All questions of Geomorphology for UPSC CSE Exam

Explanation:

Volcanoes and earthquakes are natural phenomena that occur due to the movement of tectonic plates. These plates make up the Earth's crust and are constantly shifting and colliding with each other. The majority of volcanoes and earthquakes in the world are located at plate margins.

Plate Margins:

Plate margins are the boundaries where two tectonic plates meet. There are three main types of plate boundaries:

1. Divergent Boundaries: This is where two plates move away from each other. This movement creates a gap between the two plates which magma rises up to fill, creating new crust. This is where most of the world's volcanoes are located.

2. Convergent Boundaries: This is where two plates move towards each other. This movement can cause one plate to be forced under the other, creating a subduction zone. This can cause earthquakes and volcanic eruptions.

3. Transform Boundaries: This is where two plates slide past each other horizontally. This can cause earthquakes but rarely causes volcanic eruptions.

Conclusion:

In conclusion, the majority of volcanoes and earthquakes in the world are located at plate margins. The movement of tectonic plates at these boundaries causes geological activity such as volcanic eruptions and earthquakes. Understanding plate tectonics and plate boundaries is important for predicting and mitigating the risks associated with these natural phenomena.

The question is asking about the incorrect statement but here both statement are correct so the option (D) is correct.

Explanation:
Not sedimentary rocks:
- Limestone: Limestone is a sedimentary rock formed from the remains of marine organisms such as coral and shells. It is composed mostly of calcium carbonate.
- Marble: Marble is a metamorphic rock formed from limestone that has undergone heat and pressure. It is composed of recrystallized carbonate minerals.
Therefore, limestone and marble are not sedimentary rocks, unlike sandstone and slate.

Oldest Rocks in the World

The oldest rocks in the world are found in Western Australia.

Evidence

- The rocks in Western Australia are known as the Jack Hills group and have been dated to be 4.4 billion years old.
- These rocks were formed during the Hadean Eon, which lasted from the formation of the Earth around 4.6 billion years ago to the beginning of the Archean Eon around 4 billion years ago.
- The rocks contain tiny zircon crystals which have been used to determine their age.
- The zircon crystals have been found to be up to 4.4 billion years old, making them the oldest known rocks in the world.

Importance

- The discovery of these rocks in Western Australia has important implications for our understanding of the early Earth.
- It suggests that the planet was able to cool and solidify much faster than previously thought.
- It also suggests that conditions on the early Earth were more hospitable for life than previously thought, as life is believed to have emerged around 3.5 billion years ago.

Conclusion

In conclusion, the oldest rocks in the world are found in Western Australia and are known as the Jack Hills group. These rocks have been dated to be 4.4 billion years old and contain tiny zircon crystals which have been used to determine their age. The discovery of these rocks has important implications for our understanding of the early Earth and the emergence of life.

Explanation:

Pole fleeing force is a term used to describe the outward-directed force associated with the spinning of the Earth. This force is also known as centrifugal force. It is the force that causes objects at or near the Earth's equator to experience a slight outward push. This force is due to the rotation of the Earth on its axis.

The centrifugal force is a result of the Earth's rotation, which causes the equator to bulge outwards slightly and the poles to flatten slightly. It is important to note that the pole fleeing force is not responsible for the bulging at the Earth's poles, which is primarily caused by the Earth's rotation and the gravitational pull of the Sun and Moon.

The pole fleeing force is an important factor to consider when studying the Earth's rotation. It influences the Earth's shape, the distribution of mass within the Earth, and the motion of the Earth's oceans and atmosphere.

Conclusion:

In summary, the pole fleeing force is the outward-directed force associated with the spinning of the Earth. It is not responsible for the bulging at the Earth's poles but is an important factor to consider when studying the Earth's rotation.

The Mid-Ocean Ridge system forms the most extensive chain of mountains on Earth, with more than 90% of the mountain range lying in the deep ocean - with a total length of about 60,000 km. Mid-ocean ridges are geologically important because they occur along divergent plate boundaries, where the new ocean floor is created as the Earth’s tectonic plates spread apart. As the plates separate, some molten rock rises to the seafloor, producing enormous volcanic eruptions of basalt, and building the longest chain of volcanoes in the world. Because most of these eruptions occur deep under the water, they often go unnoticed.

Difference between Extrusive and Intrusive Rocks

Introduction
Extrusive and intrusive rocks are two types of igneous rocks that differ in their formation, texture, and the duration of their formation. Understanding these differences is important in the study of geology and helps in identifying and classifying various rock formations.

Formation
1. Extrusive Rocks: Extrusive rocks are formed from magma, which is molten rock that reaches the Earth's surface through volcanic activity. When magma erupts from a volcano, it cools rapidly and solidifies to form extrusive rocks. Examples of extrusive rocks include basalt, obsidian, and pumice.

