The following terms you must know when taking into consideration the above-mentioned topic. Get ready for a spelling test.

UNIT 4 ROCKS AND MINERALS

COMPREHENSION

Terms

The following terms you must know when taking into consideration the above-mentioned topic. Get ready for a spelling test.

weathering                        выветривание

weathered rock (s)            выветрелая порода

erosion                              эрозия

transportation                  перенос

deposition                         отложение (осадочного материала)

sedimentary sequence       осадочный комплекс

sequence of sedimentation последовательность осадконакопления

compaction                       уплотнение

cementation                      цементация

sedimentary rock(s)          осадочная порода

metamorphism                 метаморфизм

metamorphic rock            метаморфическая порода

igneous rock(s)                 магматическая порода

effusive                             эффузивный, вулканический

intrusive                           интрузивный, плутонический

melt                                  расплав

melting                              плавка, плавление

magma                              магма

extrusion                          экструзия

intrusion                           интрузия (магмы)

Definitions

These definitions are necessary when reading and discussing the text

«ROCK CYCLE»

Weathering – the process by which Earth materials change when exposed to

conditions at or near the Earth's surface and different from the ones under

which they formed.

Weathered rocks –rocks that have undergone weathering.

Erosion – the set of all process by which particles of rock and soil are

loosened and moved.

Transportation- the movement of a particle from one location on the Earth’s

surface to another.

Mobile sediments – rock material, which can be moved by water, wind or

gravity.

Deposition – physical settling of mineral and other material from water, air,

or ice, or chemical or biological precipitation of minerals from water.

Sedimentary sequences – sediments laid down (ex. by slowing water

currents, slowing wind currents, melting ice)

Compaction – reduction of pore space between individual particles as the

result of overlying sediments or of tectonic movements.

Cementation – the process by which clastic sediments are converted into

sedimentary rock by precipitation of mineral cement between the sediment

grains, forming an integral part of the rock.

Sedimentary rocks – rocks formed by the consolidation of sediment settled

out of water, ice or air and accumulated on the Earth’s surface.

Metamorphism – the processes, which produce structural and mineralogical

changes in any type of rock in response to physical and chemical conditions

(differing from those under which the rocks originally formed). Regional

metamorphism – heat and pressure; thermal metamorphism – heat from an

intrusion.

Metamorphic rocks – rocks formed by change in heat and pressure without

melting.

Extrusive (effusive) rocks – rocks crystallized from lava (fast cooling) or

blasted from a volcano.

Melting – solid rocks becoming liquid.

Magma – molten rock that forms naturally within the Earth; comes from

partial melting of the mantle below the crust.

Extrusion – erupting magma at the surface through the volcanoes as lava,

ash and blocks (lava eruption, explosive eruption).

Intrusion – forcing of magma into other rocks and solidifying.

Intrusive rocks – rocks crystallized from magma underground.

Fig.12 Rock cycle

Read the following text and fulfill the after task exercises

THE ROCK CYCLE

Different paths and successions characterize the crustal histories of Earth materials from different geologic environments. The cycle has been repeated in variable sequence, depending on local geologic circumstances, since formation of the planet. So, what is a rock cycle?

The rock cycle is the extensive reworking of Earth’s materials. The rock cycle relates the history of formation of various units to one another, to their immediate and ultimate sources and to the continuing compositional differentiation and growth of the crust. This chemical differentiation involves crystal-melt fractionation (including partial fusion) of the uppermost mantle and lowermost crust, weathering, differential solution, mechanical and chemical transport, sedimentation and metamorphic fluid-rock chemical exchange. The following steps in the rock cycle:

1. igneous rocks crystallize at considerable depths or on the surface

2. many are eventually uplifted, weathered and eroded

3. the products of erosion are bodily transported

4. after mixing with contrasting materials, deposited as sediments

5. then lithified during and after burial

6. may be metamorphosed or even partially remelted near the base of the continental crust (the products of these changes are metamorphic and secondary plutonic igneous rocks)

Both sedimentary and metamorphic rocks are derived ultimately from igneous parents – the primary sources of crustal crust. Both sedimentary and metamorphic rocks may be subjected to the changes described above:

1. erosion and deposition as new sediments

2. granulation and recrystallization to produce metamorphic rocks

3. partial fusion giving rise to igneous rocks and residual, refractory to metamorphic.

