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Predicted Questions with Model Answers
Q1 (5 marks — 50 words): Describe the major geographical features of the Rocky Mountains.
Model Answer:
The Rocky Mountains extend 4,800 km from British Columbia (Canada) to New Mexico (USA), formed 85–55 Ma during the Laramide Orogeny. Highest peak: Mount Elbert (4,399 m). They form the Continental Divide separating Pacific drainage (Columbia, Colorado rivers) from Atlantic/Gulf drainage (Missouri, Arkansas). Rich in gold, silver, molybdenum; Yellowstone supervolcano located within the system.
Q2 (5 marks — 50 words): Name and locate the six major deserts of Australia.
Model Answer:
Australia's six major deserts: (1) Great Victoria Desert (424,400 km² — Western Australia/South Australia, largest); (2) Great Sandy Desert (267,250 km² — NW Western Australia); (3) Tanami Desert (184,500 km² — NT/WA border); (4) Simpson Desert (176,500 km² — NT/QLD/SA); (5) Gibson Desert (156,000 km² — central WA); (6) Little Sandy Desert (111,500 km² — SW WA). All lie in the subtropical interior and west.
Q3 (5 marks — 50 words): Distinguish between fold mountains and block mountains with examples.
Model Answer:
Fold mountains form when tectonic plates converge and compress sedimentary strata into folds — examples: Himalayas (India-Asia collision, 8,848 m), Andes (7,000 km, 6,961 m), Alps (Mont Blanc 4,808 m). Block mountains form by faulting — horsts (raised) between grabens (sunken) — examples: Vosges-Rhine Graben-Black Forest system (Germany-France); Satpura (between Narmada-Tapti rift valleys, India). Block mountains are typically lower and more eroded.
Q4 (10 marks — 150 words): Classify and describe the major types of deserts of the world with their distribution and formation mechanisms.
Model Answer:
Deserts — areas receiving less than 250 mm annual precipitation — cover 33% of Earth's land surface (~50 million km²). They are classified by four formation mechanisms:
1. Subtropical Hot Deserts — Located at 20°–30° latitude where the descending limb of the Hadley Cell creates dry sinking air. Sahara (9.2 million km², North Africa — world's largest hot desert), Arabian Desert (2.3 million km² — Rub' al Khali is world's largest sand sea), Thar (200,000 km², NW India-Pakistan). Temperature extremes: 58°C maximum (Sahara); 0°C winter nights (Thar).
2. Cold Continental Deserts — Interior locations far from oceanic moisture, with rain shadow effects. Gobi (1.3 million km², Mongolia-China — Asia's largest cold desert; dinosaur fossil treasure), Taklamakan (270,000 km², China — shifting dunes 300 m tall), Patagonian (670,000 km², Argentina — Andes rain shadow).
3. Coastal Deserts — Cold ocean currents stabilise and dry coastal air despite oceanic proximity. Namib (Benguela Current, Namibia — world's oldest desert at ~55 Ma), Atacama (Humboldt Current, Chile — Earth's driest non-polar place; some areas no rainfall in 400 years).
4. Rain Shadow Deserts — Mountain barriers intercept moisture. Ladakh (India — rain shadow of Himalayas and Karakoram; 3,500 m+), Great Basin (USA — between Sierra Nevada and Rockies, 492,000 km²).
Australia has six major deserts (Great Victoria 424,400 km², Great Sandy 267,250 km², Tanami 184,500 km², Simpson 176,500 km², Gibson 156,000 km², Little Sandy 111,500 km²) — all subtropical interior, covering ~44% of the continent.
Q5 (10 marks — 150 words): Discuss the world distribution of major plateaus, their types, and economic significance.
Model Answer:
Plateaus — elevated flatlands with steep sides — cover ~45% of Earth's land. They fall into three types based on formation:
Intermontane Plateaus: Enclosed by mountain ranges — typically highest and most rugged. The Tibetan Plateau (avg 4,500 m, 2.5 million km²) is the world's highest — the "Roof of the World" and "Third Pole," source of Asia's major rivers (Yangtze, Mekong, Brahmaputra, Indus). The Bolivian Altiplano (3,800 m) hosts Lake Titicaca (3,812 m — world's highest navigable lake) and lithium reserves (world's largest, ~20 million tonnes).
Continental/Lava Plateaus: Formed by extensive basaltic lava flows or broad tectonic uplift. The Deccan Plateau (India, ~6.5 lakh km², avg 600 m) — formed by Deccan Traps (~67 Ma), rich in black cotton soil (regur) for cotton cultivation, and mineral resources (iron ore, manganese). The Columbia Plateau (USA, 400,000 km²) has the famous basalt columns and the Columbia River system.
Piedmont Plateaus: At mountain bases — Malwa Plateau (India, 500 m, Chambal-Betwa drainage), Appalachian Plateau (eastern USA, coal-bearing Carboniferous rocks — Pennsylvania coalfields).
Economic significance of plateaus: Mineral wealth (Brazil's iron ore on Brazilian Plateau, DRC's copper on African plateaus); pastoral economy (Tibetan yaks, Bolivian llamas); tourism (Grand Canyon on Colorado Plateau, Yellowstone); hydropower (plateau edges create waterfalls — Niagara, Jog Falls on Deccan).