MPPSC 2023 Prelims Paper-I · Question 54 of 100

Correct — B, Heterogenic. The standard classification of diastrophism (crustal deformation by internal/endogenic forces) covers orogenic movements (mountain-building, mainly compressive folding and faulting at plate margins) and epeirogenic movements (broad, largely vertical upliftment/subsidence of continental blocks). Plate tectonics is the modern theory explaining what drives these movements, and earthquakes are the sudden release of the stress that diastrophic forces build up along faults. 'Heterogenic' is not a recognised term in this classification — it does not name a real geological process — so it is the one that does not come under diastrophism.

• (a)Orogenic — Orogenic movements ARE a core category of diastrophism — the mountain-building process driven by intense, mainly compressive crustal forces.
• (c)Earthquakes — Earthquakes are the sudden release of stress built up by ongoing diastrophic (tectonic) deformation along faults — closely tied to diastrophism, not separate from it.
• (d)Plate Tectonics — Plate tectonics is the driving mechanism behind diastrophic crustal movements (both orogenic and epeirogenic), not a process excluded from it.

Diastrophism is the deformation of the Earth's crust by internal (endogenic) forces, traditionally split into two categories: epeirogenic movements (slow, large-scale, chiefly vertical upliftment or subsidence of continental crust) and orogenic movements (more intense, mainly horizontal compressive forces that fold and fault rock to build mountain ranges). Plate tectonic theory explains what drives both, and earthquakes are a direct, sudden expression of the stress these movements build up.

MPPSC likes 'which of these does NOT belong' questions in physical geography — the trap is picking a genuinely related term (earthquakes or plate tectonics) instead of spotting the one option that isn't even a real classification term.

• Diastrophism means crustal deformation caused by internal (endogenic) forces
• Its two standard categories are epeirogenic (vertical, continent-scale) and orogenic (mountain-building)
• Plate tectonics is the mechanism that drives diastrophic movements
• Earthquakes result from the sudden release of diastrophic (tectonic) stress

• Picking earthquakes or plate tectonics as 'not diastrophism' because they sound like separate topics — both are actually tied to diastrophic activity
• Not recognising 'heterogenic' as a non-standard/invented term rather than a real classification

MPPSC's physical geography section favours 'odd one out' questions on the classification of endogenic/exogenic forces — read every option carefully for terms that don't actually exist in the standard classification.

No directly related past PYQ was found.

• practice — not a real PYQ

  Epeirogenic movements, one of the two classical categories of diastrophism, are primarily:

  • (a)Horizontal, mountain-building movements
  • (b)Vertical, continent-scale movements
  • (c)Sudden shock movements
  • (d)Movements confined to ocean floors only

  Answer(b) Vertical, continent-scale movements — as opposed to orogenic (horizontal, mountain-building) movements.

• practice — not a real PYQ

  Which of the following best describes orogenic movements?

  • (a)Slow vertical upliftment of a continent
  • (b)Intense folding and faulting that builds mountain ranges
  • (c)Sudden release of seismic energy alone
  • (d)Volcanic eruption of magma

  Answer(b) Intense folding and faulting that builds mountain ranges.