Testing XRF identification of marine washover sediment beds in a Coastal Lake in Southeastern Texas, USA

What Are the Most Effective Proxies in Identifying Storm‐Surge Deposits in Paleotempestology? A Quantitative Evaluation From the Sand‐Limited, Peat‐Dominated Environment of the Florida Coastal Everglades

“…In particular, Ca and Sr concentrations, Ca/Ti ratio, and marine microfossils of the allochthonous sample group are also significantly higher than the autochthonous sample group in all three cores (Figure 4a). The higher concentrations of Ca and Sr have been widely used as indicators for marine originated source materials (Bianchette et al., 2016; Dietz et al., 2022; Rodrigues et al., 2021; Yao et al., 2018, 2020, 2021), and the Ca/Ti ratio and marine microfossils have also been broadly recognized as marine indicators in coastal and estuarine environments (K. B. Liu et al., 2014; McCloskey, Smith, Liu, Marot, & Haller, 2018; H. F. Williams et al., 2022). Thus, the results of the two‐step statistical selection procedure indicate that Ca and Sr concentrations, Ca/Ti ratio, and marine microfossils are four of the most sensitive proxies to distinguish high salinity and marine originated sediments in coastal and estuarine environments.…”

“…On PC2, Cl/Br ratio has the highest positive loadings, while Mz has the lowest negative loadings (Figure 4b). Since allochthonous sediments from high‐energy dynamic environments (e.g., nearshore and offshore) are typically characterized by coarser grains (described in Section 3.3) than those from stable, low‐energy environments (K. B. Liu & Fearn, 1993, 2000; H. F. Williams et al., 2022), PC2 likely indicates an energy gradient (Figure 4b). Moreover, the proxy‐based method in paleotempestology is very site‐specific.…”

“…Moreover, in the dynamic coastal and estuarine environment, the mixing of marine sediment input from storm surge with fluvial input from precipitation may make it hard to distinguish between the storm deposit and in situ deposit (e.g., Yao et al., 2019). Thus, more and more studies apply a combination of multiple proxies to detect overwash events in the sediment profile (Sabatier et al., 2012; H. F. Williams et al., 2022; Zhou et al., 2019). Because each method has its own advantages and disadvantages, it is still unclear what are the most effective proxies to identify storm surge overwash deposits, particularly from sand‐limited and peat‐dominated environmental settings, such as the coastal zones along Florida.…”

“…Since these storm‐surge or overwash deposits are typically characterized by coarser clastic sediments with a clear boundary from the in situ sediments (K. B. Liu, 2004), the traditional approach to identify these allochthonous materials relies primarily on sedimentological analyses such as loss‐on‐ignition (LOI) and grain‐size analysis (Ercolani et al., 2015; Lane et al., 2011; D. J. Wallace et al., 2014; E. Wallace et al., 2019; Winkler et al., 2020). With the advancement of analytical techniques in recent years, many studies have started to utilize inorganic geochemical analysis such as X‐ray fluorescence (XRF) to identify the elevated marine signals in overwash deposits (Dietz et al., 2022; H. F. Williams et al., 2022; Yang et al., 2020; Yao et al., 2018, 2020). In addition, analyses of stable isotopes of bulk sedimentary organic matter (e.g., 13 C and 15 N) (Jahan et al., 2021) and micropaleontological proxies (e.g., diatoms, phytoliths, palynomorphs, foraminifera) (e.g., K. B. Liu et al., 2008; Lul & Liu, 2005; Scott et al., 2003; Wang et al., 2019; Xian et al., 2022) have also been used in paleotempestological studies.…”

“…Moreover, in the dynamic coastal and estuarine environment, the mixing of marine sediment input from storm surge with fluvial input from precipitation may make it hard to distinguish between the storm deposit and in situ deposit (e.g., Yao et al, 2019). Thus, more and more studies apply a combination of multiple proxies to detect overwash events in the sediment profile (Sabatier et al, 2012;H. F. Williams et al, 2022;Zhou et al, 2019).…”