2. Intrusive Rocks: Intrusive rocks, on the other hand, are formed from lava, which is magma that has reached the Earth's surface. Instead of erupting, lava flows out of the volcano and cools slowly beneath the surface. This slow cooling allows for the formation of large mineral crystals, resulting in coarse-grained textures. Examples of intrusive rocks include granite, gabbro, and diorite.

Texture
1. Extrusive Rocks: Extrusive rocks have a fine-grained texture due to their rapid cooling. As the magma cools quickly at the surface, there is insufficient time for large mineral crystals to form. Instead, small crystals or even glassy structures are observed in extrusive rocks.

2. Intrusive Rocks: Intrusive rocks have a coarse-grained texture because of their slow cooling process. As the magma cools slowly beneath the surface, there is ample time for large mineral crystals to develop. These crystals are often visible to the naked eye and contribute to the coarse-grained appearance of intrusive rocks.

Duration of Formation
1. Extrusive Rocks: Extrusive rocks are formed relatively quickly, as the magma reaches the surface and cools rapidly. This process typically takes place over a short duration of time, such as days or weeks.

2. Intrusive Rocks: In contrast, the formation of intrusive rocks occurs over a much longer duration of time. The slow cooling of lava beneath the surface can take thousands or even millions of years, allowing for the growth of large mineral crystals.

Conclusion
In summary, extrusive and intrusive rocks differ in their formation, texture, and the duration of their formation. Extrusive rocks are formed from magma, have a fine-grained texture, and are formed relatively quickly. In contrast, intrusive rocks are formed from lava, have a coarse-grained texture, and are formed over a longer duration of time. Understanding these differences is essential in the study of igneous rocks and helps in identifying and classifying various geological formations.

Formation Location:
- Alluvial fans are formed in the higher reaches of the river, while deltas form at lower reaches.

Composition of Load:
- Alluvial fans are made of much coarser load compared to deltas.

Stratification:
- Alluvial fans do not show clear stratification of river load during deposition, whereas deltas exhibit clear stratification.

Therefore, the correct answer is option 'D' as all the given points highlight the key differences between alluvial fans and deltas.

The correct answer is option 'A' (1 only).


- Mesas and buttes are table-like land masses found in desert regions.
- They are characterized by their very resistant horizontal top layers and steep slopes.
- These landforms are formed due to the differential erosion of sedimentary rock layers.
- The hard and resistant top layer protects the softer layers underneath from erosion.
- Over time, the softer layers erode away, leaving behind the resistant top layer, which forms a flat-topped mesa or butte.
- The steep slopes of mesas and buttes are often referred to as "scarps" and can be several hundred meters high.
- These landforms are commonly found in arid regions, including deserts.


- Zeugen are not isolated residual round hills found in the desert.
- Zeugen are actually elongated ridges or hills that are formed as a result of erosion.
- They are typically found in areas where there are horizontal layers of rock with alternating hard and soft layers.
- The soft layers erode more quickly, leaving behind the hard layers, which form the elongated ridges or hills.
- Zeugen are not exclusive to desert regions and can be found in various landscapes.

In conclusion, statement 1 is correct as mesas and buttes are table-like land masses with very resistant horizontal top layers and steep slopes. However, statement 2 is incorrect as zeugen are not isolated residual round hills found in the desert.

Weathering of rocks:
- Weathering is the process by which rocks are broken down into smaller pieces or undergo chemical changes due to exposure to various environmental factors such as wind, water, and temperature changes.
- As rocks undergo weathering, the minerals present in them are released and become available for other processes to act upon.
- This weathering process can be physical, such as the freezing and thawing of water in cracks, or chemical, such as the reaction of rock minerals with water or acids.
- The weathering of rocks plays a significant role in the enrichment of minerals in rocks because it breaks down the rock into smaller particles, exposing more surface area for chemical reactions to occur.

Erosional and depositional action of rivers:
- Rivers play a crucial role in the transportation and deposition of sediments.
- As rivers flow, they erode the land, carrying sediments such as rocks, minerals, and soil particles.
- These sediments are transported downstream and eventually deposited when the river's velocity decreases, such as in river bends or at the mouth of the river.
- During this process, minerals that were weathered from rocks in the upstream areas are carried by the river and deposited in new locations.
- The erosional and depositional action of rivers helps in redistributing and concentrating minerals, thereby contributing to the enrichment of minerals in rocks.

Both (a) and (b):
- Both weathering of rocks and the erosional and depositional action of rivers contribute to the enrichment of minerals in rocks.
- Weathering breaks down rocks, releasing minerals and making them available for other processes.
- Rivers then transport these minerals and deposit them in new locations, contributing to the enrichment of minerals in rocks.
- The combined action of weathering and rivers helps in the concentration and redistribution of minerals, ultimately leading to the enrichment of minerals in rocks.

