Английский язык в сфере профессиональной коммуникации. Геология. Учебное пособие

IV. Прочитайте и переведите текст:

Definition of a Rock. A rock in the geological sense is the material that forms the solid crust of the earth. It includes loose incoherent masses, such as a bed of sand, gravel, clay or volcanic ash, as well as solid masses of granite, sandstone, limestone and the like. Most rocks are aggregates of one or more minerals, but some are composed entirely of natural glass or of a mixture of glass and minerals. Some may be composed of a mixture of organic compounds or of a mixture of minerals and organic material. A rock may be simple if composed of a single mineral (marble made of calcite, or quartzite made of quartz), or compound if composed of several minerals (granite made up of a mixture of feldspar, quartz, and frequently mica).

Geologists divide rocks into three great classes based on their modes of origin. These are (1) igneous rocks, solidified from molten material called magma; (2) sedimentary rocks (also called stratified rocks), laid down chiefly under water (aqueous) by mechanical, chemical, or organic agents; and a smaller group of windformed rocks (eolian); (3) metamorphic rocks, formed from original igneous or sedimentary rocks by alteration, though the action of subsequent processes which have resulted in obscuring partly or wholly the characters of the original rock.

IGNEOUS ROCKS: OCCURENCE AND ORIGIN

Igneous rocks, formed by the consolidation of molten material, have their source within the earth at some unknown depth beneath the surface. Under proper conditions this molten material is forced upward at times for one cause or another towards the surface of the earth and invades other kinds of rocks. It may be arrested at some depth below the surface where it is cooled and solidified under the influence of the surrounding rocks, or it may reach the surface and be poured out upon it, solidifying to form hard rock.

Therefore, two subdivisions of igneous rocks are recognized: 1) those that have solidified at considerable depths beneath the surface are called intrusive or plutonic;

(2) those that have solidified at or on the surface are called extrusive or volcanic.

The molten rock from which igneous rocks are formed is usually called magma when it is deep below the earth's surface and lava when it comes near the earth's surface or upon it.

Magma may be regarded as a very hot solution of certain substances. Some of them are volatile (gaseous), such as water vapor, carbon dioxide and sulphurous gases, whereas others are non — volatile mainly oxides of silicon, aluminium, iron, calcium, magnesium, potassium and sodium. These oxides produce the minerals of igneous rocks.

The relative amounts of magmatic substances vary greatly, and hence the igneous rocks produced from magmas show wide differences in both chemical and mineral composition.

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EXERCISES

V. Найдите русские эквиваленты английских слов, обращая внимание на глаголы, образованные с помощью суффиксов -fy, -ly, -en.

IX. Подберите в правом столбике термин к определениям:

X. Ответьте на вопросы:

1.What is a rock?

2.What rock is called a simple one and what rock is called a compound one?

3.What are the three great classes of rocks?

4.How are igneous rocks formed?

5.What igneous rocks are called intrusive or plutonic?

6.What igneous rocks are called extrusive or volcanic?

XI. Составьте вопросы, ответами на которые являются следующие предложения:

1.Yes, most rocks are aggregated of one or more minerals.

2.Yes, geologists divide rocks into three great classes.

3.Yes, extrusive rocks have solidified at or near the earth’s surface.

XII. Перескажите текст по плану, используя слова, данные в скобках:

1.Definition of a rock (to form the solid crust; to include loose, incoherent, solid masses, simple, compound rocks).

2.Three great classes of rocks and the mode of their origin (igneous rocks, to solidify from magma, sedimentary rocks, to lie down under water, metamorphic rocks, to form from original rocks).

3.Two subdivisions of igneous rocks (intrusive, to solidify at considerable depth, extrusive, at or near surface).

4.Chemical composition of magma (hot solution, volatile, non — volatile substances).

XIII. Прочитайте текст без словаря и выполните тесты:

Igneous rocks are one of the three great classes of rocks that make up the crust of our planet. They have been formed at high temperature by solidification of molten material on cooling. Such molten material is discharged (выделяется) as streams (потоки) of lava from many volcanoes and at such places we can see the formation of igneous rocks.

Molten matter rising from the depths and which is highly charged (насыщена) with gases is called magma. There are many kinds of magmas and they vary widely in composition: for example, the magma erupted (извергаться) bу Vesuvius differs greatly from that discharged by Etna.

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There are two principal modes of occurrence of igneous rocks: the intrusive and the extrusive. In forming intrusive rocks magma rises from depths of the Earth to higher levels of the crust but it does not reach the surface. It cools and solidifies deep underground. In forming extrusive rocks magma reaches the surface by being erupted from volcanoes on the Earth’s surface where it solidifies. Extrusive rocks are composed mainly of microscopic mineral crystals and glass.

It is clear that intrusive and extrusive rocks are formed in quite different geologic conditions. In intrusive bodies the magma cools and consolidates very rapidly. Nevertheless (тем не менее) intrusive and extrusive rocks are closely connected and pass (переходят) from one into the other.

XIV. Определите какой из заголовков соответствует прочитанному тексту:

1.The composition of igneous rocks.

2.Intrusive rocks.

3.Igneous rocks.

XV. Укажите номера предложений, в которых содержатся ответы на вопросы:

a.Under what conditions have igneous rocks been formed?

b.Where can we see the formation of igneous rocks?

c.What is magma?

d.How are intrusive rooks formed?

e.How are extrusive rocks formed?

f.Are intrusive and extrusive rooks closely connected?

