INTEGRATED GEOPHYSICAL APPROACH TO STUDY SOLANI KNEE-BEND NEAR CHHUTMALPUR, UTTARAKHAND

Abstract

The Himalayan literature is quite rich in geoscientific studies as many illustrious geological work has been carried out in this region, but its exposure to geophysical work has been quite narrow & confined. Therefore, this research work is a comprehensive geophysical study that has been carried out over a specific study area, specially the interpreted resistivity structure to boost Himalayan literature. Solani river, which is a torrent in initial stages but takes the shape of an important river of considerable magnitude, originates in North-west Himalaya and flows parallel to many other rivers & seasonal streams, but it undergoes sharp knee-bend turn after crossing Chhutmalpur region of Uttarakhand, India. Therefore, this dissertation work has got two-fold objectives. Firstly, to introduce the 1-D resistivity structure of the survey area for the very first time & secondly, to use integrated geophysical methods (Electrical resistivity (yES), Gravity, Magnetic & MASW) to explicate the local tectonic happening & the location of the feature responsible for this knee-bend turn. Electrical resistivity (Vertical electrical sounding) survey has been carried with Schiumberger configuration over a total of 6 profiles (3 across the river while other 3 being along the river). Interpretation alludes towards the presence of a north-eastward dipping feature with its approximate location. Moreover, interpreting the resistivity models near the knee-bend also results into the simplified bedding pattern at the two sides of the river. Magnetic method predicts that there is a decrement in the depth of the layer of the dominating magnetic field in the North-East direction. Thus, the survey area is characterized by the presence of a geological feature which is dipping in the North- Eastward direction. Gravity method results into the bouguer anomaly pattern whose interpretation delineates the exact trend and orientation of the feature which is confirmed as fault by this method itself. The trend or orientation of the fault is deciphered as N29054'54", E77050'46.3" to N29056'29.9", E77048'21" to N30°00'54", E77°45'54".