Exercises:

1. Answer the questions:

1. What are minerals in the dietary sense?

2. What do mineralogists call a mineral?

3. How many criteria must a mineral meet?

4. What are these criteria?

2. Translate into English:

1. Багато людей не знає геологічного визначення для мінералу.

2. Мінерал повинен бути неорганічною речовиною.

3. Більшість мінералів володіє усіма чотирма необхідними властивостями.

3. Retell the text.

31. How we use minerals

The minerals that make up rocks can be very useful. How we use the minerals depends on their properties.

The mineral graphite is soft. This makes it a perfect choice for what you use it for almost every day. The black stuff in your pencil is made of graphite. Because it’s soft, it will rub off on your paper as you write. The line you draw on your paper is the true color of the graphite.

Diamonds are also used for other things besides jewelry. Diamonds are the hardest of all minerals. This makes them good for drilling or cutting other hard materials such as rocks. Drill bits are coated with diamond dust. This makes them able to drill through very hard rock.

32. Plate tectonics model

From the mapping of earthquake foci, geologists have inferred that Earth’s crust is made up of large moving pieces called plates. As the plates move, they interact with one another at their boundaries. They collide at convergent boundaries, move away from each other at divergent boundaries, or slide past each other at transform boundaries.

Different processes take place at each type of boundary. At transform boundaries, rocks move along strike - slip faults. At colliding boundaries, one plate is forced down beneath another plate, melting the crust on the leading edge of the plate in a process called subduction. At divergent boundaries, new crust is formed along rifts in the crust. Patterns of magnetized rock show that old rock is pushed to other side of a rift as new rock forms. When the rift is on an ocean floor, sea-floor spreading takes place.

Scientists have synthesized evidence from rocks, fossils, and earthquake to formulate the current model of Earth: plate tectonics. In this model, Earth’s plates are moved by convection currents in the underlying upper crust. As the plates move and interact with one another, new crust is formed and old crust is destroyed. In this way, Earth’s crust is continually recycled. The plate tectonics model explains many Earth processes because it is based on many kinds of evidence. Like all models, however, this model will need to be modified as more evidence becomes available.

Exercises:

1. Answer the questions:

1. How do the plates interact?

2. What types of boundaries do you know?

3. What is the current model of Earth?

4. Why does the plate tectonics model explain many Earth processes?

2. Translate into English:

1. Земна кора сформована з великих кусків, що рухаються, які називають платформами.

2. Різні процеси відбуваються у кожному типі границь.

3. Вчені синтезували отримані данні, та сформулювали сучасну модель землі.

3. Retell the text.

33. THE WORK OF EROSION

The earth's crust is about 30 miles thick, but the rocks are not of the same thickness in all points of the earth which can be physically described as a ball of rock, partly covered by water and wrapped in an envelope of air. The crust of our earth undergoes slow but great alteration.

Erosion may be defined as the process of wearing away. As applied to geology, it signifies the wearing away of the rocks at the surface, chiefly by the action of streams or waves. Exposed rocks break up at the surface under the influence of heat and cold, frost and thaw, rain and wind, the roots of trees and plants, and the decomposing acids, chiefly derived from vegetation, which soak down into the rocks and attack them. The result is that such rocks crumble into sand and clay. Vegetation takes root, flourishes and dies, and new generations of plants arise; thus a top loam is formed, by the accumulation of vegetable remains. On account of its looseness, it usually moves downhill, into the valleys, and out towards the sea.

In mountains, running water wears deeply instead of widely, producing deep gorges and valleys in the solid rock. Between the gorges the rock remains as hills, even as mountains. Many mountains have this origin. The region which has been covered by glaciers shows a characteristic type of erosion, which has resulted in an irregular surface, with many lakes. There are many other peculiar types of erosion, produced in various ways such as the fretting of rocks on the seashore by waves. In the desert, driving sand has also been responsible for erosion.

Notes:

the process of wearing away – процес руйнування

which has resulted in – яка призвела до утворення

produced in various ways – викликана різними шляхами

Exercises:

1. Get ready to answer the following questions:

1. What is the thickness of the earth’s crust?

2. How may erosion be defined?

3. What does erosion signify?

4. What types of erosion do you know?

5.What does running water do in mountains?

2. Translate into English:

1. А.Карпінський описав геологічне минуле європейської частини нашої країни.

2. Територія сучасного Донбасу раніше була затокою великого моря.

3. Великі дерева та інші рослини росли на узбережжі цього моря.

4. Товщина земної кори складає 30 миль.

3. Get ready to retell the text.

34. FOLDS AND FAULTS.

Physical forces produce changes in the earth’s crust. They produce bending and breaking in the rocks. A fold is a bend in the rocks. Folds are chiefly divided into two kinds, according to whether they are open above or below. These are called, respectively, synclines and anticlines. A fault is a break in the rocks. Faulting generally takes place along a plane or narrow zone along which the rock mass on one side slips relatively to that on the other side. This is the fault plane, or the fault zone.

The inclination of a bed, vein, dike, fault, etc., is called the dip, which is measured in degrees from the horizontal. The strike is the direction of a horizontal line which lies within the plane of the bed, vein, dike or fault. The upper side of a vein, dike or fault is called by miners and geologist the hanging wall; the lower side is the footwall.

Most fault planes have an inclination or dip somewhere between the horizontal and vertical. When the rocks on the upper side have moved down relative to the rock on the under side, the fault is called normal. If the reverse movement has taken place, the fault is called a reversed or thrust fault. The majority of faults are normal, but reversed faults are frequent. Speaking broadly, faulting is apt to have taken place more freely in a shallow zone of the crust, from the surface down for some thousands of feet. Here the rocks are brittle. Many thousands of feet down, sedimentary rocks tend to buckle and yield by slow plastic movement, producing much folding. At great depths the pressure and the gases make the rocks still more plastic, and they yield by stow general flowage, producing gneisses.

Notes:

hanging wall – висячий бік, покрівля

footwall – лежачий бік, грунт

faulting is apt to have taken place more freely – скиди мають схильність до більш численних утворень

sedimentary rocks tend to buckle and yield – осадові породи мають тенденцію до згину та осідання.