Therefore, the correct answer is option 'C' - Both (a) and (b).

All are correct.

• The catchments of large rivers are called river basins while those of small rivulets and rills are often referred to as watersheds.
• There is, however, a slight difference between a river basin and a watershed. Watersheds are small in area while the basins cover larger areas.
• River basins and watersheds are marked by unity. What happens in one part of the basin or watershed directly affects the other parts and the unit as a whole.
• That is why they are accepted as the most appropriate micro-, meso- or macro-planning regions. Every tributary too has a watershed. Sum of watersheds gives rise to river basin.

Sedimentary rocks are studied by geologists because:

1. They provide a record of Earth's history:
- Sedimentary rocks are formed from the accumulation and consolidation of sediments, which can include particles of minerals, rocks, and organic materials.
- These sediments are deposited in layers over time, preserving a chronological record of Earth's history.
- Geologists can study the composition, texture, and structure of sedimentary rocks to understand past environmental conditions, such as climate, sea level changes, and tectonic activity.
- By analyzing the different layers and their characteristics, geologists can reconstruct the geological history of an area, including the formation of mountains, the erosion of landforms, and the deposition of sediments in ancient lakes, rivers, and oceans.

2. They may contain important mineral resources:
- Sedimentary rocks often contain economically valuable mineral resources, such as coal, oil, natural gas, and various types of ores.
- Geologists study sedimentary rocks to identify and assess the potential for these mineral resources.
- By examining the geological processes that led to the formation and accumulation of these resources, geologists can provide insights into their distribution, abundance, and quality.
- This information is crucial for resource exploration, extraction, and management, as it helps in locating and estimating the economic viability of mineral deposits.

3. They may contain fossils, providing a history of life including human evolution:
- Sedimentary rocks are the primary repository of fossils, which are the preserved remains or traces of ancient organisms.
- Fossils found in sedimentary rocks provide important evidence for the history of life on Earth, including the evolution of different species, ecosystems, and even the emergence of humans.
- Geologists study fossils embedded in sedimentary rocks to understand past biodiversity, paleoenvironments, and the relationships between different organisms.
- This information helps in reconstructing the evolutionary history of life, identifying extinct species, and understanding the processes that have shaped biological diversity over millions of years.

Conclusion:
Geologists study sedimentary rocks because they provide a valuable record of Earth's history, contain important mineral resources, and preserve fossils that offer insights into the evolution of life, including human evolution. Understanding sedimentary rocks is crucial for various fields of geology, including paleontology, stratigraphy, and resource exploration.

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Sources of earthquakes

• Tectonic earthquakes - sliding of plates along a fault plane.
• Volcanic earthquakes - Collapse of roofs of underground mines.

Sedimentary rocks can be directly formed from which of the following:

1. Magma
2. Igneous rocks
3. Metamorphic rocks

The correct answer is option 'B' which is 2 and 3 only.

Explanation:
Sedimentary rocks are formed from the accumulation of sediments or organic matter that have been deposited in layers over time. These sediments can come from a variety of sources such as weathering and erosion of other rocks, as well as the remains of plants and animals.

Sedimentary rocks can be directly formed from two types of rocks:

1. Igneous rocks: These rocks are formed from the cooling and solidification of magma or lava. When these rocks are weathered and eroded, they can break down into sediments which can then be deposited and compacted to form sedimentary rocks.

2. Metamorphic rocks: These rocks are formed from the alteration of pre-existing rocks due to heat and pressure. When these rocks are weathered and eroded, they can break down into sediments which can then be deposited and compacted to form sedimentary rocks.

However, sedimentary rocks cannot be directly formed from magma as it cools and solidifies to form igneous rocks, nor from metamorphic rocks as they are already altered from pre-existing rocks.

Therefore, the correct answer is option 'B' which is 2 and 3 only.

Rapids and cataracts are formed by Fluvial action.

Fluvial action refers to the processes related to the movement of water in rivers, streams, and other bodies of water. It includes erosion, transportation, and deposition of sediment by the action of flowing water. Rapids and cataracts are specific landforms that are created as a result of fluvial action.

Here is a detailed explanation of how rapids and cataracts are formed by fluvial action:

1. Erosion: Erosion is the first step in the formation of rapids and cataracts. As water flows over uneven surfaces, it exerts a force on the surrounding rocks and sediment. Over time, this force can wear away the rock and create irregularities in the riverbed. The erosive action of the flowing water can be enhanced by the presence of sediment and rocks carried by the river.

2. Differential erosion: In some areas, the rocks may be more resistant to erosion than others. This differential erosion leads to the formation of irregularities and variations in the riverbed. The resistant rocks may form small barriers or obstacles that disrupt the flow of water and create turbulence. These irregularities contribute to the formation of rapids.

