Geomorphology

Question 3

How are block mountains formed?

Answer 3

Through large-scale faulting where large blocks of earth are broken and displaced vertically or horizontally.

Question 4

What are the uplifted and lowered blocks called in block mountain formation?

Answer 4

Uplifted blocks are horsts, and lowered blocks are graben.

Question 5

How are fold mountains formed?

Answer 5

When sedimentary rock strata in geosynclines are subjected to compressive forces.

Question 6

Give an example of a block mountain.

Answer 6

The Vosges mountains in Eastern France.

Question 7

Give examples of fold mountains.

Answer 7

The Alps (Europe), Appalachians (North America), Andes (South America).

Question 8

What is the ‘solution’ process in chemical weathering?

Answer 8

The dissolving of minerals by water, especially rainwater containing carbon dioxide (which makes it a weak acid).

Question 9

Why is solution a particularly potent weathering process in limestone regions?

Answer 9

Because rainwater attacks and dissolves the calcium carbonate which chiefly forms limestone, widening joints and creating features like caves.

Question 10

What is ‘oxidation’ in chemical weathering?

Answer 10

The reaction of oxygen (from air or water) with minerals in the rock, such as iron turning into iron oxide (rust).

Question 11

How does oxidation weaken rocks?

Answer 11

The product (e.g., iron oxide) often crumbles easily and is more easily eroded than the original mineral, loosening the rock structure.

Question 12

What is the difference between magma and lava?

Answer 12

Magma is molten rock material within the Earth (specifically mentioned as upper mantle portion); Lava is magma once it starts moving towards or reaches the Earth’s surface.

Question 13

What materials can be ejected during a volcanic eruption?

Answer 13

Lava flows, pyroclastic debris, volcanic bombs, ash, dust, and gases (like nitrogen compounds, sulfur compounds, chlorine, hydrogen, argon).

Question 14

What are the two main types of seismic waves?

Answer 14

Body waves (travel through Earth’s interior) and Surface waves (travel along the surface).

Question 15

What are the two types of body waves, and which arrives first?

Answer 15

P-waves (primary) and S-waves (secondary). P-waves are faster and arrive first.

Question 16

How do particles vibrate in P-waves?

Answer 16

Parallel to the direction of wave propagation (compressional).

Question 17

How do particles vibrate in S-waves?

Answer 17

Perpendicular to the direction of wave propagation (transverse).

Question 18

How is black soil typically formed in the Deccan Plateau region of India?

Answer 18

By the weathering of fissure volcanic rock (basaltic rock) under moderate rainfall conditions.

Question 19

Under India’s MMDR Act, 1957, is sand classified as a major or minor mineral?

Answer 19

Minor mineral.

Question 20

Which level of government primarily regulates minor minerals in India?

Answer 20

State governments are empowered to frame rules regarding leases and other matters for minor minerals.

Question 21

Which level of government has jurisdiction over controlling illegal mining in India?

Answer 21

State governments.

Question 22

What two major geological/climatic processes have influenced the evolution of organisms?

Answer 22

Continental drift and Glacial cycles.

Question 23

What was the name Alfred Wegener gave to the proposed single supercontinent?

Answer 23

PANGAEA.

Question 24

What were the names of the two large landmasses Pangaea first broke into?

Answer 24

Laurasia (northern component) and Gondwanaland (southern component).

Question 25

List five major forces/phenomena responsible for bringing dynamic changes to the Earth's surface.

Answer 25

Electromagnetic radiation (solar energy), Geothermal energy, Gravitational forces (tides), Plate movements (tectonics), Earth's Rotation (Coriolis effect).

Question 26

How does Earth's rotation influence surface dynamics?

Answer 26

Causes the Coriolis effect, deflecting wind and ocean currents, influencing weather patterns.

Question 27

How does Earth's revolution influence surface dynamics?

Answer 27

Causes the change of seasons by altering the angle/duration of solar insolation received at different latitudes.

Question 28

What is soil conservation?

