Geomorphology MCQ Quiz - Objective Question with Answer for Geomorphology - Download Free PDF

The correct answer is Volcano.Key Points 

• The term "caldera" is associated with Volcano.
• A caldera is a large, usually circular depression at the summit of a volcano.
• It is formed when a major eruption leads to the collapse of the mouth of the volcano.
• This happens when the magma chamber empties during an eruption and can no longer support the weight of the volcano, causing the top of the volcano to collapse inward.
• Calderas can be tens of kilometers in diameter and are often filled with water, forming a lake.

Additional Information 

• A volcano is a vent (opening) in the earth’s crust through which molten material erupts suddenly from a magma chamber below the surface.
• Due to very high temperatures, some rocks slowly melt and turn into a thick flowing matter known as magma. Since it is lighter than the solid rock around it, the magma rises and gets collected in magma chambers which eventually push through fissures and vents on the earth’s surface.
• They are generally found where tectonic plates (like Eurasian, Pacific, Somali, etc) diverge or converge. Examples- volcanoes occurring in the mid-oceanic ridge and the Ring of Fire.

The correct answer is 2 and 3 only.

Key Points

• Weathering, mass-wasting, and erosion are collectively referred to as degradational processes because they contribute to the breakdown, movement, and removal of Earth's surface materials.
• Erosion does not necessarily require weathering as a precondition; erosion can occur independently, such as when flowing water or wind transports loose particles.
• Deposition occurs as a direct consequence of erosion when the transported material settles in a new location due to a decrease in the energy of the transporting medium.
• Statement 1 is incorrect because erosion can also act on previously loose or unconsolidated material without requiring prior weathering.
• Statements 2 and 3 are correct as they accurately describe the processes of erosion and its outcomes.

Additional Information

• Weathering: It is the process of breaking down rocks and minerals into smaller particles through physical, chemical, or biological means without movement.
• Mass-Wasting: It refers to the downslope movement of soil and rock under the influence of gravity, such as landslides, rockfalls, and soil creep.
• Erosion: It involves the removal and transportation of surface material by natural agents like water, wind, ice, or gravity.
• Deposition: The process by which eroded materials are laid down or settled in new locations, forming features such as deltas, sand dunes, or alluvial plains.
• Degradational Processes: These are natural geological processes that lead to the wearing down or destruction of landforms, contributing to landscape evolution over time.

The correct answer is Iron and Nickel.

Key Points

• The core of the Earth consists primarily of iron (Fe) and nickel (Ni), with iron being the predominant element.
• The Earth's core is divided into two layers: the outer core (liquid) and the inner core (solid).
• The inner core is composed of approximately 80-85% iron, along with nickel and trace amounts of lighter elements such as oxygen, sulfur, or silicon.
• The outer core generates the Earth's magnetic field through the motion of liquid iron and nickel, a process known as the geodynamo.
• The core's high temperature and pressure make it one of the most extreme environments on Earth, with the inner core reaching temperatures of up to 5,700°C (comparable to the surface of the Sun).

Additional Information

• Earth's Layers:
  • The Earth is divided into three main layers: crust, mantle, and core.
  • The core lies beneath the mantle and is about 3,500 kilometers in radius.
• Seismic Evidence:
  • The composition of the Earth's core is inferred from seismic wave studies, as direct sampling is not possible.
  • Seismic waves behave differently when traveling through solid versus liquid, helping scientists understand the core's structure.
• Density and Composition:
  • The high density of the core (around 12-13 g/cm³) aligns with iron and nickel's physical properties.
  • Light elements such as sulfur or silicon may also be present in small amounts in the outer core.
• Geodynamo Effect:
  • The Earth's magnetic field arises due to the movement of molten iron and nickel in the outer core.
  • This phenomenon is critical for shielding the planet from harmful solar and cosmic radiation.
• Formation of the Core:
  • The Earth's core formed during the planet's early stages, as heavier elements like iron and nickel sank towards the center due to gravity in a process called planetary differentiation.

