1. Who proposed the Geosyncline Theory?
a) Alfred Wegener
b) Arthur Holmes
c) A. K. Wadia
d) Leopold Kober
Answer: d) Leopold Kober
Kober, a German geologist, proposed the Geosyncline Theory to explain the formation of fold mountains.
2. According to Kober's theory, what is a Geosyncline?
a) A deep ocean trench
b) A stable continental shield
c) A large, linear trough or depression
d) A volcanic plateau
Answer: c) A large, linear trough or depression
A geosyncline is a long, narrow, and shallow depression that accumulates sediments and later forms fold mountains.
3. In Kober’s theory, the rigid and stable landmasses on either side of a geosyncline are called:
a) Plates
b) Shields
c) Kratogens
d) Orogenes
Answer: c) Kratogens
Kratogens are stable, ancient blocks that flank the geosyncline and push sediments together during mountain building.
4. What causes the sediments in a geosyncline to fold into mountains, according to Kober?
a) Sea-floor spreading
b) Horizontal compressional forces from kratogens
c) Volcanic activity
d) Gravitational pull
Answer: b) Horizontal compressional forces from kratogens
Kober believed horizontal pressures from the kratogens caused the sediments in the geosyncline to fold and form mountains.
5. According to Kober, the final mountain structure formed from the uplifted geosyncline is called:
a) Horst
b) Rift Valley
c) Orogen
d) Shield
Answer: c) Orogen
An orogen is the folded mountain chain formed from the compressed geosynclinal sediments.
6. What is a geosyncline according to Kober's theory?
a) A rigid landmass with no sedimentation
b) A volcanic cone formed due to subduction
c) A long, shallow, water-filled depression that collects sediments
d) A faulted valley formed due to crustal rifting
Answer: c) A long, shallow, water-filled depression that collects sediments
Geosynclines are mobile zones between rigid masses where sediments accumulate and later form mountains.
7. What is the correct sequence of stages in mountain building according to Kober’s Geosyncline Theory?
a) Orogenesis → Lithogenesis → Gliptogenesis
b) Lithogenesis → Gliptogenesis → Orogenesis
c) Lithogenesis → Orogenesis → Gliptogenesis
d) Orogenesis → Gliptogenesis → Lithogenesis
Answer: c) Lithogenesis → Orogenesis → Gliptogenesis
Kober’s theory includes three stages: sedimentation (Lithogenesis), compression and uplift (Orogenesis), and further uplift and erosion (Gliptogenesis).
8. What is the primary force responsible for mountain building in Kober’s theory?
a) Convection currents in the mantle
b) Plate collision due to plate tectonics
c) Volcanic eruptions and mantle plumes
d) Contraction of the Earth due to cooling
Answer: d) Contraction of the Earth due to cooling
Kober's theory is based on the idea that cooling of the Earth causes contraction, leading to compressional forces.
9. Which of the following is a criticism of Kober’s Geosyncline Theory?
a) It ignores the role of sedimentation
b) It underestimates the force of gravity
c) The contraction force is not strong enough to form high mountains
d) It does not explain the formation of ocean basins
Answer: c) The contraction force is not strong enough to form high mountains
A major criticism is that the force of contraction due to Earth's cooling is insufficient to form massive fold mountains like the Himalayas.
10. According to Kober's Geosyncline Theory, what are the "marginal mountain ranges"?
a) Fold mountains formed at the center of a geosyncline
b) Erosional remnants of volcanic arcs
c) Mountains formed by uplifted sediments at the edges of a geosyncline
d) Underwater ridges at the ocean floor margins
Answer: c) Mountains formed by uplifted sediments at the edges of a geosyncline
Kober stated that due to compressional forces, sediments in the geosyncline are uplifted to form parallel ranges along the margins of the depression, which he termed marginal mountain ranges.
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