Day 25 – Q.1 What is a continental rift zone? How do they form? Explain. Give an example of an active continental rift zone.

What is a continental rift zone? How do they form? Explain. Give an example of an active continental rift zone.

महाद्वीपीय भ्रंश क्षेत्र क्या है? वे कैसे बनते हैं? समझाएं। सक्रिय महाद्वीपीय भ्रंश क्षेत्र का एक उदाहरण दीजिए।

Approach

Candidates can start the answer with giving basic idea of continental rift zone and simply as per demand highlight its formation and give examples on active continental rift zone world over.

Introduction

Continental rift zones occur in weak spots in the continental lithospheric plate. Rift zones are found both on the continents and on the floor of ocean basins.

Body

Formation:

• In terms of the theory of plate tectonics, they occur in divergence zones, belts where two of the various lithospheric plates that make up the Earth’s surface are separating.
• Where tectonic plates move away from one another the lithosphere thins. The underlying asthenosphere rises and expands like a hot-air balloon, elevating a broad region. If the plate is capped by thick continental crust, the resulting continental rift zone rises high above sea level.

Examples of continental rift zone:

• The biggest active continental rift valleys on Earth are the East African Rift, the Baikal Rift Valley, the West Antarctic Rift, and the Rio Grande Rift.

Great Rift Valley:

• The Great Rift Valley is a geographical feature running north to south for around 6,400 kilometres from northern Syria to central Mozambique in East Africa.
• The northernmost part of the Rift forms the Beqaa Valley in Lebanon.
• Farther south, the valley is the home of the Jordan River which continues south through the Jordan Valley into the Dead Sea on the Israeli-Jordanian border.

East African Rift Valley:

• The Eastern Rift Valley (also known as Gregory Rift) includes the main Ethiopian Rift, running eastward from the Afar Triple Junction, which continues south as the Kenyan Rift Valley.
• The Western Rift Valley includes the Albertine Rift, and farther south, the valley of Lake Malawi.
• To the north of the Afar Triple Junction, the rift follows one of two paths: west to the Red Sea Rift or east to the Aden Ridge in the Gulf of Aden.

Pacific Ocean:

• In the Pacific Ocean, the East Pacific Rise has created rift valleys where the Pacific plate is separating from the North American plate, Cocos plate, Nazca plate, and Antarctic plate.

Baikal Rift Zone:

• The Baikal Rift Valley is formed by a divergent plate boundary, where the Amur plate is slowly tearing itself away from the Eurasian plate, and has been doing so for about 25 million years.

Conclusion

The Rift zone is being formed, most likely as a result of mantle plumes and eventually as a result of the African super swell. The Rift Structures are a complicated system of rift segments that serves as a modern analogy their evolution provide background research for sustaining loss and resistive measures.