Topic: Salient features of world’s physical geography.
1. Explain the concept of sea floor spreading. How does the sea floor spread impact global warming? (250 words)
Difficulty level: Moderate
Why the question:
Seafloor spreading, caused by an upwelling of magma, has led to episodes of global warming in the geologic past; the spread rate has slowed down in last 19 million years, but could gather momentum.
Key Demand of the question:
To explain sea floor spreading and its relation with global warming.
Explain – Clarify the topic by giving a detailed account as to how and why it occurred, or what is the context. You must be defining key terms wherever appropriate and substantiate with relevant associated facts.
Structure of the answer:
Begin by describing sea floor spreading.
Explain the causative factors of the sea floor spreading. Explain the mechanism involved.
Seafloor spreading and other tectonic activity processes are the result of mantle convection. Mantle convection is the slow, churning motion of Earth’s mantle. Convection currents carry heat from the lower mantle and core to the lithosphere. Convection currents also “recycle” lithospheric materials back to the mantle. Use suitable diagrams to explain the processes involved in sea floor spreading.
In the second half of the answer, explain the relation between sea floor spreading – upwelling of magma and its impact on global warming.
Conclude by summarising.