Erosional features identification along a recently prograding coastal barrier by ground penetrating radar facies analysis: Paradeep, Odisha, India

摘要

Coastal barrier dynamics is a complicated system which mainly involves shoreline changes due to accretion and erosion of the coast. Erosional activity in the coastal area of Paradeep, Odisha is risking the lives of the people and the community/factory infrastructures of this major port city, adjoining to the Bay of Bengal. So, understanding of the complex barrier dynamics is more important in this study area. The purpose of this study was to identify several erosional features within sedimentary beddings by Ground Penetrating Radar (GPR) survey and to understand the processes involved in this microtidal barrier from obtained GPR facies/radar facies. GPR reflection survey, with 200MHz antenna, along (17 profiles) and across (21 profiles) the barrier was done to delineate shapes and sizes of the sedimentary features, erosional surfaces, channels, scour-and-fill structures, progradational beddings and internal geometry of the beach ridge deposits. GPR facies analyses of the beach ridge have established the longshore drift of sediments from nearby river mouths e.g. Mahanadi and Devi river mouths. This interpretation technique has also characterized the palaeo-tidal channels of the study area into two types - (a) larger channels which are perpendicular to the shoreline having channel width of about 400m with maximum depth of 3.4m from the surface and (b) smaller channels (width up to 60m) flow parallel to the shoreline. Here, seaward-dipping beach progradational facies is positioned within oblique erosional surfaces below the facies boundary. This describes the cyclicity of erosion and accretion activity at Paradeep coastal barrier.