This complex sequence of lithologic addition and reworking is repeated over and over in different orders as dictated by geologic circumstances. The process results in the increasing heterogeneity and compositional differentiation of the crust, as well as in the gradual increase in the total volume of continental mass. The entire cycle is intimately related to the deformational process. The rocks and minerals that constitute the dynamic Earth are constantly involved in the processes of breakdown and formation anew.

(Robert Lauterbach “The World of Geology -The Earth then and now” 1983 Leipzig)

VOCABULARY

path – путь

succession – последовательность (напластования)

sequence – последовательность

variable –изменчивый; непостоянный

reworking –переработка

differentiation – дифференциация; разделение

fractionation – разделение на фракции

fusion – плавление

sedimentation – осадконакопление, седиментация

fluid – флюид

exchange – обмен

crystallize (recrystallization) – кристаллизоваться (перекристаллизация)

uplift – подъем, поднятие

erode (erosion) – эродировать, разрушать (эрозия)

deposit (deposition) – отлагаться (отложение)

lithify (lithification) – литифицировать (литификация)

metamorphose (metamorphism) – изменять; превращать (метаморфизм)

remelt (remelting) – переплавлять (переплавление)

granulation – грануляция

residual – остаточный

refractory – тугоплавкий

heterogeneity – гетерогенность; неоднородность

breakdown – разрушение, распад

deform (deformation) – деформировать (деформация)

EXERCISES

Spelling dictation

Fig. 13 Rock cycle

Sedimentary, weathering (x2), source rock, path/paths, breakdown, differentiation, magma, metamorphism, lithification, cycle, processes, transport, melting, igneous, crustal, crystallization, deposition.

The geochemical (1) _________  is a (2) ____________  followed by an

individual element or group of elements in the (3) _______________  and

subcrustal regions of the Earth. During the cycle there occur

(4) ____________    – both separation of elements and elemental

recombination. For the lithosphere, the cycle begins with the

(5) ___________   of (6) ___________   at the surface or at depth.

Decomposition of the (7) _____________  rock by surface alteration and

(8) ____________    is followed by (9) ______________    and (10)

______________  of the sediment, (11) ___________    and possibly

(12) ____________  and eventually (13) __________  with the generation

of a new magma. A number of different (14) ______________  could be

followed within this idea cycle. Each element will be affected differently as the cycle progresses; for example, partial melting of

(15) ____________  rock to form a (16) ___________  separates elements

according to the melting characteristics of the constituent minerals. Magmatic

(17) ___________    processes produce a wide range of chemical

compositions among igneous rocks and in particular tend to increase the concentration of Si, Al, Ca, Na and K and other lithophile elements in the evolved magmas.

(18) _________  processes are also effective in separating chemical

components, for example, during the (19) ________  of an igneous rock,

magnesium released by the (20) ________  of ferromagnesian minerals can

be removed solution.

(The Concise Oxford Dictionary of Earth Science, Oxford University Press,

1991)

READING COMPREHENSION

PART 2

3.2.2 Read the text and fulfill the after-reading exercises. (R.P – 4.3, 4.6) Physical Properties

Physical properties of minerals are often the only guidelines for field identification of specimens that may occur combined with other minerals or in very small amounts in a particular sample.

1. Minerals grow into consistent crystal shapes, which are controlled by the chemical composition of the minerals. There are six crystal systems that include all minerals. Some mineral compounds can form more than one mineral with entirely different crystal structures. Some examples of the crystal form are:

• isometric,

• elongated,

• flattened.