The correct answer is Guttenberg’s Discontinuity.

Key Points

• There is an abrupt change in the seismic waves that flow through Earth at the Gutenberg discontinuity.
• It is located in the interior of the planet at a depth of roughly 2,900 km below the surface, separating the core of the earth from the mantle.
• At this depth, primary seismic waves slow down while secondary seismic waves completely vanish.
• It is assumed that the unit above the discontinuity is solid and the unit below is in a liquid, or molten state since S waves shear material and cannot pass through liquids.
• The Gutenberg discontinuity was named after Beno Gutenberg, a seismologist.​​

Additional Information

• Moho discontinuity:
  • The discontinuity between the crust and mantle is called the Mohorovich Discontinuity or Moho discontinuity.
• Conrad Discontinuity:
  • The discontinuity between the hydrosphere and crust is termed the Conrad Discontinuity.
• Repetti Discontinuity:
  • The discontinuity between the upper mantle and the lower mantle is known as Repetti Discontinuity.

The correct answer is Erosion.

Key Points

• The phenomenon of wearing down of relief variation of the surface of the earth through erosion is known as gradation.
  • Water, wave, wind, ice etc are the important gradational agents which act on the surface of the earth. 
  • These forces break up rock materials erode them, transport them, and deposit them.
• Erosion is the geological process in which earthen materials are worn away and transported by natural forces such as wind or water.
  • ​In chemical erosion, rock’s chemical composition changes. e.g: when limestone dissolves due to carbonation. 
    In physical erosion, the rock breaks down but its chemical composition remains unaltered. e.g: during a landslide.

Additional Information

• The deposition is the opposite process of erosion.
• Volcanism is the phenomenon of eruption of molten rock, volcanic gases to the surface through a vent.
• Diastrophism is the deformation of the Earth’s crust due to deforming movements like folding, faulting, warping etc.

The correct answer is outer core.

Important Points

• The interior of the earth is divided into three parts namely Crust, Mantle, and Core.
• The core is the innermost layer of the earth.
• The radius of the innermost layer(core) is about 3500 km.
• The core is made up of material constituted by nickel and iron.
• The temperature and pressure of the central core are very high.

Key Points

• The core is further subdivided into two layers called the outer core and inner core.
• The outer core of the earth is in a liquid state.
• The inner core is in solid-state
• The outer core is responsible for the earth's magnetic field.

Additional Information

• The crust is the outermost of the earth.
  • It is brittle in nature.
  • it the thinnest layer of Earth.
  • The thickness of the crust varies under the oceanic and continental areas.
• The mantle is the second layer in the interior of the earth.
  • The mantle extends from Moho’s discontinuity to a depth of 2,900 km.
  • The upper portion of the mantle is called the asthenosphere.

The correct answer is 4.

Important Points

• Based on historical seismic activity, the Bureau of Indian Standards has categorized regions in India into four seismic zones: zones II, III, IV and V.
• Of these, the most seismically active area is Zone V and the least active is Zone II. 
• There is a history of devastating earthquakes on the Indian subcontinent.
• The key cause for the high frequency and severity of earthquakes is that the Indian plate is driving into Asia at a rate of roughly 47 mm/year.
• India's geological figures indicate that about 54 percent of the land is prone to earthquakes.
• Research by the World Bank and the United Nations predicts that by 2050, about 200 million urban dwellers in India will be vulnerable to storms and earthquakes.
• The most recent edition of India's seismic zoning map given in India's earthquake-resistant design code [IS 1893 (Part 1) 2002] assigns four degrees of seismicity in terms of zone factors for India.
• In other words, unlike its previous edition, which consisted of five or six zones for the region, India's earthquake zoning map divides India into four seismic zones (Zone 2, 3, 4, and 5).
• According to the new zoning map, the maximum degree of seismicity is predicted in Zone 5, while the lowest level of seismicity is correlated with Zone 2.

Revised earthquake hazard zone map of India

Option 2 is correct, i.e. Aluminium.

