Introduction and Syllabus Scope

Why This Topic Matters

Topic 73 is among the most consistently tested geography topics in RPSC Mains. Over the 6-year PYQ record (2013–2023), it has yielded 29 marks at an average of 5.8 marks per year — the highest among the five World Geography topics (73–77) in Paper II. Questions have been asked in 2016, 2018, 2021, and 2023, making it one of the safest bets for 2026.

Two Interconnected Themes

The topic covers:

• (a) Structural layers of Earth's interior — composition, thickness, temperature, and the discontinuities between them
• (b) Geological time scale — Earth's 4.6-billion-year history divided into eons, eras, periods, and epochs, with key biological and physical events marking each division

Exam Strategy

For 5-mark answers, precise numbers — depths, temperatures, time ranges in million years — are essential. For 10-mark answers, connect the interior structure to plate tectonics, or trace the evolution of life through the geological time scale.

RPSC has asked both "fact retrieval" questions (Mesozoic era time range, Structure of Sial, Carboniferous characteristics) and conceptual questions (plate tectonics, rock types).

Scope Note

This topic is world-scope (global physical geography). Do not confuse with Topic 78 (Physiography of India) or Topic 83 (Physiography of Rajasthan). The geological time scale is universal; specific reference to Indian geology (Gondwana coalfields, Deccan Traps) is valid supporting evidence but not the focus.

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