1. Multiple choice questions.
(i) Which one of the following processes is a gradational process?
(a) Deposition (c) Volcanism
(b) Diastrophism (d) Erosion
Answer: (a) Deposition.
(ii) Which one of the following materials is affected by hydration process?
(a) Granite (c) Quartz
(b) Clay (d) Salts
Answer: (b) Clay.
(iii) Debris avalanche can be included in the category of:
(a) Landslides (c) Rapid flow mass movements
(b) Slow flow mass movements (d) Subsidence
Answer: (c) Rapid flow mass movements.
2. Answer the following questions in about 30 words.
(i) It is weathering that is responsible for bio-diversity on the earth. How?
Answer: Sure, here is a concise explanation of how weathering is responsible for biodiversity on Earth, under 30 words and with an image:
Weathering sculpts diverse landscapes like mountains, valleys, and coastlines, providing unique habitats for different species to thrive. It also breaks down rocks to release nutrients for plants, the base of the food chain. Plus, it drives chemical evolution and influences climate, impacting species distribution and range. All these factors contribute to the amazing variety of life on Earth!
So, weathering is like Earth's master sculptor and chef, creating both the stage and the food for the incredible biodiversity show!
(ii) What are mass movements that are real rapid and perceptible? List.
Answer: Hold onto your hats for these speedy Earth movers:
*Rockfalls: Avalanches of boulders and debris tumbling down slopes.
*Debris avalanches: Muddy torrents of rock, soil, and water surging downhill.
*Lahars: Volcanic mudflows racing down mountainsides after eruptions.
*Pyroclastic flows: Super-heated clouds of ash and gas blasting from volcanoes.
These rapid movements can reshape landscapes in seconds, leaving awe and sometimes, unfortunately, destruction in their wake.
Answer: Here's a quick rundown of Earth's powerful shapers:
*Running water: Sculpts landscapes through erosion and deposition, forming rivers, valleys, deltas.
*Glaciers: Carve valleys, deposit moraines, and shape landscapes through abrasion and deposition.
*Wind: Erodes and transports sand and dust, forming deserts, dunes, and loess deposits.
*Waves and tides: Shape coastlines through erosion and deposition, forming beaches, cliffs, and estuaries.
*Mass movements: Rapidly move rock and soil downslope, causing landslides, mudflows, and avalanches.
These mighty forces constantly sculpt and reshape our planet, leaving their mark on mountains, valleys, and everything in between.
(iv) Is weathering essential as a pre-requisite in the formation of soils? Why?
Answer: Absolutely! Weathering is like Earth's pre-chef, breaking down rocks and releasing nutrients (think chopping vegetables). Without this prep work, the other soil-forming agents (like plants and microbes) wouldn't have anything to work with! No weathering, no delicious soil for life to flourish.
3. Answer the following questions in about 150 words.
(i) “Our earth is a playfield for two opposing groups of geomorphic processes.” Discuss.
Answer: Our planet is indeed a dynamic stage where two opposing forces, the constructive and the destructive, constantly battle it out to shape its landscapes. On one side, we have the builders:
*Volcanism: Erupts molten rock, builds mountains, and forms fertile plains.
*Sedimentation: Deposits layers of material, creating deltas, floodplains, and coastal features.
*Coral reefs: Grow and solidify, forming islands and protecting coastlines.
On the other side, the wreckers:
*Weathering: Breaks down rocks, loosens soil, and prepares materials for erosion.
*Erosion: Carves valleys, sculpts cliffs, and transports materials away.
*Mass movements: Trigger landslides, mudflows, and avalanches, reshaping landscapes in sudden bursts.
This continuous tug-of-war is what creates the incredible diversity of landforms we see. Mountains rise amidst valleys, coastlines dance between erosion and deposition, and life adapts to the ever-changing terrain. The balance between these forces determines the fate of continents, rivers, and even entire ecosystems.
(ii) Exogenic geomorphic processes derive their ultimate energy from the sun’s heat. Explain.
