Geomorphic and environmental controls on microbial mat fabrics on Little Ambergris Cay, Turks and Caicos Islands

作者：Nathaniel Stein, J. P. Grotzinger, Daven P. Quinn, Usha Lingappa, Theodore M. Present, Elizabeth J. Trower, Maya Gomes, E. A. Orzechowski, Marjorie Cantine, Kyle Metcalfe, Woodward W. Fischer, B. L. Ehlmann, Justin V. Strauss, Andrew H. Knoll · 发表于：Sedimentology · 年份：2023 · DOI：10.1111/sed.13100 · 被引用次数：10 · 研究领域：Geology and Paleoclimatology Research、Methane Hydrates and Related Phenomena、Paleontology and Stratigraphy of Fossils

Abstract To interpret microbially influenced paleoenvironments in the sedimentary record, it is crucial to understand what processes control the development of microbial mats in modern environments. This article reports results from a multiyear study of Little Ambergris Cay, Turks and Caicos Islands, an uninhabited island floored by broad tracts of well‐developed microbial mats on the wind‐dominated and wave‐dominated Caicos Platform. Uncrewed aerial vehicle‐based imaging, differential global positioning system topographic surveys, radiocarbon data, and in situ sedimentological and microbial ecological observations were integrated to identify and quantify the environmental factors that influence the distribution and morphologies of Little Ambergris Cay microbial mats, including their response to large storm events. Based on these data, this study proposes that Little Ambergris Cay initially developed from the accretion and rapid lithification of carbonate sediment delivered by converging wave fronts in the lee of adjacent Big Ambergris Cay. Broad tracts of microbial mats developed during late Holocene time as the interior became restricted due to beach ridge development. Minor elevation differences regulate subaerial exposure time and lead to three categories of microbial mats, differentiated by surface texture and morphology: smooth mats, polygonal mats and blister mats. The surface texture and morphology of the mats is controlled by subaerial exposure time. In addition to e...