Key Points

• Aluminium is the most plentiful (most abundant) of metals in the crust of the earth.
• Aluminium is around 8.1 per cent of the total metals on the surface of the earth.

Important Points

• The most plentiful non-metal in the earth's surface is Oxygen.
• The most plentiful metalloid in the crust of the earth is Silicon.
• O > Si > Al > Fe > Ca are the most abundant elements in the earth crust.

The correct answer is L waves.

Key Points

• L waves, or Love waves, are one type of surface wave in seismic activity.
  • Named after British mathematician A.E.H. Love, who first mathematically predicted their existence.
  • Love waves move the ground from side to side in a horizontal plane perpendicular to the direction of propagation.
  • As they travel along the Earth's surface, they cause horizontal shearing and produce entirely horizontal motion.
  • L waves are the slowest of all seismic waves and therefore the last to be recorded by seismographs.
  • These waves are particularly damaging to the foundations of structures due to their horizontal motion.

Additional Information

• P waves:
  • P waves, or Primary waves, are body waves that travel through the interior of the Earth.
  • They are the fastest seismic waves and thus the first to be detected by seismographs.
  • P waves cause particles to move in the same direction as the waves, creating a push-and-pull motion.
• S waves:
  • S waves, or Secondary waves, are also body waves that move through the Earth's interior.
  • They are slower than P waves but faster than surface waves.
  • S waves cause particles to move perpendicular to the wave direction, creating an up-and-down or side-to-side motion.
• R waves:
  • Also known as the Rayleigh wave.
  • It has both compressional and shear motions.
  • These waves result from the interaction of P-waves and vertically polarized S-waves with the surface and can exist in any solid medium.

• Block mountains are the type of mountains in which the middle part of the mountain is lower and the parts on both sides are higher. 
• The middle part is known as the rift valley. 
• Black Forest (Germany), Salt Range (Pakistan), Vindhya and Satpura (India) are examples of block mountains. 
• The Ural is a fold mountain. Fold mountains are formed because of folds in the rocks due to the internal movements of the earth. 
• Block mountains - 

 

The correct answer is 30 km.

Key Points

• Earth’s crust:
  • The interior of the earth is made up of several concentric layers which are the crust, the mantle, the outer core and the inner core.
  • The crust is the outermost layer of the earth making up 0.5-1.0% of the earth’s volume and less than 1% of Earth’s mass.
  • Materials that initially stayed in their liquid phase during this process, called “incompatible elements,” ultimately became Earth's brittle crust. 
  • The lower layer of the crust consists of basaltic and ultra-basic rocks.
  • Density increases with depth, and the average density is about 2.7 g/cm3 (the average density of the earth is 5.51 g/cm³).
  • The thickness of the crust varies in the range of 5-30 km in the case of the oceanic crust and 50-70 km in the case of the continental crust.
  • The mean thickness of the oceanic crust is approximately 7 km, while the mean thickness of the continental crust is about 35-40 km.

Important Points

The correct answer is Increases

Key Points

• A rise in temperature with an increase in depth is observed in mines and deep wells.
• These evidence along with molten lava erupted from the earth’s interior supports that the temperature increases towards the centre of the earth.
• While in the upper 100kms, the increase in temperature is at the rate of 120C per km and in the next 300kms, it is 200C per km. But going further deep, this rate reduces to a mere 100C per km.
• It is assumed that the rate of increase in the temperature beneath the surface is decreasing towards the centre.
• Temperature is always increasing from the earth’s surface towards the centre.
• The temperature at the centre is estimated to lie somewhere between 30000C and 50000C, maybe that much higher due to the chemical reactions under high-pressure conditions.

​

The correct answer is i - b, ii - a, iii - c

Key Points

Lithification:

• It refers to the process by which loose and under-consolidated sediment particles transform into hard and solid rocks.
• This process includes a number of geological processes, such as consolidation, deep bury, cementation, recrystallization, and dehydration.