Answer 28

A methodology to maintain soil fertility, prevent soil erosion and exhaustion, and improve degraded soil conditions.

Question 29

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Answer 29

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Question 30

What is recommended for agricultural use on lands with a slope gradient of 15-25 percent?

Answer 30

Cultivation should ideally be avoided, but if necessary, terraces should be carefully constructed.

Question 31

List some remedial measures often adopted to reduce soil erosion.

Answer 31

Contour bunding, contour terracing, regulated forestry, controlled grazing, cover cropping, mixed farming, and crop rotation.

Question 32

How can gully erosion be controlled or prevented?

Answer 32

Finger gullies can be eliminated by terracing. In bigger gullies, constructing check dams, gully plugging, terracing, or planting cover vegetation can reduce water's erosive velocity.

Question 33

How can cultivable lands in arid and semi-arid areas be protected from sand dune encroachment?

Answer 33

By developing shelter belts of trees, sand fences, wind breaks, and practicing agro-forestry.

Question 34

What should be done with land not suitable for cultivation?

Answer 34

It should be converted into pastures for grazing.

Question 35

What materials reaching the ground are included during volcanic eruptions?

Answer 35

Lava flows, pyroclastic debris, volcanic bombs, ash and dust and gases such as nitrogen compounds, sulphur compounds and minor amounts of chlorene, hydrogen and argon.

Question 36

What are the main gases dissolved in magma?

Answer 36

Water vapour, carbon dioxide, and sulphur gases, with lesser amounts of hydrogen, hydrochloric acid, and hydrofluoric acid.

Question 37

What type of lava is typically very fluid and hot when erupted, forming volcanoes that are not steep?

Answer 37

Basaltic lava.

Question 38

Under what condition might a typically low-explosivity basaltic volcano become explosive?

Answer 38

If water somehow gets into the vent.

Question 39

What type of rock forms when volcanic lava cools?

Answer 39

Igneous rocks.

Question 40

What is the difference between volcanic and plutonic igneous rocks?

Answer 40

Volcanic rocks form from lava cooling at the surface, while plutonic rocks form from magma cooling in the crust.

Question 41

What are dykes in geology?

Answer 41

Wall-like intrusive structures formed when lava solidifies in cracks or fissures, often nearly perpendicular to the ground. These are common in western Maharashtra area and considered feeders for the Deccan Traps.

Question 42

What does the Mercalli scale measure regarding earthquakes?

Answer 42

The intensity of an earthquake based on the visible damage caused by the event. Its range is 1-12.

Question 43

What does the Richter scale measure regarding earthquakes?

Answer 43

The magnitude of an earthquake, related to the energy released during the quake. It uses absolute numbers, 0-10.

Question 44

How much does the wave amplitude increase for each whole number increase on the Richter scale?

Answer 44

The wave amplitude increases by 10 times (e.g., amplitude at magnitude 6 is 10 times greater than at magnitude 5).

Question 45

Approximately how much does the energy released increase for each whole number increase on the Richter scale?

Answer 45

About 31.7 times.

Question 46

How are sedimentary rocks formed?

Answer 46

From fragments of pre-existing rocks (igneous, sedimentary, metamorphic) that are weathered, transported, deposited (often in layers by agents like water or wind), and then lithified (compacted and cemented).

Question 47

Can sedimentary rocks contain fossils?

Answer 47

Yes, they may contain fossils of plants, animals, and other microorganisms that lived when the sediments were deposited.

Question 48

What is the correct sequence of water erosion processes mentioned?

Answer 48

Splash erosion -> Sheet erosion -> Rill erosion -> Gully erosion.

Question 49

What is splash erosion?

Answer 49

The initial stage where raindrop impact on bare soil breaks up aggregates and splashes soil particles.

Question 50

What is sheet erosion?

Answer 50

Removal of a thin, uniform layer of soil by runoff water, often on level land after heavy rain; it can be harmful as it removes fertile topsoil.