Weathering In The Desert Reading Answers

Jan 23, 2023

Weathering In The Desert Reading Answers contains 13 questions that are to be answered in 40 minutes. IELTS topic- Weathering In The Desert Reading Answers deals with information about weathering changes in rocks.Weathering In The Desert Reading Answers, contains two IELTS reading question types. They are choosing the correct answer and identifying whether the statements can be inferred. Candidates need to skim through the passage for the best answer. They can also refer to IELTS Reading practice papers.

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Section 1

Read the Passage to Answer the Following Questions

Weathering In The Desert Reading Answers

WEATHERING IN THE DESERT

In the deserts, as elsewhere, rocks at the earth's surface are changed by weathering, which may be defined as the disintegration of rocks where they lie. Weathering processes are either chemical, when alteration of some of the constituent particles is involved; or mechanical, when there is merely the physical breaking apart and fragmentation of rocks. Which process will dominate depends primarily on the mineralogy and texture of the rock and the local climate, but several individual processes usually work together to the common end of rock disintegration.

The great daily changes in temperature of deserts have long been supposed to be responsible for the disintegration of rocks, either by the differential heating of the various rock-forming minerals or by differential heating between the outer and inner parts of rock masses. However, both field observations and laboratory experiments have led to a reassessment of the importance of ’ exposure to the sun's rays in desert weathering. Almost half a century ago Barton remarked that the buried parts of some of the ancient monuments in Egypt were more weathered than were those parts fully exposed to the sun's rays, and attributed this to the effects of water absorption below the ground surface. Laboratory experiments have shown that rocks subjected to many cycles of large temperature oscillations (larger than those experienced in nature) display no evidence of fissuring or fragmentation, as a result. However, when marked fluctuations of temperature occur in moist conditions small rock fragments quickly form.

The expansive action of crystallising salts is often alleged to exert sufficient force to disintegrate rocks. Few would dispute that this mechanism is capable of disrupting fissile or well-cleaved rocks or rocks already weakened by other weathering agencies; wood is splintered, terracotta tiles disintegrated and clays disturbed by the mechanism, but its importance when acting upon fresh and cohesive crystalline rocks remains uncertain.

Weathering achieves more than the disintegration of rocks, though this is its most important geomorphic effect. It causes specific landforms to develop. Many boulders possess a superficial hard layer of iron oxide and/or silica, substances which have migrated in solution from the inside of the block towards the surface. Not only is the exterior thus case-hardened but the depleted interior disintegrates easily. When weathering penetrates the shell the inside is rapidly attacked and only the hard outer layer remains to give hollowed or 'tortoiseshell' rocks.

Another superficial layer, the precise nature of which is little understood, is the well-known desert varnish or patina, a shiny coat on the surface of rocks and pebbles and characteristic of arid environments. Some varnishes are colourless, others light brown, yet others so dark a brown as to be virtually black. It's origin is unknown but is significant, for it has been suggested that the varnish grows darker with the passage of time; obviously before such a criterion could be used with confidence as a chronological tool its origin must be known with precision. Its formation is so slow that in Egypt, for example, it has been estimated that a light brown coating requires between 2,000 and 5,000 years to develop, a fully formed blackish veneer between 20,000 and 50,000 years.

The development of relatively impermeable soil horizons that are subsequently exposed at the surface because of erosion of once overlying, easily eroded materials, and which thus become surface crusts, is widespread in arid regions, although it is also known outside the deserts, and indeed many of the examples in arid lands probably originated in former periods of humid climate. The crusts prevent the waters of occasional torrential downpours from penetrating deeply into the soil, and thus they contribute to the rapid runoff associated with desert storms. Also, after erosion has cut through the crust and exposed underlying soil layers, the hard layer forms a resistant capping (duricrust) on plateaux and mesas, such as are common in many parts of arid and semi-arid Australia.

Some duricrust layers have been used as time markers for landforms and geological formations. The necessary conditions for this are that the crust forms fairly rapidly, and that it is sufficiently distinct in appearance to preclude the possibility of confusion with other crusts formed at other times. The Barrilaco calcrete of Mexico for instance is believed to date from about 7,000 B.C. The main silcrete of the northern districts of South Australia is believed to date from the Lower Miocene, the laterite of northern Australia to be of the Lower or Middle Miocene age.