3. Velocity and gradient: The velocity of the flowing water plays a crucial role in the formation of rapids and cataracts. When the gradient of the river is steep, and the water flows rapidly, it encounters more resistance from the irregularities in the riverbed. This resistance causes the water to churn, creating turbulent currents and rapids.

4. Deposition: In some cases, the erosion and turbulence caused by the flowing water may lead to the deposition of sediment downstream. This deposition can further contribute to the formation of rapids and cataracts by creating obstacles and irregularities in the riverbed.

In summary, rapids and cataracts are formed by the erosive action of flowing water in rivers and streams. The presence of resistant rocks, variations in the riverbed, and high velocity of the water contribute to the formation of these dynamic and visually striking landforms. Fluvial action is responsible for shaping and reshaping the landscape through erosion, transportation, and deposition of sediment, ultimately leading to the formation of rapids and cataracts.

Overview:
River capture is a geomorphological process in which a stream or river drainage system is diverted from its own bed and flows instead down the bed of a neighboring stream. It is also known as river beheading and can occur due to tectonic Earth movements or erosion.

Explanation:
The given statements are as follows:

Statement 1: It is a geomorphological phenomenon occurring when a stream or river drainage system or watershed is diverted from its own bed and flows instead down the bed of a neighboring stream.

This statement is correct. River capture is a natural process where water from one river or stream is diverted to flow into another river or stream. This can happen due to various factors such as changes in the landscape, erosion, or tectonic activities. When a river captures another, it usually occurs at a point where the two river systems are close to each other and the water can easily flow from one to another.

Statement 2: It is also called river beheading.

This statement is correct. River capture is also known as river beheading because one river captures the drainage of another river, leading to the diversion of water flow.

Statement 3: Apart from tectonic Earth movements, erosion also results in river capture.

This statement is correct. River capture can occur due to both tectonic Earth movements and erosion. Tectonic movements, such as the uplift of land or the creation of a new fault line, can alter the landscape and cause changes in the drainage patterns of rivers. Erosion, on the other hand, can occur due to the wearing away of the land by the force of the flowing water, leading to changes in the river courses and potential river capture.

Conclusion:
In conclusion, all the given statements are correct. River capture is a geomorphological phenomenon that can occur due to tectonic Earth movements or erosion. It involves the diversion of a river or stream from its own bed to flow down the bed of a neighboring stream.

Type of dune: Seif

A seif dune is a long, narrow sand dune or chain of dunes that is generally oriented in a direction parallel to the prevailing wind or a direction resulting from two or more winds blowing at acute angles to each other.

Characteristics of a Seif dune:
- Orientation: Parallel to the prevailing wind direction or a direction resulting from two or more winds blowing at acute angles to each other.
- Shape: Long and narrow with a gentle slope on the windward side and a steep slope on the leeward side.
- Size: Can be several meters to several kilometers long and up to 150 meters high.
- Formation: Results from the movement of sand grains by wind.

Other types of dunes:
- Barchan dune: Crescent-shaped and formed by winds blowing predominantly from one direction.
- Loess: A type of sediment formed from wind-blown dust and silt.
- Erg: Large area covered with sand dunes.

This question belongs to the UPSC category, which is the Union Public Service Commission in India.

Understanding Well-Sorted and Well-Rounded Sand Grains
Well-sorted and well-rounded sand grains provide significant insights into the sediment's transportation history and source.
Characteristics of Well-Sorted Sand
- Uniform Size: Well-sorted sand grains are similar in size, suggesting that they have undergone a consistent process of sorting, likely during transport.
- Indication of Energy: The uniformity in grain size indicates that the sediment was subjected to a consistent energy level, often found in environments with strong currents or waves.
Characteristics of Well-Rounded Sand
- Erosion and Transport: Well-rounded grains have been weathered and eroded over time, indicating extensive transport. The rounding process occurs as grains collide with each other and with other materials, smoothing their edges.
- Distance from Source: The more rounded and sorted the grains are, the further they have traveled from their source. This is because the process of rounding takes time and distance.
Why Option C is Correct
- Transportation from Distant Source: The combination of well-sorted and well-rounded grains strongly suggests that the sediment has traveled from a distant source area. The grains have likely been subjected to various environmental forces, such as water or wind, over a prolonged period.
- Comparison with Other Options:
- Option A (nearby source) is unlikely, as nearby sources usually yield poorly sorted grains.
- Option B (deposited at the location) does not align with the characteristics of well-rounded grains.
- Option D (not influenced by weathering) contradicts the very nature of well-rounded grains, which have been significantly weathered.
In summary, the evidence of well-sorted and well-rounded sand grains indicates they have traveled from a distant area, making option C the correct answer.

