Answer the question in maximum 200 words. This question carries 11 marks. [MPPSC 2022] Give a brief explanation of the Earth’s genesis hypotheses.
Classification of Mountains Based on Geomorphological Characteristics Mountains are significant landforms that can be classified based on their geomorphological characteristics, which pertain to their origin, structure, and formation processes. Here’s a detailed classification along with recent examRead more
Classification of Mountains Based on Geomorphological Characteristics
Mountains are significant landforms that can be classified based on their geomorphological characteristics, which pertain to their origin, structure, and formation processes. Here’s a detailed classification along with recent examples:
1. Fold Mountains:
Definition: Fold mountains are formed primarily by the collision of tectonic plates, which causes the Earth’s crust to fold. These mountains are characterized by complex structures with numerous folds, including anticlines (upward folds) and synclines (downward folds).
Examples:
- Himalayas: Formed by the collision of the Indian Plate with the Eurasian Plate, the Himalayas include notable peaks like Mount Everest. This region is still tectonically active, and earthquakes are common.
- Andes: Stretching along the western coast of South America, the Andes result from the subduction of the Nazca Plate beneath the South American Plate. Recent volcanic activity in Chile, like the 2023 eruption of the Láscar Volcano, exemplifies the ongoing geological activity in this range.
2. Block Mountains:
Definition: Block mountains, also known as fault-block mountains, are created by tectonic forces that cause the Earth’s crust to fracture into blocks. These blocks are then uplifted or down-dropped relative to each other along faults.
Examples:
- Sierra Nevada: Located in the western United States, the Sierra Nevada mountains are a classic example of block mountains. The uplifted block forms high peaks like Mount Whitney, and recent seismic activity has highlighted the tectonic processes shaping this range.
- Vosges Mountains: Situated in northeastern France, these mountains are also block mountains, characterized by their uplifted blocks and significant fault lines.
3. Volcanic Mountains:
Definition: Volcanic mountains are formed by volcanic activity where magma from the Earth’s mantle erupts through the crust, creating cones or domes of volcanic material.
Examples:
- Mount Fuji: This iconic peak in Japan is a stratovolcano that erupted last in 1707. It is a prominent example of volcanic mountains formed by repeated explosive and effusive volcanic activity.
- Kilauea: Located in Hawaii, Kilauea is one of the world’s most active volcanoes. Its recent eruptions, such as those in 2021, have added new land and reshaped the landscape around it.
4. Residual Mountains:
Definition: Residual mountains, also known as denudation mountains, are formed through the process of erosion. They are typically old mountains that have been worn down over time, leaving behind remnants of their original structure.
Examples:
- Appalachian Mountains: This mountain range in eastern North America is a classic example of residual mountains. Erosion has worn down the once-high peaks, leaving behind rounded, eroded landforms.
- Aravalli Range: Located in India, the Aravalli Range is one of the oldest mountain ranges in the world. Its current form is the result of extensive erosion and denudation over millions of years.
5. Dome Mountains:
Definition: Dome mountains are formed when magma pushes the Earth’s crust upwards without erupting. The uplifted rock forms a dome shape, which may later be eroded to expose the underlying structure.
Examples:
- Black Hills: Located in South Dakota, USA, the Black Hills are an example of dome mountains. The region features rounded peaks like Harney Peak, and the uplifted granite domes are a result of ancient volcanic activity.
- Gros Ventre Range: Found in Wyoming, USA, this range showcases dome-like structures formed by tectonic forces pushing the crust upward.
Conclusion
The classification of mountains based on geomorphological characteristics provides insight into their formation processes and structural features. Recent geological activities and studies in regions like the Himalayas, Sierra Nevada, and Kilauea enhance our understanding of these diverse mountain types.
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Theories of the Origin of the Earth: An Overview Introduction The origin of Earth has intrigued scientists for centuries. Several theories have been proposed to explain how our planet came into existence. These theories range from early speculations to modern scientific models supported by astronomiRead more
Theories of the Origin of the Earth: An Overview
Introduction The origin of Earth has intrigued scientists for centuries. Several theories have been proposed to explain how our planet came into existence. These theories range from early speculations to modern scientific models supported by astronomical observations and geological evidence. Here’s a brief overview of the major theories:
1. The Nebular Hypothesis
2. The Protoplanetary Disk Model
3. The Giant Impact Hypothesis
4. The Fission Theory
5. The Capture Theory
6. The Accretion Theory
Recent Developments and Evidence
Conclusion
Theories of Earth’s origin range from the Nebular Hypothesis and Protoplanetary Disk Model to the Giant Impact Hypothesis and beyond. Each theory offers a different perspective on the formation of Earth, supported by varying degrees of evidence. Ongoing research and technological advancements continue to refine these theories and enhance our understanding of Earth’s origins.
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