Day 13 – Q 1. How does volcanism lead to landform evolution? Discuss with the help of suitable examples.
1. How does volcanism lead to landform evolution? Discuss with the help of suitable examples.
स्थालाकृति विकास में ज्वालामुखी की भूमिका क्या होती है? उपयुक्त उदाहरणों की मदद से चर्चा करें।
Introduction:
A volcano is a place where gases, ashes and/or molten rock material – magma/ lava escape to the ground. in this process, molten rock material called magma in asthenosphere find their way to the surface where it is called as lava. The way a volcano erupts and the materials that make up the magma and lava of a particular volcano affects the formation of the volcanic landforms, such as craters, calderas, lava domes and lava plateaus.
Volcanism and landform evolution:
Some of the landforms associated with volcanism are-
- Craters: crater is a bowl-shaped depression at the top of a volcano caused by past volcanic eruptions. A volcanic crater is relatively small, usually spanning about a half a mile in diameter or less, and can fill with water to form a crater lake.
- Caldera: If a volcanic eruption causes the magma chamber to empty, the volcano can implode, forming a larger depression known as a caldera. eg. Yellostone caldera.
- Volcanic domes: Volcanic Domes result from the extrusion of highly viscous, gas poor andesitic and rhyolitic lava. Since the viscosity is so high, the lava does not flow away from the vent, but instead piles up over the vent.
- Basalt plateau: Basalt plateau is formed due to outpouring of extremely large volume of low viscosity basaltic magma from fissure vents. The basalts spread huge areas of relatively low slope and build up plateaus. eg. Deccan plateau, Columbian plateau.
Intrusive landforms:
- Dykes – when magma solidifies in vertical fissures. Eg. Many Scottish Islands, such as Mull and Skye
- Sills – Horizontal bodies of intrusive igneous rocks. Eg. Great Whin Sill (which carries part of Hadrian’s Wakk) and Drumadoon on the Isle of Arran
- Batholiths – magma that cools in the deeper depth & develop in the form of large domes. Eg. Sierra Nevada Batholith, California
- Laccoliths – these are large dome shaped intrusive bodies having a pipe like conduit from below. Eg. Eildon Hills on the Scottish Borders
Conclusion:
Volcanism thus results into varied forms of landforms both intrusive and extrusive.
Best answer: Abhishek Singh