Igneous Rocks:

• As igneous rocks form out of magma and lava from the interior of the earth, they are known as primary rocks.
• The igneous rocks (Ignis – in Latin means ‘Fire’) are formed when magma cools and solidifies.
• When magma in its upward movement cools and turns into a solid form it is called igneous rock.
• The process of cooling and solidification can happen in the earth’s crust or on the surface of the earth.
• Igneous rocks are classified based on texture which depends upon the size and arrangement of grains or other physical conditions of the materials.
• Granite, gabbro, pegmatite, basalt, volcanic breccia, and tuff are some examples of igneous rocks.

Sedimentary Rocks

• The word ‘sedimentary’ is derived from the Latin word sediment, which means settling.
• Rocks (igneous, sedimentary, and metamorphic) of the earth’s surface are exposed to denudational agents and are broken up into various sizes of fragments.
• Such fragments are transported by different exogenous agencies and deposited.
• These deposits through compaction turn into rocks.
• In many sedimentary rocks, the layers of deposits retain their characteristics even after lithification.
• Hence, we see a number of layers of varying thickness in sedimentary rocks like sandstone, shale, geyserite, chalk, limestone, coal etc.

Metamorphic Rocks

• Metamorphic means ‘change of form’.
• These rocks form under the action of pressure, volume, and temperature (PVT) change.
• Metamorphism occurs when rocks are forced down to lower levels by tectonic processes or when molten magma rising through the crust comes in contact with the crustal rocks or the underlying rocks are subjected to great amounts of pressure by overlying rocks.
• Metamorphic rocks are formed due to the proximity of sedimentary rocks with molten magma.
• Mechanical disruption and reorganization of the original minerals within rocks due to breaking and crushing without any appreciable chemical changes are called dynamic metamorphism.
• Examples- Marble, Quartzite, Schist, etc.

Additional Information

Foliation:

• In the process of metamorphism in some rocks grains or minerals get arranged in layers or lines.
• Such an arrangement of minerals or grains in metamorphic rocks is called foliation or lineation.

The correct answer is Tethys Sea.

Important Points

• India is a part of Gondwana land.
• Around 200 million years ago, the large landmass called Panagea started splitting into two large continental masses called Laurasia and Gondwana.
• Gondwana was a supercontinent.
• It existed from the Neoproterozoic period until the Jurassic period.
• Laurasia is a continental mass in the Northern Hemisphere.
• It includes North America, Europe, and Asia except peninsular India.
• The Tethys Sea was an ocean during the Mesozoic era.

Additional Information

• The Black Sea separates Europe and Asia.
• The Red Sea lies between Africa and Arabia.
• The pacific ocean extends from the Arctic Ocean in the North to the Southern Ocean in the South.

The correct answer is Sandstone.

• Sandstone is NOT a metamorphic rock.

Key Points

• Metamorphic rocks are rocks that have become changed by intense heat or pressure while forming.
  • In the very hot and pressured conditions deep inside the Earth's crust, both sedimentary and igneous rocks can be changed into metamorphic rock.
  • ​Metamorphic rock can be formed locally when rock is heated by the intrusion of hot molten rock called magma from the Earth's interior.
    • Some examples of metamorphic rocks are gneiss, slate, marble, schist, and quartzite.
  • Marble, Slate, and quartz are formed after metamorphism. They changed in their original form due to extreme temperatures and pressure.
  • The three types of metamorphism are Contact, Regional, and Dynamic metamorphism.
  • Contact Metamorphism occurs when magma comes in contact with an already existing body of rock.

Additional Information

• Sandstone :
  • Sandstone is a sedimentary rock composed of sand-size grains of mineral, rock, or organic material.
    • It also contains a cementing material that binds the sand grains together and may contain a matrix of silt- or clay-size particles that occupy the spaces between the sand grains.
  • Sandstone is a sedimentary rock composed mostly of quartz sand, but it can also contain significant amounts of feldspar, and sometimes silt and clay.
  • Sandstone that contains more than 90% quartz is called quartzose sandstone.