Geosyncline's concept helps to understand the mountain-building process especially fold mountains and the evolution of landforms.
Our earth's crust can be divided into two parts based on its strength:
As per Kober, there are two zones:
Litho genesis:
Orogenesis:
Orogenesis is the mountain-building stage. Under the orogenesis stage, due to the continuation of the contraction force of the earth, both forelands( rigid landmass) start moving towards each other( coming closer), so compression sources are generated due to movement which leads to the upliftment of the sediments. Parallel mountain ranges are formed in geosyncline regions which Kober called marginal mountain ranges.
Gliptogenesis:
Due to the continuation of contraction forces, these marginal mountain ranges are uplifted further which leads to the creation of the fold mountain like the Himalayas.
What are Geosynclines?
Geosynclines are the area of long, wide, and shallow depressions of the water body bordered by rigid masses and get huge sedimentation deposition from surrounding areas.Our earth's crust can be divided into two parts based on its strength:
- Rigid Masses
- Mobile zone of water
Geosynclines theory by Kober:
Kober explained the concept of geosynclines and mountain building based on the force of Contraction which is produced by the cooling of the earth.As per Kober, there are two zones:
- Orogen or mobile zone: the place of mountain building
- Kartogen or rigid zone: Orogen is surrounded by Kartogen.
- Litho-genesis
- Orogenesis
- Gliptogenesis
Litho genesis:
Litho-genesis is the first stage of mountain building which involved the creation of geosyncline( orogen) areas due to the force of contraction during the cooling of the earth.
Over time, eroded sediments from the foreland ( two rigid landmasses) get deposited in geo-synclines areas.
Geosynclines areas lead to gradual subsidence due to pressure generated by huge sediments.
Due to sedimentation and subsidence, an enormous amount of sediments get deposited in geosyncline areas.
Orogenesis:
Orogenesis is the mountain-building stage. Under the orogenesis stage, due to the continuation of the contraction force of the earth, both forelands( rigid landmass) start moving towards each other( coming closer), so compression sources are generated due to movement which leads to the upliftment of the sediments. Parallel mountain ranges are formed in geosyncline regions which Kober called marginal mountain ranges.
Gliptogenesis:
Due to the continuation of contraction forces, these marginal mountain ranges are uplifted further which leads to the creation of the fold mountain like the Himalayas.
Criticism:
Force of contraction by cooling is not such power to make high mountains.
Try to solve the following questions:
- Evaluate how far Kober's geosynclinal theory explains the mountain-building process. ( UPSC 2018, 250 words, 20 marks)
- “Mountains have originated in geosynclines.” Explain this statement by giving suitable examples. ( UPPSC 2009)
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