Model Answer
0 min readIntroduction
The Cretaceous-Paleogene (K-Pg) boundary, approximately 66 million years ago, marks a significant turning point in Earth’s history, associated with a mass extinction event. A key geological feature linked to this period is the Deccan Traps, a large igneous province (LIP) located in western India. These extensive basaltic lava flows represent one of the largest volcanic features on Earth, formed during the late Cretaceous and early Paleogene periods. Understanding the Deccan Traps is crucial for comprehending not only the geological evolution of the Indian subcontinent but also its potential role in global climate change and the K-Pg extinction.
Geological Setting and Formation
The Deccan Traps are primarily located in the states of Maharashtra, Gujarat, Madhya Pradesh, and Karnataka, covering an area of approximately 500,000 square kilometers. The formation of the Deccan Traps is attributed to mantle plume activity, where a hot spot beneath the Indian plate resulted in extensive volcanism. This occurred as India was moving towards and colliding with Eurasia.
Composition and Structure
The Deccan Traps are characterized by thick sequences of basaltic lava flows, interbedded with sedimentary rocks. The basalt is predominantly tholeiitic in composition, with relatively low silica content. The lava flows are typically horizontal, forming characteristic step-like landscapes. The total thickness of the lava flows can exceed 2,000 meters in some areas.
Stratigraphy of the Deccan Traps
The Deccan Traps are divided into several formations based on lithological variations and stratigraphic position. These include:
- Lower Traps: Characterized by thicker, more massive lava flows.
- Main Traps: The most extensive part of the sequence, consisting of numerous thin lava flows.
- Upper Traps: Marked by the presence of interbedded sedimentary rocks, including red bauxite and laterite.
Volcanic Activity and Timing
The main phase of Deccan Traps volcanism occurred over a relatively short period, spanning approximately 66 to 62 million years ago. However, recent high-resolution dating techniques suggest that the bulk of the eruptions occurred within a remarkably short timeframe, potentially coinciding with the K-Pg extinction event. The volcanic activity involved both effusive eruptions (lava flows) and explosive eruptions (ash and gas emissions).
Table: Key Characteristics of the Deccan Traps
| Characteristic | Description |
|---|---|
| Location | Western India (Maharashtra, Gujarat, Madhya Pradesh, Karnataka) |
| Area | Approximately 500,000 sq km |
| Rock Type | Basalt (Tholeiitic) |
| Thickness | Up to 2,000 meters |
| Age | 66-62 million years ago (Cretaceous-Paleogene) |
Environmental Impact
The massive volcanic eruptions of the Deccan Traps released enormous quantities of gases, including carbon dioxide and sulfur dioxide, into the atmosphere. These gases had a significant impact on global climate, potentially causing both short-term cooling (due to sulfur dioxide aerosols) and long-term warming (due to carbon dioxide). The release of these gases is hypothesized to have contributed to the K-Pg extinction event, which wiped out approximately 76% of plant and animal species on Earth, including the non-avian dinosaurs.
Conclusion
The Cretaceous volcanic province of India, represented by the Deccan Traps, is a remarkable geological feature with profound implications for understanding Earth’s history. Its formation through mantle plume activity, extensive basaltic lava flows, and potential link to the K-Pg extinction event make it a crucial area of study for geologists and paleontologists. Further research into the timing and environmental impact of the Deccan Traps will continue to refine our understanding of this pivotal period in Earth’s evolution.
Answer Length
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