The dynamic nature of Earth’s geology has been unveiled through compelling evidence from palaeomagnetism and the concept of sea floor spreading, fundamentally challenging the traditional notion of stationary continents and ocean basins. Palaeomagnetism, the study of ancient magnetic fields recorded in rocks, provides a remarkable archive of Earth’s past magnetic orientations. Concurrently, the theory of sea floor spreading, proposed by Harry Hess and further developed by Fred Vine and Drummond Matthews, revolutionized our understanding of plate tectonics. Together, these scientific revelations assert that continents and ocean basins are not fixed entities but are instead part of a dynamic, ever-changing system. In this discourse, we will explore the compelling evidence supporting these concepts, accompanied by illustrative diagrams that visually elucidate the processes behind the constant reshaping of Earth’s surface.
Answer
Evidences from paleomagnetism and seafloor spreading have validated the age-old hypothesis of taylor and wagner that continents and ocean basins have never been stationary. They are:
1. Increasing age of rocks farther from the mid-oceanic ridge:
- Found by Harry Hess and team in 1960’s.
- Suggests that the crusts is getting created after subsequent eruptions.
- Radiometric dating suggests that seafloor rocks are younger than continental ones.
2. Reverse polarity bands:
- Magnetic anomaly of bands of rocks on either side of atlantic mid-oceanic ridge conclusive of movement of continents and ocean basins.
- Other paleomagnetic evidences such as polar wandering curve hypothesis by Blackett proves wagner’s hypothesis.
3. Trenches:
- Trenches along the subduction boundaries suggests the destruction of crust created by sea-floor spreading at mid-oceanic ridge.
4. Accretionary Prism:
- Sediments from the subducting plates pile up along the other plates’s edge .
- Contains sediments from the both plates(marine and terrestrial).
- Form high mountains along ocean-continent boundaries.( shows movement of crust and basin).
5. Volcanism:
- Volcanism at zones of subduction result in andesitic lava erupting along with from the hotspots. E.g. Reunion island.
- Volcanism shows the movement of plates and andesitic lava eruption due to partial melting of rocks.
Therefore Paleomagnetism and sea-floor spreading have proven that continents and ocean basin are not stationary. This is further substantiated by plate tectonics and new age technologies such as SONAR and SOUND ACOUSTIC studies.
In case you still have your doubts, contact us on 9811333901.
For UPSC Prelims Resources, Click here
For Daily Updates and Study Material:
Join our Telegram Channel – Edukemy for IAS
- 1. Learn through Videos – here
- 2. Be Exam Ready by Practicing Daily MCQs – here
- 3. Daily Newsletter – Get all your Current Affairs Covered – here
- 4. Mains Answer Writing Practice – here
