The study of modern hurricane deposits is useful in both identifying ancient hurricane deposits in the rock record and predicting patterns of deposition and erosion produced by future storm events. Hurricane deposits on carbonate platforms have been studied less frequently than have been those along continental coasts. Here we present observations of the characteristics of deposition and scour caused by Hurricane Irma on Little Ambergris Cay, a small uninhabited island located near the southeastern edge of the Caicos platform in the Turks and Caicos Islands. Hurricane Irma passed directly over Little Ambergris Cay on 7 September 2017 as a Category 5 hurricane. We described and sampled multiple types of hurricane deposits and determined that the washover fans were the best sedimentological records for hurricane conditions, as they were subject to very little reworking over time. We compared different model predictions of storm tide and wave height with eyewitness reports and distributions of scour. Examining the washover fans allowed for the construction of a conceptual model for hurricane deposits formed in a high‐energy storm event on a carbonate platform. Characteristics of the washover fans were their small size, the lack of sedimentary structures, and very well sorted sediment. The size and distribution of carbonate boulders eroded and transported by the storm are consistent with depth‐averaged flow velocities in the range of 1.5–5.3 m/s. The strength of the storm and the low‐lying topography, distinct features of a carbonate platform setting, contributed to high levels of sediment bypass and high flow velocities, resulting in small, unstructured deposits.

中文翻译：

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碳酸盐台地上的飓风沉积物：以小龙涎香礁，特克斯和凯科斯群岛为例的飓风艾玛沉积物

对现代飓风沉积物的研究对于识别岩石记录中的古代飓风沉积物以及预测未来风暴事件产生的沉积和侵蚀模式均非常有用。研究碳酸盐岩平台上的飓风沉积物的频率低于大陆沿海地区。在这里，我们观察到由伊尔飓风引起的小龙涎香礁（一个小小的无人岛，位于特克斯和凯科斯群岛的凯科斯平台东南边缘附近）造成的沉积和冲刷特征。伊尔玛飓风于2017年9月7日直接越过小龙涎香礁，成为第5类飓风。我们描述并采样了多种类型的飓风沉积物，并确定冲洗风扇是飓风条件的最佳沉积学记录，因为随着时间的流逝，它们几乎不需要再加工。我们将目击者的报告和冲刷分布与风暴潮和波高的不同模型预测进行了比较。检查冲洗风扇可以为碳酸盐岩平台上高能风暴事件中形成的飓风沉积物建立概念模型。冲刷风机的特点是体积小，缺乏沉积结构以及沉淀物分类良好。暴风雨侵蚀和运输的碳酸盐巨石的大小和分布与1.5-5.3 m / s范围内的深度平均流速一致。风暴的强度和低洼的地形，是碳酸盐台地的独特特征，导致高水平的泥沙绕过和高流速，导致了小而无结构的沉积物。