Explanation:

Metamorphic rocks are formed when existing rocks, either igneous or sedimentary, undergo a transformation due to intense heat and pressure. This process causes the minerals in the rocks to recrystallize, resulting in a new rock with different physical and chemical properties.

The correct conversions to metamorphic rocks are:

1. Clay to slate: Clay is a sedimentary rock composed mainly of fine-grained minerals. Under high pressure and temperature, the minerals in the clay recrystallize, forming a dense, fine-grained rock called slate. Slate is characterized by its ability to be easily split into thin, flat sheets.

2. Coal to graphite: Coal is a sedimentary rock formed from the remains of plant material. When subjected to high temperature and pressure, coal undergoes a metamorphic transformation and turns into graphite. Graphite is a crystalline form of carbon with a layered structure and is known for its lubricating properties and use in pencils.

3. Sandstone to quartzite: Sandstone is a sedimentary rock composed of sand-sized grains of mineral, rock, or organic material. Under intense heat and pressure, the sand grains in sandstone recrystallize and fuse together, forming a harder and more compact rock called quartzite. Quartzite is composed mainly of quartz and is known for its durability and resistance to weathering.

4. Shale to schist: Shale is a sedimentary rock composed of fine particles of clay minerals. When subjected to high temperature and pressure, shale undergoes metamorphism and transforms into a metamorphic rock called schist. Schist is characterized by its foliated texture, with minerals aligned in layers or bands.

Therefore, the correct conversions to metamorphic rocks are 1, 2, 3, and 4. Thus, option 'D' - "All of the above" is the correct answer.

The major characteristics of the Archaean rock system can be summarized as follows:

a) Formed before the appearance of life in the geologic sequence:
The Archaean rock system refers to the oldest rock system on Earth, which formed between 4 to 2.5 billion years ago. It predates the appearance of life on Earth, as the first evidence of life dates back to around 3.5 billion years ago. Therefore, the Archaean rock system was formed before the appearance of life in the geologic sequence.

b) Not the first metamorphic sedimentary rock:
While the Archaean rock system is known for its high-grade metamorphic rocks, it is not the first metamorphic sedimentary rock system. Metamorphic rocks are formed from pre-existing rocks under conditions of high temperature and pressure. The Archaean rock system is primarily composed of igneous rocks, which were formed through volcanic activity.

c) Not the host of major coal deposits of India:
The major coal deposits of India are primarily found in the Gondwana rock system, which formed during the Permian and Carboniferous periods, around 300 to 200 million years ago. The Archaean rock system, being much older, does not host the major coal deposits of India.

d) Largely igneous rocks:
The Archaean rock system is predominantly composed of igneous rocks. Igneous rocks are formed through the solidification and crystallization of molten magma or lava. The Archaean rock system is characterized by the presence of various types of igneous rocks, including granite, gneiss, and greenstone belts. These rocks provide valuable insights into the early history of Earth's formation and the processes that shaped its crust.

In conclusion, the major characteristic of the Archaean rock system is that it was formed before the appearance of life in the geologic sequence. This rock system is primarily composed of igneous rocks and is distinct from the later rock systems that host coal deposits and exhibit metamorphic sedimentary characteristics.

Geos and gloups are the landforms formed by the action of waves.

Waves are a powerful force of nature that constantly shape the Earth's coastlines. They are primarily formed by the wind blowing across the surface of the ocean, which creates ripples that eventually develop into waves. As waves approach the shore, they undergo various processes that lead to the formation of landforms such as geos and gloups.

Formation of Geos:
- Geos are narrow, steep-sided inlets or clefts in coastal cliffs. They are formed through the process of wave erosion.
- When waves approach the coastline, their energy is concentrated on headlands or areas of more resistant rock.
- The power of the waves, combined with the presence of joints or faults in the rock, causes the cliffs to be eroded and weakened over time.
- As the waves continue to crash against the cliffs, they exploit these weaknesses and create narrow, deep indentations known as geos.
- The erosion process is typically more pronounced during stormy weather or high tides when the waves are stronger.

Formation of Gloups:
- Gloups are circular or oval-shaped depressions in coastal cliffs that are also formed through wave erosion.
- Similar to geos, gloups are created by the relentless action of waves against the cliffs.
- However, the formation of gloups is influenced by the presence of caves or softer layers of rock within the cliffs.
- As the waves batter the cliffs, they gradually erode these weaker areas, creating cavities or caves.
- Over time, the roofs of these caves may collapse, resulting in the formation of depressions known as gloups.
- Gloups are often found near the base of the cliffs and can vary in size and depth.

Conclusion:
In conclusion, geos and gloups are landforms that are formed by the action of waves. Through the process of wave erosion, waves shape the coastal cliffs, exploiting weaknesses in the rock to create these distinctive features. Understanding the formation of geos and gloups is important in studying coastal processes and the evolution of coastlines.

