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m etam orphism is determ ined by four ... param eters.

22. Переведите наречия, образованные от прилагательных с помощью суффикса -1у.

chief главный —chiefly..., generalобщий, основной —gener- ally ..., commonобщий —commonly..., originalпервоначальный

— originally ..., particular особенный —particularly ..., practical

практический, фактический practically— ..., usual обычный —

usually..., wideширокий —widely...

23. Прочитайте следующие сочетавм слов. Переведите их:

24.Определите значения выделенных слов по сходству их корней с соответствующих слов в русском языке:

m etam orphicrocks; som e changes texture;in in m ineral composition andstructure;the description ofm etam orphismschistose; structure; the roleof water; four variableg ologicallyrelatedpa-

ram eters;flakym aterials; the m echanism of m etam orphic deform- a tion; crystallineschists; the greatdislocationsof the Earth's crust; duringnorm al progressive m etam orphism

25. Прочитайте текст Б и найдите в нем ответы на следующие вопросы:

1.W hat is m etam orphism?

2.Why can metamorphic rocks cleave easily?

3.Why is the study of metamorphic rocks important?

ТЕКСТ Б

Metam orphic Rocks

The problem discussed concerns metamorphic rocks which compose the third large family of rocks. "Metamorphic" means "changed frop". It shows that the original^ rock has been changed from its primary form to a new one. Being Subjected to, pressure, heat and chemically active fluids beneath the Earth's surface, various rocks in the Earth's crust rundergo changes in texture, in mineral corhpositioh and structure and are transformed into metamorphic rocks. The process describeci is called metamorphism.

As is known, metamorphic rocks have been developed from ear lier igneous and sedimentary rocks by the action of heat and pressure. ^ Gneisses, mica schists, phyllites, marries, slate, quartz, etc. belong to the 7sarhe group of rocks, ija'yirijj the same mineral cdniposition as granite, gneisses consist chiefly of quartz, orthoclase andl mica^. However uhMe granite, they have a schistose structure. It rtfeans tjjat their constituents are Aisfnbutejdf in bands or layers and rar^ parallel to each other in one'Direction. If 4|sjturbed jhe rock Cleaves easily into separate plates.

The role of water in rnetamorphism is deterrnine^ by at least four v^riaDle'geologically refuted parameters: rock pressure, temperature .water pressure, and the am'oimt of water present.

? During a normal progressive metamorphism rock pressure and temperature are iriterciependent, and the amount of water and the pressure of water arejrela|e<! ?t^ the sediments and to the degree of metamorphism in'such a^way'tfiat, gerienBry. speaking, the low-grade metamorphic rocks are characterized by the excess of water. The mediumgrade rocks defined by some deficiency of water and the high-grade metamorphic rocks are characterized by the absence of water.

Many of the metamorphic rocks -mentioned above consjst,of flaky materials such as mica and chlorite. These minerals cause the' rock to split into thin sheets, and rocks become foliated.сг-оисъи

Slate, phyllite, schist and gneiss belfcng to the group of foliated metamorphic rocks. Marble and quartzite are non-foliated metamor phic rocks,

The structure of nietamo,rphic rocks is of importance because it shows the nature of i>re-existmg j;ocks and the mechanism of metamorphic deformation. Every trace ofc/6nginal structure is of great importance to geologists. It gives an opportunity of analysing the causes of its metamorphism.

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Being often called crystalline schists, metamorphic rocks such asi gneisses and mica have a schistose structure. Metamorphic rocks represent the oldest portion of the Earth's crust. They are mostly found in the regions of mountain belts where great dislocations on the Earth once took place.

УПРАЖНЕНИЯ

26. Укажите, какие предложен» соответствуют содержанию текста Б. Подтвердите свои ответы фактами из текста.

1.Generally speaking, metamorphic rocks have been developed from ores.

2.Marble, slate and phyllite belong to the group of metamor phic rocks.

3.As is known, unlike granite metamorphic rocks have a schis tose structure.

4.It is quite obvious that the role of water in metamorphism is

great.

5.As a rule, low-grade metamorphic rocks are characterized by the absence of water.

6.Flaky materials cause the rock to split into thin sheets.

7.It should be noted that marble and quartzite are foliated metamorphic rocks.

8.The structure of metamorphic rocks shows the nature of older pre existing rocks and the mechanism of metamorphic deformation as well.

9.All metamorphic rocks are non-foliated.

27.Ответьте на следующие вопросы:

1.Do you know how metamorphic rocks have been formed?

2.Which rocks belong to the group of metamorphic?

3.Does gneiss have the same structure as granite?

