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      https://www.ias.ac.in/article/fulltext/jess/119/03/0297-0305

    • Keywords

       

      Extreme wave events; grain size analysis; tsunami deposits; texture; surges; sorting.

    • Abstract

       

      Extreme wave events of 1000 and 1500 years (radiocarbon ages) have been recently reported in Mahabalipuram region, southeast coast of India. Subsequently, we carried out extensive sedimentological analysis in regions covering a total lateral coverage of 12 km with a new archeological site as the central portion of the study area. Twelve trenches in shore normal profiles exhibit landward thinning sequences as well as upward fining sequences confirming with the global signatures of extreme wave events. The sediment size ranges from fine-to-medium and moderately well sorted-to-well sorted, and exhibit positive skewness with platykurtic-to-leptokurtic nature. We now propose the abrupt winnowing or back and forth motion including unidirectional transport of these deposited sediments, which results in positive skewness. Textural analyses derived from scanning electron microscope studies (SEM) demonstrate the alteration produced, in the ilmenite mineral with vivid presence of pits and crescents with deformation observed on the surface due to extreme wave activities. This is further confirmed with the predominance of high-density mineral such as magnetite (5.2) and other heavy minerals in these deposits inferred the high-intensity of the reworking process of the beach shelf sediments.

    • Author Affiliations

       

      C S Vijaya Lakshmi1 P Srinivasan2 S G N Murthy2 Deshraj Trivedi1 Rajesh R Nair1

      1. Department of Geology & Geophysics, Indian Institute of Technology, Kharagpur 721 302, India.
      2. Structural Engineering Research Centre, Chennai 600 113, India.
    • Dates

       
  • Journal of Earth System Science | News

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