Answer:

Rocks That Make Up the Crust of Earth

The crust of the Earth is made up of various types of rocks, but some of them make up for large portions of it. These rocks are:

1. Granitic rocks
2. Basaltic rocks

Explanation:

Granitic rocks are igneous rocks that are light-colored and have a coarse-grained texture. They are formed from the slow cooling of magma beneath the Earth's surface. They are found in the continental crust and make up a large portion of it.

Basaltic rocks, on the other hand, are dark-colored igneous rocks that have a fine-grained texture. They are formed from the rapid cooling of lava on the Earth's surface. They are found in the oceanic crust and make up a significant portion of it.

Pumice rocks and obsidian rocks are also types of igneous rocks, but they do not make up large portions of the Earth's crust. Pumice rocks are formed from the rapid cooling of lava that is rich in gas bubbles, while obsidian rocks are formed from the rapid cooling of lava that is rich in silica.

Conclusion:

Therefore, the correct answer to this question is option 'B' - 1 and 2 only, as granitic rocks and basaltic rocks make up for large portions of the Earth's crust.

Himalayan region and its poor mineral resources

There are several factors that contribute to the Himalayan region being poor in mineral resources. However, the most significant reason is the complex rock structure in the region.

Complex rock structure

The Himalayan region is characterized by a complex geological history, resulting in the formation of diverse rock types and structures. The region is mainly composed of metamorphic and sedimentary rocks, which are less likely to contain significant mineral deposits compared to other types of rocks such as igneous rocks. Metamorphic rocks are formed through the transformation of pre-existing rocks under high pressure and temperature conditions, which often leads to the loss of mineral resources.

Unfavorable terrain and adverse climatic conditions

While the undulating terrain and adverse climatic conditions in the Himalayan region certainly pose challenges for mineral exploration and extraction, they are not the primary reasons for the region's poor mineral resources. These factors may make it difficult to access certain areas and conduct mining operations, but they do not directly impact the presence or absence of mineral resources in the region.

Crystalline rocks and mineral resources

The statement mentioned that the Himalayan region is made up of crystalline rocks, which do not hold mineral resources anywhere in India. This is incorrect. Crystalline rocks can indeed contain mineral resources, although their presence and abundance vary from region to region. Crystalline rocks, such as granite and gneiss, can host valuable minerals such as gold, silver, copper, and tin. However, in the case of the Himalayan region, the primary reason for the lack of mineral resources is the complex rock structure rather than the presence of crystalline rocks.

In conclusion, the Himalayan region's poor mineral resources can be attributed to its complex rock structure, which is dominated by metamorphic and sedimentary rocks. While other factors such as unfavorable terrain and adverse climatic conditions might pose challenges for mineral extraction, they are not the main reasons for the region's limited mineral resources.

Mount Aso is located in Japan and is an active volcano. However, the statement that it was an active volcano a few decades back, but is an inactive volcano now is incorrect. Therefore, statement 1 is incorrect.

The correct statements about Mount Aso are:

Location:
- Mount Aso is located in Japan.

Activity:
- Mount Aso is an active volcano.
- The explosions in Mount Aso can be of high intensity at times.

Therefore, the correct answer is option 'D' (2 only).

Sandstone is a sedimentary rock formed by sedimentation of sand grains.

Vertical erosion is dominant in the upper courses of the river.

Introduction:
Oxbow lakes are a common feature found in the upper courses of rivers. They are formed when a meandering river creates a loop or bend that eventually gets cut off from the mainstream due to erosion and deposition processes. Oxbow lakes are also known as bayous or cut-offs in the USA.

Explanation:
Let's analyze each statement given in the question to determine their correctness:

Statement 1: Oxbow lakes are formed when an almost circular meander is cut off from the mainstream.
This statement is correct. Oxbow lakes are formed when a river's meander loop becomes so pronounced that the river cuts through the narrow neck of the loop, creating a new straight channel. This process is known as "cutoff" or "abandonment." The loop, which is left isolated from the main river, becomes an oxbow lake.

Statement 2: Oxbow lakes are observed in the upper courses of a river.
This statement is correct. Oxbow lakes are typically found in the upper courses of rivers where the gradient is steep and the river is more prone to meandering. As the river flows through its course, it erodes the outer bank of a bend and deposits sediment on the inner bank, causing the bend to become more pronounced and eventually cutoff.

Statement 3: Oxbow lakes are also called Bayous or cut-offs in the USA.
This statement is correct. In the USA, oxbow lakes are commonly referred to as bayous or cut-offs. The term "bayou" is derived from the Choctaw word "bayuk," meaning a small river. These terms are often used interchangeably to describe the same landforms.

