Tectonic Setting of Bengal Basin

The structural setting of Bengal basin is fundamentally related to the collision pattern Indian, Eurasian and Burmese plates. The northern part of the Indian plate is subducted beneath the Eurasian plate, resulting the development of great Himalaya.

Whereas the Indian plate is subducting beneath the Burmese plate in the east side resulting the rise of Indo-Burma ranges. (Alam et al., 2003).

The northern border of the surma basin is marked by the Dauki Fault. This fault system of regional importance described as “Dauki tear-fault “by Evans (1964) is the result of vertical tensions caused by subduction complexes along the southern and northern edges of this part of Indian craton also known as Shilong Foreland Shield (Reimann, 1993). The south of the Bengal basin comprises the Bay of Bengal.

According to Guha (1978), GSB (1990) and (Riemann, 1993) The physiographic divisions of Bengal basin is as follows:

  • Himalayan Fore deep
  • Rangpur Saddle
  • Stable shelf
  • Hinge zone
  • Madhupur-Tripura Threshold
  • Tripura Uplift
  • Surma Basin
  • Faridpur Trough
  • Barisal Gravity High
  • Hatiya Trough

Figure: Tectonic Map of Bengal Basin

The Bengal Basin is situated in the northeastern part of the Indian subcontinent and is characterized by a complex tectonic setting. The tectonic evolution of the Bengal Basin is influenced by the convergence of the Indian and Eurasian tectonic plates. The main tectonic features of the Bengal Basin include:

1. **Plate Tectonics:**
– The Indian plate is moving northwards and converging with the Eurasian plate.
– The convergence between the Indian and Eurasian plates is a result of the ongoing Himalayan orogeny, where the Indian plate is colliding with the Eurasian plate, leading to the uplift of the Himalayan mountain range.

2. **Subduction Zone:**
– The northern boundary of the Bengal Basin is influenced by the subduction of the Indian plate beneath the Eurasian plate. This subduction process contributes to the tectonic activity in the region.

3. **Tectonic Structures:**
– The Bengal Basin is characterized by various tectonic structures, including faults and folds, resulting from the tectonic forces associated with the convergence of the Indian and Eurasian plates.

4. **Sedimentary Basins:**
– The basin is also a sedimentary basin, accumulating sediments over millions of years. The sedimentary fill in the Bengal Basin is composed of a variety of deposits, including those from fluvial, deltaic, and marine environments.

5. **Active Tectonics:**
– The region is seismically active due to the ongoing tectonic processes. Earthquakes can occur as a result of the release of accumulated stress along faults in response to the tectonic forces.

6. **Delta Formation:**
– The Bengal Basin is home to the Ganges-Brahmaputra Delta, one of the largest river deltas in the world. The interaction of the rivers with the tectonic processes has contributed to the formation and evolution of this deltaic system.

In summary, the tectonic setting of the Bengal Basin is primarily influenced by the convergence of the Indian and Eurasian plates, leading to various tectonic structures, seismic activity, and the formation of a significant deltaic system.

The tectonic setting of the Bengal Basin is important for several reasons:

1. **Seismic Activity and Earthquakes:**
– Understanding the tectonic setting helps in assessing the seismic risk in the region. The convergence of the Indian and Eurasian plates results in tectonic activity, and knowledge of this activity is crucial for earthquake hazard assessment and preparedness.

2. **Natural Resource Exploration:**
– The tectonic setting influences the geological processes that lead to the accumulation of natural resources. The Bengal Basin is a sedimentary basin, and its tectonic history is vital for identifying and exploring potential oil and gas reserves, as well as other mineral resources.

3. **Deltaic Processes and Coastal Dynamics:**
– The tectonic setting plays a significant role in the formation and evolution of deltaic systems. The Ganges-Brahmaputra Delta in the Bengal Basin is a dynamic and complex system influenced by tectonic processes. Understanding these processes is crucial for managing coastal dynamics, land use, and mitigating the impact of natural hazards such as cyclones and storm surges.

4. **Climate and Environmental Impact:**
– The tectonic setting affects the climate and environmental conditions in the region. Tectonic processes can influence rainfall patterns, river discharge, and sediment transport, all of which have implications for agriculture, water resources, and ecosystems.

5. **Geological Evolution and Research:**
– Studying the tectonic setting provides insights into the geological evolution of the region over geological time scales. This information is essential for researchers and geologists studying the Earth’s history and the processes that have shaped the landscape.

6. **Infrastructure Planning and Development:**
– The knowledge of the tectonic setting is crucial for infrastructure planning and development. Understanding the seismic risk helps in designing buildings and infrastructure that can withstand potential earthquakes, enhancing the resilience of communities in the region.

7. **Water Management and River Behavior:**
– Tectonic processes influence river behavior and water management in the Bengal Basin. The movement of tectonic plates can affect river courses, sediment deposition, and water flow, impacting water resources and infrastructure projects.

In summary, the tectonic setting of the Bengal Basin is important for a wide range of applications, from assessing seismic risk to guiding natural resource exploration, managing coastal areas, understanding climate patterns, and informing infrastructure development and environmental conservation efforts.

Tectonic Setting of Bengal Basin