Distinguishing depositional environments in the beach-dune system of Chandipur, India, based on sediment texture and quartz grain surface features

An attempt has been made to discern sedimentary environments in a tropical coastal setting in Chandipur, India, using variations in grain size. Samples were collected along one 100 m-long cross-shore transect extending from the tide/aqueous-influenced seaward region to the aeolian-dominated landward region. Various grain size data analysis approaches, like bivariate data plots and discrimination functions, were used to discriminate the sedimentary environments and establish the process of sediment deposition. The analytical results suggest that diverse granulometric parameters translate different sedimentary environments such as tidal flat, beach and dune. Additionally, the surface morphologies of quartz grains were used to understand the evolution of recent mechanical, chemical and mechanical-chemical processes in this tropical coastal region. Changes in the surficial microtextural properties of quartz grains were documented at various sites of all geomorphic units along this transect, from the tidal flat to the dune. One-way analysis of variance (ANOVA) was used to understand the significant differences in microtextural features between these units. Subaqueous surface textures such as large conchoidal fractures, sharp edges, arcuate steps and straight and curved grooves were dominant in the grains of the tidal flat. The presence of meandering ridges, upturned plates, bulbous edges and adhering particles on quartz gradually increases as the transect ascends landward. Correlation plots between distance and microtextures, along with ANOVA, suggest that aeolian transportation modulated the surface textures. Such assessment of distinct sedimentary characteristics and transport processes may serve as a modern analogue for ancient deposits on the siliciclastic coast.