Conclusion:
In conclusion, both statements 1 and 3 are correct. Oxbow lakes are formed when a meander loop is cut off from the mainstream, and they are also known as bayous or cut-offs in the USA. However, statement 2 is incorrect as oxbow lakes are found in the upper courses of rivers, not exclusively in the upper courses. Therefore, the correct answer is option 'C' - 1 and 3 only.

Soil creep indicates slow movement while solifluction is fast movement.

The correct answer is option 'D' - Deccan Traps.

Explanation:
The Deccan Traps is a large volcanic province located in west-central India. It is composed of multiple layers of solidified basalt lava flows. The rocks of the Deccan Traps were formed during the Late Cretaceous period, approximately 66 million years ago.

Formation of the Deccan Traps:
1. Geological Activity: The formation of the Deccan Traps can be attributed to intense volcanic activity that occurred during the breakup of the supercontinent Gondwana.
2. Massive Eruptions: The volcanic activity resulted in massive eruptions that released vast amounts of basaltic lava onto the surface.
3. Lava Flows: The lava flows spread over an area of approximately 500,000 square kilometers, covering the present-day states of Maharashtra, Madhya Pradesh, Gujarat, and Karnataka.
4. Layered Structure: Over time, the successive eruptions led to the formation of multiple layers of solidified lava flows, creating a distinctive layered structure.
5. Thickness and Extent: The Deccan Traps cover an immense thickness of up to 2,000 meters and are considered one of the largest volcanic provinces in the world.

Importance of the Deccan Traps:
1. Geological Significance: The Deccan Traps hold immense geological significance as they provide valuable insights into the Earth's history, climate changes, and mass extinctions.
2. Mass Extinction Event: The timing of the Deccan Traps' formation coincides with the mass extinction event that resulted in the extinction of the dinosaurs. It is believed that the volcanic activity and the release of gases and aerosols had a significant impact on the global climate, contributing to the extinction event.
3. Mineral Resources: The Deccan Traps also contain various mineral resources, including basalt, granite, and limestone, which are important for construction and industrial purposes.

In conclusion, the rocks of the Deccan Traps in India were formed the earliest among the given options. The intense volcanic activity during the Late Cretaceous period led to the deposition of multiple layers of solidified basalt lava flows, creating the distinctive geological formation known as the Deccan Traps.

Factors Aiding the Weathering of Rocks

Weathering refers to the process by which rocks are broken down into smaller fragments or transformed into different minerals through physical, chemical, and biological processes. Several factors contribute to the weathering of rocks. The correct answer, option 'D', states that all of the following factors aid in the weathering of rocks:

1. Intense heating during the day and rapid cooling at night:
- Temperature changes play a significant role in the weathering of rocks. When rocks are exposed to intense heating during the day, they expand. As a result, cracks and fractures develop within the rocks.
- At night, the rapid cooling causes the rocks to contract. This contraction further enhances the development of cracks and fractures. Over time, these cracks and fractures become pathways for water and other weathering agents to penetrate deeper into the rocks, accelerating the weathering process.

2. Pore pressure of water seeping into rocks:
- Water is one of the most important agents of weathering. When water seeps into rocks, it exerts pressure on the rock material, known as pore pressure.
- The pore pressure of water can weaken the rocks, especially if the water freezes and expands within the rock crevices. This process, known as frost wedging, causes the rocks to crack and break apart.

3. Thawing of rocks:
- Thawing refers to the process of melting frozen water within rocks. When water freezes within the rock crevices, it expands, exerting pressure on the surrounding rock material.
- During thawing, the ice melts, releasing the pressure within the rock. This repeated freezing and thawing cycle weakens the rocks, leading to the development of cracks and fractures.

In summary, all three factors mentioned in the given options contribute to the weathering of rocks. Intense heating and rapid cooling lead to thermal expansion and contraction, pore pressure of water seeping into rocks causes frost wedging, and the thawing process weakens the rocks. These processes eventually break down the rocks into smaller fragments, facilitating the further breakdown and transformation of the rocks through weathering processes.

Answer:

Factors responsible for changes on Earth's surface:

There are several factors responsible for bringing changes on the surface of the Earth. Some of the major factors are discussed below:

1. Tectonic forces:

Tectonic forces include processes like plate tectonics, earthquakes, volcanic eruptions, and mountain building. These forces are responsible for the creation of new landforms and the destruction of existing ones. Plate tectonics is the key process that drives the movement of the Earth's crust.

2. Gravitational force:

The gravitational force of the Earth is responsible for many changes on its surface. It causes erosion, weathering, and mass wasting. Erosion is the process by which the surface of the Earth is worn away by the action of water, wind, or ice. Weathering is the breakdown of rocks into smaller pieces due to the action of weather. Mass wasting is the downhill movement of soil and rock under the influence of gravity.

