Day 59 – Q 2. What is seafloor spreading? How does it occur? What are the landforms and features associated with seafloor spreading? Discuss. (10 Marks)

2. What is seafloor spreading? How does it occur? What are the landforms and features associated with seafloor spreading? Discuss. (10 Marks)

समुद्रतल फैलाव क्या है? यह कैसे होता है? समुद्र तल के फैलाव से जुड़ी भू–आकृतियां और विशेषताएं क्या हैं? चर्चा करें।

Approach 

Students are expected to write about the fintech industry and discuss the location factors affecting the it. 

Introduction 

Sea floor spreading theory was given by Harry Hess. The theory states that in the middle of ocean, the oceanic plates are moving away from each other in the middle of the oceans. Whereas, at the oceanic continental plate boundary, the oceanic plate gets sub ducted under the continental plate.

Body

Forces that cause Seafloor spreading 

• Convectional current theory which was  was proposed by Arthur Holmes addresses the forces which cause the sea floor spreading.
• According to Holmes the heat which is generated from the radioactive decay of substances deep inside the Earth (the mantle) creates magma which consists of molten rocks, volatiles, dissolved gases among other material.
• Further this magma, heat and gases seek a path to escape which leads to the formation of convection currents in the mantle.
• According to the theory of Seafloor spreading, convectional cells are the force behind drifting of continents thus these conventional cells are explained by convectional current theory of Holmes
• These ocean plates get subducted under the continental plates (since ocean plates are denser than continental plates), when these two types of plates converge.

Landforms and features associated with sea floor spreading:

• Rocks on either side of the crest of oceanic ridges having equidistant locations from the crest were found to have similarities both in terms of their constituents, their age and magnetic orientation.
• Rocks closer to the mid-oceanic ridges have normal polarity and are the youngest and the age of the rocks increases as one moves away from the crest (ridge).
• The rocks of the oceanic crust near the oceanic ridges are much younger than the rocks of the continental crust.
• Geophysical formations- various phenomenon mentioned above causes geophysical formations on sea bed such as sea mount, guyots, young fold mountains or deep trenches are formed at the boundary of oceanic continental plates.

Conclusion

Geographers have combined the knowledge from Plate tectonic theory, Sea floor spreading theory as well as continental drift theory to explain the formation of various physical features and geological processes on earth.Further these theories combined with modern technological advancements have helped humankind to predict various disasters more efficiently and save lives this making lives more secure and economy resilient.