Textural and Sediment Component Dataset of Unconsolidated Sediments from Agatti and Kavaratti Lagoon

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. This dataset includes sedimentological (grain size and sediment component) and depth, along with the location of samples (unconsolidated sediments from lagoon) compiled in Excel file format. Field investigations were conducted for Agatti and Kavaratti in March and October 2023. Grid sampling with an approx. spacing of 500m was conducted across the lagoons. Forty-two samples were collected from Agatti lagoon (area- 17.5 km2) and twenty-four samples from Kavaratti lagoon (area – 5 km2). Wet sieving of the subsamples was conducted to categorize them into the following grain size fractions - 4 – 2mm, 2 – 0.5mm, 0.5 – 0.25mm, 0.25 – 0.125mm, 0.125 – 0.063mm, <0.063mm. The samples were then categorized texturally, based on the Dunham classification. The thin sections from sample locations (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 a sediment component due to its significance as a major sediment producer. This dataset consists of four Excel files (1)Depth, (2) Dunham texture, (3 and 4) Sediment component analysis for Agatti and Kavaratti. The location of all the samples collected is also attached to the dataset. These datasets will aid in understanding the mechanisms governing the sediment dynamics in atoll islands.拉克沙群岛（Lakshadweep Archipelago）坐落于北印度洋，是印度半岛外海由36座岛屿与5处淹没礁体构成的群岛。本数据集涵盖沉积学（粒度与沉积物组分）、水深数据，以及样本位置信息（取自泻湖的未固结沉积物），所有数据以Excel文件格式汇编。 2023年3月与10月，研究团队分别对阿格蒂（Agatti）与卡瓦拉蒂（Kavaratti）开展野外调查。以约500米的间距在两处泻湖全域实施网格采样：阿格蒂泻湖（面积17.5平方千米）共采集42份样本，卡瓦拉蒂泻湖（面积5平方千米）共采集24份样本。 对采集的子样开展湿筛操作，将其划分为以下粒级：4–2mm、2–0.5mm、0.5–0.25mm、0.25–0.125mm、0.125–0.063mm 及＜0.063mm。随后基于邓哈姆分类（Dunham classification）对样本进行结构分类。 针对各粒级（2–0.5mm、0.5–0.25mm、0.25–0.125mm），在阿格蒂泻湖的15个采样点与卡瓦拉蒂泻湖的9个采样点处制备薄片，并使用徕卡DM750偏光显微镜（Leica DM750 polarizing microscope）开展分析。使用JMicroVision软件对各沉积物组分开展点计数分析。已识别的主要沉积物组分包括珊瑚碎屑、软体动物、藻类、仙掌藻属（Halimeda）与有孔虫类（forams）；鉴于仙掌藻属（Halimeda）作为主要沉积物生产者的重要性，将其单独列为一类沉积物组分。 本数据集包含4个Excel文件：(1) 水深数据；(2) 邓哈姆结构分类结果；(3)、(4) 分别对应阿格蒂与卡瓦拉蒂的沉积物组分分析结果。所有采集样本的位置信息也一并附于数据集内。该数据集将有助于阐明控制环礁岛屿沉积动力学的作用机制。