Daily Quiz: UPSC Prelims Marathon (Geography) – June 26, 2020

Sedimentary rocks are formed by the accumulation of sediments. There are three basic types of sedimentary rocks.

• Clastic sedimentary rockssuch as breccia, conglomerate, sandstone, siltstone, and shale are formed from mechanical weathering debris.
• Chemical sedimentary rocks, such as rock salt, iron ore, chert, flint, some dolomites, and some limestone, form when dissolved materials precipitate from solution.
• Organic sedimentary rockssuch as coal, some dolomites, and some limestone, form from the accumulation of plant or animal debris.

Fold Mountains are created through a process called orogeny. An orogenic event takes millions of years to create a fold mountain.

• When a tectonic plate gets pressure from two sides, it gets folded. Some of its portion becomes elevated and forms the mountains.
• The depressions form the valleys. The Himalayas, the Rockies, the Andes and the Alps are examples of Fold Mountain.
• They are the young mountains of the world and hence they have some of the highest peaks of the world.

A caldera is a large depression formed when a volcano erupts and collapses.

• During a volcanic eruption, magma present in the magma chamber underneath the volcano is expelled, often forcefully.
• When the magma chamber empties, the support that the magma had provided inside the chamber disappears.
• As a result, the sides and top of the volcano collapse inward. Calderas vary in size from one to 100 kilometers (0.62 to 62 miles) in diameter.
• Some calderas form a lake as the bowl-shaped depression fills with water. A famous example is Crater Lake, in Oregon.
• This caldera formed about 7,000 years ago when a stratovolcano, Mt. Mazama, violently erupted.
• For several thousand years after this eruption, smaller volcanic eruptions continued inside the caldera.
• One of these eruptions was so large it formed an island in Crater Lake named Wizard Island.

The Great Lakes are, from west to east:  Superior, Michigan, Huron, Erie and Ontario.

• They are a dominant part of the physical and cultural heritage of North America.
• Shared with Canada and spanning more than 750 miles (1,200 kilometers) from west to east, these vast inland freshwater seas provide water for consumption, transportation, power, recreation and a host of other uses.
• The Great Lakes are one of the world’s largest surface freshwater ecosystems.

When the soil is completely saturated with water the individual particles are almost suspended in the water and move easily over one another and over the underlying rock. The soil acts like a liquid and a soil-flow occurs.

In areas of peat soils, the peat absorbs much moisture. However if saturation point is reached the peaty soil may flow down-slope. In Ireland such flows are known as bog-bursts.

An isohyet is also known as isohyetal line, and it is a line on a map which connects points that have the same amounts of precipitation in a given period or for a particular storm. The method used in estimating average rainfall across a particular area is known as an isohyetal method.

• Isotherm: a line on a map connecting points having the same temperature at a given time or on average over a given period.
• Isobar: A line drawn on a weather map connecting points of equal pressure is called an isobar. The isobars are generated from mean sea level pressure reports and the pressure values are given in millibars.

All clouds are made up of basically the same thing: water droplets or ice crystals that float in the sky.

But all clouds look a little bit different from one another, and sometimes these differences can help us predict a change in the weather.

• Cirrus clouds are delicate, feathery clouds that are made mostly of ice crystals. Their wispy shape comes from wind currents which twist and spread the ice crystals into strands.
• Altocumulus clouds have several patchy white or gray layers, and seem to be made up of many small rows of fluffy ripples. They are lower than cirrus clouds, but still quite high. They are made of liquid water, but they don’t often produce rain.
• Cumulus clouds look like fluffy, white cotton balls in the sky. They are beautiful in sunsets, and their varying sizes and shapes can make them fun to observe!
• Stratocumulus clouds are patchy gray or white clouds that often have a dark honeycomb-like appearance.

Savanna Climate.

Statement 1 is correct: Savanna Climate is a type of climate has alternate wet and dry seasons similar to monsoon climate but has considerably less annual rainfall. Also, there is no distinct rainy season like in monsoon climate.

Statement 2 is correct: It is confined within the tropics and is best developed in Sudan, hence its name the Sudan Climate.

Temperature inversion is a reversal of the normal behavior of temperature in the troposphere, in which a layer of cool air at the surface is overlain by a layer of warmer air. (Under normal conditions, temperature usually decreases with height).

Ideal Conditions for Temperature Inversion:

• Long nights, so that the outgoing radiation is greater than the incoming radiation.
• Clear skies, which allow unobstructed escape of radiation.
• Calm and stable air, so that there is no vertical mixing at lower levels.

Aridisols are largest single soil order occurs in dry regions of the world.

• These soils occupy nearly 19 per cent of the earth’s land surface.
• Pale and light near the surface, deficit in moisture.
• These soils are lack in organic matter.
• Salinisation is the main problem of these soils.
• Salinisation complicates farming in Aridisols.