Table 3 Mohs Hardness Scale

3. Color is a physical property of limited value in mineral identification. For example, quartz can be of nearly any color because of slight mineral impurities. Quartz can be cloudy, white, pink, purple, red, black, smoky, orange and brown. Color is not usually sufficient by itself to identify a mineral; however, in combination with other physical properties it can assist in mineral identification.

4. The streak of a mineral is its color in the powered form. Streak is obtained by drawing the mineral across an unglazed porcelain plate. In many minerals the streak is more diagnostic than color and is often very different from the mineral color. Minerals that are harder than the porcelain plate produce no streak.

5. Minerals have different weights relative to each other. Some are relatively heavy and others are light. Specific gravity of a mineral is its weight relative to the weight of an unequal volume of water. It is obtained by dividing the

weight of the mineral in air by the difference between its weight in air and its weight in water. Most minerals specimens are difficult to measure for specific gravity because they are usually associated with other minerals. However, very heavy or very light minerals are most easily recognized by specific gravity.

6. How a mineral reflects light determines its type of luster. Most minerals are considered to have metallic or nonmetallic luster, with a few having a submetallic luster.

Fig. 21 Conchoidal fracture

9. Some minerals have very distinctive taste qualities that facilitate their
immediate identification. Rock salt (halite) and sylvite are two minerals with
distinctive tastes.

10. A few minerals respond to common chemical reagents. Calcite responds
to hydrochloric acid. Dolomite responds weakly to hot hydrochloric acid but
reacts more when it is powered.

11. Radioactive minerals emit particles that activate various types of
detectors and counters.
(Geology Link- http://college.hmco.com\geology\resources….)

Give examples of the following physical properties of minerals FOR EXAMPLE: Quartz can be of nearly any color because of slight mineral impurities. Quartz can be cloudy, white, pink, purple, red, black, smoky, orange and brown.

1. color –                                      6. streak –

2. luster –                                     7. specific gravity –

3. hardness –                                8. taste –

4. cleavage –                                 9. chemical reagents –

5. fracture –                                  10. crystal system –

3.3 DETAILED READING – Basic rock types (R.P – 4.2) Read the following text and fulfill the following task- state which statements are T (TRUE) or F (FALSE):

Geologists recognize three main rock-forming processes, therefore, three principal classes of Earth-forming substances. In the first process, molten rock, or magma, solidifies either to glass or to an aggregate of one or more minerals, or to some combination of glass and minerals; such rocks are termed igneous. Ignis is the Latin word for “fire”; igneous rocks are, in a sense, formed from fire deep inside the Earth. Lava flows and ash falls are good examples. Sedimentary rocks consist of mechanically accumulated fragments of preexisting Earth materials, as well as, chemical or biochemical precipitations from a fluid medium. Sedimentum is the Latin for “a settling”, and sedimentary rocks have had their constituents settle out from the transporting medium, either air or, more generally, water. Such processes take place at the Earth’s surface. Metamorphic rocks include all those rocks whose original minerals or textures, or both have been altered markedly by recrystallization or deformation; metamorphism generally takes place at considerable depth within the Earth. The Greek word meta is translated as “successive” or “change”; a metamorphic rock represents a later configuration of minerals or textures different from those of the original material. (Barret E., Hunt A. And Milner B.” Earth and Atmosphere”, 1993, Longman)

 

LISTENING COMPREHENSION

TASK ONE

1. A decomposition B disintegration C weathering

2. A Chemical weathering B Physical decomposition C Physical weathering

3. A Rock failure
B Rock fissure

C Rock transformation

4. A Their roots destroy rocks

B Their branches destroy rocks

C Their fractures destroy rocks

5. A many
B a few
C few

TASK TWO

DISCUSSION

5.1 Complete the mind map. Discuss the following questions:

• What are the 2 properties of a mineral (rock)?