Section 2

Solution and Explanation

Questions 1-7 Reading Passage 1 has seven sections, A-G. Which paragraph contains the following information? Write the appropriate letter, A-G, in boxes 1-7 on your answer sheet.

the idea that crystalline salts may not disintegrate solid rock as easily as other substances

Answer: C
Supporting Sentence: The expansive action of crystallising salts is often alleged to exert sufficient force to disintegrate rocks.
Keywords: crystallising salts, sufficient force, disintegrate rocks.
Keyword Location: Paragraph C, lines 1-2
Explanation: The supporting sentence from paragraph C imply that crystalline salt does not disintegrate solid rock that easily like the other substances.

the fact that daily temperature changes cause rocks to weather may not be as important as supposed

Answer: B
Supporting Sentence: Laboratory experiments have shown that rocks subjected to many cycles of large temperature oscillations (larger than those experienced in nature) display no evidence of fissuring or fragmentation
Keywords: rocks, subjected, large temperature oscillations, display, no evidence of fissuring
Keyword Location: Paragraph-B, lines 9-11
Explanation: Paragraph B states that laboratory experiments have proved that the regular temperature fluctuations have no significant impact on rocks when it comes to their fragmentation.

the regions where weathering creates a thick layer of earth that water cannot penetrate easily

Answer: F
Supporting Sentence :The crusts prevent the waters of occasional torrential downpours from penetrating deeply into the soil
Keywords: The crusts prevent, waters, penetrating deeply, into the soil
Keyword Location: Paragraph F, lines 5-6
Explanation: Paragraph F does mention that the crusts prevent occasionally torrential downpours from allowing water to deeply penetrate the soil.

the fact that weathering not only breaks down rocks, but also shapes the landscape

Answer: D
Supporting Sentence: Weathering achieves more than the disintegration of rocks,
Keywords: Weathering, achieves, more, disintegration of rocks
Keyword Location: Paragraph D, line 1
Explanation: From paragraph D, it is clear that the weathering also has other impacts than the rocks being damaged.

the idea of using impenetrable layers of earth to measure chronology

Answer: G
Supporting Sentence: Some duricrust layers have been used as time markers for landforms and geological formations
Keywords: duricrust layers, used, time markers, geological formations
Keyword Location: Paragraph G, lines 1-2
Explanation: Paragraph G does state that some duricrust layers have been utilised as geological and landform timers. This does mean that impenetrable layers are used in study to measure chronology. Also there are a few examples in the paragraph to support this.

the two different kinds of weathering in rocks

Answer: A
Supporting Sentence: Weathering processes are either chemical, when alteration of some of the constituent particles is involved; or mechanical,
Keywords: Weathering processes, chemical, or mechanical
Keyword Location: Paragraph A, lines 2-3
Explanation: Paragraph A does talk about two types of weathering in rocks. Chemical and mechanical weathering processes involve the physical breaking apart and fragmentation of rocks.

the possibility of using the colour of the shiny surface on rocks to measure chronology

Answer: E
Supporting Sentence: obviously before such a criterion could be used with confidence as a chronological tool
Keywords: could be used, chronological tool
Keyword Location: Paragraph E, lines 5-6
Explanation: From Paragraph E, it can be inferred that there is a potential for measuring chronology by the colour of a shiny rock surface.

Questions 8-13 Do the following statements agree with the information given in Reading Passage 1? In boxes 8-13 on your answer sheet, write

TRUE if the statement is true
FALSE if the statement is false
NOT GIVEN if the information is not given in the passage

Desert rocks can become weathered when there is a chemical reaction within the rock.

Answer: TRUE
Supporting Sentence :Weathering processes are either chemical
Keywords: Weathering processes, are either chemical
Keyword Location: Paragraph A, lines 2-3
Explanation: The given statement is true as the passage does mention that desert rocks can also have changes because of a chemical reaction within. There is also a proof for this as the passage mentions that even some buried rocks had significant weather changes.

The parts of Egyptian monuments exposed to sunlight were found to be affected by the weather more than those below the ground.

Answer: FALSE
Supporting Sentence: buried parts of some of the ancient monuments in Egypt were more weathered than were those parts fully exposed to the sun's rays,
Keywords: : buried parts, ancient monuments, more weathered, than, parts fully exposed, sun's rays
Keyword Location: Paragraph B, lines 6-7
Explanation: The given statement is false as it is completely in contrast with the supporting sentence from paragraph B.

Granite which has been subjected to huge temperature swings tends not to exhibit any signs of disintegration as a result.

Answer: NOT GIVEN
Explanation: The information in the given statement cannot be inferred from the passage.

It is estimated that dark patina originated between 2,000 and 5,000 years ago.

Answer: FALSE
Supporting Sentence: it has been estimated that a light brown coating requires between 2,000 and 5,000 years to develop,
Keywords: light brown coating, requires between, 2,000 and 5,000, years to develop
Keyword Location: lines 7-8
Explanation: The given statement is false as it does not match with the supporting sentence. Only light patina originated from 2000 to 5000 years ago and not dark patina.

Because of surface crusts, water from torrential rains cannot be fully absorbed into the ground and as a result causes run offs in arid regions.

Answer: TRUE
Supporting Sentence: The crusts prevent the waters of occasional torrential downpours from penetrating deeply into the soil, and thus they contribute to the rapid runoff
Keywords: The crusts prevent, waters, penetrating deeply, into the soil, contribute to, rapid runoff
Keyword Location: Paragraph F, lines 5-6
Explanation: The given statement is true because the supporting statement does state that the crusts contribute to rapid runoff because they prevent the waters from occasional torrential downpours from penetrating deeply into the soil.