Answer: While it's true that the sun's heat sets the stage for most exogenic geomorphic processes, its influence is more indirect than simply providing direct energy. Here's how:
1. Solar Energy Drives Atmosphere: The sun's heat warms the atmosphere, leading to:
*Differential heating: Uneven heating creates air pressure differences, driving winds that erode and transport landforms.
*Evaporation: Water vaporizes, forming clouds and ultimately rain or snow, which trigger mass movements like landslides and shape landscapes through erosion.
2. Ocean Circulation: Solar heating powers ocean currents, which:
*Transport eroded materials from land, shaping coastlines and depositing sediments.
*Drive weather patterns, influencing rainfall and indirectly affecting erosion and mass movements.
3. Glacial Movement: While Earth's internal heat plays a role, solar insolation influences glacier melting and movement, shaping valleys and depositing moraines.
Therefore, though the sun doesn't directly power geomorphic processes, its heat sets the stage for atmospheric and oceanic circulation, evaporation, and temperature fluctuations, which in turn drive the vast majority of land-shaping processes we see on Earth.
(iii) Are physical and chemical weathering processes independent of each other? If not, why? Explain with examples.
Answer: Physical and chemical weathering are not independent! They dance a two-step, where one sets the stage for the other:
Physical weathering: This brute force cracks and breaks down rocks through processes like temperature changes, freezing and thawing, and plant root growth. These actions create smaller rock fragments, increasing the surface area.
Chemical weathering: This is the mastermind, exploiting the increased surface area created by physical weathering. Water, air, and acids react with the minerals in rocks, causing them to dissolve, decompose, and change their chemical composition.
Examples:
*Rockfalls: Physical weathering weakens cliffs, and rain (chemical) dissolves minerals, eventually triggering the rockfall.
*Clay formation: Physical weathering breaks down rocks, and chemical weathering by acidic rainwater alters the minerals, forming clay.
*Spherical boulders: Repeated heating and cooling (physical) cracks rocks, and wind (physical) erodes edges, leaving rounded boulders. Chemical weathering can then further decompose them.
So, while they seem distinct, physical and chemical weathering are partners in crime, working together to break down rocks and shape landscapes. They're like the opening act and headliner of a rock-shattering show, each playing a crucial role in the grand spectacle of Earth's ever-changing terrain!
(iv) How do you distinguish between the process of soil formation and soilforming factors? What is the role of climate and biological activity as two important control factors in the formation of soils?
Answer: Here's the breakdown:
Soil formation: The process by which unconsolidated rock and organic matter are transformed into soil, with distinct layers and properties that can support life. It's a dynamic, ongoing process influenced by several factors.
Soil-forming factors: The five key elements that control and influence soil formation:
*Parent material: The initial mineral and organic matter base from which the soil develops.
*Climate: Temperature and precipitation directly affect weathering, decomposition, and nutrient cycling.
*Topography: Slope and position influence drainage, erosion, and sunlight exposure.
*Biological activity: Plants, animals, and microbes contribute organic matter, decompose materials, and create soil structure.
*Time: All these factors interact over time, leading to gradual changes and soil profile development.
Role of climate and biological activity:
*Climate:
.Temperature: Higher temperatures accelerate weathering and decomposition, while colder temperatures slow them down.
.Precipitation: Rainfall affects leaching of nutrients, erosion, and water availability for plants.
.Affects the types of organisms that can thrive, influencing organic matter input and decomposition rates.
*Biological activity:
.Plants contribute organic matter, stabilize soil, and influence nutrient cycling.
.Animals mix and aerate soil, create pores, and contribute organic matter through waste.
.Microbes decompose organic matter, release nutrients, and cycle elements within the soil.
The interplay between these two factors shapes the soil's character, influencing everything from its fertility and texture to its acidity and drainage. Understanding their roles is crucial for managing soil health, sustainable agriculture, and predicting how soils might respond to environmental changes.
Answer By: Himashree Bora.