• What are the main features of a mineral (rock)?

• What is the definition of a mineral (rock)

MINERALS

Formulas.

Communicative formulas

 

No doubt / undoubtedly	It’s of great value / no value
It permits (the growing, the spreading) of…	I’m afraid I disagree with you I entirely agree with you
It’s the only observation method of….	One believes that
What’s the role of…	My impressions is that
This is essential for…	I think / I guess
The way (period, process) I’ve mentioned	Besides, …..
In particular	My question is whether…
At a wide (narrow) angle of view	The point is that…
For instance…	The more…the greater…

Terms

Coarse-grained-крупнозернистый	Arrangement- размещение, характер укладки
Fine-grained- мелкозернистый	Homogeneity- однородность
Crystalline- кристаллический	Texture- структура
Glassy- стекловатый	Structure- текстура
Crystal face- кристаллическая грань/плоскость	Constituent- составная часть; компонент
Bulk- валовая	Bedding- слоистость, напластование
Spatial- пространственный	Foliation- сланцеватость
Schistosity- сланцеватость	Cavity- каверна (в породе)
Abundance-    относительное содержание; масса	Vesicularity-              пористость, пузырчатость (о текстуре)

Table 4 Rocks and minerals

WORDLIST

PRONUNCIATION

TERMS

cementation

compaction

deposition

effusive

erosion

extrusion

extrusive

igneous rock(s)

intrusion

intrusive

magma

melt

metamorphic rock(s)

metamorphism

rock cycle

sedimentary rock(s)

sedimentary sequence

weathered rock(s)

weathering

WORDS AND PHRASES

breakdown

crystallize

deform (deformation)

deposit (deposition)

differentiation

erode (erosion)

exchange

fluid

fractionation

fusion

granulation

heterogeneity

lithify (lithification)

metamorphose (metamorphism)

path recrystallization

цементация

уплотнение

отложение (осадочного материала)

эффузивный, вулканический

эрозия

экструзия (магмы)

экструзивный

магматическая порода

интрузия (магмы)

интрузивный, плутонический

магма

расплав

метаморфическая порода

метаморфизм

геохимический цикл

осадочная порода

осадочный комплекс

выветрелая порода

выветривание

разрушение, распад

кристаллизироваться

деформировать (деформаця)

осаждаться (отложение)

дифференциация, разделение

эродировать (эрозия)

обмен

текучая среда, флюид

разделение на фракции

расплавление; синтез, слияние

грануляция

гетерогенность, неоднородность

литифицироваться (литификация)

подвергаться метаморфизму,

изменяться (метаморфизм)

тропа, путь, дорога

перекристаллизация

refractory                                     тугоплавкий

remelt (remelting)                         переплавляться (переплавление)

residual                                         остаточный

reworking                                     переработка

sedimentation                               осаждение, осадконакопление

to accelerate                                  ускорять

to penetrate                                  проникать внутрь

uplift                                            поднятие

variable                                        изменчивый, переменная величина

 

UNIT 4 ROCKS AND MINERALS

COMPREHENSION

Terms

The following terms you must know when taking into consideration the above-mentioned topic. Get ready for a spelling test.

weathering                        выветривание

weathered rock (s)            выветрелая порода

erosion                              эрозия

transportation                  перенос

deposition                         отложение (осадочного материала)

sedimentary sequence       осадочный комплекс

sequence of sedimentation последовательность осадконакопления

compaction                       уплотнение

cementation                      цементация

sedimentary rock(s)          осадочная порода

metamorphism                 метаморфизм

metamorphic rock            метаморфическая порода

igneous rock(s)                 магматическая порода

effusive                             эффузивный, вулканический

intrusive                           интрузивный, плутонический

melt                                  расплав

melting                              плавка, плавление

magma                              магма

extrusion                          экструзия

intrusion                           интрузия (магмы)

Definitions