Last interglacial sea-level history from speleothems: a global standardized database

Abstract

Abstract. Speleothems (secondary cave carbonate precipitates) are archives of valuable information for reconstructing past sea levels as they are generally protected from weathering and erosion by their location and can be dated with U-series methods. Two main categories of speleothems are recognized as sea-level indicators: phreatic overgrowth on speleothems (POSs) and submerged vadose speleothems (SVSs). POSs have the great advantage that they precipitate on preexisting supports (vadose speleothems or cave walls) at a brackish water level equivalent to sea level when air-filled chambers of coastal caves are flooded by rising sea. SVSs are also useful, but sea level is inferred indirectly as periods of growth provide constraints on maximum sea-level positions, whereas growth hiatuses, sometimes difficult to observe, may indicate times when cave passages are submerged by sea highstands; hence they record minimum sea-level elevations. Here we describe a compilation that summarizes the current knowledge of the complete last interglacial (in its broadest sense from ∼ 140 to 70 ka, also known as marine isotope stage (MIS) 5) sea level captured by speleothems. We used the framework of the World Atlas of Last Interglacial Shorelines (WALIS), a comprehensive sea-level database, to provide a standardized format in order to facilitate scientific research on MIS 5 sea level. The discussion is focused on MIS 5e, but records that capture MIS 5d, 5c, 5b, and 5a are also included. We present the data from 71 speleothems (36 sea-level index points and 37 limiting points) in coastal caves located in 10 different locations, and we include the spatial coverage, the samples used, and their accuracy as indicators of sea level, U and Th isotopes used to generate the chronologies, and their scientific relevance to understand past sea-level changes. Furthermore, the paper emphasizes the usefulness of these indicators not only to render information regarding the eustatic sea level, but also for their contribution to refine the glacial isostatic adjustment models and to constrain regional tectonic uplift rates. The standardized sea-level database presented here is the first of its kind derived from speleothems and contains all the information needed to assess paleo relative sea levels and the chronological constraints associated with them. The database is available open-access at https://doi.org/10.5281/zenodo.4313860 (Dumitru et al., 2020). We refer the readers to the official documentation of the WALIS database at https://walis-help.readthedocs.io/en/latest/ (last access: 20 January 2021), where the meaning of each field is explained in detail.

Last Interglacial sea-level proxies in the western Mediterranean

“…This was based on the reported ages and, if present, correlated discussions in the original paper. While we did not include in our compilations the cave deposits from Mallorca and Croatia (that were, as noted in the introduction, already compiled in WALIS by Dumitru et al, 2021b), we inserted several speleothems that were dated in southern Italy and Morocco to support the chronological attribution of sealevel indicators in these areas (Fig. 5c).…”

“…(RSL ID 901). Meschis et al (2020) mapped the marine terraces along the Syracuse coast by a synchronous correlation method using as age constraints U-series dating on speleothems (Dutton et al, 2009a), which provide a terrestrial-limiting point for the end of MIS 5a (Plemmiro Cave, RSL ID 3577). The MIS 5e terrace, according to the reconstruction by Meschis et al (2020), spans from ∼ 30 up to ∼ 70 m a.s.l.…”

“…On the eastern Mediterranean side, compilations are available for Israel (Sivan and Galili, 2020) and Cyprus (Zomeni, 2021). We did not include in the database cave deposits previously used as sea-level indicators in Mallorca (Spain) and Croatia in order to avoid duplication of data within WALIS, as these deposits are part of another compilation (Dumitru et al, 2021b). Overall, the western Mediterranean database contains 328 sea-level index points (for which paleo relative sea level can be calculated), 43 marine-limiting points (indicating that sea level at the time of formation was above the reported facies), and 25 terrestriallimiting points (indicating that sea level at the time of formation was below the reported facies).…”

The World Atlas of Last Interglacial Shorelines (Version 1.0)

“…(respectively: Chutcharavan and Dutton, 2021a;Dumitru et al, 2021;Thompson and Creveling, 2021b). Most manuscripts are instead focused on specific regions.…”

Teasing Apart Impacts of Human Activity and Regional Drought on Madagascar’s Large Vertebrate Fauna: Insights From New Excavations at Tsimanampesotse and Antsirafaly

“…Stalagmites from coastal caves can be used, along with global records of the rise in sea level, to reconstruct the history of cave flooding (Dumitru et al, 2021). This history can in turn be used to determine a minimum age for bones that must have accumulated in certain locations prior to when the water table reached their top depths within the caves.…”