Model Answer
0 min readIntroduction
The Deccan Traps, a large igneous province located in western India, represent one of the largest volcanic features on Earth. Formed during the late Cretaceous and early Paleogene periods (approximately 66 million years ago), this massive outpouring of basaltic lava significantly altered the Indian subcontinent’s geological landscape and is believed to have played a crucial role in the Cretaceous-Paleogene extinction event. The statement "Deccan volcanism marks an important event in Indian Geology" is profoundly accurate, as it not only shaped the physical geography but also influenced the evolution of life and the distribution of natural resources in the region.
Understanding the Deccan Traps
The Deccan Traps cover an area of approximately 500,000 square kilometers, primarily in the states of Maharashtra, Gujarat, Madhya Pradesh, and Karnataka. The name "Deccan" is derived from the Sanskrit word 'Dakshin', meaning 'the South'. The 'Traps' refer to the step-like appearance of the landscape, formed by successive lava flows. These flows accumulated over a relatively short geological period, creating a thick pile of basaltic rock.
The Volcanic Event: Timing and Extent
Deccan volcanism occurred in three distinct phases:
- Phase 1 (66.2 – 65.8 Ma): Initial phase with relatively low eruption rates.
- Phase 2 (65.8 – 65.2 Ma): The most intense phase, characterized by massive lava flows and significant gas emissions. This phase coincides with the Cretaceous-Paleogene (K-Pg) boundary.
- Phase 3 (65.2 – 63.7 Ma): A waning phase with decreasing eruption rates.
The total volume of lava erupted is estimated to be over 1.5 million cubic kilometers, making it one of the largest volcanic provinces in the world. The lava flows range in thickness from a few meters to over 2000 meters in some areas.
Causes of Deccan Volcanism
The prevailing theory attributes Deccan volcanism to a mantle plume – a localized upwelling of abnormally hot rock from deep within the Earth’s mantle. This plume is believed to have interacted with the Reunion hotspot track, causing decompression melting and the generation of vast quantities of basaltic magma. The Indian plate’s movement over this hotspot is considered the primary driver of the volcanic activity.
Geological Features Associated with Deccan Volcanism
- Basaltic Lava Flows: The dominant feature, forming the characteristic step-like topography.
- Intertrappean Sediments: Layers of sedimentary rocks (like limestone, chert, and shale) deposited between lava flows, providing valuable insights into the paleoenvironment.
- Dykes and Sills: Vertical and horizontal intrusions of magma into pre-existing rocks.
- Calderas: Large volcanic craters formed by the collapse of magma chambers.
Impact and Significance
Deccan volcanism had profound impacts on the Indian subcontinent and global climate:
- Climate Change: The massive release of volcanic gases (sulfur dioxide, carbon dioxide) led to significant climate fluctuations, including short-term cooling due to sulfate aerosols and long-term warming due to increased carbon dioxide levels.
- K-Pg Extinction Event: While the Chicxulub impact is widely considered the primary cause of the K-Pg extinction, Deccan volcanism likely exacerbated the environmental stresses, contributing to the demise of dinosaurs and other species. Recent research suggests a more complex interplay between the impact and volcanism.
- Formation of Fertile Soils: Weathering of basaltic lava created fertile black cotton soils (Regur soils) which are ideal for cotton cultivation.
- Mineral Resources: The Deccan Traps are a source of various minerals, including bauxite, manganese, and iron ore.
- Groundwater Resources: The porous nature of the basaltic rocks allows for significant groundwater accumulation, making it a vital water source for the region.
| Impact | Details |
|---|---|
| Climate | Short-term cooling (sulfate aerosols), long-term warming (CO2) |
| Extinction | Exacerbated K-Pg extinction event |
| Soil | Formation of fertile black cotton soils |
| Resources | Source of bauxite, manganese, iron ore, groundwater |
Conclusion
In conclusion, Deccan volcanism represents a pivotal event in Indian geological history. Its immense scale, prolonged duration, and far-reaching consequences have profoundly shaped the subcontinent’s landscape, climate, and biological evolution. The event not only contributed to a major extinction event but also laid the foundation for the region’s fertile soils and valuable mineral resources. Continued research into the Deccan Traps will undoubtedly reveal further insights into the complex interplay between volcanism, climate change, and life on Earth.
Answer Length
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