10-December-2024-Editorial

THE NINETYEAST RIDGE AND ITS FORMATION

The Ninetyeast Ridge, a 5,000-kilometer underwater mountain chain in the Indian Ocean, has long intrigued geologists. Traditionally believed to have formed from a stationary hotspot, recent research challenges this idea, suggesting the ridge was created by a moving hotspot.

Key Findings of the Study

Formation by a Moving Hotspot

• The study identifies the Kerguelen hotspot, located on the Kerguelen Plateau in the southern Indian Ocean, as the origin of the Ninetyeast Ridge.
• Unlike earlier theories of a stationary hotspot, evidence shows the hotspot moved several hundred kilometers within Earth’s mantle.
• This is the first recorded instance of a moving hotspot in the Indian Ocean, offering new support for the theory of dynamic hotspots.

Age Estimates

• Advanced dating methods reveal that the Ninetyeast Ridge formed over 40 million years, from approximately 83 million to 43 million years ago.

Impact on Tectonic Models

• The research provides a refined reconstruction of Earth’s tectonic history.
• It emphasizes the role of mantle dynamics and hotspot movement in understanding geological phenomena and improving natural disaster prediction.

About the Ninetyeast Ridge

Geographical and Structural Features

• The Ninetyeast Ridge aligns almost parallel to the 90th meridian east, giving it its name.
• It spans from the Bay of Bengal in the north to the Southeast Indian Ridge in the south.

Distinct Segments

• The northern section features large volcanoes.
• The middle section comprises small seamounts and straight segments.
• The southern part is taller and more continuous.

Role in Dividing the Indian Ocean

• The ridge acts as a natural boundary, separating the western and eastern Indian Ocean basins.

Formation Process

• It likely formed as the Indo-Australian tectonic plate moved northward over the Kerguelen hotspot.
• Formation ceased due to a reorganization of tectonic plate boundaries.

Composition

• The ridge primarily consists of Ocean Island Tholeiites (OIT), a type of basaltic rock.
• Rocks in the southern region are younger (43 million years) than those in the north (81 million years).

Geological Significance of Hotspots

What Are Hotspots?

• Hotspots are regions where plumes of magma rise from deep within Earth’s mantle, creating volcanic activity on the surface.
• Unlike most volcanoes, which form along tectonic plate boundaries, hotspot volcanoes emerge within plates.

Hotspot Volcanism vs. Submarine Volcanism

• Submarine volcanism occurs at tectonic plate boundaries due to plate interactions.
• Hotspot volcanism is driven by stationary or dynamic plumes beneath moving plates.

Hotspot Tracks

• As a tectonic plate moves over a hotspot, a chain of volcanoes forms.
• The youngest and most active volcano is located above the plume, while older volcanoes are further along the track.
• The Hawaiian Islands are a well-known example of a hotspot track.

Dynamic Nature of Hotspots

• Recent findings suggest hotspots may not be stationary, as traditionally thought.
• This dynamic behavior could explain irregular volcanic patterns in regions like the Cook-Australs and Line Islands.

Impact of Hotspots on Tectonic Plates and Natural Disasters

Influence on Tectonic Plates

• Hotspots provide evidence of tectonic plate movements through volcanic chain formation.
• The spacing of these volcanic chains helps scientists estimate plate motion and speed.

Rifting and Continental Breakup

• Hotspots can weaken the lithosphere, leading to the splitting of continents, as seen in the East African Rift.

Role in Natural Disasters

• Earthquakes: Movement of tectonic plates and mantle plumes can trigger earthquakes. Understanding these processes aids in identifying high-risk zones and developing early warning systems.
• Tsunamis: Underwater volcanic eruptions and earthquakes linked to hotspots can generate tsunamis. Studying these patterns improves predictions and safety measures for coastal regions.

Conclusion

The discovery of the Ninetyeast Ridge’s formation by a moving hotspot reshapes our understanding of Earth’s geological history. It highlights the dynamic nature of hotspots, the importance of mantle dynamics, and their role in shaping tectonic plates and influencing natural disasters. This research underscores the value of geological studies in improving disaster preparedness and understanding Earth’s intricate processes.