XVI. Расскажите на английском языке о различии в образовании интрузивных и эффузивных пород.

XVII. Прочитайте текст и передайте его содержание на английском языке:

IGNEOUS ROCKS

Igneous rocks have been formed from molten material that solidified on cooling. The molten rock material is called lava or magma which varies widely in composition.

There are two subdivisions of igneous rocks: there are extrusive and intrusive rocks. The extrusive or volcanic igneous rocks are rocks which solidified from magma, on the surface of the Earth or near it.

The intrusive or plutonic rocks which hardened from molten material deep below the Earth’s surface. The intrusive and extrusive rocks are closely connected and pass from one into the other.

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Composition. The numerous analyses made of igneous rocks from all parts of the world show them to be chiefly silicate magmas. Analyses further show that igneous rocks are composed of acid-forming oxide, silica (SiO2); and of the metallic oxides (bases), alumina (Al2O3); iron oxides (FeO and Fe2O3); magnesia (Mg); lime (CaO); soda (Na2O); and potash (K2O).

Mineral composition. Most igneous rocks are aggregates of minerals, a few are composed wholly of glass and still others are made up of a mixture of minerals and glass. The important groups of these include feldspars, quartz, and the ferromagnesian minerals.

EXERCISES

IV. Найдите в списках слов А и В синонимы:

A.1. principal, 2. bedding, 3. stratified, 4. fragmental, 5. variety, 6. expose,

7.Stratum.

B.a. type, b. bedded, c. clastic, d. outcrop, e. bed, f. stratification, g. chief.

V. Найдите в списках слов А и В антонимы:

A.1. fine-grained, 2. result in, 3. below, 4. huge, 5. molten.

B.a. above, b. small, c. solidified, d. coarse-grained, e. result from.

VI. Образуйте существительные и переведите их на русский язык:

IX. Подберите в правом столбике термин к определениям:

3.A lenticular or dome-shaped mass of magma intruded e. intrusive sheet between strata.

4.Huge masses of intrusive igneous rocks, generally composed

of granite which now are exposed at the surface by erosion.

5. Molten material erupted from a volcanic vent and solidified.

X. Перескажите текст по вопросам:

1.What are the principal modes of occurrence of intrusive igneous rocks?

2.What is a dike?

3.What is an intrusive sheet?

4.What is a laccolith and what is its typical form?

5.What is a batholith and what rocks does it usually consist of?

6.How are extrusive rocks formed?

7.What is the composition of igneous rocks?

XI. Поставьте вопросы к подчеркнутым членам предложения:

a.Dikes are formed by filling fissures of other rocks by molten material.

b.Batholiths commonly consist of granite.

XII. Прочитайте текст без словаря и выполните тесты:

The intrusive igneous rocks are structural elements in the architecture of the crust. There are six principal kinds of them: dikes, sills, laccoliths, batholiths, volcanic necks and stocks (штоки).

The simplest form of an intrusive rock is a dike. A dike is a mass of igneous rock, which in a molten condition was forced (проникла) into a fissure within the

Earth’s crust and consolidated there. Dikes vary in length from a few feet to fifty or hundred miles and in width from a few inches to two or three hundred feet. They may be composed of almost any kind of igneous or metamorphic rocks.

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Sills. Where a mass of molten material has been forced in the form of a sheet between beds it cools to form an intrusive sill. A sill is a special kind of a dike. Sills may lie in horizontal or inclined positions. They vary greatly in thickness and their extent may be many square miles.

Laccoliths. A laccoliths is a dome-shaped mass of rock which in molten condition has been forced between strata, arching up (изгибать) the overlying beds.

Batholiths. Batholiths are gigantic masses of igneous rocks, generally composed of granite or granodiorite.

XIII. Определите какой из заголовков соответствует содержанию прочитанного текста:

1.Intrusive forms of igneous rocks.

2.Extrusive igneous rocks.

3.Sills.

XIV. Определите какие предложения соответствуют содержанию текста:

1.There are two modes of occurrence of igneous rocks.

2.There are six principal kinds of intrusive rocks.

3.Extrusive rocks are formed by consolidation of molten material on or near the Earth’s surface.

4.Dikes may be composed of any kind of igneous or metamorphic rocks.

5.Batholiths are the largest masses of intensive igneous rocks.

6.Dikes are the simplest form of intrusive rooks.

XV. Напишите краткое содержание прочитанного текста.

XVI. Прочитайте текст:

Intrusive rocks form various structures, such as sills, dikes, laccoliths and batholiths.

Batholiths are the largest of them. They are formed when solidifies at considerable depth. They are composed of acid rocks of granite type. They form roots of mountains and are exposed by erosion.

A laccolith is an intrusion of igneous rock into sedimentary rock. They are dome-shaped bodies and they arch up the overlying rocks into the form of domes. Their diameter varies from hundreds of meters to several kilometers.

Sills and dikes may be from some inches to many feet thick. The type of rock which is usually found in sills and dikes is dark-coloured and fine-grained and is usually called diabase.

XVII. Ответьте на вопросы:

1.What structures of intrusive rocks do you know?

2.At what depth are batholith formed?

3.Of what rocks are batholith composed?

4.How are batholith exposed?

5.Of what form are laccolith and what is their diameter?

6.What type of rock is characteristic of sills and dikes and how is it called?

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