1. Ответьте на следующие вопросы по тексту:

   1. What classes of sedimentary rocks do you know?

   2. What sediments are called mechanical?

   3. What sediments are called organic?

   4. What sediments are called chemical?

   5. How can the organic and chemical sediments be subdivided further?

   6. What is a pebble?

   7. What types of pebbles can one find in nature?

   8. What is breccia?

   9. What do most sand grains consist of?

   10. What does far travelled sand contain?

   11. What do wind-borne sands contain?

   12. What is specific gravity?

   13. What specific gravity do heavy minerals have?

2. Найдите в тексте предложения, содержащие словосочетания из комментариев и переведите их письменно. Составьте свои предложения с этими словосочетаниями.

3. Выразите свое согласие или несогласие со следующими утверждениями, используя разговорные формулы:

That’s right

Agreed

Certainly

Of course

You’re absolutely right

That’s what I thought too

Yes, but don’t you think

Yes, but on the other hand

No, I’m afraid not

I don’t particularly like

I’d really rather not

I’m afraid, I can’t agree with you

1. Sedimentary rocks are classified in accordance with their origin.

2. The mechanical sediments cannot be further subdivided according to the size of their constituent parts.

3. Pebbles are larger than cobbles but smaller than granites.

4. Beach and river pebbles have the same form.

5. Angular fragments are called sedimentary breccias.

6. Most sand grains consist of feldspar and muscovite.

4. Вставьте следующие слова в текст:

layered igneous action crust sandstone conditions

chemicals sedimentary conglomerates kinds metamorphic

Sedimentary rocks

All rocks which can be found in the Earth’s … can be divided into three groups: sedimentary, igneous and metamorphic. … rocks consist of particles or fragments of pre-existing rocks. … rocks have solidified from magma. … rocks take their origin from either sedimentary or igneous rocks. Most sedimentary rocks are … . Sediments are formed by the … water, heat and organisms. Such sediments as clay, sand and gravel can be transformed into … . The most principal … of sedimentary rocks are conglomerate, shale, limestone, dolomite, siltstone and … . Sedimentary rocks provide evidence that for at least billion years … on the earth’s surface were very similar to the conditions of today. The sun, rain, wind, water and … were changing the surface rocks and they keep on changing them now.

5. Опишите основные особенности осадочных горных пород, пользуясь следующей схемой:

TEXT 4.2.

VOCABULARY WORK:

• Запомните следующие слова:

Научный вокабуляр:

glacier ['glxsIq] - глетчер, ледник

settle ['setl] - оседать, садиться, опускаться вниз

suspension [sq'spenSn] - взвешенное состояние; суспензия; взвесь

buoyancy ['bOIqnsI] - плавучесть; способность держаться на поверхности воды

dispersion [dI'spE:Sn] - разбрасывание; рассеивание

silica ['sIlIkq] - кварц, кремнезём

Общеязыковой вокабуляр:

occur [q'kE:] - происходить, случаться, совершаться

mountain ['mauntIn] - гора

mud [mAd] - грязь

reach [rJC] - достигать

likewise ['laIkwaIz] - подобно

solution [sq'lHSn] - раствор

precipitated [prI'sIpI‚teItId] - осаждённый

mixture ['mIksCq] - смесь

especially [I'speSlI] - особенно, в особенности, главным образом

quantity ['kwOntqtI] - количество

annually ['xnjuqlI] - ежегодно

constantly ['kOnstqntlI] - непрерывно, постоянно

estimate ['estI‚meIt] - оценивать; подсчитывать

• Прочтите следующий текст и переведите его:

The Formation of Sediments

The formation of the sediments occurs thanks to the action of heat, organisms and mainly water (streams, rivers, glaciers, lakes and seas). Water running down the mountains makes deep valleys in the solid rocks. Owing to rivers the mud is carried to the sea. On reaching the sea the coarse gravel is usually deposited near the river mouths, while the finer material is carried further on. In lakes, the material which has been brought down by the streams likewise settles on the bottom.

Surface waters carry many substances in suspension, that is a dispersion of fine solid particles in a fluid, particles being supported by buoyancy, for example mud, sand or gravel. What’s more the surface waters contain substances in solution, that is a homogeneous mixture of two or more substances in which the molecules or atoms of the substances are completely dispersed. The constituents can be solids, liquids, or gases. In limestone districts, for example, the waters contain lime. Other minerals are as chemically precipitated in ocean and lake waters as well, especially silica, but all in a far less degree. Rivers are constantly bringing large quantities of mineral matter to the sea, both in suspension and solution.

It has been estimated that annually 2,735,000,000 tons of mineral substances are added in solutions to the oceans from all the world rivers.

Комментарии к тексту:

coarse [kLs] gravel - крупный гравий, галечник

river mouth [mauT] - устье реки

fine material [mq'tIqrIql] - мелкозернистый материал

further ['fE:Dq] on - далее

on the bottom ['bOtqm] - на дне

surface ['sE:fIs] water - наземная, поверхностная вода

in a far less degree - в гораздо меньшей степени

READING COMPREHENSION