Geomorphology Questions and Answers

Answer: A

An earthquake can cause landslides, tsunamis (when it occurs under the sea) and floods (for example by breaking dams or blocking rivers), so (ii), (iv) and (v) are correct.

Lightning and thundering are atmospheric electrical effects and are not caused by earthquakes, so the options containing (i) or (iii) are wrong, and (ii) only or (ii) and (v) are incomplete.

A tsunami follows an undersea earthquake, and landslides are triggered by the shaking of slopes, which are the two best-known secondary effects of an earthquake.

Answer: C

The Himalayas were folded in the Caenozoic (Cenozoic) era.

The Himalayas rose as the Indian plate collided with the Eurasian plate. The main uplift took place in the Tertiary period of the Cenozoic era, which began about 66 million years ago, and the range is still rising, which makes it one of the youngest mountain systems on Earth.

The Palaeozoic is the era of older ranges such as the Appalachians, the Mesozoic is the age of dinosaurs, and Azoic is an old name for the earliest era, before life. None of them is when the Himalayas were folded.

Answer: A

Ravines and badlands are formed by water.

Running water cuts gullies into soft, bare soil, and the gullies deepen and widen into a dense network of ravines. The Chambal ravines of Madhya Pradesh, Rajasthan and Uttar Pradesh are the best-known example in India, and the land they ruin is called badlands.

Wind forms sand dunes and mushroom rocks, sea waves form cliffs, caves and stacks, and glaciers carve U-shaped valleys and cirques; none produces gully-and-ravine country.

Answer: B

Landslides are the rapid, perceptible downslope movement of a relatively dry mass of earth, debris or bedrock. They happen suddenly, as the mass slides or falls along a slope when its support is lost.

Downslope movement that is usually not perceptible describes creep, and the slow to very rapid movement of water-saturated debris describes mudflows and debris flows. A slow-flowing mass saturated with water is solifluction. So the dry, rapid and visible movement is the landslide.

Answer: C

The pair that is not correct is Sonoran desert with West Asia. The Sonoran Desert lies in North America, across southern Arizona, California and northwestern Mexico, and not in West Asia.

The Atacama is in South America, mainly Chile, the Gobi is in Central Asia, in Mongolia and northern China, and the Great Victorian Desert is in Australia. Options A, B and D are therefore correct matches.

Answer: D

A panplain is a plain formed by the joining of adjacent flood plains, as the meandering rivers widen their valleys and the flood plains of neighbouring streams merge. The term was introduced by Crickmay in 1933 and used in the Davisian cycle of erosion.

A peneplain, in contrast, is a level surface formed in the old age of the fluvial cycle (option A), and a level surface formed by wind erosion is a pediplain or desert plain. A plain formed by marine action is a plain of marine abrasion or deposition. So panplain is option D.

Answer: C

The removal of material by solution is called corrosion (chemical erosion): the water dissolves soluble minerals such as limestone and carries them away in solution.

Attrition is the wearing of the transported load as the particles knock against each other. Corrasion (abrasion) is the mechanical wearing of the bed and banks by the load. Sapping is the undermining of a slope or cliff at its base by spring flow. So only corrosion fits.

Answer: C

The key credits Hutton with the idea that the present is the key to the past, the principle of uniformitarianism: the processes now acting on the earth are those that acted in the past, over very long periods. James Hutton set it out in his Theory of the Earth in 1795.

Charles Lyell later popularised it in his Principles of Geology, and Playfair explained Hutton's ideas in 1802, which is why those names are also linked with it, but the key names Hutton. Buffon is known for his work on the age of the earth and for natural history.

Answer: A

Louis Agassiz is usually credited with establishing the validity of the ice age idea. In Etudes sur les glaciers (1840) and in lectures from 1837 he put forward the idea that ice sheets had once covered much of northern Europe, supported by erratics, striations and moraines.

Ramsay and Jukes are British geologists known for work on glaciers and denudation, and Penck is known for the glacial sequence in the Alps and for the cycle of morphology. The first to establish the ice age theory is Agassiz.

Answer: D

Most of the details of the present topography belong to the Cenozoic era. The Cenozoic, the most recent era, saw the Himalayan and Alpine mountain building reach its peak, the carving of river valleys and the glaciation of the Pleistocene, so the landforms we see today (young fold mountains, present drainage, glacial and fluvial features) are mostly products of it.

The Pre-Cambrian and Paleozoic eras are far older, and their surfaces have been eroded, buried or reworked many times. The Mesozoic is also earlier, so its features survive mainly as the rock structure beneath the Cenozoic surface rather than as present topography.