Origins of Sundarban Delta Area In West Bengal

The origin of the Sunderbans is as baffling and mysterious as its crisscrossed riverine basin. It gives fascinating topics of research for scientists, historians, geologists and naturalists alike. A sundarban tour is a should for folks like us. The most typical perception is {that a} sequence of tectonic exercise inflicting elevations and depressions of the gneissic hills occured within the Gondwana belt 200 million years in the past. This coupled with the gradual deposition of alluvial silt introduced from the folded Himalayas within the North by centuries, resulted within the primary formation of this decrease Gangetic delta. Beforehand the marshy land stretched upto Rajmahal hills of the Chotanagpur space of what’s now the state of Jharkhand. Round 35 million years in the past within the late Tertiary interval, the particles from the Himalayas stuffed the complete space. Some specialists affirm that the Ganga and Brahmaputra have been east-flowing rivers till the block-faulting within the Garo-Rajmahal Hills, modified their course southwards. Through the sundarban tour ,the slope of the river mattress on this area being lower than 12 cm, the river present was gradual. It precipitated an enormous deposit of silt from the Himalayas, inflicting quite a few islands to type by the ages.

In response to the geologist and structuralist Oldham the entire space of the Sunderbans is a delta fashioned solely by the drainage of the mighty rivers of the Gangetic plain. Whereas his sundarban tour he additionally instructed that the trough of the land was the results of the strain of an enormous alluvial deposit. It pushed the earth’s crust down. However right here once more confusions come up, as some fossils of an estuarine nature have been discovered whereas digging a deep-well close to Backyard Attain, Kolkata, at a depth of 950 ft. One other geologist, J. Fargusson, on his sundarban journey said that the complete Bengal basin was a shallow marine land within the early Pleistocene age. Within the late Pleistocene age, the ocean receded fully from this space. The majority of the alluvial deposit carried by the rivers lined the marine sediments. Nevertheless, not many traces of marine animals have been discovered beneath the bottom. Some scientists on hid sundarban tour learning the physiography of the area have studied the Sunderbans in relation to tidal motion. They contend that resulting from tidal waves and the presence of innumerable tidal estuaries, the silt rushed again from the Bay of Bengal. It was pushed again into the moribund channels. The river mattress obtained raised. This blocked water led to the formation of an island. The soil research confirmed that the alluvial deposit of this space is enriched with varied salts. Thus, no chronological scientific historical past of this space may be traced; nevertheless excavations, assumptions and theories verify that simultaneous upheavals and subsidence nonetheless proceed and that the low-lying Sunderbans continues to be underneath formation. Other than this, periodic flooding, and alluvial and diluvion deposits on the banks have modified the course of the innumerable waterways. These crisscross over area forming the world’s largest delta-the Sunderbans.