Supplementary Dataset: Carbonate sediment dynamics in oceanic atoll lagoons of Lakshadweep Archipelago
Description
Lakshadweep Archipelago, located in the Northern Indian Ocean, is a group of 36 islands and five submerged reefs, off the coast of the Indian Peninsula. For this study, field investigations were conducted for Agatti and Kavaratti in March and October 2023. Grid sampling along E-W transects, with an approx. spacing of 500m was conducted across the lagoon. Forty-two samples were collected from Agatti (area- 17.5 km2) and twenty-four samples from Kavaratti (area – 5 km2). Wet sieving of the subsamples was done to categorize them into the following grain size fractions - >4mm, 4 – 2mm, 2 – 0.5mm, 0.5 – 0.25mm, 0.25 – 0.125mm, 0.125 – 0.063mm, <0.063mm. The samples were classified based on grain size fraction - >2mm(gravel), 2 – 0.063mm (sand), and <0.063mm (mud). The samples were then categorized texturally, based on the percentage of 0.063mm fraction. The thin sections from specific transects (n = 15, Agatti and n = 9, Kavaratti) for each grain size fraction (2 – 0.5mm, 0.5 – 0.25mm, 0.25 – 0.125mm) were analyzed with a Leica DM750 polarizing microscope. Point counting of each sediment component was carried out using JMicroVision software. The major sediment components identified include coral clasts, molluscs, algae, Halimeda and forams. Halimeda was identified separately as chosen as a separate sediment component due to its significance as a major sediment producer. These datasets will aid in understanding the mechanisms governing the sediment dynamics in atoll islands.