Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published August 2020 | Supplemental Material + Published
Journal Article Open

Hurricane Deposits on Carbonate Platforms: A Case Study of Hurricane Irma Deposits on Little Ambergris Cay, Turks and Caicos Islands

Abstract

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.

Additional Information

© 2020 American Geophysical Union. Issue Online: 31 July 2020; Version of Record online: 31 July 2020; Accepted manuscript online: 26 June 2020; Manuscript accepted: 25 June 2020; Manuscript revised: 15 June 2020; Manuscript received: 29 February 2020. This work was supported by the Agouron Institute Grant SGIA‐277.19.1UCB, NASA Exobiology Grant 80NSSC18K0278, and the CU Boulder Department of Geological Sciences. The authors acknowledge logistical support from Paul Mahoney and James Seymour and field assistance from Maya Gomes, Alistair Hayden, Usha Lingappa, Taleen Mahseredjian, and Theodore Present. Pim Maydhisudhiwongs ran Camsizer analyses of WF‐J18 core samples. This project was carried out under Scientific Research Permit 19‐06‐01‐20 from the Department of Environment and Coastal Resources of the Turks and Caicos Islands. S. J. T. thanks David Budd and Katherine Lininger for helpful feedback. We thank Evan Goldstein, Katherine Anarde, and two anonymous reviewers for their constructive reviews. Data Availability Statement: The raw data associated with Camsizer, tidal current velocity, and tide gauge measurements are available at https://doi.org/10.17605/OSF.IO/UNTGP.

Attached Files

Published - 2020JF005597.pdf

Supplemental Material - jgrf21220-sup-0001-2020jf005597-si.docx

Files

2020JF005597.pdf
Files (25.7 MB)
Name Size Download all
md5:95c630dfbd9822772006bd3025dd341b
6.4 MB Download
md5:a672b0549e0ab00e84ef34cafed34bc5
19.3 MB Preview Download

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023