1.2 Endogenetic and Exogenetic Forces
Case Study 1: Himalayan Uplift and Ongoing Tectonic Activity
- Relevant Theories/Models: Plate Tectonics Theory; Isostasy
- Recent Data: The Himalayas continue to rise at an average rate of 5 mm/year due to the ongoing convergence between the Indian and Eurasian plates. Notably, Mount Everest has experienced an anomalous uplift of approximately 15–50 meters over the past 89,000 years, attributed to isostatic rebound following significant erosion from river drainage changes.
- Spatial Variation: Uplift rates vary across the Himalayas, with central Nepal experiencing rates up to 7 mm/year, while other regions exhibit lower rates.
- Temporal Variation: The major phase of Himalayan uplift began around 50 million years ago, with significant acceleration during the early Miocene (~23 Ma).
- Source: USGS; Nature Geoscience; ScienceDirect
- Insight: The Himalayas exemplify endogenetic forces through active tectonic uplift, while exogenetic processes like erosion and river dynamics contribute to ongoing landscape evolution.
Case Study 2: Chambal Badlands – Interaction of Natural and Anthropogenic Forces
- Relevant Theories/Models: Davisian Geomorphic Cycle; Fluvial Erosion Models
- Recent Data: The Chambal region encompasses approximately 5 lakh hectares of badlands, characterized by severe soil erosion due to a combination of natural factors and human activities such as deforestation and overgrazing.
- Spatial Variation: The badlands are predominantly found in parts of Rajasthan, Madhya Pradesh, and Uttar Pradesh, with varying degrees of severity.
- Temporal Variation: The intensification of erosion and badland formation has been significant since the mid-20th century, correlating with increased human intervention.
- Source: Geological Survey of India
- Insight: The Chambal badlands illustrate the interplay between endogenetic forces (tectonic uplift) and exogenetic forces (erosion), compounded by anthropogenic factors, leading to significant geomorphological changes.
