A Geochemical Record of Late‐Holocene Hurricane Events From the Florida Everglades
A Geochemical Record of Late‐Holocene Hurricane Events From the Florida Everglades
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DOI：
10.1029/2019wr026857
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发表时间：
2020-08
影响因子：
5.4
通讯作者：
Q. Yao;Kam‐biu Liu;Erika Rodrigues;T. Bianchette;A. A. Aragón-Moreno-A.;Zhenqing Zhang
中科院分区：
文献类型：
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作者：
Q. Yao;Kam‐biu Liu;Erika Rodrigues;T. Bianchette;A. A. Aragón-Moreno-A.;Zhenqing Zhang
为研究晚全新世强烈飓风登陆的历史，对取自佛罗里达州大沼泽地国家公园鲨鱼河河口红树林的一根5.25米长的沉积岩芯SRM - 1以及45份表层样品，进行了X射线荧光分析和碳同位素分析。针对飓风“威尔玛”形成的风暴沉积物对表层样品开展的显著性检验表明，在我们的研究区域，锶（Sr）和氯（Cl）的元素浓度以及氯溴比（Cl/Br）是重大飓风事件最敏感的指标。岩芯SRM - 1的地球化学数据集确定了过去3500年间五个强烈飓风活动活跃期，分别约在距今3400 - 3000年、2200 - 1500年、1000 - 800年、600 - 300年以及距今约150年（校正年代）至今。这是目前南佛罗里达最长的古飓风记录。我们的研究结果与以下观点一致，即南佛罗里达的强烈飓风活动受到热带辐合带（ITCZ）移动、厄尔尼诺/南方涛动（ENSO）活动以及北大西洋涛动（NAO）强度的调节。本研究通过证明地球化学信号，尤其是海水入侵信号，能够在千年时间尺度上保存在沉积物剖面中，并可通过X射线荧光技术进行测量，从而推动了古风暴学研究的方法进步，使得像佛罗里达大沼泽地这样原本沙源有限的沿海系统也能获取更多风暴记录。要探索利用地球化学和稳定同位素分析来检测沙源有限的沿海环境中的风暴信号，还需开展更多工作。
A 5.25‐m sediment core SRM‐1 and 45 surface samples from mangrove forests at the Shark River Estuary in the Everglades National Park, Florida, were examined by using X‐ray fluorescence and carbon isotopic analyses to study the history of intense hurricane landfall during the Late‐Holocene. Significance testing of the surface samples in relation to storm deposits from Hurricane Wilma suggests that elemental concentration of Sr and Cl and the ratio of Cl/Br are the most sensitive indicators for major hurricane events in our study area. The geochemical data sets of core SRM‐1 identified five active periods of intense hurricane activities during the last 3,500 years at ~3,400–3,000, ~2,200–1,500, ~1,000–800, ~600–300, and ~150 calibrated years before present to present. This is the longest paleohurricane record to date from South Florida. Our results are consistent with the view that intense hurricane activities in South Florida were modulated by Intertropical Convergence Zone (ITCZ) movements, El Niño/Southern Oscillation (ENSO) activities, and North Atlantic Oscillation (NAO) strength. This study contributes to the methodological advancement in paleotempestological studies by demonstrating that geochemical signals, particularly signals of saltwater intrusions, can be preserved in the sediment profiles on millennial time‐scale and measured by X‐ray fluorescence techniques, thereby enabling more storm records to be produced from otherwise suboptimal sand‐limited coastal systems such as the Florida Everglades. More work needs to be done to explore the use of geochemical and stable isotopic analyses in detecting storm signals from sand‐limited coastal environments.