The Meghalaya Plateau and the Karbi Anglong Hills are structural extensions of the main Peninsular Plateau of India. Which of the following tectonic and geomorphological processes accounts for their physical detachment from the Chota Nagpur Plateau?
- Down-faulting created the Garo-Rajmahal Gap (Malda Fault), which was subsequently filled by heavy alluvial sediments deposited by the Ganga and Brahmaputra river systems.Answer
- BSubduction of the Indian Plate beneath the Burmese Microplate caused localized uplift of the intervening relief, creating an impassable high-altitude watershed.
- CExtensive rifting along the Narmada-Son lineament displaced the Meghalaya block northeastward during the Deccan Trap volcanic eruptions, leaving behind a basaltic rift valley.
- DGlacial action during the Pleistocene epoch eroded the intervening crystalline rocks, creating a broad U-shaped glaciated trough that redirected regional drainage.
Answer
The physical detachment of the Meghalaya Plateau from the Chota Nagpur Plateau was caused by down-faulting that produced the Garo-Rajmahal Gap (Malda Fault), which was later filled with alluvial deposits by the Ganga and Brahmaputra river systems.
Geologically, the Meghalaya Plateau and Karbi Anglong Hills are part of the Peninsular Plateau. During the movement of the Indian plate, down-faulting occurred between the Rajmahal Hills and the Garo Hills, forming the Malda Fault (Garo-Rajmahal Gap). The gap was later buried under thick layer of alluvium brought by the Ganga and Brahmaputra rivers, creating a contiguous lowland plain.
Step-by-Step Solution
Key Concept
Tectonic detachment and alluvial infilling of the Garo-Rajmahal Gap (Malda Fault)
Estimated Time:1m 30s