the most efficient. .
1.
always , often , seldom , already , usually , sometimes , soon , never .. :
Combustible shales often -
occur as horizontal
beds. .
Coal is usually used as
fuel. .
doesn 't ever play
tennis. .
, , , :
Yesterday a group of -
students visited the -
concentration plant. .
I was very busy yesterday. .
, , , , :
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|
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a chemically pure substance ;
a highly developed industry .
3. -1
, -ly: nice nicely, great greatly, careful carefully, definite definitely, excellent excellently
.
, -1, :
UnitS
| real -direct -hard -ready large | really -directly -hardly -readil -largely - |
,
,
,
: , , -Yy. :
| higb high |
| close close , |
wide near late
wide near late
bight , ,
widely ,
nearly
lately ,
closely ,
19. ) :
[i:] be'neath, mean, heat, cleave, 'easy, 'easily, 'medium
[] some, run, such, a'bove, 'structure, 'other
[ei] 'nature, 'slate, 'layer, 'flaky, 'trace, great
[ai] 'mica, 'primary, de'fine, 'crystalline
[ou] show, low, slow, com'pose, 'process, know
[:] third, Earth, oc'cur, 'surface
[a:] marble, large
) :
gneiss (nais], chlorite ['kb:rait], phyllites ['filaits], quartzite [ 'kwo:tsait]
) :
the nature of pre-existing rock and the mechanism of the meta-
morphic deformation
an opportunity of analysing the causes of its metamorphism
to be subjected to pressure, heat and chemically active fluids
beneath the Earth's surfaqe
Unit 5
to consist of quartz, orthoclase and mica to be determined by at least four variable geologically related parameters