4.Is the role of water great in metamorphism?

5.What rocks do we call foliated? What can you say about nonfoliated metamorphic rocks?

6.How can geologists trace the original structure of metamorphic

rocks?

7.Why are metamorphic rocks often called crystalline schists?

28.i) Найдите в правой колонке русские эквиваленты следующих слов и сочетаний слов:

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to cause more complex and varied changes to penetrate deeper

to become more and more destroyed to decompose at a slower rate

There are deeper and wider cracks.

The action of plants is even more destructive.

6) Переведете сочетаем слов с врвлагателшшв в варешмв в сравветелыюй стевевв, обравша вввмавве ва случав усвяеввл сраввеввв:

to be more than 0.5 mm

to intrude into older pre-existing rocks to have even finer grains

less than 0.5 mm

to form smaller rock masses to be much longer

to cool much more rapidly to cool more slowly

to crystallize to a larger-grain size coarse-grained intrusive rocks

31. а) Подберете вз сввсков А в Б блвзкве во звачеввю слова:

б) Подберете вз сввсков А в Б протввоволожвые во эвачеввю слова.

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32. а) Прочитайте следующие сочетания слов с причастием прошедшего времени в функции правого определения и переведите их.

Образец: The equipment used is ...— используемое оборудование является ...

1.New sources of fueldescribedncluded ....

2.Modern colliery visited used ....

3.Economic achievements written about are ... .

4.Average coal output of the quarry designed will reach ....

6)Прочитайте следующие предложения. Найдите в каждом из них группу «подлежащее-сказуемое». Определите функции слов с суффиксом -ed:

l.The prospecting party provided with new equipment planned to begin its work in spring.

2. The prospecting party provided new data on useful minerals discovered in the region.

З.Тпе prospecting party is provided with new equipment. 4. The rocks described represented the oldest portion of the Earth's crust.

33. Заполните пропуски в предложениях, употребив данный в скобках глагол в соответствующем времени н залоге:

4. W ater greatly... the decom position of rocks. It is quite obvious that weathering ... by the action of water,(to facilitate)

34. Определите, какие функции в предложении выполняют совпадающие по форме выделенные слова. Переведите предложения:

1. The term "prospecting" includes the whole range ofgeologi cal workdirectedto discovering deposits of valuable m inerals. The Moscow Mining Academydirectedthe activities of the Academy 's research institutions.

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2. Limestones occupied vast areas of the Earth's surface. It is quite obvious that the regions occupied by limestones have been covered by seas.

3. Modern deposits of Kamchatka volcanoes investigated by Russian geologists show that volcanism is active there. The Institute of Volcanology of the Siberian Department of the Academy of Sciences investigated friable (рыхлый) volcanic deposits of Kamchatka.

4. The clayey mass obtained by the decomposition of orthoclase is white and is called kaolin. Chemists obtained phosphorus from phosphorite.

35. П ереведите предлож ения, обращ ая вним ание на перевод причастия прош едш его времени.

Образец 1: Them iningm ethoduseddependson m any factors. -»Используемыйметод разработки зависит от многих факторов.

1.The problems discussed are connected with the investigations of the Earth's crust depths.

2.Metamorphic rocks described represent the oldest part of the Earth's crust.

3.The process of metamorphism mentioned above creates such minerals as tremolite, sillimanite and others which are uncommon in sedimentary and igneous rocks.

4.In all the mines visited automated computerised control sys tems were used.

5.A new system of planning employed gives an opportunity of supplying correct information quickly which is essential for man agement control of modern mines.

Образец 2: When burnt, coal produced heat. -> При сжигании уголь выделяет тепло.

1.If disturbed, rocks cleave easily into separate plates.

2.When needed the additional experiments are carried out.

3.When subjected to pressure, heat and chemically active fluids, various rpcks in the Earth's crust are transformed into metamorphic rocks.

36.Н айдите в тексте Б и вы пиш ите причастия прош едш его врем ени в функции правого определения.

37.П ереведите предложения, используя сочетания слов:

to be form ed; to belong to; toik e;betol be of v alue; to giv e an opportunity

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of; unlik e; to be of im portance; pre-ex isting rock s; schistose structure; to determ ine

1.Метаморфические породы образовались из извержен-ных

иосадочных пород.

2.Гнейс, сланец, мрамор и другие породы относятся к группе метаморфических пород.

3.Гнейс похож на гранит, но, в отличие от гранита, он имеет слоистую структуру.

4.Вообще говоря, описанные метаморфические породы имеют большое значение, так как их структура дает возмож ность установить следы существовавших ранее пород.

38. Задайтевопросыпообразцу.

