Mizoram forests by Lalnunfela Hlawndo · CC BY-SA 4.0
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Tripura and Mizoram have a stunning geological feature—long, rolling hills separated by deep valleys. This landscape is a direct result of a geological phenomenon known as the Tripura–Mizoram Fold-and-Thrust Belt. Around 20 million years ago, the region was a shallow marine and deltaic Surma Basin, where rivers deposited thick layers of sand, silt and mud. As the Indian Plate collided with the Burma Plate, these sedimentary layers were compressed and folded into giant anticlines and synclines. Millions of years of erosion then sculpted these folds into the spectacular parallel ridges and valleys we see today. What's even more fascinating is that this mountain belt is still tectonically active and continues to evolve. #science #didyouknow #nature #geology #earthscience
Notes & corrections
As always, if you notice any mistakes in my understanding or explanation, please feel free to correct me🙏🏻
The main scientific paper I referred to while researching this topic is:
Nandy, D. R., Dasgupta, S., Sarkar, K., & Ganguly, A. (1983). Tectonic Evolution of the Tripura–Mizoram Fold Belt, Surma Basin, Northeast India.
* I have said that sandstone settled at the bottom and mudstone settled at the top, which is an oversimplification. In reality, since this process happened over millions of years, alternating layers of sandstone, mudstone and other sedimentary rocks were deposited as rivers shifted course, deltas advanced and retreated, and sea levels changed. As a result, the ridges and hills of Tripura and Mizoram are a geological treasure for studying different layers and periods of the Indian subcontinent's history.
* Another important factor in shaping the landscape is differential erosion. Sandstone is generally more resistant to erosion than mudstone or shale, so sandstone tends to remain as ridges, while the softer rocks erode more easily to form valleys. This is a simplification, as erosion also depends on factors such as rock structure, fractures, climate and drainage.
* The Tripura–Mizoram Fold-and-Thrust Belt is still geologically active today. The hills are still slowly being uplifted as the Indian Plate continues to push towards the Burmese Plate, while erosion is constantly shaping the landscape.
References
- Nandy, D. R., Dasgupta, S., Sarkar, K., & Ganguly, A. (1983). Tectonic Evolution of the Tripura–Mizoram Fold Belt, Surma Basin, Northeast India.
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