3. Electromagnetic radiation:

Electromagnetic radiation from the sun is responsible for many changes on the Earth's surface. It causes weather patterns, ocean currents, and the growth of plants. The sun's energy is also responsible for the water cycle, which is the process by which water evaporates from the surface of the Earth and is later returned as precipitation.

Correct answer:

All of the above (1, 2, and 3) are responsible for bringing changes on the surface of the Earth.

Explanation:

Alpine mountain building phase is the recent phase to which the Himalayan mountains belong to. The Ural Mountains were not formed during the Alpine orogeny (mountain building phase).

Therefore, the correct answer is option 'A' - 1 only.

- Alpine Mountain Building Phase
The Alpine mountain building phase is the most recent phase and began about 40 million years ago. This phase is ongoing and still forming mountains today in areas such as the Himalayas, the Alps, and the Andes.

- Himalayan Mountains
The Himalayan Mountains are a range of fold mountains located in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. They were formed during the ongoing Alpine mountain building phase.

- Ural Mountains
The Ural Mountains are a range of fold mountains located in western Russia, separating Europe and Asia. They were formed during the Variscan orogeny, which occurred about 300 million years ago, and not during the Alpine mountain building phase.

Therefore, statement 1 is correct, and statement 2 is incorrect.

Volcanic Origin of Galapagos Islands:
- The first statement is correct. The Galapagos Islands are of volcanic origin. They were formed by volcanic activity over millions of years. The islands are located on the Nazca Plate, a tectonic plate in the Pacific Ocean.

Unique Adaptations and Endemic Species:
- The second statement is also correct. The Galapagos Islands have a unique ecosystem with diverse and distinct plant and animal species. The islands' harsh and isolated conditions, including stark rocky landscapes and limited freshwater sources, have created challenges for survival.
- Many species have adapted to these conditions over time, resulting in the evolution of new endemic species found only on the Galapagos Islands. These adaptations can include changes in physical characteristics, behavior, and feeding habits.

Galapagos Islands and Darwin's Theory of Evolution:
- The third statement is correct as well. The Galapagos Islands were instrumental in the development of Charles Darwin's Theory of Evolution. Darwin visited the islands during his famous voyage on the HMS Beagle in the 1830s.
- The unique and diverse species he encountered on the islands, such as the Galapagos finches and giant tortoises, played a crucial role in shaping his ideas about natural selection and the process of evolution.
- Darwin observed variations among these species, which he later concluded were adaptations to different ecological niches. This led him to propose that species could change over time through the process of natural selection, where those individuals with advantageous traits are more likely to survive and reproduce.

Conclusion:
- In conclusion, all three statements are correct. The Galapagos Islands are volcanic in origin and were never attached to any continent. The unique environment and limited resources on the islands have led to the evolution of new endemic species. Moreover, the Galapagos Islands played a pivotal role in the development of Darwin's Theory of Evolution.

**Introduction:**
Volcanoes are geological features that occur when magma, gas, and other materials from the Earth's interior are released through openings in the Earth's surface. They are typically found in specific geological locations that are associated with tectonic plate boundaries or areas of geological activity. In this context, we will explore the likelihood of the occurrence of volcanoes in the given geological locations.

**Coastal Mountain Ranges:**
Coastal mountain ranges are formed by the collision or subduction of tectonic plates. These tectonic activities create intense pressure and heat, leading to the melting of rocks and the formation of magma. As the magma rises through cracks and fissures in the Earth's crust, it can erupt onto the surface and form volcanoes. Notable examples of volcanic activity in coastal mountain ranges include the Cascade Range in North America and the Andes in South America.

**Off-Shore Islands:**
Off-shore islands, especially those located near tectonic plate boundaries, are commonly associated with volcanic activity. These islands are often formed by volcanic eruptions that occur underwater. As the magma rises and reaches the surface, it cools and solidifies, eventually forming new landmasses. Well-known examples of volcanic islands include the Hawaiian Islands, which were formed by a hotspot beneath the Pacific Plate.

**Midst of Deep Ocean Beds:**
Deep ocean beds are generally associated with tectonic plate boundaries, which are hotspots for volcanic activity. Underwater volcanic eruptions can occur along mid-ocean ridges, where tectonic plates are diverging, or at subduction zones, where one tectonic plate is being forced beneath another. These volcanic activities contribute to the formation of seamounts and underwater volcanoes. One such example is the Axial Seamount located off the coast of Oregon in the United States.

**Conclusion:**
Based on the geological processes and locations described, it is evident that volcanic activity is likely to occur in all three given geological locations: coastal mountain ranges, off-shore islands, and the midst of deep ocean beds. These areas are associated with tectonic plate boundaries, where the conditions for magma generation and eruption are favorable. Therefore, the correct answer is option 'D': All of the above.