Образец: Metamorphic rocks are mostly found in the regions of mountain belts, (where?) -> Where are metamorphic rocks mostly found?

1.Metamorphic rocks have been developed from earlier igne ous and sedimentary rocks, (what rocks?)

2.The constituents of gneisses are distributed in bands or layers.

(how?)

3.Mica and chlorite cause the rock to split into thin sheets, (what materials?)

4.The structure of metamorphic rocks is of importance, (why?)

39. Закончите предложения подходящими по смыслу слотами из текста Б:

1.As for the origin of metamorphic rocks they ....

2.When we say that a mineral has a schistose structure it means ... .

3.It should be noted that the role of water in the formation of metamorphic rocks is great. It is known that high-grade metamorphic rocks are characterized by the absence of water while medium-grade rocks... .

4.Geologists should know every trace of the original structure of metamorphic rocks because ....

40. Суммируйте содержание текста Б, используя слова в скобках:

1.The process of metamorphism. (to mean, to show, to undergo changes, to be transformed, to call)

2.The role of water in the formation of metamorphic rocks, (to be interdependent, to be related to, in such a way, generally speaking, to be characterized by)

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3.The difference between foliated and non-foliated metamor phic rocks,(flaky, to cause, to split into, to cleave)

4.The structure of metamorphic rocks,(to be of importance, trace, pre-existing rocks, to give an opportunity of)

41. Расскажите коротко (8-10 предложений), что вы знаете о горных породах в земной коре, об их происхождении, залегания н минералах, которыми они богаты. Используйте данную ниже схему н следующие разговорные формулы:

as for as I know; as is known; as for; I'd like to say a few words about...; it should be noted that...; as a rule; generally speaking и др.

Practical value of each type of rocks (metals they are rich in)

42. Прочитайте текст В без словаря и скажите, о чем ои.

Слова для понимания текста:

profit — прибыль; польза residual — осадочный

alloy — сплав cast iron— чу гу н

ТЕКСТ В

Minerals that make up rocks, are defined as inorganic substances which occur naturally and have a definite chemical composition and physical properties which vary within known limits.

The major properties are colour, crystal form, hardness, cleavage and others. Cleavage is one of the most diagnostically useful mineralogical properties which can be found throughout the mineral.

Minerals of use to man can be grouped into two broad categories: 1) metals, such as aluminium, copper, gold, silver, iron, tin, platinum, chromium, nickel, lead and zinc, and 2) non-me- tallic minerals, such as diamonds, salt, limestone, cement, sulphur, and asbestos. When minerals occur so that they can be worked at a profit they are called ore deposits. Mineral deposits are seldom equally rich throughout.

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Economic minerals are those which are of economic importance and include both metallic and non-metallic minerals.

Most minerals consist of several elements. Such elements are oxygen, silicon, titanium, aluminium, iron, magnesium, calcium, sodium, potassium and hydrogen. They make up more than 99 per cent by weight of all the rock-forming minerals. Of these, aluminium, iron and magnesium are industrial metals. The other metals are present in small quantities, mostly in igneous rocks.

For example, iron is one of the most abundant metals in the Earth's crust. There are three important classes of iron deposits: deposits associated with igneous rocks; residual deposits and sedimentary deposits. Iron deposits associated with igneous rocks are usually small but very rich bodies either of haematite or magnetite. Large concentrations have been successfully mined in Pennsylvania (the USA) and in the Russian Federation.

Residual deposits of iron minerals are formed wherever weathering occurs. Iron deposits formed this way are very widespread. It should be stressed that the residual deposits were among the first to be exploited by man.

Sedimentary iron deposits make up most of the world's current production.

As the essential component of every variety of steel, iron is obviously the most important of all industrial metals. It has played a large part in the development of our modern civilization. Iron ores are mainly used for producing cast iron, steels and ferro-alloys. From a scientific point of view, iron's most important property is that it becomes magnetized.

The magnetic iron ore is the main wealth of the Kursk Magnetic Anomaly (KMA). It is necessary to say that only in the last century was the secret of the unusual magnetism of enormous iron ore masses discovered underground.

Iron fields are worked by surface mining which is more economical. But the KMA is rich not only in iron ores. Its deposits contain bauxite, phosphorite, cement, sand and clays.

43. Р азд ел и тетек с тВ м л о ги ч е ск иче ас ти. В к а жд о й ис та те к ста вайднте предложение, передающее ее основную мысль. Озаглавьте каждую часть текста В .

44. Найдите в тексте В ответы на следующие вопросы:

1.Why is cleavage the most important property of minerals?

2.How can ore deposits be defined?