Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

N. V. N. Durga Prasada Rao ¹

Affiliations
1 Institute of Marine Sciences, King Abdulaziz University, Jeddah, SA

Abstract

The effect of storm associated tidal wave, that struck the Andhra Coast, on the sediments of the Krishna Delta is investigated. Granulometric analysis of the pre- and post-tidal wave estuanne sediments of the Krishna River revealed a remarkable increase in the silt content of the post-tidal wave sediments. Enormous quantity of silt was transported from the shelf and deposited io the estuarine environment by the tidal wave. A slight difference is noticed in the chemical composition of the pre- and post-tidal wave estuarine sediments. Deposition of silt-sized sediments is also observed in the interdistributary area during the field survey. Stabilisation of coastal dunes with proper vegetation is suggested to minimise the effects of tidal waves and storm surges on the coastal region.

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N. Purna Chander Reddy ¹, N. V. N. Durga Prasada Rao ²

Affiliations
1 National Institute of Oceanography, Regional Centre, Visakhapatnam 530023, IN
2 Department of Geology, Kakatiya University, Warangal 508006, IN

Abstract

Beach sediments with a phi mean size varying from 1.07 to 2.9 are well to moderately sorted and to a great extent negatively skewed. On the inner shelf, the sediments exhibit a wide range (0.9φ and 10φ) in mean grain-size. While most of the inner shelf is covered with fine silts and clays, sandy sediments occupy a linear belt in the outer parts (-25 to -30 m) of the shelf. These moderately sorted sands are considered to be relict and deposited during a standstill of the Holocene transgression. The CM pattern suggests that the sandy sediments in the inner shelf like the beach sands were deposited under high energy conditions. The well-preserved sands indicate that the existing hydrodynamic conditions on the inner shelf are neither strong enough to rework the sediments nor transport the modern river-contributed fine sediments to the outer parts.

Keywords

Continental Shelf, Holocene Transgression, Strand Line Deposit, West Coast, Cochin.

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