1. Ответьте на следующие вопросы по тексту:

   1. What groups can all minerals be divided into?

   2. What is the ore?

   3. What groups can rock-forming minerals be divided into?

   4. What minerals are called essential?

   5. What is silicate?

   6. What is the basis for silicates classification?

   7. What is the second most common of all the elements? Where does it occur?

   8. What other elements are common?

   9. Are the rarer elements scattered in sands?

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

3. Составьте вопросы, ответами на которые послужат следующие предложения:

1. Yes, it is. Mineral is any of a class of naturally occurring solid inorganic substances.

2. Yes, they can. All minerals can be divided into the ores and the rock-forming minerals.

3. Yes, they are. The accessory minerals present only in small quantities.

4. Yes, it is. Silicate is a salt.

5. Yes, they do. Silicates constitute a large proportion of the earth’s minerals.

6. Yes, it has. The basis for this grouping has been confirmed by their atomic structure research.

7. Yes, it does. The science of geology also focuses on the study of all the elements distribution.

8. Yes, they are. The rarer elements are also scattered through the rocks.

9. Yes, they are. The next most common elements are aluminium, iron, sulphur, etc.

TEXT 2.5.

VOCABULARY WORK:

• Запомните следующие слова:

Научный вокабуляр:

copper ['kOpq] - медь

sulphide ['sAlfaId] - сульфид, сернистое соединение

platinum ['plxtInqm] - платина

arsenide ['Rsq‚naId] - арсенид

telluride ['telju‚raId] - теллурид

oxide ['OksaId] - окись; оксид

titaniferous [‚taItq'nIfqrqs] magnetite - титаномагнетит

chromite ['krqumaIt] - хромит; хромистый железняк

galena [gq'lJnq] - галенит (минерал, сульфид свинца с ярким серебряно-белым металлическим блеском)

chrome [krqum] iron ['aIqn] - хромистое железо

orebody [‚L'bOdI] - рудное тело

chalcopyrite [‚kxlkq'paIraIt] - халькопирит, медный колчедан

barium ['beqrIqm] - барий

tin [tIn] - олово

fluorite ['fluqraIt] - флюорит, плавиковый шпат

topaz ['tqu‚pxz] - топаз

lithia ['lITIq] - литин, окись лития

wolfram ['wulfrqm] - вольфрам

vein [veIn] - жила

iron pyrites [paIraItJz] - пирит, серный [железный] колчедан

Общеязыковой вокабуляр:

conductor [kqn'dAktq] - проводник

electropositive [I‚lqktrqu'pOzItIv] - электроположительный

compound ['kOmpaund] - соединение

precipitate [prI'sIpI‚teIt] - осаждаться

predominant [prI'dOmInqnt] - преобладающий

give off - выделять, испускать

vapour ['veIpq] - пар; пары; испарения

associate [q'squsI‚eIt] - ассоциировать, связывать

deposition [‚depq'zISn] - отложение, осаждение

correlate ['kOrq‚leIt] - находиться в связи

otherwise ['ADq‚waIz] - иначе

intimately ['IntImqtlI] - близкий, тесный

• Прочтите следующий текст и переведите его:

Ore Minerals

It is common knowledge that metals are any of a number of chemical elements, such as iron or copper, that are often lustrous ductile solids, have basic oxides, form positive ions, and are good conductors of heat and electricity. For the most part metals are deposited in the deeper regions, largely as sulphides. Sulphide is a compound of sulphur with a more electropositive element. Metals can also be precipitated in the original form, as is the case with gold, platinum, and copper. They may form rarer combinations, such as arsenides, tellurides, etc. What’s more they may be deposited as oxides. Oxide is any compound of oxygen with another element.

Oxides formation usually takes place at the surface, as for the sulphides, they are the deeper regions natural products. As a matter of fact sulphides generally change into oxides during weathering. But oxides can also be produced under the opposite extreme conditions from those predominant closer to the surface, to be more exact, considerable heat and high pressure, and the presence of strong solutions and vapours.

As it is known hematite is an oxide of iron often deposited from gases in volcanoes. Magnetite and hematite are also found in contact deposits, formed by the highly concentrated, heated and compressed solutions and vapours given off from cooling masses of magma.

Within slowly solidifying rock magmas, oxides of iron (magnetite and titaniferous magnetite) and probably oxides of iron and chromium (chromite, chrome iron) are accumulated to such an extent as to form orebodies. It should be noted that these oxide orebodies may also occur on or near the contact with the igneous rock or near by, in the intruded rock. Since their temperature of consolidation is nearly that of the igneous rocks, the oxide orebodies are more closely associated with them than are the sulphide ores.

There are more or less marked associations between different minerals in ore deposits due to chemical affinities (the fact of having similar properties of solution and deposition).

Lead and silver are closely correlated. Galena is a grey mineral, found in hydrothermal veins. It is the chief source of lead. Most galena contains a greater or smaller amount of silver. By and large lead, zinc and iron are closely associated and often occur together.

Copper and iron, whether in the common form of chalcopyrite (sulphide of copper and iron) or otherwise, are intimately associated as well. Lead and barium are frequently related, too. Among the metals and minerals possessing commercial value which often occur in company with tin are tourmaline, fluorite, topaz, lithia, mica and wolfram.

On the whole gold is frequently found in veins of quartz and is especially associated with iron pyrites.

Комментарии к тексту:

lustrous ['lAstrqs] ductile ['dAktaIl] solids - блестящее поддающееся обработке твердое тело

basic ['beIsIk] oxide - основной оксид, оксид основного характера

as a matter ['mxtq] of fact - фактически, на самом деле

opposite ['OpqzIt] extreme [Ik'strJm] conditions [kqn'dISnz] - противоположные экстремальные условия

to be more exact [Ig'zxkt] - если быть более точным

high pressure - высокое давление

contact ['kOntxkt] deposit - контактовое месторождение

highly concentrated ['kOnsn‚treItId] - высоко концентрированный

compressed [kqm'prest] solution [sq'lHSn] - сжатый раствор

to such an extent [Ik'stent] - в такой степени, в такой мере

chemical affinity [q'fInqtI] - химическое сродство

chief [CJf] source [sLs] - основной источник

by and large [lRG] - в общем и целом, в общем

READING COMPREHENSION