Exercises:

1. Translate into Ukrainian paying attention to ‘ing’ – forms:

1.In prospecting virgin coal-fields, aerial photography will, in future, play a very important part.

2.The findings of the geologists and geophysicists will be examined by a competent mining engineer.

3.Exploration by boring provides data and information relating to the existence of coal seams and intervening strata.

4. Boring is an expensive operation.

5.Desining new mining machines, engineers pay attention to geological condition in the mines.

6.The method of extraction is longwall, the faces being rather long.

2. Get ready to answer the following questions:

1.What do physical force produce in the earth’s crust?

2.What is fold?

3.What is fault?

4.Where does faulting generally take place?

5.Into what kinds are folds divided?

6.What do miners and geologists call the hanging wall, the footwall?

3. Ask questions on all the parts of the following sentences:

1.Drilling apparatus and techniques have undergone wide improvements.

2.Various methods have also been applied to collect supplementary information.

4. Get ready to retell the text.

35. Fractures and fissures

The term fractures is generally applied to cracks in rocks, large enough to be distinctly visible to the naked eye. The fractures may also come under the head of joints, in which case they are joint fractures. Fractures are, like joints and faults, the result of the straining and cracking of rocks under pressures. According to the way motion takes place in the crust, certain portions may be stretched or compressed. By both these methods fractures and fissures may originate.

As a rule, fractures, like joints and faults, being due to stress, are straight, approaching as near as possible mathematical planes. Even in greatly disturbed, folded, faulted and jointed rocks, open fissures, larger than cracks, are relatively rare and unimportant. Near the very surface, the shrinkage of volume in rocks resulting from chemical changes, and the falling apart under the influence of gravity, cause many fissures, but these conditions are characteristic only near the surface. The rock encountered in the mines is much more solid.

Notes:

distinctly visible to the naked eye - що можна чітко побачити неозброєним оком

shrinkage - стиснення, усадка

may also come under the head of - можуть також класифікуватись під назвою

fissure - тріщина, розрив

fracture - перелом, тріщина

Exercises:

1. Read and translate and answer following questions.

1.What is a fracture?

2.What are fractures result of?

3.What processes can cause fissures?

2. Translate into English.

1. Тріщини в породі утворюються під впливом тиску.

2. Стиснення породи часто є результатом різних хімічних змін.

3. Відкриті тріщини – явище відносно рідке і маловажливе.

4. Земля складається з чотирьох пластів.

3. Retell the text.

36. ORIGIN OF MECHANICAL SEDIMENTS WEATHERING OF ROCK

All rocks which are exposed on the Earth’s surface (high mountain peaks, deserts) are decomposed to a certain degree. The process of superficial disintegration of rocks is called weathering. This phenomenon is often referred to in geology because weathering is an active process. It takes place in the upper layers of the Earth’s crust. There are three kinds of weathering.

Physical Weathering. The chief reason of physical weathering is the change in temperature that takes place with the succession of day of day and night. This phenomenon can best be observed in the deserts and high mountains where the changes in temperature are common.

During the day under the influence of heat rocks expand whereas at night they begin to contract. As rocks are generally composed of different minerals their expansion and contraction do not occur uniformly. As a result of this rocks crack. At the beginning these crack or fissures are hardly noticeable but gradually they become wider and deeper until the whole surface of rock is finally transformed into gravel, sand and dust.

In the regions of moderate or cold climate, where the temperature in winter goes down to below 0 (zero), the decomposition of rocks is greatly facilitated by the action of water. When water freezes it increases in volume and develops enormous lateral pressure. Under the action of water rocks decompose to pieces of varied forms and size.

As rocks are of unequal hardness and are composed of different minerals, their disintegration does not take place at an equal rate. Hard, homogeneous rocks decompose at a heterogeneous mineral composition.

The decomposition of rocks under the direct influence of heat and cold is called physical or mechanical weathering.

It should be noted that this process is purely mechanical and does not cause any change in the chemical composition of rocks.

Chemical Weathering. Rocks are subjected not only to physical decomposition, but also to the influence of chemical agents, such as a water, carbon dioxide and oxygen. The fact that natural waters contain a great variety of dissolved mineral substances shows that they can act as solvents. Only few minerals and rocks are resistant to the action of natural waters. The solvent action of water is stronger when it contains carbon dioxide. Water causes more complex and varied changes. With the participation of oxygen and carbon dioxide up to 90 per cent of rocks is transformed into soluble minerals, which are carried away by the waters.

Organisms and plants also take part in the disintegration of rocks. Certain marine animals, for example, accelerate the destruction of rocks by making holes in them to live in. The action of plants can often be even more destructive. Their roots penetrate into the fissures of rocks and develop the lateral pressure which fractures and destroys rocks.

As is known, weathering has much been written about by the scientist.